View AD9847AKST_3255378.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

rev. a information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. no license is granted by implication or otherwise under any patent or patent rights of analog devices. trademarks and registered trademarks are the property of their respective companies. a ad9847 one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781/329-4700 www.analog.com fax: 781/326-8703 ?2003 analog devices, inc. 10-bit 40 msps ccd signal processor with integrated timing driver functional block diagram clamp dout ccdin pblk vrt vrb internal registers 2db to 36db sync generator sdata sck sl clpob 10 vga ad9847 4 6db precision timing core adc vref clamp internal clocks pxga cds horizontal drivers 4 rg h1?4 hd vd cli clpdm general description the ad9847 is a highly integrated ccd signal processor for digital still camera applications. the ad9847 includes a com- plete analog front end with a/d conversion, combined with a programmable timing driver. the precision timing core allows adjustment of high speed clocks with approximately 500 ps resolution at clock speeds of 40 mhz. the ad9847 is specified at pixel rates of 40 mhz. the analog front end includes black level clamping, cds, pxga , vga, and a 10-bit a/d converter. the timing driver provides the high speed ccd clock drivers for rg and h1?4. operation is programmed using a 3-wire serial interface. packaged in a space-saving 48-lead lqfp, the ad9847 is speci- fied over an operating temperature range of ?0 c to +85 c. features correlated double sampler (cds) ? db to +10 db pixel gain amplifier ( pxga ) 2 db to 36 db 10-bit variable gain amplifier (vga) 10-bit 40 mhz a/d converter black level clamp with variable level control complete on-chip timing driver precision timing core with 500 ps resolution at 40 msps on-chip 5 v horizontal and rg drivers 48-lead lqfp package applications digital still cameras
rev. a e2e ad9847 especifications general specifications parameter min typ max unit temperature range operating e20 +85 c storage e65 +150 c maximum clock rate 40 mhz power supply voltage analog (avdd1, 2, 3) 2.7 3.6 v digital1 (dvdd1) h1eh4 3.0 5.5 v digital2 (dvdd2) rg 3.0 5.5 v digital3 (dvdd3) d0ed11 3.0 v digital4 (dvdd4) all other digital 3.0 v power dissipation dvdd1 (@ 5 v, 100 pf h loading, 40 msps) 450 mw dvdd2 (@ 5 v, 20 pf rg loading, 40 msps) 45 mw dvdd1 (@ 3 v, 100 pf h loading, 40 msps) 180 mw dvdd2 (@ 3 v, 20 pf h loading, 40 msps) 15 mw avdd1, 2, 3, dvdd3, 4 (@ 3 v, 40 msps) 200 mw total shutdown mode 1 mw specifications subject to change without notice. parameter symbol min typ max unit logic inputs high level input voltage v ih 2.1 v low level input voltage v il 0.6 v high level input current i ih 10 a low level input current i il 10 a input capacitance c in 10 pf logic outputs high level output voltage, i oh = 2 ma v oh 2.2 v low level output voltage, i ol = 2 ma v ol 0.5 v cli input high level input voltage (avdd1, 2 + 0.5 v) v ihecli 1.85 v low level input voltage v ilecli 0.85 v rg and h-driver outputs high level output voltage (dvdd1, 2 e 0.5 v) v oh 4.75 v low level output voltage v ol 0.5 v maximum output current (programmable) 24 ma maximum load capacitance 100 pf specifications subject to change without notice. (t min to t max , avdd1 = dvdd3, dvdd4 = 2.7 v, dvdd1, dvdd2 = 5.25 v, c l = 20 pf, unless otherwise noted.) digital specifications
rev. a e3e ad9847 analog specifications (t min to t max , avdd = dvdd = 3.0 v, f cli = 40 mhz, unless otherwise noted.) parameter min typ max unit notes cds gain 0 db allowable ccd reset transient * 500 mv max input range before saturation * 1.0 v p-p max ccd black pixel amplitude * 150 mv pixel gain amplifier ( pxga ) max input range 1.0 v p-p max output range 1.6 v p-p gain control resolution 64 steps gain monotonicity guaranteed gain range min gain (32) e2 db med gain (0) 4 db med gain (4 db) is default setting max gain (31) 10 db variable gain amplifier (vga) max input range 1.6 v p-p max output range 2.0 v p-p gain control r esolution 1024 steps gain monotonicity guaranteed gain range low gain (91) 2 db max gain (1023) 36 db black level clamp clamp level resolution 256 steps clamp level measured at adc output min clamp level (0) 0 lsb max clamp level (255) 63.75 lsb a/d converter resolution 10 bits differential nonlinearity (dnl) 0.4 1.0 lsb no missing codes guaranteed full-scale input voltage 2.0 v voltage reference reference top voltage (vrt) 2.0 v reference bottom voltage (vrb) 1.0 v system performance specifications include entire signal chain gain accuracy gain includes 4 db default pxga low gain (91) 5 6 7 db max gain (1023) 38 db peak nonlinearity, 500 mv input signal 0.2 % 12 db gain applied total output noise 0.25 lsb rms ac grounded input, 6 db gain applied power supply rejection (psr) 40 db measured with step change on supply * input signal characteristics defined as follows: 500mv typ reset transient 150mv max optical black pixel 1v max input signal range specifications subject to change without notice.
rev. a ad9847 e4e timing specifications parameter symbol min typ max unit master clock (cli) cli clock period t cli 25 ns cli high/low pulsewidth t adc 12.5 ns delay from cli to internal pixel period position t clidly 6ns external mode clamping clpdm pulsewidth t cdm 41 0p ixels clpob pulsewidth * t cob 220 pi xels sample clocks shp rising edge to shd rising edge t s1 10 ns data outputs output delay from programmed edge t od 6ns pipeline delay 9 cycles serial interface maximum sck frequency f sclk 10 mhz sl to sck setup time t ls 10 ns sck to sl hold time t lh 10 ns sdata valid to sck rising edge setup t ds 10 ns sck falling edge to sdata valid hold t dh 10 ns sck falling edge to sdata valid read t dv 10 ns * maximum clpob pulsewidth is for functional operation only. wider typical pulses are recommended to achieve low noise clamp refe rence. specifications subject to change without notice. (c l to 29 pf, f cli = 40 mhz, serial timing in figures 3a and 3b, unless otherwise noted.)
rev. a ad9847 e5e ordering guide temperature package package model range description option AD9847AKST e20 c to +85 ct hin plastic quad flatpack (lqfp) st-48 absolute maximum ratings avdd1, 2, 3 to avss . . . . . . . . . . . . . . . . . . . e0.3 to +3.9 v dvdd1, 2 to dvss . . . . . . . . . . . . . . . . . . . . e0.3 to +5.5 v dvdd3, 4 to dvss . . . . . . . . . . . . . . . . . . . . e0.3 to +3.9 v digital outputs to dvss3 . . . . . . . . e0.3 to dvdd3 + 0.3 v clpob, clpdm, blk to dvss4 . e0.3 to dvdd4 + 0.3 v cli to avss . . . . . . . . . . . . . . . . . . . e0.3 to avdd + 0.3 v sck, sl, sdata to dvss4 . . . . . e0.3 to dvdd4 + 0.3 v vrt, vrb to avss . . . . . . . . . . . . . e0.3 to avdd + 0.3 v byp1e3, ccdin to avss . . . . . . . . e0.3 to avdd + 0.3 v junction temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 150 c lead temperature (10 sec) . . . . . . . . . . . . . . . . . . . . . . 300 c caution esd (electrostatic discharge) sensitive device. electrostatic charges as high as 4000 v readily accumulate on the human body and test equipment and can discharge without detection. although the ad9847 features proprietary esd protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. therefore, proper esd precautions are recommended to avoid performance degradation or loss of functionality. thermal characteristics thermal resistance 48-lead lqfp package . . . . . . . . . . . . . . . . . . . ja = 92 c/w
rev. a ad9847 e6e pin configuration 36 35 34 33 32 31 30 29 28 27 26 25 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8 9 10 11 12 48 47 46 45 44 39 38 37 43 42 41 40 pin 1 identifier top view (not to scale) sl reft refb cmlevel avss3 avdd3 ccdin ( lsb) d0 d1 d2 dvss3 dvdd3 d3 d4 byp2 avdd2 ad9847 d5 avss2 nc nc dvdd4 dvss4 hd vd pblk hblk clpdm clpob sck sdi h1 h2 dvss1 dvdd1 h3 h4 dvss2 rg dvdd2 avss1 cli avdd1 d6 ( msb) d9 byp1 byp3 d7 d8 nc = no connect pin function descriptions pin no. mnemonic type * description 1e5 d0ed4 do data outputs 6 dvss3 p digital ground 3?data outputs 7 dvdd3 p digital supply 3?data outputs 8e12 d5ed9 do data outputs (d9 i s msb) 13, 14 h1, h2 do horizontal clocks (to ccd) 15 dvss1 p digital ground 1?h drivers 16 dvdd1 p digital supply 1?h drivers 17, 18 h3, h4 do horizontal clocks (to ccd) 19 dvss2 p digital ground 1?rg driver 20 rg do reset gate clock (to ccd) 21 dvdd2 p digital supply 2?rg driver 22 avss1 p analog ground 1 23 cli di master clock input 24 avdd1 p analog supply 1 25 avss2 p analog ground 2 26 avdd2 p analog supply 2 27 byp1 ao bypass pin (0.1 f to avss) 28 byp2 ao bypass pin (0.1 f to avss) 29 ccdin ai analog input for ccd signal 30 byp3 ao bypass pin (0.1 f to avss) 31 avdd3 p analog supply 3 32 avss3 p analog ground 3 33 cmlevel ao internal bias level decoupling (0.1 f to avss) 34 refb ao reference bottom decoupling (1.0 f to avss) 35 reft ao reference top decoupling (1.0 f to avss) 36 sl di 3-wire serial load (from p) 37 sdi di 3-wire serial data input (from p) 38 sck di 3-wire serial clock (from p) 39 clpob di optical black clamp pulse 40 clpdm di dummy black clamp pulse 41 hblk di hclk blanking pulse 42 pblk di preblanking pulse 43 vd di vertical sync pulse 44 hd di horizontal sync pulse 45 dvss4 p digital ground 4?vd, hd, clpob, clpdm, hblk, pblk, sck, sl, sdata 46 dvdd4 p digital supply 4?vd, hd, clpob, clpdm, hblk, pblk, ck, sl 47, 48 nc nc internally not connected * type: ai = analog input, ao = analog output, di = digital input, do = digital output, p = power
rev. a ad9847 e7e r avdd2 avss2 avss2 circuit 1. ccdin (pin 29) avdd1 avss1 330 cli 25k 1.4v circuit 2. cli (pin 23) dvdd4 dvdd3 dvss4 dvss3 data three- state dout circuit 3. data outputs d0ed9 (pins 1e5, 8e12) dvdd4 dvss4 330 circuit 4. digital inputs (pins 36e44) dvdd1 dvss1 data enable e nl aanelb nelb na
rev. a ad9847 e8e system overview figures 1a and 1b show the typical system application diagrams for the ad9847. the ccd output is processed by the ad9847?s afe circuitry, which consists of a cds, pxga , vga, black level clamp, and a/d converter. the digitized pixel information is sent to the digital image processor chip, where all post-processing and compression occurs. to operate the ccd, ccd timing param- eters are programmed into the ad9847 from the image processor through the 3-wire serial interface. from the system master clock, cli, provided by the image processor, the ad9847 generates the high speed ccd clocks and all internal afe clocks. all ad9847 clocks are synchronized with vd and hd. ccd serial interface dout digital image processing asic v-driver hd, vd cli v1ev4, vsg1evsg8, subck h1eh4, rg ccdin ad9847 integrated afe + td figure 1a. typical application (internal mode) figure 1a shows the ad9847 used in internal mode, in which all the horizontal pulses (clpob, clpdm, pblk, and hblk) are programmed and generated internally. figure 1b shows the ad9847 operating in external mode, in which the horizontal pulses are supplied externally by the image processor. the h-drivers for h1eh4 and rg are included in the ad9847, allowing these clocks to be directly connected to the ccd. the ad9847 supports h-drive voltage of 5 v. ccd serial interface dout digital image processing asic v-driver hd, vd cli v1ev4, vsg1evsg8, subck h1eh4, rg ccdin ad9847 integrated afe + td pblk hblk clpdm clpob figure 1b. typical application (external mode) figure 2 shows the horizontal and vertical counter dimensions for the ad9847. all internal horizontal clocking is programmed using these dimensions to specify line and pixel locations. maximum field dimensions 12-bit horizontal = 4096 pixels max 12-bit vertical = 4096 lines max figure 2. vertical and horizontal counters
rev. a ad9847 e9e serial interface timing sdata a0 a1 a2 a4 a5 a6 a7 d0 d1 d2 d3 d4 d5 xx xx sck sl a3 notes 1. sdata bits are latched on sck rising edges. 2. 14 sck edges are needed to write address and data bits. 3. for 16-bit systems, two extra dummy bits may be written. dummy bits are ignored. 4. new data is updated either at the sl rising edge or at the hd falling edge after the next vd falling edge. 5. vd/hd update position may be delayed to any hd falling edge in the field using the update register. vd hd sl updated vd/hd updated t ds t dh t ls t lh figure 3a. serial write operation sdata a0 a1 a2 a4 a5 a6 a7 d0 d1 d2 d3 d4 d5 sck sl a3 notes 1. multiple sequential registers may be loaded continuously. 2. the first (lowest address) register address is written, followed by multiple 6-bit data-words. 3. the address will automatically increment with each 6-bit data-word (all six bits must be written). 4. sl is held low until the last desired register has been loaded. 5. new data is updated either at the sl rising edge or at the hd falling edge after the next vd falling edge. d0 d1 d2 d3 d4 d5 d0 ... ... ... data for starting register address data for next register address d2 d1 figure 3b. continuous serial write operation complete register listing table i. sl updated registers register description register description oprmode afe operation modes ctlmode afe control modes preventpdate prevents loading of vd-updated registers readback enables serial register readback mode vdhdpol vd/hd active polarity fieldval internal field pulse value hblkretime retimes the h1 hblk to internal clock tgcore_rstb reset bar signal for internal tg core h12pol h1/h2 polarity control h1posloc h1 positive edge location h1negloc h1 negative edge location h1drv h1 drive current h2drv h2 drive current h3drv h3 drive current h4drv h4 drive current rgpol rg polarity rgposloc rg positive edge location rgnegloc rg negative edge location rgdrv rg drive current shpposloc shp sample location shdposloc shd sample location notes all addresses and default values are expressed in hexadecimal. all registers are vd/hd updated as shown in figure 3a, except for those that are sl updated.
rev. a ad9847 ?0 bit default address content width value register name register description afe registers # bits 56 00 [5:0] 6 00 oprmode[5:0] afe operation m ode (see afe register breakdown) 01 [1:0] 2 00 oprmode[7:6] 02 [5:0] 6 16 ccdgain[5:0] vga gain 03 [3:0] 4 02 ccdgain[9:6] 04 [5:0] 6 00 refblack[5:0] black clamp level 05 [1:0] 2 02 refblack[7:6] 06 [5:0] 6 00 ctlmode control mode (see afe register breakdown) 07 [5:0] 6 00 pxga gain0 pxga color 0 gain 08 [5:0] 6 00 pxga gain1 pxga color 1 gain 09 [5:0] 6 00 pxga gain2 pxga color 2 gain 0a [5:0] 6 00 pxga gain3 pxga color 3 gain miscellaneous/extra # bits 26 0f [5:0] 6 00 initial2 see r eco mm end ed power up sequence section. should be set to ? decimal (000100). 16 [0] 1 00 out_cont output control (0 = make all outputs dc inactive) 17 [5:0] 6 00 update[5:0] serial data update control (sets the line within the field 18 [5:0] 6 00 update[11:6] for serial data update to occur) 19 [0] 1 00 preventupdate prevent the up date of the vd/hd updated registers 1b [5:0] 6 00 doutphase dout phase control 1c [0] 1 00 disablerestore disable ccdin dc restore circuit during pblk (1 = disable) 1d [0] 1 00 vdhdpol vd/hd active polarity (0 = low active, 1 = high active) 1e [0] 1 01 fieldval internal field pulse value (0 = next field odd, 1 = next field even) 1f [0] 1 00 hblkretime re-sync hblk to h1 clock 20 [5:0] 6 00 initial1 see r eco mm end ed power up sequence. should be set to ?3 d ecimal (110101). 26 [0] 1 00 tgcore_rstb tg core reset_bar (0 = hold tg core in reset, 1 = resume normal operation) accessing a double-wide register there are many double-wide registers in the ad9847, e.g., oprmode, clpdmtog1_0, and clpdmscp3, and so on. these regis- ters are configured into two consecutive 6-bit registers with the least significant six bits located in the lower of the two addresses and the remaining most significant bits located in the higher of the two addresses. for example, the six lsbs of the clpdmscp3 register, clpdmscp3[5:0], are located at address 0x81. the most significant six bits of the clpdmscp3 register, clpdmscp3[11:6], are located at address 0x82. the following rules must be fol- lowed when accessing double-wide registers: 1. when accessing a double-wide register, both addresses must be written to. 2. the lower of the two consecutive addresses for the double- wide register must be written to first. in the example of the clpdmscp3 register, the contents of address 0x81 must be written first, followed by the contents of address 0x82. the register will be updated after the completion of the write to register 0x82, either at the next sl rising edge or the next vd/hd falling edge. 3. a single write to the lower of the two consecutive addresses of a double-wide register that is not followed by a write to the higher address of the registers is not permitted. this will not update the register. 4. a single write to the higher of the two consecutive addresses of a double-wide register that is not preceded by a write to the lower of the two addresses is not permitted. although the write to the higher address will update the full double-wide register, the lower six bits of the register will be written with an indetermi- nate value if the lower address was not written to first.
rev. a ad9847 e11e bit default address content width value register name register description clpdm # bits 146 64 [0] 1 01 clpdmdir clpdm internal/external (0 = internal, 1 = external) 65 [0] 1 00 clpdmpol clpdm external active polarity (0 = low active, 1 = high active) 66 [0] 1 01 clpdmspol0 sequence #0: start polarity for clpdm 67 [5:0] 6 2c clpdmtog1_0[5:0] sequence #0: toggle position 1 for clpdm 68 [5:0] 6 00 clpdmtog1_0[11:6] 69 [5:0] 6 35 clpdmtog2_0[5:0] sequence #0: toggle position 2 for clpdm 6a [5:0] 6 00 clpdmtog2_0[11:6] 6b [0] 1 01 clpdmspol1 sequence #1: start polarity for clpdm 6c [5:0] 6 3e clpdmtog1_1[5:0] sequence #1: toggle position 1 for clpdm 6d [5:0] 6 02 clpdmtog1_1[11:6] 6e [5:0] 6 16 clpdmtog2_1[5:0] sequence #1: toggle position 2 for clpdm 6f [5:0] 6 03 clpdmtog2_1[11:6] 70 [0] 1 00 clpdmspol2 sequence #2: start polarity for clpdm 71 [5:0] 6 3f clpdmtog1_2[5:0] sequence #2: toggle position 1 for clpdm 72 [5:0] 6 3f clpdmtog1_2[11:6] 73 [5:0] 6 3f clpdmtog2_2[5:0] sequence #2: toggle position 2 for clpdm 74 [5:0] 6 3f clpdmtog2_2[11:6] 75 [0] 1 01 clpdmspol3 sequence #3: start polarity for clpdm 76 [5:0] 6 3f clpdmtog1_3[5:0] sequence #3: toggle position 1 for clpdm 77 [5:0] 6 3f clpdmtog1_3[11:6] 78 [5:0] 6 3f clpdmtog2_3[5:0] sequence #3: toggle position 2 for clpdm 79 [5:0] 6 3f clpdmtog2_3[11:6] 00 0 clpdmscp0 clpdm sequence-change-position #0 (hardcoded to 0) 7a [1:0] 2 00 clpdmsptr0 clpdm sequence pointer for scp #0 7b [5:0] 6 3f clpdmscp1[5:0] clpdm sequence-change-position #1 7c [5:0] 6 3f clpdmscp1[11:6] 7d [1:0] 2 00 clpdmsptr1 clpdm sequence pointer for scp #1 7e [5:0] 6 3f clpdmscp2[5:0] clpdm sequence-change-position #2 7f [5:0] 6 3f clpdmscp2[11:6] 80 [1:0] 2 00 clpdmsptr2 clpdm sequence pointer for scp #2 81 [5:0] 6 3f clpdmscp3[5:0] clpdm sequence-change-position #3 82 [5:0] 6 3f clpdmscp3[11:6] 83 [1:0] 2 00 clpdmsptr3 clpdm sequence pointer for scp #3
rev. a ad9847 e12e bit default address content width value register name register description clpob # bits 146 84 [0] 1 01 clpobdir clpob internal/external (0 = internal, 1 = external) 85 [0] 1 00 clpobpol clpob external active polarity (0 = low active, 1 = high active) 86 [0] 1 01 clpobpol0 sequence #0: start polarity for clpob 87 [5:0] 6 0e clpobtog1_0[5:0] sequence #0: toggle position 1 for clpob 88 [5:0] 6 00 clpobtog1_0[11:6] 89 [5:0] 6 2b clpobtog2_0[5:0] sequence #0: toggle position 2 for clpob 8a [5:0] 6 00 clpobtog2_0[11:6] 8b [0] 1 01 clpobpol1 sequence #1: start polarity for clpob 8c [5:0] 6 2b clpobtog1_1[5:0] sequence #1: toggle position 1 for clpob 8d [5:0] 6 06 clpobtog1_1[11:6] 8e [5:0] 6 3f clpobtog2_1[5:0] sequence #1: toggle position 2 for clpob 8f [5:0] 6 3f clpobtog2_1[11:6] 90 [0] 1 00 clpobspol2 sequence #2: start polarity for clpob 91 [5:0] 6 3f clpobtog1_2[5:0] sequence #2: toggle position 1 for clpob 92 [5:0] 6 3f clpobtog1_2[11:6] 93 [5:0] 6 3f clpobtog2_2[5:0] sequence #2: toggle position 2 for clpob 94 [5:0] 6 3f clpobtog2_2[11:6] 95 [0] 1 01 clpobspol3 sequence #3: start polarity for clpob 96 [5:0] 6 3f clpobtog1_3[5:0] sequence #3: toggle position 1 for clpob 97 [5:0] 6 3f clpobtog1_3[11:6] 98 [5:0] 6 3f clpobtog2_3[5:0] sequence #3: toggle position 2 for clpob 99 [5:0] 6 3f clpobtog2_3[11:6] 00 0c lpobscp0 clpob sequence-change-position #0 (hardcoded to 0) 9a [1:0] 2 03 clpobsptr0 clpob sequence pointer for scp #0 9b [5:0] 6 01 clpobscp1[5:0] clpob sequence-change-position #1 9c [5:0] 6 00 clpobscp1[11:6] 9d [1:0] 2 01 clpobsptr1 clpob sequence pointer for scp #1 9e [5:0] 6 02 clpobscp2[5:0] clpob sequence-change-position #2 9f [5:0] 6 00 clpobscp2[11:6] a0 [1:0] 2 00 clpobsptr2 clpob sequence pointer for scp #2 a1 [5:0] 6 37 clpobscp3[5:0] clpob sequence-change-position #3 a2 [5:0] 6 03 clpobscp3[11:6] a3 [1:0] 2 03 clpobsptr3 clpob sequence pointer for scp #3
rev. a ad9847 e13e bit default address content width value register name register description hblk # bits 147 a4 [0] 1 01 hblkdir hblk internal/external (0 = internal, 1 = external) a5 [0] 1 00 hblkpol hblk external active polarity (0 = low active, 1 = high active) a6 [0] 1 01 hblkextmask hblk external masking polarity (0 = mask h1 and h3 low, 1 = mask h1 and h3 high) a7 [0] 1 01 hblkmask0 sequence #0: masking polarity for hblk a8 [5:0] 6 3e hblktog1_0[5:0] sequence #0: toggle low position for hblk a9 [5:0] 6 00 hblktog1_0[11:6] aa [5:0] 6 0d hblkbtog2_0[5:0] sequence #0: toggle high position for hblk ab [5:0] 6 06 hblkbtog2_0[11:6] ac [0] 1 01 hblkmask1 sequence #1: masking polarity for hblk ad [5:0] 6 38 hblktog1_1[5:0] sequence #1: toggle low position for hblk ae [5:0] 6 00 hblktog1_1[11:6] af [5:0] 6 3c hblktog2_1[5:0] sequence #1: toggle high position for hblk b0 [5:0] 6 02 hblktog2_1[11:6] b1 [0] 1 00 hblkmask2 sequence #2: masking polarity for hblk b2 [5:0] 6 3f hblktog1_2[5:0] sequence #2: toggle low position for hblk b3 [5:0] 6 3f hblktog1_2[11:6] b4 [5:0] 6 3f hblktog2_2[5:0] sequence #2: toggle high position for hblk b5 [5:0] 6 3f hblktog2_2[11:6] b6 [0] 1 01 hblkmask3 sequence #3: masking polarity for hblk b7 [5:0] 6 3f hblktog1_3[5:0] sequence #3: toggle low position for hblk b8 [5:0] 6 3f hblktog1_3[11:6] b9 [5:0] 6 3f hblktog2_3[5:0] sequence #3: toggle high position for hblk ba [5:0] 6 3f hblktog2_3[11:6] 00 0 hblkscp0 hblk sequence-change-position #0 (hardcoded to 0) bb [1:0] 2 00 hblksptr0 hblk sequence pointer for scp #0 bc [5:0] 6 3f hblkscp1[5:0] hblk sequence-change-position #1 bd [5:0] 6 3f hblkscp1[11:6] be [1:0] 2 00 hblksptr1 hblk sequence pointer for scp #1 bf [5:0] 6 3f hblkscp2[5:0] hblk sequence-change-position #2 c0 [5:0] 6 3f hblkscp2[11:6] c1 [1:0] 2 00 hblksptr2 hblk sequence pointer for scp #2 c2 [5:0] 6 3f hblkscp3[5:0] hblk sequence-change-position #3 c3 [5:0] 6 3f hblkscp3[11:6] c4 [1:0] 2 00 hblksptr3 hblk sequence pointer for scp #3
rev. a ad9847 e14e bit default address content width value register name register description pblk # bits 146 c5 [0] 1 01 pblkdir pblk internal/external (0 = internal, 1 = external) c6 [0] 1 00 pblkpol pblk external active polarity (0 = low active, 1 = high active) c7 [0] 1 01 pblkspol0 sequence #0: start polarity for pblk c8 [5:0] 6 3d pblktog1_0[5:0] sequence #0: toggle position 1 for pblk c9 [5:0] 6 00 pblktog1_0[11:6] ca [5:0] 6 2a pblkbtog2_0[5:0] sequence #0: toggle position 2 for pblk cb [5:0] 6 06 pblkbtog2_0[11:6] cc [0] 1 00 pblkspol1 sequence #1: start polarity for pblk cd [5:0] 6 2a pblktog1_1[5:0] sequence #1: toggle position 1 for pblk ce [5:0] 6 06 pblktog1_1[11:6] cf [5:0] 6 3f pblktog2_1[5:0] sequence #1: toggle position 2 for pblk d0 [5:0] 6 3f pblktog2_1[11:6] d1 [0] 1 00 pblkspol2 sequence #2: start polarity for pblk d2 [5:0] 6 3f pblktog1_2[5:0] sequence #2: toggle position 1 for pblk d3 [5:0] 6 3f pblktog1_2[11:6] d4 [5:0] 6 3f pblktog2_2[5:0] sequence #2: toggle position 2 for pblk d5 [5:0] 6 3f pblktog2_2[11:6] d6 [0] 1 01 pblkspol3 sequence #3: start polarity for pblk d7 [5:0] 6 3f pblktog1_3[5:0] sequence #3: toggle position 1 for pblk d8 [5:0] 6 3f pblktog1_3[11:6] d9 [5:0] 6 3f pblktog2_3[5:0] sequence #3: toggle position 2 for pblk da [5:0] 6 3f pblktog2_3[11:6] 00 0 pblkscp0 pblk sequence-change-position #0 (hardcoded to 0) db [1:0] 2 02 pblksptr0 pblk sequence pointer for scp #0 dc [5:0] 6 01 pblkscp1[5:0] pblk sequence-change-position #1 dd [5:0] 6 00 pblkscp1[11:6] de [1:0] 2 01 pblksptr1 pblk sequence pointer for scp #1 df [5:0] 6 02 pblkscp2[5:0] pblk sequence-change-position #2 e0 [5:0] 6 00 pblkscp2[11:6] e1 [1:0] 2 00 pblksptr2 pblk sequence pointer for scp #2 e2 [5:0] 6 37 pblkscp3[5:0] pblk sequence-change-position #3 e3 [5:0] 6 03 pblkscp3[11:6] e4 [1:0] 2 02 pblksptr3 pblk sequence pointer for scp #3 h1eh4, rg, shp, shd # bits 53 e5 [0] 1 00 h1pol h1/h2 polarity control (0 = no inversion, 1 = inversion) e6 [5:0] 6 00 h1posloc h1 positive edge location e7 [5:0] 6 20 h1negloc h1 negative edge location e8 [2:0] 3 03 h1drv h1 drive strength (0 = off, 1 = 3.5 ma, 2 = 7 ma, 3 = 10.5 ma, 4 = 14 ma, 5 = 17.5 ma, 6 = 21 ma, 7 = 24.5 ma) e9 [2:0] 3 03 h2drv h2 drive strength ea [2:0] 3 03 h3drv h3 drive strength eb [2:0] 3 03 h4drv h4 drive strength ec [0] 1 00 rgpol rg polarity control (0 = no inversion, 1 = inversion) ed [5:0] 6 00 rgposloc rg positive edge location ee [5:0] 6 10 rgnegloc rg negative edge location ef [2:0] 3 02 rgdrv rg drive strength (0 = off, 1 = 3.5 ma, 2 = 7 ma, 3 = 10.5 ma, 4 = 14 ma, 5 = 17.5 ma, 6 = 21 ma, 7 = 24.5 ma) f0 [5:0] 6 24 shpposloc shp (positive) edge sampling location f1 [5:0] 6 00 shdposloc shd (positive) edge sampling location
rev. a ad9847 e15e bit default address content width value register name register description afe register breakdown serial address: oprmode [7:0] 8'h0 8'h00 {oprmode[5:0]}, 8'h01 {oprmode[7:6]} [1:0] 2'h0 powerdown[1:0] full power 2'h1 fast recovery 2'h2 reference standby 2'h3 total shutdown [2] disblack disable black loop clamping (high active) [3] test mode test mode?should be set low [4] test mode test mode?should be set high [5] test mode test mode?should be set low [6] test mode test mode?should be set low [7] test mode test mode?should be set low ctlmode [5:0] 6'h0 serial address: 8'h06 {cltmode[5:0]} [2:0] 3'h0 ctlmode[2:0] off 3'h1 mosaic separate 3'h2 vd selected/mosaic interlaced 3'h3 mosaic repeat 3'h4 three-color 3'h5 three-color ii 3'h6 four-color 3'h7 four-color ii [3] enablepxga enable pxga (high active) [4] 1'h0 outputlat latch output data on selected dout edge 1'h1 leave output latch transparent [5] 1'h0 tristateout adc outputs are driven 1'h1 adc outputs are three-stated precision timing high speed timing generation the ad9847 generates flexible high speed timing signals using the precision timing core. this core is the foundation for generating the timing used for both the ccd and the afe, the reset gate rg, horizontal drivers h1eh4, and the shp/shd sample clocks. a unique architecture makes it routine for the system designer to optimize image quality by providing precise control over the hori- zontal ccd readout and the afe correlated double sampling. notes 1. pixel clock period is divided into 48 positions, providing fine edge resolution for high speed clocks. 2. there is a fixed delay from the cli input to the internal pixel period positions ( t clidly = 6 ns typ). p[0] p[48]=p[0] p[12] p[24] p[36] 1 pixel period ... ... cli t clidly position figure 4. high speed clock resolution from cli master clock input timing resolution the precision timing core uses a 1 master clock input (cli) as a reference. this clock should be the same as the ccd pixel clock frequency. figure 4 illustrates how the internal timing core divides the master clock period into 48 steps or edge positions. therefore, the edge resolution of the precision timing core is (t cli /48). for more information on using the cli input, see the applications information section.
rev. a ad9847 e16e high speed clock programmability figure 5 shows how the high speed clocks rg, h1eh4, shp, and shd are generated. the rg pulse has programmable rising and falling edges and may be inverted using the polarity control. the horizontal clocks h1 and h3 have programmable rising and falling edges and polarity control. the h2 and h4 clocks are always inverses of h1 and h3, respectively. table ii summarizes the high speed timing registers and their parameters. the edge location registers are 6 bits wide, but there are only 48 valid edge locations available. therefore, the register values are mapped into four quadrants, with each quadrant containing 12 edge locations. table iii shows the correct register values for the corresponding edge locations. figure 6 shows the range and default locations of the high speed clock signals. table ii. h1eh4, rg, shp, shd timing parameters register name length range description pol 1b high/low polarity control for h1, h3, and rg (0 = no inversion, 1 = inversion) posloc 6b 0e47 edge location positive edge location for h1, h3, and rg sample location for shp, shd negloc 6b 0e47 edge location negative edge location for h1, h3, and rg drv 3b 0e7 current steps drive current for h1eh4 and rg outputs (3.5 ma per step) table iii. precision timing edge locations quadrant edge location (decimal) register value (decimal) register value (binary) i0 to 11 0 to 11 000000 to 001011 ii 12 to 23 16 to 27 010000 to 011011 iii 24 to 35 32 to 43 100000 to 101011 iv 36 to 47 48 to 59 110000 to 111011 h1/h3 h2/h4 ccd signal rg (1) (2) (3) (4) (5) (6) notes programmable clock positions: (1) rg rising edge and (2) falling edge (3) shp and (4) shd sample location (5) h1/h3 rising edge position and (6) falling edge position (h2/h4 are inverse of h1/h3) figure 5. high speed clock programmable locations
rev. a ad9847 e17e h-driver and rg outputs in addition to the programmable timing positions, the ad9847 features on-chip output drivers for the rg and h1eh4 outputs. these drivers are powerful enough to directly drive the ccd inputs. the h-driver current can be adjusted for optimum rise/fall time into a particular load by using the drv registers. the rg drive current is adjustable using the rgdrv register. each 3-bit drv register is adjustable in 3.5 ma increments, with the mini- mum setting of 0 equal to off or three-state and the maximum setting of 7 equal to 24.5 ma. as shown in figure 7, the h2/h4 outputs are inverses of h1/h3. the internal propagation delay resulting from the signal inversion is less than 1 ns, which is significantly less than the typical rise time driving the ccd load. this results in a h1/h2 crossover voltage at approximately 50% of the output swing. the crossover voltage is not programmable. p[0] pixel period rg h1/h3 rgf[12] p[48] = p[0] hf[24] shp[28] ccd signal p[24] p[12] p[36] hr[0] rgr[0] shd[48] notes 1. all signal edges are fully programmable to any of the 48 positions within one pixel period. 2. default positions for each signal are shown above. position t s1 figure 6. high speed clock default and programmable locations h2/h4 h1/h3 h1/h3 h2/h4 t rise t pd << t rise fixed crossover voltage t pd figure 7. h-clock inverse phase relationship digital data outputs the ad9847 data output phase is programmable using the doutphase register. any edge from 0 to 47 may be programmed, as shown in figure 8. notes 1. digital output data (dout) phase is adjustable with respect to the pixel period. 2. within 1 clock period, the data transition can be programmed to any of the 48 locations. p[0] p[48] = p[0] cli 1 pixel period p[12] p[24] p[36] dout t od figure 8. digital output phase adjustment
rev. a ad9847 e18e (3) (2) (1) hd clpob clpdm pblk . . . notes programmable settings: (1) start polarity (clamp and blank region are active low) (2) first toggle position (3) second toggle position . . . clamp clamp figure 9. clamp and preblank pulse placement (2) (1) hd hblk . . . notes programmable settings: (1) first toggle position = start of blanking (2) second toggle position = end of blanking . . . blank blank figure 10. horizontal blanking (hblk) pulse placement table iv. clpob, clpdm, pblk individual sequence parameters register name length range description spol 1b high/low starting polarity of clamp and blanking pulses for sequences 0e3 tog1 12b 0e4095 pixel location first toggle position within the line for sequences 0e3 tog2 12b 0e4095 pixel location second toggle position within the line for sequences 0e3 table v. hblk individual sequence parameters register name length range description hblkmask 1b high/low masking polarity for h1 for sequences 0e3 (0 = h1 low, 1 = h1 high) hblktog1 12b 0e4095 pixel location first toggle position within the line for sequences 0e3 hblktog2 12b 0e4095 pixel location second toggle position within the line for sequences 0e3 horizontal clamping and blanking the ad9847?s horizontal clamping and blanking pulses are fully programmable to suit a variety of applications. as with the vertical timing generation, individual sequences are defined for each signal and are then organized into multiple regions during image readout. this allows the dark pixel clamping and blanking patterns to be changed at each stage of the readout, in order to accom- modate different image transfer timing and high speed line shifts. individual clpob, clpdm, and pblk sequences the afe horizontal timing consists of clpob, clpdm, and pblk, as shown in figure 9. these three signals are indepen- dently programmed using the registers in table iv. spol is the start polarity for the signal, and tog1 and tog2 are the first and second toggle positions of the pulse. all three signals are active low and should be programmed accordingly. up to four individual sequences can be created for each signal. individual hblk sequences the hblk programmable timing shown in figure 10 is similar to clpob, clpdm, and pblk. however, there is no start polarity control. only the toggle positions are used to designate the start and the stop positions of the blanking period. additionally, there is a polarity control, hblkmask, that designates the polarity of the horizontal clock signals h1eh4 during the blanking period. setting hblkmask high will set h1 = h3 = low and h2 = h4 = high during the blanking, as shown in figure 11. up to four individual sequences are available for hblk.
rev. a ad9847 e19e hd hblk . . . . . . h1/h3 h1/h3 h2/h4 . . . . . . the polarity of h1 during blanking is programmable (h2 is opposite polarity of h1) figure 11. hblk masking control horizontal sequence control the ad9847 uses sequence change positions (scp) and sequence pointers (sptr) to organize the individual horizontal sequences. up to four scps are available to divide the readout into four separate regions, as shown in figure 12. the scp 0 is always hard-coded to line 0, and scp1e3 are register programmable. during each region bounded by the scp, the sptr registers designate which sequence is used by each signal. clpob, clpdm, pblk, and hblk each have a separate set of scp. for example, clpobscp1 will define region 0 for clpob, and in that region any of the four individual clpob sequences may be selected with the clpobsptr registers. the next scp defines a new region, and in that region each signal can be assigned to a different individual sequence. the sequence control registers are summarized in table vi. up to four individual horizontal clamp and blanking regions may be programmed within a single field, using the sequence change positions. sequence change of position #1 sequence change of position #2 sequence change of position #3 single field (1 vd interval) clamp and pblk sequence region 0 sequence change of position #0 (v-counter = 0) clamp and pblk sequence region 3 clamp and pblk sequence region 2 clamp and pblk sequence region 1 figure 12. clamp and blanking sequence flexibility table vi. horizontal sequence control parameters for clpob, clpdm, pblk, and hblk register name length range description scp1escp3 12b 0e4095 line number clamp/blank scp to define horizontal regions 0e3 sptr0esptr3 2b 0e3 sequence number sequence pointer for horizontal regions 0e3
rev. a ad9847 ?0 h-counter synchronization the h-counter reset occurs on the sixth cli rising edge following the hd falling edge. the pxga steering is synchronized with the reset of the internal h-counter (see figure 13). power-up procedure recommended power-up sequence when the ad9847 is powered up, the following sequence is recommended (refer to figure 14 for each step). 1. turn on power supplies for ad9847. 2. apply the master clock input cli, vd, and hd. 3. the precision timing core must be reset by writing a ??to the tgcore_rstb register (address x026) followed by writ- ing a ??to the tgcore_rstb register. this will start the internal timing core operation. next, initialize the internal 000 1 12 111 0 03 11 00 012345678910111214150123 023 4 h-counter reset vd notes 1. internal h-counter is reset on the sixth cli rising edge following the hd falling edge. 2. pxga steering is synchronized with the reset of the internal h-counter (mosaic separate mode is shown). 3. vd falling edge should occur one clock cycle before hd falling edge for proper pxga line synchronization. hd xx xxx x x pxga gain register cli xx xxx x x h-counter (pixel counter) 3ns min 23 5 3ns min x x figure 13. h-counter synchronization vdd (input) serial writes vd (output) 1 h odd field even field digital outputs clocks active when out_cont register is updated at vd/hd edge h1/h3, rg h2/h4 t pwr cli (input) hd (output) 1v *** *** *** *** figure 14. recommended power-up sequences circuitry by first writing ?10101?or ?3?decimal to the initial1 register (address x020). finally, write ?00100 or ??decimal to the initial2 register (address x00f). 4. write a ??to the preventupdate register (address x019). this will prevent the updating of the serial register data. 5. write to the desired registers to configure high speed timing and horizontal timing. 6. write a ??to the out_cont register (address x016). this will allow the outputs to become active after the next vd/hd rising edge. 7. write a ??to the preventupdate register (address x019). this will allow the serial information to be updated at the next vd/hd falling edge. 8. the next vd/hd falling edge allows register updates to occur, including out_cont, which enables all clock outputs.
rev. a ad9847 ?1 analog front end description and operation the ad9847 signal processing chain is shown in figure 15. each processing step is essential in achieving a high quality image from the raw ccd pixel data. dc restore to reduce the large dc offset of the ccd output signal, a dc-restore circuit is used with an external 0.1 f series coupling capacitor. this restores the dc level of the ccd signal to approxi- mately 1.5 v, to be compatible with the 3 v analog supply of the ad9847. correlated double sampler the cds circuit samples each ccd pixel twice to extract the video information and reject low frequency noise. the timing shown in figure 6 illustrates how the two internally generated cds clocks, shp and shd, are used to sample the reference level and data level of the ccd signal, respectively. the placement of the shp and shd sampling edges is determined by the setting of the shpposloc and shdposloc registers located at addresses 0xf0 and 0xf1, respectively. placement of these two clock signals is critical in achieving the best performance from the ccd. input clamp a line-rate input clamping circuit is used to remove the ccd? optical black offset. this offset exists in the ccd? shielded black reference pixels. the ad9847 removes this offset in the input stage to minimize the effect of a gain change on the system black level, usually called the ?ain step. another advantage of removing this offset at the input stage is to maximize system headroom. some area ccds have large black level offset voltages, which, if not corrected at the input stage, can significantly reduce the available headroom in the internal circuitry when higher vga gain settings are used. horizontal timing examples are shown on the last page of the applications information section. it is recommended that the clpdm pulse be used during valid ccd dark pixels. clpdm may be used during the optical black pixels, either together with clpob or separately. the clpdm pulse should be a minimum of four pixels wide. pxga the pxga provides separate gain adjustment for the individual color pixels. a programmable gain amplifier with four separate values, the pxga has the capability to ?ultiplex?its gain value on a pixel-to-pixel basis (see figure 17). this allows lower out- put color pixels to be gained up to match higher output color pixels. also, the pxga may be used to adjust the colors for white balance, reducing the amount of digital processing that is needed. the four different gain values are switched according to the color steering circuitry. seven different color steering modes for different types of ccd color filter arrays are programmed in the ad9847 afe register, ctlmode, at address 0x06 (see figures 16a to 16g for timing examples). for example, mosaic separate steering mode accommodates the popular ?ayer?arrangement of red, green, and blue filters (see figure 18). 0.1 f 0.1 f 0.1 f 1.0 f 1.0 f 0.1 f 0.1 f 0db to 36db clpdm ccdin digital filter clpob dc restore optical black clamp 10-bit adc vga 8-bit dac clamp level register 8 vg a gain register 10 cds internal v ref 2v full scale ?db to +10db 10 precision timing generation byp1 byp 2 shp shd pxga 1.5v output data latch reft refb dout phase v- h timing generation shp shd dout phase clpdm clpob pblk pblk 1.0v 2.0v dout byp 3 input offset clamp cml av d d 2 internal biasing ad9847 figure 15. analog front end block diagram
rev. a ad9847 e22e 220 33 1 1 vd notes 1. vd falling edge will reset the pxga gain register steering to 0101 line. 2. hd falling edges will alternate the pxga gain register steering between 0101 and 2323 lines. 3. fld status is ignored. hd 11 0 x x pxga gain register fld 0 odd field even field 0220 33 1 1 11 0 0 0 0 figure 16a. mosaic separate mode 000 11 1 1 vd notes 1. fld falling edge (start of odd field) will reset the pxga gain register steering to 0101 line. 2. fld rising edge (start of even field) will reset the pxga gain register steering to 2323 line. 3. hd falling edges will reset the pxga gain register steering to either 0 (fld = odd) or 2 (fld = even). hd 11 0 x x pxga gain register fld 0 odd field even field 0222 33 3 3 33 2 2 2 0 figure 16b. mosaic interlaced mode 110 22 1 1 vd notes 1. vd falling edge will reset the pxga gain register steering to 0101 line. 2. hd falling edges will alternate the pxga gain register steering between 0101 and 1212 lines. 3. all fields will have the same pxga gain steering pattern (fld status is ignored). hd 11 0 x x pxga gain register fld 0 odd field even field 0110 22 1 1 11 0 0 0 0 figure 16c. mosaic repeat mode 020 10 0 1 vd notes 1. each line follows 012012 steering pattern. 2. vd and hd falling edges will reset the pxga gain register steering to 0. 3. fld status is ignored. hd 10 2 x x pxga gain register fld 0 odd field even field 2020 10 0 1 10 2 0 2 0 figure 16d. three-color mode
rev. a ad9847 e23e 200 12 0 1 vd notes 1. vd falling edge will reset the pxga gain register steering to 012012 line. 2. hd falling edges will alternate the pxga gain register, steering between 012012 and 210210 lines. 3. fld status is ignored. hd 10 2 x x pxga gain register fld 0 odd field even field 2200 12 0 1 10 2 0 2 0 figure 16e. three-color mode ii 020 13 3 1 vd notes 1. each line follows 01230123 steering pattern. 2. vd and hd falling edges will reset the pxga gain register steering to gain register 0. 3. fld status is ignored. hd 13 2 x x pxga gain register fld 0 odd field even field 2020 13 3 1 13 2 0 2 0 figure 16f. four-color mode 200 31 3 1 vd notes 1. vd falling edge will reset the pxga gain register steering to 01230123 line. 2. hd falling edges will alternate the pxga gain register steering between 01230123 and 23012301 lines. 3. fld status is ignored. hd 13 2 x x pxga gain register fld 0 odd field even field 2200 31 3 1 13 2 0 2 0 figure 16g. four-color mode ii
rev. a ad9847 e24e color steering control 4:1 mux 3 gain0 gain1 gain2 gain3 pxga pxga steering mode selection 2 6 vd hd pxga gain registers control register bits d0ed2 shp/shd vga cds figure 17. pxga block diagram rgr rgr gb b gb b rgr rgr gb b gb b gain0, gain1, gain0, gain1... line0 gain2, gain3, gain2, gain3... line1 gain0, gain1, gain0, gain1... line2 ccd: progressive bayer mosaic separate color steering mode figure 18a. ccd color filter example: progressive scan rgr rgr rgr r gr rgr rgr rgr r gr gain0, gain1, gain0, gain1... line0 gain0, gain1, gain0, gain1... line1 gain0, gain1, gain0, gain1... line2 ccd: interlaced bayer even field vd selected color steering mode gb b gb b gb b gb b gb b gb b gb b gb b gain2, gain3, gain2, gain3... line0 gain2, gain3, gain2, gain3... line1 gain2, gain3, gain2, gain3... line2 odd field figure 18b. ccd color filter example: interlaced the same bayer pattern can also be interlaced, and the vd selected mode should be used with this type of ccd (see figure 18b). the color steering performs the proper multiplexing of the r, g, and b gain values (loaded into the pxga gain registers) and is synchronized by the user with vertical (vd) and horizontal (hd) sync pulses. for more detailed information, see the pxga timing section. the pxga gain for each of the four channels varies from e2 db to +10 db, controlled in 64 steps through the serial inter- face. the pxga gain curve is shown in figure 19. pxga gain register code 10 32 pxga gain e db 40 48 58 0 8 16 24 31 8 6 4 2 0 e2 (011111) (100000) figure 19. pxga gain curve variable gain amplifier the vga stage provides a gain range of 2 db to 36 db, program- mable w ith 10-bit resolution through the serial digital interface. combined with 4 db from the pxga stage, the total gain range for the ad9847 is 6 db to 40 db. the minimum gain of 6 db is needed to match a 1 v input signal with the adc full-scale range of 2 v. when compared to 1 v full-scale systems (such as adi?s ad9803), the equivalent gain range is 0 db to 34 db. the vga gain curve is divided into two separate regions. when the vga gain register code is between 0 and 511, the curve follows a (1 + x)/(1 e x) shape, which is similar to a linear-in-db character- istic. from code 512 to code 1023, the curve follows a linear-in-db shape. the exact vga gain can be calculated for any gain register value by using the following two equations: code range gain equation (db) 0e511 gain = 20 log 10 ([658 code ] / [658 e code ]) e 0.4 512e1023 gain = (0.0354)( code ) e 0.04 vga gain register code 36 0 vga gain e db 127 255 383 511 639 767 895 1023 30 24 18 12 6 0 figure 20. vga gain curve (gain from pxga not included)
rev. a ad9847 e25e optical black clamp the optical black clamp loop is used to remove residual offsets in the signal chain and to track low frequency variations in the ccd?s black level. during the optical black (shielded) pixel interval on each line, the adc output is compared with a fixed black level reference, selected by the user in the clamp level register. the value can be programmed between 0 lsb and 63.75 lsb with 8-bit resolution. the resulting error signal is filtered to reduce noise, and the correction value is applied to the adc input through a d/a converter. normally, the optical black clamp loop is turned on once per horizontal line, but this loop can be updated more slowly to suit a particular application. if external digital clamping is used during the post processing, the ad9847 optical black clamping may be disabled using bit d2 in the oprmode register. when the loop is disabled, the clamp level register may still be used to provide programmable offset adjustment. the clpob pulse should be placed during the ccd?s optical black pixels. it is recommended that the clpob pulse duration be at least 20 pixels wide to minimize clamp noise. shorter pulse- widths may be used, but clamp noise may increase, and the ability to track low frequency variations in the black level will be reduced. see the section on horizontal clamping and blanking and also the applications information section for timing examples. a/d converter the ad9847 uses a high performance 10-bit adc architecture, optimized for high speed and low power. differential nonlinearity (dnl) performance is typically better than 0.4 lsb. the adc uses a 2 v input range. better noise performance results from using a larger adc full-scale range. see tpc 1 and tpc 2 for typical linearity and noise performance plots for the ad9847. applications information external circuit configuration the ad9847 recommended circuit configuration for external mode is shown in figure 21. all signals should be carefully routed on the pcb to maintain low noise performance. the ccd output signal should be connected to pin 29 through a 0.1 f capacitor. the ccd timing signals h1eh4 and rg should be routed directly to the ccd with minimum trace lengths, as shown in figures 22a and 22b. the digital outputs and clock inputs are located on pins 1e12 and pins 36e44 and should be connected to the digital asic, away from the analog and ccd clock signals. the cli signal from the asic may be routed under the package to pin 23. this will help separate the cli signal from the h1eh4 and rg signal routing. grounding and decoupling recommendations as shown in figure 21, a single ground plane is recommended for the ad9847. this ground plane should be as continuous as possible, particularly around pins 25 e 35. this will ensure that all analog decoupling capacitors provide the lowest possible impedance path between the power and bypass pins and their respective ground pins. all decoupling capacitors should be located as close as possible to the package pins. placing series resistors close to the digital output pins (pins 1e12) may help reduce digital code transition noise. if the digital outputs must drive a load larger than 20 pf, buffering is recommended to minimize additional noise. power supply decoupling is very important in achieving low noise performance. figure 21 shows the local high frequency decoupling capacitors, but additional capacitance is recommended for lower frequencies. additional capacitors and ferrite beads can further reduce noise. 3v digital supply serial interface 3 ccd signal clock inputs 6 0.1 f 36 35 34 33 32 31 30 29 28 27 26 25 3v driver supply 13 14 15 16 clock input 17 18 19 20 21 22 23 24 1 2 rg driver supply 3 h driver supply 4 5 6 7 8 9 10 11 3v analog supply 12 48 47 46 45 44 39 38 37 43 42 41 40 pin 1 identifier top view (not to scale) sl reft refb cmlevel 0.1 f avss3 avdd3 byp3 ( lsb) d0 d1 1 f d2 d3 d4 dvss3 1 f dvdd3 d5 d6 d7 d8 ccdin byp2 byp1 avdd2 ad9847 ( msb) d9 avss2 nc nc 3v analog supply dvdd4 dvss4 hd vd pblk hblk clpdm 0.1 f clpob sck sdi h1 h2 dvss1 dvdd1 h3 h4 dvss2 rg dvdd2 avss1 cli avdd1 3v analog supply data outputs 10 0.1 f 0.1 f 0.1 f 0.1 f 0.1 f 0.1 f 0.1 f 0.1 f 0.1 f high-speed clocks 5 figure 21. recommended circuit configuration for external mode
rev. a ad9847 e26e 17 ccd imager signal out 18 13 14 20 29 h2 rg h3 h4 h1 h2 h1 rg ad9847 ccdin figure 22a. ccd connections (2 h-clock) ccd imager signal out 13 14 20 29 rg h3 h4 h2 h1 rg ad9847 ccdin h2 h1 17 18 h1 h2 figure 22b. ccd connections (4 h-clock) driving the cli input the ad9847?s master clock input (cli) may be used in two different configurations, depending on the application. figure 23a shows a typical dc-coupled input from the master clock source. when the dc-coupled technique is used, the master clock signal should be at standard 3 v cmos logic levels. as shown in figure 23b, a 1000 pf ac-coupling capacitor may be used between the clock source and the cli input. in this configuration, the cli input will self-bias to the proper dc voltage level of approximately 1.4 v. when the ac-coupled technique is used, the master clock signal can be as low as 500 mv in amplitude. cli 23 master clock ad9847 asic figure 23a. cli connection, dc-coupled cli 23 master clock ad9847 asic lpf 1nf figure 23b. cli connection, ac-coupled internal mode circuit configuration the ad9847 may be used in internal mode using the circuit configuration of figure 24. internal mode uses the same circuit as figure 21, except that the horizontal pulses (clpob, clpdm, pblk, and hblk) are internally generated in the ad9847. these pins may be grounded when internal mode is used. only the hd and vd signals are required from the asic. hd/vd inputs 2 44 39 43 42 41 40 hd vd pblk hblk clpdm clpob ad9847 figure 24. internal mode circuit configuration timing examples for different sequences 2 4 48 10 v h 28 sequence 3 sequence 2 sequence 2 figure 25. typical ccd
rev. a ad9847 e27e timing examples (continued) vert shift dummy invalid pixels vert shift invalid pixels ccdin shp shd h1/h3 h2/h4 hblk pblk clpob clpdm figure 26. sequence 1: vertical blanking eff. pixels optical black vert shift dummy vert shift ccdin shp shd h1/h3 h2/h4 hblk pblk clpob clpdm optical black figure 27. sequence 2: vertical optical black eff. pixels optical black vert shift dummy ccdin shp shd h1/h3 h2/h4 hblk pblk clpob clpdm optical black vert shift effective pixels ob figure 28. sequence 3: effective pixels
rev. a e28e ad9847 outline dimensions 48-lead plastic quad flatpack [lqfp] 1.4 mm thick (st-48) dimensions shown in millimeters top view (pins down) 1 12 13 25 24 36 37 48 0.27 0.22 0.17 0.50 bsc 7.00 bsc seating plane 1.60 max 0.75 0.60 0.45 view a 7 3.5 0 0.20 0.09 1.45 1.40 1.35 0.15 0.05 0.08 max coplanarity view a rotated 90 ccw pin 1 indicator 9.00 bsc compliant to jedec standards ms-026bbc seating plane c02626e0e1/03(a) printed in u.s.a. revision history location page 1/03?data sheet changed from rev. 0 to rev. a. change to pin function descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 change to register description table e hblk # bits 147 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 changes to recommended power sequence section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 updated outline dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

▲Up To Search▲

Price & Availability of AD9847AKST

	To Download AD9847AKST Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .