this document is for maintenance purposes only and is not recommended for new designs
pca3000 1 pca3000 5v 6 channel magneto-resistive read/ thin film write pre-amplifier the gec plessey semiconductors pca3000 is a bipolar monolithic integrated circuit designed for use with a combined magneto-resistive read head and thin film write head. the gps pca3000 can be used in disk drive applications with up to 6 channels, and provides the necessary bias current for the mr head from a single 5 volt supply whilst keeping the voltage on the mr head to a minimum. circuit operation with the chip select input ( c s ) high the chip is put in its idle state with supply current reduced to the minimum for power saving. with chip select low the function of the chip is controlled by the read/write pin ( r/ w ), and the head selection by the hs pins. c s and r/ w have internal pull-up resistors and the hs pins have internal pull-down resistors. features n designed for operation with single stripe mr heads n single +5 volt supply operation n high performance read circuit features - adjustable bias current = 5 to 15ma - typical mr head voltage = 225mv - gain = 320v/v - input noise = 0.7nv/ ? h z max. - input capacitance = 10pf typ. - bandwidth = 60mhz n thin film write circuit features - 20:1 programmable write current source - minimum head voltage swing 6vpp - write unsafe indicator - head short to ground protection - power supply fault protection august 1994 target information ds3829 -1.5 fig. 1 block diagram iwset tfc wdi wdi hs0 hs1 hs2 dummy cs r/ w fast c1 c2 v gnd dsbf fault rdx rdy write current source fault detector cc r0p r0n rip rin r2p r2n r3p r3n r4p r4n r5p r5n irset w0x w0y w1x w1y w2x w2y w3x w3y w4x w4y w5x w5y head select mode select read bias current source toggle l l l l write current switches read pre-amps gndr
pca3000 2 fault detector in write mode this function disables the write current function when either of the faults below are detected. l power supply voltage too low l head short to ground in addition the following conditions will put a high level on the fault open collector output. l wdi frequency too low l device in read mode l chip disabled l write current to low l open circuit head in read mode the voltage across the mr head is monitored and fault will be driven low in the case of an extended head to media short, or an open circuit read head. the read mode fault detection is enabled by pulling the dsbf pin low. packaging the pca3000 is available in surface mount packaging. the target package will be a 48 and 64 pin tqfp. read mode (mr) in the mr read mode the mr bias currents, set by the irset pin, are applied to the selected single stripe magneto- resistive head. the differential output voltage is amplified and output on the rdx and rdy pins. in idle or write modes these two outputs become high impedance, allowing wire-or connection for multiple head/chip applications. the current in the read head is set by the external resistor r rc where: i r = v rc r rc r rc is connected between the pin irset and v cc . pins are provided for filter capacitors for the bias generator and the current loop control. the fast pin enables either the fast or normal settling mode of the read current bias control loops. write mode (tf) in the write mode, the selected head switches current between x and y sides of the head. if toggle is enabled, the write current changes direction on the falling edge of the wdi input. on power-up or when selecting write mode, the write data flip-flop is initialised to pass current into the x side of the head. if toggle is disabled, the direction of the write current is determined by the polarity of the wdi/ w d i inputs. the current in the write driver is set by the external resistor r wc where: i w = a i .v wc r wc + 40 r wc is connected between the pin iwset and v cc . note: in read and idle modes the write current source is deactivated. any other combination of the hs inputs will select the dummy head if in read mode, or turn the write current driver off and set fault high if in write mode. mode description hs2 hs1 hs0 head 0 0 0 0 c s r/ w mode 0 0 1 1 0 0 write 0 1 0 2 0 1 read 0 1 1 3 1 0 idle 1 0 0 4 1 1 idle 1 0 1 5
pca3000 3 recommended operating conditions parameter rating unit dc supply voltage v cc 5?0% vdc operating junction temperature tj +25 to +110 ? write head load range l h 0.2 to 1 ? read head resistance r mr 15 to 45 w pin descriptions name type description hs0,hs1,hs2 ? i head select: selects one of six heads c s i chip select: a high inhibits the chip r/ w ? i read/write: a high selects read mode dummy ? i selects a dummy read head fault ? o fault - in write mode a high indicates an unsafe writing condition - in read mode a low indicates a head to media short dsbf i high level disables read head fault flag wdi - w d i ? i write data in: changes the direction of the current in the recording head. pseudo ecl inputs w0x - w5x; w0y - w5y o x, y head connections for thin film heads r0p - r5p; r0n - r5n i head connections for mr read heads rdx, rdy ? o x, y read data: differential read data output iwset ? write current set: used to set the magnitude of the write current irset ? read bias current set c1 filter for the mr bias current loop c1s o servo drive for c1 c2 filter for the mr bias current set c2s (64 tqfp) o servo drive for c2 fast i high level enables fast settling mode of the read tfc i toggle flop control high sets ? v cc i +5v supply gnd i ground gndr i read circuitry ground ? these signals can be wire or'ed
pca3000 4 absolute maximum ratings operation at absolute maximum ratings is not implied. exposure to stresses greater than those listed could cause permanent damage to the device. parameter rating units dc supply voltage v cc -0.3 to +6 vdc write current iw 50 ma digital input voltage vin -0.3 to v cc +0.3 vdc head port voltage vh -0.3 to v cc +0.3 vdc output current: rdx,rdy i0 -10 ma fault +12 ma storage temperature tstg -65 to +150 ? dc characteristics recommended operating conditions apply. parameter condition min. typ. max. units v cc supply current read mode i w = 20ma 40+ i r 56+ i r ma write mode i r = 15ma 30+ i w 42+ i w ma idle mode 1 2 ma power dissipation read mode tba mw write mode tba mw idle mode tba mw parameter condition min. max. units input low voltagev il * 0.8 v input high voltagev ih * 2.0 v input low current i il * vil = 0.8v -400 ? input high current i ih * vih = 2.0v 100 ? input low voltagev il ( wdi/ w d i ) v cc -1.9 v cc -1.6 v input high voltagev ih ( wdi/ w d i ) v cc -1.0 v cc -0.7 v input low current i il ( wdi/ w d i ) vil = v cc -1.6v 80 ? input high current i ih ( wdi/ w d i ) vih = v cc -1.0v 100 ? fault output low voltage (vol) i ol = 2ma 0.5 v v cc fault voltage i w < 0.2ma 3.5 4.2 v *except wdi / w d i digital inputs recommended operating conditions apply.
pca3000 5 write characteristics recommended operating conditions apply. read characteristics recommended operating conditions apply. (cl = 20pf rl = 1k) parameter condition min. typ. max. units mr read bias current range (i r ) 5 15 ma read current voltage (v rc ) 1.27 v mr head potential note 1 225 mv mr differential voltage gain 320 v/v mr bandwidth -3db vin = 1mv p-p 60 80 mhz mr integrated input noise voltage 0.7 nv/ ? h z mr input capacitance 10 pf mr input resistance note 1 4 w power supply rejection ratio @5mhz -30 db channel rejection ratio -45 db differential output offset 200 mv single ended output resistance 40 w output current 1 ma common mode output voltage 2 3.5 v note 1: rmr = 20 w , imr = 11ma note 1 vin = 1mv p-p f = 1mhz note 1 bw = 1mhz - 15mhz parameter condition min. typ. max. units write current voltage (vwc) tbd 1.27 tbd v i w to head current gain (a i ) tbd 20 tbd ma/ma differential head voltage swing open head 6 vp-p unselected head current 1 ma(pk) write driver output capacitance 25 pf write driver output resistance 500 w write current range (iw) 5 35 ma write bandwidth 50 mhz
pca3000 6 switching characteristics recommended operating conditions apply unless otherwise specified . iw = 20ma, lh = 0.5?, rh = 30 w , f(data) = 5mhz. td3 td1 td2 wdi wus head current (lx - ly) parameter conditions min. nom. max. units r/w read to write r/w to 90% of write current 0.2 0.5 ? write to read fast = low 5 15 ? fast = high 0.5 1 ? cs cs to read fast = low 10 25 fast = high 3 5 ? hs hs to any head 1 5 ? fault:safe to unsafe (td1) 0.6 3.6 ? unsafe to safe (td2) 1.0 ? head current: lh = 0, rh = 0 wdi to ix - iy (td3) from 50% level 30 ns asymmetry wdi has 1ns rise/fall time 1 ns rise/fall time 10% to 90% level 3 5 ns lh = 0 rh = 0 10% to 90% 7 ns lh = 0.5? rh = 30 w
pca3000 7 pinout diagrams
pca3000 8 part no. description package pca3006tpa six channel 64tqfp pca3006tpb six channel 48tqfp PCA3004TPB four channel 48tqfp part numbering when ordering please use the following part numbers: this publication is issued to provide information only which (unless agreed by the company in writing) may not be used, applied or reproduced for any purpose nor form part of any order or contract nor to be regarded as a representation relating to the products or services concerned. no warranty or guarantee express or implied is made regarding the capability, performance or suitability of any product or service. the company reserves the right to alter without prior knowledge the specification, design or price of any product or service. information concerning possible methods of use is provided as a guide only and does not constitute any guarantee that such methods of use will be satisfactory in a specific piece of equipment. it is the user's responsibility to fully determine the performance and suitability of any equipment using such information and to ensure that any publication or data used is up to date and has not been superseded. these products are not suitable for use in any medical products whose failure to perform may result in significant injury or death to the user. all products and materials are sold and services provided subject to the company's conditions of sale, which are available on request. customer service centres france & benelux les ulis cedex tel: (1) 64 46 23 45 fax: (1) 64 46 06 07 germany munich tel: (089) 3609 06-0 fax: (089) 3609 06-55 italy milan tel: (02) 66040867 fax: (02) 66040993 japan tokyo tel: (03) 5276-5501 fax: (03) 5276-5510 north america scotts valley, usa tel: (408) 438 2900 fax: (408) 438 7023 south east asia singapore tel: (65) 3827708 fax: (65) 3828872 sweden stockholm, tel: 46 8 702 97 70 fax: 46 8 640 47 36 taiwan, roc taipei, tel: 886 2 5461260 fax: 886 2 7190260 uk, eire, denmark, finland & norway swindon tel: (01793) 518510 fax: (01793) 518582 these are supported by agents and distributors in major countries world-wide. ?gec plessey semiconductors 1994 publication no.ds3829 issue no. 1.5 aug 1994. technical documentation - not for resale. printed in united kingdom. headquarters operations gec plessey semiconductors cheney manor, swindon, wiltshire, united kingdom sn2 2qw. tel: (01793) 518000 fax: (01793) 518411 gec plessey semiconductors p.o. box 660017 1500 green hills road, scotts valley, california 95067-0017, united states of america. tel: (408) 438 2900 fax: (408) 438 5576 united kingdom: swindon, tel: (01793) 518000 fax: (01793) 518411. oldham, tel: (0161) 682 6844, fax: (0161) 688 7898. lincoln, tel: (01522) 500500 fax: (01522) 500550. united states of america: scotts valley, ca, tel: (408) 438 2900 fax: (408) 438 5576. boston, ma, tel: (617)251-0100. fax: (617) 251-0104. irvine, ca, tel: (714) 455-2950. fax: (714) 455-9671. australia: rydalmere, nsw, tel: (612) 638 1888. fax: (612) 638 1798. france: les ulis cedex, tel: (1) 64 46 23 45 fax: (1) 64 46 06 07. italy: milan, tel: (02) 66040867 fax: (02) 66040993. germany: munich, tel: (089) 3609 06 0 fax: (089) 3609 06 55. japan: tokyo, tel: (3) 5276-5501. fax: (3) 5276-5510. primary semi-custom design centres
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