View IRDC3894-P1V2_4696556.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

IRDC3894-P1V2 12/22/2011 1 user guide for ir3894 evaluation board 1.2vout description the ir3894 is a synchronous buck converter, providing a compact, high performance and flexible solution in a small 5mm x 6 mm power qfn package. key features offered by the ir3894 include internal digital soft start/soft stop, precision 0.5vreference voltage, power good , thermal protection, programmable switching frequency, enable input, input under-voltage lockout for proper start-up, enhanced line/ load regulation with feed forward, external frequency synchronization with smooth clocking, smart internal ldo and pre-bias start-up. output over-current protection function is implemented by sensing the voltage developed across the on-resistance of the synchronous rectifier mosfet for optimum cost and performance and the current limit is thermally compensated. this user guide contains the schematic and bill of materials for the ir3894 evaluation board. the guide describes operation and use of the evaluation board itself. detailed application information for ir3894 is available in the ir3894 data sheet. board features ? v in = +12v (+ 13.2v max) ?v out = +1.2v @ 0- 12a ? f s =600khz ? l= 0.51uh ? c in = 4x10uf (ceramic 1206) + 1x330uf (electrolytic) ? c out =8x22uf (ceramic 0805) sup ir buck tm
IRDC3894-P1V2 12/22/2011 2 connections and operating instructions table i. connections connection signal name vin+ vin (+12v) vin- ground of vin vout+ vout(+1.2v) vout- ground for vout vcc+ vcc/ ldo_out pin vcc- ground for vcc input enable enable pgood power good signal gnd analog ground a well regulated +12v input supply should be connected to vin+ and vin-. a maximum of 12a load should be connected to vout+ and vout-. the input and output connections of the board are listed in table i. ir3894 has only one input supply and internal ldo generates vcc from vin. if operation with external vcc is required, then r15 can be removed and external vcc can be applied between vcc+ and vcc- pins. vin pin and vcc/ldoout pins should be shorted together for external vcc operation (use zero ohm resistor for r29). the output can track voltage at the vp pin. for this purpose, vref pin is to be connected to ground (use zero ohm resistor for r21). the value of r14 and r28 can be selected to provide the desired tracking ratio between output voltage and the tracking input. layout the pcb is a 4-layer board (2.23?x2?) using fr4 material. all layers use 2 oz. copper. the pcb thickness is 0.062?. the ir3894 and other major power components are mounted on the top side of the board. power supply decoupling capacitors, the bootstrap capacitor and feedback components are located close to ir3894. the feedback resistors are connected to the output at the point of regulation and are located close to the supirbuck ic. to improve efficiency, the circuit board is designed to minimize the length of the on-board power ground current path.
IRDC3894-P1V2 12/22/2011 3 vin gnd gnd vout enable vddq vref sync s_ctrl agnd pgood vsns vcc+ vcc- fig. 1: connection diagram of ir3895/94 evaluation boards top view bottom view
IRDC3894-P1V2 12/22/2011 4 fig. 2: board layout-top layer fig. 3: board layout-bottom layer single point connection between analog gnd and pgnd
IRDC3894-P1V2 12/22/2011 5 fig. 4: board layout-mid layer 1 fig. 5: board layout-mid layer 2
IRDC3894-P1V2 12/22/2011 6 fig. 6: schematic of the ir3894 evaluation board
IRDC3894-P1V2 12/22/2011 7 bill of materials item qty part reference value description manufacturer part number 1 1 c1 330uf smd electrolytic f size 25v 20% panasonic eev-fk1e331p 2 4 c2 c3 c4 c5 10uf 1206, 25v, x5r, 20% tdk c3216x5r1e106m 3 3 c7 c14 c24 0.1uf 0603, 25v, x7r, 10% murata grm188r71e104ka01b 4 1 c12 1nf 0603, 25v, cog, 5% murata grm1885c1e102ja01d 4 1 c8 2200pf 0603,50v,x7r,10% m urata grm188r71h222ka01b 5 1 c11 220pf 0603, 50v, cog, 5% mura ta grm1885c1h 2201ja01d 68 c15 c16 c17 c18 c19 c20 c33 c34 22uf 0805, 6.3v, x5r, 20% tdk c2012x5r0j226m 7 1 c23 2.2uf 0603, 16v, x5r, 20% tdk c1608x5r1c475m 8 1 c26 10nf 0603, 25v, x7r, 10% murata grm188r71e103ka01j 9 1 c32 1.0uf 0603, 25v, x5r, 10% murata grm188r61e105ka12d 10 1 l1 0.51uh smd 11.0x7.2x7.5mm,0.29m ? vitec 59pr9876n 11 1 r1 1.82k thick film, 0603,1/10w,1% panasonic erj-3ekf1821v 12 2 r2 r11 4.02k thick film, 0603,1/10w,1% panasonic erj-3ekf4021v 13 2 r3 r12 2.87k thick film, 0603,1/10w,1% panasonic erj-3ekf2871v 14 1 r4 100 thick film, 0603,1/10w,1% panasonic erj-3ekf1000v 15 1 r6 20 thick film, 0603,1/10w,1% panasonic erj-3ekf20r0v 16 1 r9 39.2k thick film, 0603,1/10w,1% panasonic erj-3ekf3922v 17 5 r10 r13 r14 r15 r50 0 thick film, 0603,1/10w panasonic erj-3gey0r00v 18 2 r17 r18 49.9k thick film, 0603,1/10w,1% panasonic erj-3ekf4992v 19 1 r19 7.5k thick film, 0603,1/10w,1% panasonic erj-3ekf7551v 20 1 u1 ir3894 pqfn 5x6mm ir ir3894mpbf
IRDC3894-P1V2 12/22/2011 8 typical operating waveforms vin=12.0v, vo=1.2v, io=0-12a, room temperature, no airflow fig. 10: output voltage ripple, 12a load ch 1 : v out , fig. 11: inductor node at 12a load ch 1 :switch node fig. 12: short circuit (hiccup) recovery ch 1 :v out , ch4:iout fig. 7: start up at 12a load ch 1 :v out , ch 2 :v in , ch 3 :pgood, ch 4 :enable fig. 9: start up with pre bias , 0a load, ch 1 :v o fig. 8: start up at 12a load ch 1 :v out , ch 2 :v in , ch 3 :pgood, ch 4 :vcc
IRDC3894-P1V2 12/22/2011 9 typical operating waveforms vin=12.0v, vo=1.2v, io=0-12a, room temperature, no air flow fig. 13: transient response, 6a to 12a step @2.5a/usec slew rate ch 1 :v out ch4-iout
IRDC3894-P1V2 12/22/2011 10 typical operating waveforms vin=12.0v, vo=1.2v, io=0-12a, room temperature fig. 14: bode plot at 12a load shows a bandwidth of 99.9khz and phase margin of 55.2o
IRDC3894-P1V2 12/22/2011 11 typical operating waveforms vin=12.0v, vo=1.2v, io=0-12a, room temperature, no air flow fig (16) feed forward for vin change from 6.8 to 16v and back to 6.8v ch 1 -vout ch 4 -vin fig (15) soft start and so ft stop using s_ctrl pin
IRDC3894-P1V2 12/22/2011 12 fig.18: power loss versus load current fig.17: efficiency versus load current typical operating waveforms vin=12.0v, vo=1.2v, io=0-12a, room temperature, no air flow
IRDC3894-P1V2 12/22/2011 13 thermal images vin=12.0v, vo=1.2v, io=0-12a, room temperature, no air flow fig. 19: thermal image of the board at 12a load test point 1 is ir3894 test point 2 is inductor
IRDC3894-P1V2 12/22/2011 14 ir world headquarters: 233 kansas st., el segundo, california 90245, usa tel: (310) 252-7105 tac fax: (310) 252-7903 this product has been designed a nd qualified for the industrial market visit us at www.irf.com for sales contact information data and specifications subject to change without notice. 12/11 package ? information dim milimiters inches dim milimiters inches min max min max min max min max a 0.800 1.000 0.0315 0.0394 l 0.350 0.450 0.0138 0.0177 a1 0.000 0.050 0.0000 0.0020 m 2.441 2.541 0.0961 0.1000 b 0.375 0.475 0.1477 0.1871 n 0.703 0.803 0.0277 0.0316 b1 0.250 0.350 0.0098 0.1379 o 2.079 2.179 0.0819 0.0858 c 0.203 ref. 0.008 ref. p 3.242 3.342 0.1276 0.1316 d 5.000 basic 1.969 basic q 1.265 1.365 0.0498 0.0537 e 6.000 basic 2.362 basic r 2.644 2.744 0.1041 0.1080 e 1.033 basic 0.0407 basic s 1.500 1.600 0.0591 0.0630 e1 0.650 basic 0.0256 basic t1, t2, t3 0.401 basic 0.016 bacis e2 0.852 basic 0.0335 basic t4 1.153 basic 0.045 basic t5 0.727 basic 0.0286 basic figure 20: package dimensions

▲Up To Search▲

Price & Availability of IRDC3894-P1V2

	To Download IRDC3894-P1V2 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .