µ LTC1735-1 C OSC 47pF C C2 330pF 47pF PGOOD 1 C OSC TG C SS 0.1µF 2 RUN/SS BOOST R C1 33k 3 I TH LTC1735-1 SW C C1 47pF 4 5 PGOOD SENSE V IN 1000pF 6 7 8 SENSE V OSENSE SGND BG PGND EXTV CC 10Ω 10Ω 16 15 14 13 12 11 10 9 4.7µF 5V (OPTIONAL) C B 0.22µF D1 CMDSH-3 V IN 4.5V TO 24V M1 FDS6680A L1 1.2µH D2 MBRS340T3 M2, M3 FDS6680A 2 C IN 22µF 50V CERAMIC 2 R SENSE 0.004Ω 47pF 47pF R2 15.8k 0.5% R1 10k 0.5% R3 31.6k 1% M4 2N7002 V OUT 1.3V TO 1.55V 12A C OUT 180µF 4V PANASONIC SP 4 V SEL = 1: V OUT = 1.55V V SEL = 0: V OUT = 1.3V GND 1735-1 F01 1
µ C OSC 1 RUN/SS 2 I TH 3 PGOOD 4 SENSE 5 SENSE 6 V OSENSE 7 SGND 8 GN PACKAGE 16-LEAD PLASTIC SSOP TOP VIEW 16 TG 15 BOOST 14 SW 13 V IN 12 11 BG 10 PGND 9 EXTV CC S PACKAGE 16-LEAD PLASTIC SO T JMAX = 125 C, θ JA = 140 C/W (GN) T JMAX = 125 C, θ JA = 110 C/W (S) ORDER PART NUMBER LTC1735CGN-1 LTC1735CS-1 LTC1735IGN-1 LTC1735IS-1 SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Main Control Loop I VOSENSE Feedback Current (Note 3) 4 25 na V OSENSE Feedback Voltage (Note 3) 0.792 0.8 0.808 V V LINEREG Reference Voltage Line Regulation V IN = 3.6V to 30V (Note 3) 0.001 0.02 %/V V LOADREG Output Voltage Load Regulation (Note 3) Measured in Servo Loop; V ITH = 0.7V 0.1 0.3 % Measured in Servo Loop; V ITH = 2V 0.1 0.3 % V OVL Feedback Overvoltage Lockout 0.84 0.86 0.88 V I Q Input DC Supply Current (Note 5) Normal Mode 3.6V < V IN < 30V 450 µa Shutdown V RUN/SS = 0V 15 25 µa V RUN/SS Run Pin Start Threshold V RUN/SS, Ramping Positive 1.0 1.3 1.9 V Run Pin Begin Latchoff Threshold V RUN/SS, Ramping Negative 4 4.5 V I RUN/SS Soft-Start Charge Current V RUN/SS = 0V 0.7 2 µa I SCL RUN/SS Discharge Current Soft Short Condition, V OSENSE = 0.5V, 0.5 2 4 µa V RUN/SS = 4.5V UVLO Undervoltage Lockout Measured at V IN Pin (Ramping Negative) 3.5 3.9 V V SENSE(MAX) Maximum Current Sense Threshold V OSENSE = 0.7V 65 75 85 mv I SENSE SENSE Pins Total Source Current V SENSE = V SENSE = 0.8V 60 80 µa t ON(MIN) Minimum On-Time Tested with a Square Wave, V ITH = 1.75V (Note 4) 180 ns 2
LTC1735-1 SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS TG Transition Time: TG t r Rise Time C LOAD = 3300pF 50 90 ns TG t f Fall Time C LOAD = 3300pF 50 90 ns BG Transition Time: BG t r Rise Time C LOAD = 3300pF 50 90 ns BG t f Fall Time C LOAD = 3300pF 40 80 ns Internal V CC Regulator V INTVCC Internal V CC Voltage 6V < V IN < 30V, V EXTVCC = 4V 5.0 5.2 5.4 V V LDO(INT) Load Regulation I CC = 0mA to 20mA, V EXTVCC = 4V 0.2 1 % V LDO(EXT) EXTV CC Drop Voltage I CC = 20mA, V EXTVCC = 5V 130 200 mv V EXTVCC EXTV CC Switchover Voltage I CC = 20mA, EXTV CC Ramping Positive 4.5 4.7 V Oscillator f OSC Oscillator Frequency (Note 6), C OSC = 43pF 265 300 335 khz f H /f OSC Maximum Sync Frequency Ratio 1.3 PGOOD Pin V PG(SYNC) PGOOD Threshold for Sync Ramping Negative 1.2 V V PG(FC) PGOOD Threshold for Force Cont. 0.76 0.8 0.84 V V PGL PGOOD Voltage Low I PGOOD = 2mA 0.4 V I PGOOD PGOOD Pull-Up Current V PGOOD = 0.85V 0.25 µa V PG PGOOD Trip Level V OSENSE Respect to Set Output Voltage V OSENSE Ramping Positive 7.5 % V OSENSE Ramping Negative 7.5 % 8 1 8. 477( 10 ) fosc( khz) = COSC( pf) 1 I 1 11 CHG IDIS 3
µ µ 4
R1 100k V OSENSE 6V 0.86V 0.8V 2µA RUN/SS V FB 0V g m =1.4m EA SD RUN SOFT- START OVER- CURRENT LATCHOFF R C 0.86V 0.55V 2.4V SD 2k 45k 45k ICMP IREV I 1 I2 BURST DISABLE FC 4(V FB ) A BUFFERED I TH I TH 0.74V R2 C OSC PGOOD 4 C OSC 1 SGND 8 7 2 Ω 3 OSC SYNC SLOPE COMP C S R 1.2V Q 0.25µA FORCE BOT DROP OUT DET TOP ON 30k 3mV 0.8V BOT 30k SENSE 6 5 SENSE F B FC 4.8V 13 V IN 0.8V REF SWITCH LOGIC UVL TOP BOT BOOST SW V IN 12 C 5.2V INTVCC LDO REG EXTV CC 15 TG 16 14 9 D B C B BG PGND V IN C IN D 1 L R SENSE V OUT 11 10 C OUT C SS C C 1735-1 FD 5
µ µ 6
R SENSE mv = 50 I MAX 7
. ( ) COSC( pf) = 7 16110 11 Frequency µ µ COSC VALUE (pf) 100.0 87.5 75.0 62.5 50.0 37.5 25.0 12.5 0 0 100 200 300 400 500 600 OPERATING FREQUENCY (khz) 1735-1 F02 1 IL f L V OUT = OUT 1 ()( ) VV IN 8
µ µ VOUT VIN V V IN OUT VIN PMAIN PSYNC VOUT 2 IMAX ( 1 δ) RDS( ON) VIN 2 kv ( IN) ( IMAX)( CRSS)( f) VIN VOUT 2 IMAX ( 1 δ) RDS( ON) VIN = ( ) = ( ) µ 9
12 / V V IRMS I OUT IN O( MAX) 1 VIN VOUT 1 VOUT IL ESR 4fCOUT 10
µ µ 11
R VOUT = V 2 08. 1 R1 LTC1735-1 V OSENSE SGND 1735-1 F03 47pF V OUT R2 R1 µ µ 08. V R1( Max) = 24k 24. V V OUT 12
µ µ 13. V TDELAY = A C SS = ms µ F C SS µ ( 650 / ) 2 µ 3.3V OR 5V RUN/SS RUN/SS D1 C SS V IN 3.3V OR 5V RUN/SS R SS D1 (a) C SS R SS D1 (b) C SS 1735-1 F04 RUN/SS C SS 1735-1 F05 µ µ 13
µ 30mV 1 ISC = ILSC RSENSE 2 ( ) t ON( MIN) V < V OUT IN () f 14
PGOOD PIN 4 470k 100k Q1 10k Q2 POWER GOOD 1735-1 F06 15
µ µ 16
µ µ 12V 50A I PK RATING TRANSIENT VOLTAGE SUPPRESSOR GENERAL INSTRUMENT 1.5KA24A V IN LTC1735-1 1735 F07 µ V I OUT VOUT L = 1 ()() f L VIN V V IL = 15. 1 15. = 39. A 300kHz(. 1 2µ H) 22V 17
V t OUT V ON( MIN) = ns VIN MAX f = 15. ( ) 22V( 300kHz) = 227 15. V 2 PMAIN = ( 12) [ 1 (. 0 005)( 50 C 25 C) ]( 0. 03Ω) 22V 2 1. 7( 22V) ( 12A)( 80pF)( 300kHz) = 568mW V V PSYNC = 22 1. 5 ( A ) 2 12 ( 1. 1 )( 0. 0065 V Ω) 22 = 959mW µ 18
C SS C C2 R C C OSC 1 2 C C 3 4 5 1000pF 6 7 47pF 8 C OSC RUN/SS I TH LTC1735-1 SW PGOOD SENSE SENSE V OSENSE SGND TG BOOST V IN BG PGND EXTV CC 16 15 14 13 12 11 10 9 DB 4.7µF C B M1 D1 M2 C IN V IN L1 R1 R2 C OUT R SENSE V OUT 1735-1 F08 0.007 0.0098 (0.178 0.249) 0.015 ± 0.004 (0.38 ± 0.10) 45 0 8 TYP 0.053 0.068 (1.351 1.727) 0.004 0.0098 (0.102 0.249) 0.189 0.196* (4.801 4.978) 16 15 14 13 12 11 10 9 0.016 0.050 (0.406 1.270) * DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 0.008 0.012 (0.203 0.305) 0.025 (0.635) BSC 0.229 0.244 (5.817 6.198) 1 2 3 4 5 6 7 8 0.150 0.157** (3.810 3.988) GN16 (SSOP) 1197 0.008 0.010 (0.203 0.254) 0.010 0.020 (0.254 0.508) 45 0 8 TYP 0.053 0.069 (1.346 1.752) 0.004 0.010 (0.101 0.254) 16 15 14 13 0.386 0.394* (9.804 10.008) 12 11 10 9 0.016 0.050 0.406 1.270 0.014 0.019 (0.355 0.483) * DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 0.050 (1.270) TYP 0.228 0.244 (5.791 6.197) 1 2 3 4 5 6 7 8 0.150 0.157** (3.810 3.988) S16 0695 19
C OSC 47pF C C2 330pF C1 47pF C SS 0.1µF R C1 33k C C1 47pF C S1 1000pF R7 100k PGOOD RUN JP1 LATCH-OFF R6 DISABLE 680k 1 2 C OSC RUN/SS TG BOOST 3 I TH LTC1735-1 SW 4 5 6 7 8 PGOOD SENSE SENSE V OSENSE SGND V IN BG PGND EXTV CC R5 10Ω R4 10Ω C F1 0.1µF 16 15 14 13 12 11 10 9 C2 4.7µF 5V INPUT (OPTIONAL) R8 4.7Ω C B 0.22µF D1 CMDSH-3 C4 1µF V IN 4.5V TO 24V M1 FDS6680A L1 1.2µH D2 MBRS340T3 M2, M3 FDS6680A 2 C IN 22µF 50V CERAMIC 2 R SENSE 0.004Ω C2 47pF C3 47pF R2 15.8k 0.5% R1 10k 0.5% R3 31.6k 1% M4 2N7002 V OUT 1.3V TO 1.55V 12A C OUT 180µF 4V SP 4 V SEL = 1: V OUT = 1.55V V SEL = 0: V OUT = 1.3V GND 1735-1 TA01 20 17351i 0799 0.5K PRINTED IN JAPAN LINEAR TECHNOLOGY CORPORATION 1999