µ LTC1438/LTC1439 TYPICAL APPLICATION V OUT1 5V 3.5A L1 1µH M1 D1 MBR14T3 R SENSE1.3Ω C OUT1 22µF 1V M3* M2 C B1 C C1 C C1A 22pF U D B1, CMDSH-3 R C1 1k BOOST 1 TGL1 TGS1 SW1 BG1 SENSE 1 SENSE 1 I TH1 RUN/SS1 C SS1 V PROG1 C DSC C OSC 56pF LTC1439 V PROG2 SGND M1, M2, M4, M5: Si4412DY M3, M6: IRLML283 *NOT REQUIRED FOR LTC1438 INTV CC D B2, CMDSH-3 BOOST 2 TGL2 TGS2 SW2 BG2 SENSE 2 SENSE 2 V OSENSE2 I TH2 PGND RUN/SS2 C SS2 4.7µF 16V C B2, C C2 R C2 1k C C2A 47pF Figure 1. High Efficiency Dual 5V/3V Step-Down Converter M5 M6* BOLD LINES INDICATE HIGH CURRENT PATHS M4 L2 1µH D2 MBR14T3 1438 F1 C IN 22µF 35V 4 R SENSE2.3Ω V OUT2 3.3V 3.5A C OUT 22µF 1V 5.2V TO 28V 4-259
ABSOLUTE MAXIMUM RATINGS W W W Input Supply Voltage ( )... 36V to.3v Topside Driver Voltage (BOOST 1, 2)... 42V to.3v Switch Voltage (SW1, 2)... 5V to 5V EXTV CC Voltage... 1V to.3v POR2, LBO Voltages... 12V to.3v AUXFB Voltage... 2V to.3v AUXDR Voltage... 28V to.3v SENSE 1, SENSE 2, SENSE 1, SENSE 2, V OSENSE2 Voltages... INTV CC.3V to.3v V PROG1, V PROG2 Voltages... INTV CC to.3v PLL LPF, I TH1, I TH2 Voltages... 2.7V to.3v U AUXON, PLLIN, SFB1, RUN/SS1, RUN/SS2, LBI Voltages... 1V to.3v Peak Output Current < 1µs (TGL1, 2, BG1, 2)... 2A Peak Output Current < 1µs (TGS1, 2)... 25mA INTV CC Output Current... 5mA Operating Ambient Temperature Range LTC1438C/LTC1439C... C to 7 C LTC1438I/LTC1439I... 4 C to 85 C Junction Temperature (Note 1)... 125 C Storage Temperature Range... 65 C to 15 C Lead Temperature (Soldering, 1 sec)... 3 C PACKAGE/ORDER INFORMATION U W U SENSE 1 SENSE 1 V PROG1 I TH1 *POR2 C OSC SGND LBI LBO SFB1 I TH2 V OSENSE2 SENSE 2 SENSE 2 1 2 3 4 5 6 7 8 9 1 11 12 13 14 TOP VIEW 28 27 26 25 24 23 22 21 2 19 18 17 16 15 RUN/SS1 BOOST 1 TGL1 SW1 BG1 INTV CC PGND BG2 EXTV CC SW2 TGL2 BOOST 2 RUN/SS2 ORDER PART NUMBER LTC1438CG LTC1438IG LTC1438XCG RUN/SS1 SENSE 1 SENSE 1 V PROG1 I TH1 POR2 C OSC SGND LBI LBO SFB1 I TH2 V PROG2 V OSENSE2 SENSE 2 SENSE 2 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 TOP VIEW 36 35 34 33 32 31 3 29 28 27 26 25 24 23 22 21 PLL LPF PLLIN BOOST 1 TGL1 SW1 TGS1 BG1 INTV CC PGND BG2 EXTV CC TGS2 SW2 TGL2 BOOST 2 ORDER PART NUMBER LTC1439CGW LTC1439IGW G PACKAGE 28-LEAD PLASTIC SSOP *NC ON THE LTC1438XCG T JMAX = 125 C, θ JA = 95 C/ W RUN/SS2 17 AUXDR 18 GW PACKAGE 36-LEAD PLASTIC SSOP 2 AUXON 19 AUXFB T JMAX = 125 C, θ JA = 85 C/ W Consult factory for Military grade parts. 4-26
ELECTRICAL CHARACTERISTICS T A = 25 C, = 15V, V RUN/SS1,2 = 5V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Main Control Loops I IN V OSENSE2 Feedback Current V PROG1, V PROG2 Pins Open (Note 2) 1 5 na V OUT1,2 Regulated Output Voltage (Note 2) 1.19V (Adjustable) Selected V PROG1, V PROG2 Pins Open 1.178 1.19 1.22 V 3.3V Selected V PROG1, V PROG2 = V 3.22 3.3 3.38 V 5V Selected V PROG1, V PROG2 = INT V CC 4.9 5. 5.1 V V LINEREG1,2 Reference Voltage Line Regulation = 3.6V to 2V (Note 2), V PROG1,2 Pins Open.2.1 %/V V LOADREG1,2 Output Voltage Load Regulation I TH1,2 Sinking 5µA (Note 2).5.8 % I TH1,2 Sourcing 5µA.5.8 % V SFB1 Secondary Feedback Threshold V SFB1 Ramping Negative 1.16 1.19 1.22 V I SFB1 Secondary Feedback Current V SFB1 = 1.5V 1 2 µa V OVL Output Overvoltage Lockout V PROG1,2 Pin Open, SENSE 1 and V OSENSE2 Pins 1.24 1.28 1.32 V I PROG1,2 V PROG1,2 Input Current.5V > V PROG1,2 3 6 µa INTV CC.5V < V PROG1,2 < INTV CC 3 6 µa I Q Input DC Supply Current EXTV CC = 5V (Note 3) Normal Mode 3.6V < < 3V, V AUXON = V 32 µa Shutdown V RUN/SS1,2 = V, 3.6V < < 15V 16 3 µa V RUN/SS1,2 Run Pin Threshold.8 1.3 2 V I RUN/SS1,2 Soft Start Current Source V RUN/SS1,2 = V 1.5 3 4.5 µa V SENSE(MAX) Maximum Current Sense Threshold V OSENSE1,2 = V, 5V V PROG1,2 = Pins Open 13 15 18 mv TGL1, 2 t r, t f TGL1, TGL2 Transition Time Rise Time C LOAD = 3pF 5 15 ns Fall Time C LOAD = 3pF 5 15 ns TGS1, 2 t r, t f TGS1, TGS2 Transition Time Rise Time C LOAD = 5pF 1 15 ns Fall Time C LOAD = 5pF 5 15 ns BG1, 2 t r, t f BG1, BG2 Transition Time Rise Time C LOAD = 3pF 5 15 ns Fall Time C LOAD = 3pF 5 15 ns Internal V CC Regulator TVCC Internal V CC Voltage 6V < < 3V, V EXTVCC = 4V 4.8 5. 5.2 V V LDO INT INTV CC Load Regulation I INTVCC = 2mA, V EXTVCC = 4V.2 1 % V LDO EXT EXTV CC Voltage Drop I INTVCC = 2mA, V EXTVCC = 5V 17 3 mv V EXTVCC EXTV CC Switchover Voltage I INTVCC = 2mA, EXTV CC Ramping Positive 4.5 4.7 V Oscillator and Phase-Locked Loop f OSC Oscillator Frequency C OSC = 1pF, LTC1439: PLL LPF = V (Note 4) 112 125 138 khz VCO High LTC1439, V PLLLPF = 2.4V 2 24 khz R PLLIN PLLIN Input Resistance 5 kω I PLLLPF Phase Detector Output Current LTC1439 Sinking Capability f PLLIN < f OSC 1 15 2 µa Sourcing Capability f PLLIN > f OSC 1 15 2 µa Power-On Reset V SATPOR2 POR2 Saturation Voltage I POR2 = 1.6mA, V OSENSE2 = 1V,.6 1 V V PROG2 Pin Open I LPOR2 POR2 Leakage V POR2 = 12V, V OSENSE2 = 1.2V, V PROG2 Pin Open.2 1 µa V THPOR2 POR2 Trip Voltage V PROG2 Pin Open % of V REF V OSENSE2 Ramping Negative 11 7.5 4 % t DPOR2 POR2 Delay V PROG2 Pin Open 65536 Cycles 4-261
ELECTRICAL CHARACTERISTICS T A = 25 C, = 15V, V RUN/SS1,2 = 5V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Low-Battery Comparator V SATLBO LBO Saturation Voltage I LBO = 1.6mA, V LBI = 1.1V.6 1 V I LLBO LBO Leakage V LBO = 12V, V LBI = 1.4V.1 1 µa V THLB1 LBI Trip Voltage High to Low Transition on LBO 1.16 1.19 1.22 V I INLB1 LBI Input Current V LBI = 1.19V 1 5 na V HYSLBO LBO Hysteresis 2 mv Auxiliary Regulator/Comparator I AUXDR AUXDR Current V EXTVCC = V Max Current Sinking Capability V AUXDR = 4V, V AUXFB = 1.V, V AUXON = 5V 1 15 ma Control Current V AUXDR = 5V, V AUXFB = 1.5V, V AUXON = 5V 1 5 µa Leakage when OFF V AUXDR = 24V, V AUXFB = 1.5V, V AUXON = V.1 1 µa I INAUXFB AUXFB Input Current V AUXFB = 1.19V, V AUXON = 5V.1 1 µa I INAUXON AUXON Input Current V AUXON = 5V.1 1 µa V THAUXON AUXON Trip Voltage V AUXDR = 4V, V AUXFB = 1V 1. 1.19 1.4 V V SATAUXDR AUXDR Saturation Voltage I AUXDR = 1.6mA, V AUXFB = 1V, V AUXON = 5V.4.8 V V AUXFB AUXFB Voltage V AUXON = 5V, 11V < V AUXDR < 24V (Note 5) 11.5 12. 12.5 V V AUXON = 5V, 3V < V AUXDR < 7V 1.14 1.19 1.24 V V THAUXDR AUXFB Divider Disconnect Voltage V AUXON = 5V (Note 5); Ramping Negative 7.5 8.5 9.5 V The denotes specifications which apply over the full operating temperature range. Note 1: T J is calculated from the ambient temperature T A and power dissipation P D according to the following formulas: LTC1438CG: T J = T A (P D )(95 C/W) LTC1439CGW: T J = T A (P D )(85 C/W) Note 2: The LTC1438 and LTC1439 are tested in a feedback loop which servos V OSENSE1,2 to the balance point for the error amplifier (V ITH1,2 = 1.19V). Note 3: Dynamic supply current is higher due to the gate charge being delivered at the switching frequency. See Applications Information. Note 4: Oscillator frequency is tested by measuring the C OSC charge and discharge current (I OSC ) and applying the formula: f OSC (khz) = 8.4(1 8 )[C OSC (pf) 11] 1 (1/I CHG 1/I DISC ) 1 Note 5: The auxiliary regulator is tested in a feedback loop which servos V AUXFB to the balance point for the error amplifier. For applications with V AUXDR > 9.5V, V AUXFB uses an internal resistive divider. See Applications Information section. 4-262
TYPICAL PERFORMANCE CHARACTERISTICS U W EFFICIENCY (%) 1 95 9 85 8 75 Efficiency vs Input Voltage V OUT = 3.3V V OUT = 3.3V I LOAD = 1A I LOAD = 1mA EFFICIENCY (%) 1 95 9 85 8 75 Efficiency vs Input Voltage V OUT = 5V I LOAD = 1mA I LOAD = 1A V OUT = 5V EFFICIENCY (%) 1 95 9 85 8 75 7 65 6 55 Efficiency vs Load Current = 1V V OUT = 5V R SENSE =.33Ω CONTINUOUS MODE Burst Mode OPERATION Adaptive Power MODE 7 5 1 15 2 INPUT VOLTAGE (V) 25 3 7 5 1 15 2 INPUT VOLTAGE (V) 25 3 5.1.1.1 1 LOAD CURRENT (A) 1 1438 G1 1438 G2 1435 G3.5.4 V OUT Dropout Voltage vs Load Current R SENSE =.33Ω V OUT DROP OF 5%.25 Load Regulation R SENSE =.33Ω 3. 2.5 V ITH Pin Voltage vs Output Current VIN VOUT (V).3.2 VOUT (%).5.75 1. V ITH (V) 2. 1.5 1. Burst Mode OPERATION CONTINUOUS/Adaptive Power MODE.1 1.25.5.5 1. 1.5 2. LOAD CURRENT (A) 2.5 3. 1.5.5 1. 1.5 2. LOAD CURRENT (A) 2.5 3. 1 2 3 4 5 6 7 8 9 OUTPUT CURRENT (%) 1 1438 G4 1438 G5 1438 G6 SUPPLY CURRENT (ma) 2.5 2. 1.5 1..5 Input Supply Current vs Input Voltage 5V ON 3.3V OFF 5V AND 3.3V ON SHUTDOWN CURRENT 5 1 15 2 INPUT VOLTAGE (V) 5V OFF 3.3V ON 35 3 25 2 15 1 5 25 3 SHUTDOWN CURRENT (µa) INTV CC % CHANGE, NORMALIZED (V) 2 1 1 2 INTV CC Regulation vs INTV CC Load Current EXTV CC = V 7 C 25 C 1 2 3 4 INTV CC LOAD CURRENT (ma) 5 EXTV CC INTV CC (mv) 3 2 1 EXTV CC Switch Drop vs INTV CC Load Current 7 C 25 C 45 C 5 1 15 2 25 3 INTV CC LOAD CURRENT (ma) 1438 G7 1438 G8 1438 G9 Burst Mode is a trademark of Linear Technology Corporation. 4-263
TYPICAL PERFORMANCE CHARACTERISTICS U W 1 Normalized Oscillator Frequency vs Temperature 4 RUN/SS Pin Current vs Temperature SFB1 Pin Current vs Temperature FREQUENCY (%) 5 f O 5 RUN/SS CURRENT (µa) 3 2 1 SFB CURRENT (µa).25 1.5.75 1. 1.25 1 4 15 1 35 6 85 11 135 TEMPERATURE ( C) 4 15 1 35 6 85 11 135 TEMPERATURE ( C) 1.5 4 15 1 35 6 85 11 135 TEMPERATURE ( C) 1438 G1 1438 G11 1438 G12 154 Maximum Current Sense Threshold Voltage vs Temperature Transient Response Transient Response CURRENT SENSE THRESHOLD (mv) 152 15 148 V OUT 5mV/DIV V OUT 5mV/DIV I LOAD = 5mA to 1A 1438 G14 I LOAD = 1A to 3A 1438 G15 146 4 15 1 35 6 85 11 135 TEMPERATURE ( C) 1438 G13 Burst Mode Operation Soft Start: Load Current vs Time Auxiliary Regulator Load Regulation 12.2 EXTERNAL PNP: 2N297A V OUT 2mV/DIV V ITH 2mV/DIV I LOAD = 5mA 1438 G16 RUN/SS 5V/DIV INDUCTOR CURRENT 1A/DIV 1438 G17 AUXILIARY OUTPUT VOLTAGE (V) 12.1 12. 11.9 11.8 11.7 4 8 12 16 2 AUXILIARY LOAD CURRENT (ma) 1438 G18 4-264
TYPICAL PERFORMANCE CHARACTERISTICS U W 2 Auxiliary Regulator Sink Current Available 7 Auxiliary Regulator PSRR AUX DR CURRENT (ma) 15 1 5 PSRR (db) 6 5 4 3 2 1mA LOAD 1mA LOAD 2 4 6 8 1 12 14 16 AUX DR VOLTAGE (V) 1 1 1 1 FREQUENCY (khz) 1438 G19 1438 G2 µ Table 1. Output Voltage Table CONTROLLER 1 LTC1438/LTC1438X LTC1439 5V or 3.3V Only, Secondary Feedback Loop CONTROLLER 2 Adjustable Only 5V/3.3V/Adjustable Remote Sensing Remote Sensing POR2 Output POR2 Output 4-265
µ 4-266
W FUNCTIONAL DIAGRA U U f IN PLLIN** 5k PHASE DETECTOR 2.4V DUPLICATE FOR SECOND CONTROLLER CHANNEL BOOST INTV CC D B R LP PLL LPF** C LP C OSC C OSC POR2 OSCILLATOR S Q R Q DROPOUT DETECTOR SFB BATTERY SENSE LBI LBO POWER-ON RESET V FB2 1.11V.6V I1 SHUTDOWN SWITCH LOGIC V SEC AUXON** 9V V LDO AUXDR** AUXFB** 9.8k 1k V FB SFB1* 1µA SFB 1.19V REF V REF EXTV CC INTV CC 4.8V 5V LDO REGULATOR 6V 3µA RUN SOFT START SGND INTERNAL SUPPLY TGL TGS** C B INTV CC SW BG PGND C IN I2 INTV CC C OUT R SENSE 3k 8k SENSE 18k 4k 32k SENSE V OSENSE * V OUT g m = 1m Ω V EA 61k 119k V PROG * D FB C SEC 1.28V 1.19V SHUTDOWN I TH RUN/SS C C R C C SS *NOT AVAILABLE ON BOTH CHANNELS **NOT AVAILABLE ON LTC1438 FOLDBACK CURRENT LIMITING OPTION BOLD LINES INDICATE HIGH CURRENT PATHS 1438 FD 4-267
µ 4-268
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C OSC VALUE (pf) 3 25 2 15 1 5 V PLLLPF = V mv RSENSE = 1 IMAX 1 2 3 4 5 OPERATING FREQUENCY (khz) LTC1435 F2 Figure 2. Timing Capacitor Value 4 COSC ( pf ) 1371. ( ) = 11 Frequency (khz) 1 IL f L V OUT = OUT 1 ()() V 4-27
µ INDUCTOR VALUE (µh) 6 5 4 3 2 1 V OUT = 5.V V OUT = 3.3V V OUT = 2.5V 5 1 15 2 25 3 OPERATING FREQUENCY (khz) 1438 F3 Figure 3. Recommended Inductor Values µ µ 4-271
= V OUT VIN V OUT VIN PMAIN PSYNC VOUT 2 = ( IMAX) 1 δ RDS( ON) VIN 1.85 kv ( IN) ( IMAX)( CRSS)( f) VIN VOUT 2 IMAX 1 VIN ( ) = ( ) ( ) δ RDS( ON) = ( ) 12 / ( ) [ VOUT VIN VOUT ] IMAX VIN 4-272
1 VOUT IL ESR 4fCOUT µ 4-273
LTC1438 LTC1439* TGL1 EXTV CC TGS1* R6 SW1 SFB1 R5 BG1 SGND PGND OPTIONAL EXTV CC CONNECTION 5V V SEC 9V C IN N-CH Figure 4a. Secondary Output Loop and EXTV CC Connection LTC1438 LTC1439* TGL1 TGS1* EXTV CC SW1 BG1 PGND C IN N-CH N-CH L1 1:1 1N4148 V SEC R SENSE *TGS1 ONLY AVAILABLE ON THE LTC1439 N-CH N-CH N-CH *TGS1 ONLY AVAILABLE ON THE LTC1439 BAT85 L1.22µF VN2222LL R SENSE Figure 4b. Capacitive Charge Pump for EXTV CC 1438 F4a 1µF BAT85 1µF BAT85 V OUT C OUT 1438 F4b V OUT C OUT V PROG1 SENSE 1 LTC1438 LTC1439 SGND GND: V OUT = 3.3V INTV CC : V OUT = 5V C OUT V OUT 1438 F5a Figure 5a. LTC1438/LTC1439 Fixed Output Applications 4-274
V PROG2 * V OSENSE2 LTC1438 LTC1439 SGND *LTC1439 ONLY OPEN (DC) 1.19V V OUT 9V 1pF R2 V OUT = 1.19V 1 R1 Figure 5b. LTC1438/LTC1439 Adjustable Applications ( ) 1438 F5b µ µ R2 R1 µ µ 3.3V OR 5V D1 RUN/SS1 (RUN/SS2) C SS Figure 6. RUN/SS Pin Interfacing RUN/SS1 (RUN/SS2) C SS 1438 F6 4-275
NORMALIZED FREQUENCY 1.3f O f O.7f O.5 1. 1.5 2. 2.5 V PLLLPF (V) 1438 F7 Figure 7. Operating Frequency vs V PLLLPF 4 COSC ( pf )= 2.1(1 ) 11 Frequency (khz) [ COSC( pf) 11] 8 841.( ) 1 A A V 2 PLLLPF 17µ 18µ 24. V EXTERNAL FREQUENCY PLLIN* SGND 5k PHASE DETECTOR DIGITAL PHASE/ FREQUENCY DETECTOR *LTC1439 ONLY 2.4V R LP PLL LPF* OSC C LP 1438 F8 Figure 8. Phase-Locked Loop Block Diagram C OSC C OSC 4-276
µ µ PLL LPF 2.4V MAX 18k 3.3V OR 5V LTC1435 F9 Figure 9. Directly Driving PLL LPF Pin R V LBITRIP = V 4 119. 1 R3 SGND R4 R3 LTC1438/LTC1439 LBI 1.19V REFERENCE LBO Figure 1. Low-Battery Comparator 1438 F1 VSEC N 1 VOUT 1. 19V 1 ( ) > R6 R5 4-277
R VOAUX V 8 119. 1 R 8V 7 AUXDR < 8.5V VOAUX = 12V AUXDR 12V µ µ ON/OFF INPUT SECONDARY WINDING 1:N V SEC AUXON AUXFB R6 R5 SFB1 AUXDR LTC1439 LTC1439 R6 V SEC = 1.19V 1 > 13V R5 AUXFB AUXON 1.19V REFERENCE ON/OFF AUXDR ( ) V PULL-UP < 7.5V OUTPUT 1438 F11c Figure 11c. Auxiliary Comparator Configuration V OAUX 12V 1µF 1438 F11a Figure 11a. 12V Output Auxiliary Regulator Using Internal Feedback Resistors SECONDARY WINDING 1:N V SEC R6 R5 SFB1 AUXDR AUXFB LTC1439 R6 V SEC = 1.19V 1 > V R5 OAUX AUXON ( ) ON/OFF 1438 F11b Figure 11b. 5V Output Auxiliary Regulator Using External Feedback Resistors R8 R7 V OAUX 1µF 4-278
µ 4-279
µ µ µ 12V 5A IPK RATING TRANSIENT VOLTAGE SUPPRESSOR GENERAL INSTRUMENT 1.5KA24A LTC1438 LTC1439 µ V I OUT VOUT L = 1 ()() f L VIN 33. V V IL = 1 33. A 25kHz 1µ H 22V = 112. ( ) P MAIN = ( ) [ ( ) ]( ) 33. V 2 3 1. 5 ( 5 C 25 C ). 42Ω 22V 185. 2. 5 22V 3A 1pF 25kHz 122mW ( ) ( )( )( )= 1438 F12 Figure 12. Automotive Application Protection 4-28
R LP 1k C LP.1µF R C1 1k R C2 1k C SS C C1B 22pF C C2B 47pF OUTPUT DIVIDER REQUIRED WITH V PROG OPEN 22pF C C1A C OSC C C2A 1Ω 1pF 1Ω 22pF INTV CC 1k INTV CC C SS 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 17 18 RUN/SS1 SENSE 1 SENSE 1 V PROG1 I TH1 POR2 TGS1 LTC1439 C OSC SGND LBI LBO SFB1 I TH2 V PROG2 V OSENSE2 SENSE 2 SENSE 2 RUN/SS2 AUXDR PLL LPF PLLIN BOOST 1 TGL1 SW1 BG1 INTV CC PGND BG2 EXTV CC TGS2 SW2 TGL2 BOOST 2 AUXON AUXFB 36 35 34 33 32 31 3 29 28 27 26 25 24 23 22 21 2 19 EXT CLOCK C B1 D B1 D B2 C B2 4.7µF M3 M6 M1 L1 M2 M5 L2 M4 C IN1 R SENSE1 D1 D2 C OUT1 GROUND PLANE C OUT2 R SENSE2 C IN2 V OUT1 V OUT2 1438 F13 NOT ALL PINS CONNECTED FOR CLARITY BOLD LINES INDICATE HIGH CURRENT PATHS Figure 13. LTC1439 Physical Layout Diagram 4-281
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µ TYPICAL APPLICATIONS U LTC1438 5V/3A, 3.3V/3.5A Regulator 1k 22pF 47pF 1k 56pF 221k, 1% 22pF 56pF 392k, 1% 1Ω 1Ω 1Ω 1N4148 INTV CC POR2 LBI LBO 1k 22pF 1N4148 1Ω 1 2 3 4 5 6 7 8 9 1 11 12 13 14 SENSE 1 RUN/SS1 SENSE 1 BOOST 1 V PROG1 TGL1 I TH1 SW1 POR2 C OSC BG1 LTC1438 SGND INTV CC LBI PGND LBO BG2 SFB1 EXTV CC I TH2 SW2 V OSENSE2 TGL2 SENSE 2 BOOST 2 SENSE 2 RUN/SS2 28 27 26 25 24 23 22 21 2 19 18 17 16 15 V OUT1 1Ω CMDSH-3 4.7µF 16V CMDSH-3 22µF 35V M1 M2 M4 M3 22µF 35V 1µH SUMIDA CDRH125-1MC MBRS14T3 MBRS14T3.33Ω 1µH SUMIDA CDRH125-1MC.33Ω 22µF 1V 22µF 35V 22µF 1V 22µF 35V 1438 TA1 5.2V TO 28V V OUT1 5V 3A GND V OUT2 3.3V 3.5A 5.2V TO 28V: SWITCHING FREQUENCY = 18kHz 5V, 3A/3.3V, 3.5A M1 TO M4: Si4412DY INPUT CAPACITORS ARE AVX-TPS SERIES OUTPUT CAPACITORS ARE AVX-TPSV LEVEL II SERIES 4-283
TYPICAL APPLICATIONS U LTC1439 High Efficiency Low Noise 5V/3A, 3.3V/3.5A and 12V/2mA Regulator 6V TO 28V R LP 1k R C1 1k C SS1 C C1A 22pF 11k, 1% C LP.1µF C C1 1pF 39k, 1% C C2A 47pF R C 1k C OSC 56pF POR2 LBO C C2 INTV CC 1k 1k C SS2 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 17 18 RUN/SS1 PLL LPF SENSE 1 PLLIN SENSE 1 BOOST 1 V PROG1 TGL1 I TH1 SW1 POR2 TGS1 LTC1439 C OSC SGND LBI LBO SFB1 I TH2 V PROG2 V OSENSE2 SENSE 2 SENSE 2 RUN/SS2 AUXDR BG1 INTV CC PGND BG2 EXTV CC TGS2 SW2 TGL2 BOOST 2 AUXON AUXFB 36 35 34 33 32 31 3 29 28 27 26 25 24 23 22 21 2 19 EXT CLOCK D2 CMDSH-3 D4 CMDSH-3 CIN1 22µF 35V 2 M3 4.7µF 16V M6 V OUT1 AUX ON/OFF M1 M2 M5 M4 T1* 1µH 1:1.8 MBRS11T3 R SENSE1.3Ω D1 MBRS14T3 D3 MBRS14T3 L2 1µH 3.3µF 25V C OUT1 1µF 1V 2 C OUT2 1µF 1V 2 R SENSE2.3Ω V OUT1 5V/3A V OUT2 3.3V 3.5A C IN2 22µF 35V 2 47k 4.7µF 25V MMBT 297 V OUT2 12V 2mA R6 1M 1% R5 9.9k 1% 1438 TA2 * T1 = DALE LPE-6562-A262 GAPPED E-CORE BH ELECTRONICS 51-657 GAPPED TOROID M1, M2, M4, M5 = IRF743 M3, M6 = IRLML283 L2 = SUMIDA CDRH125-1MC ALL INPUT OUTPUT CAPACITORS ARE AVX-TPS SERIES 4-284
TYPICAL APPLICATIONS U RLP 1k CLP.1µF CSS1 CC1A, 22pF CC1, RC1 1k COSC 56pF 11k, 1% 1pF 39k, 1% C C2A 47pF RC 1k 1pF 11k 1% OUTPUT DIVIDER REQUIRED WITH VPROG OPEN DC 121k 1% 22pF * T1 = DALE LPE-6562-A214 M1, M2, M4, M5 = Si941DY M3, M6 = IRLML283 L2 = SUMIDA CDRH125-1MC LTC1439 High Effciency 3.3V/2.5V Regulator with Low Noise 12V Linear Regulator 1Ω 1Ω POR2 C C2 LBO 22pF 1k 1k 1pF C SS2 1Ω 1 11 12 13 14 15 16 17 18 1 2 3 5 6 7 8 9 4 RUN/SS1 SENSE 1 SENSE 1 PLL LPF PLLIN BOOST 1 VPROG1 TGL1 I TH1 POR2 SW1 TGS1 LTC1439 COSC SGND LBI LBO SFB1 VIN BG1 INTVCC PGND BG2 ITH2 VPROG2 VOSENSE2 SENSE 2 SENSE 2 RUN/SS2 AUXDR EXTVCC TGS2 SW2 TGL2 BOOST 2 AUXON AUXFB 36 35 34 33 32 31 3 29 28 27 26 25 24 23 22 21 2 19 1Ω AUX ON/OFF EXT CLOCK D2 CMDSH-3 D4 CMDSH-3 CIN1 22µF 35V 2 M3 4.7µF 16V M6 V OUT1 M1 M2 M5 M4 T1* 9µH 1:3.74 L2 1µH MBRS11T3 D1 MBRS14T3 D3 MBRS14T3 3.3µF 35V RSENSE1.25Ω R SENSE2.2Ω C OUT2 47µF 6V 24V VOUT1 3.3V/4A C OUT1 33µF 1V V OUT2 2.5V 5A 47k CIN2 22µF 35V 2 1Ω 4.7µF 25V INPUT CAPACITORS ARE AVX-TPS SERIES OUTPUT CAPACITORS ARE AVX-TPSV LEVEL II SERIES MMBT297 ALTI VOUT2 12V 2mA VIN 4V TO 28V R6 1M R5 1k 1438 TA3 4-285
TYPICAL APPLICATIONS LTC1439/LTC1539 4-Output High Efficiency Low Noise 5V/3A, 3.3V/3A, 2.9V/2.6A, 12V/2mA Notebook Computer Power Supply (See PCB LAYOUT AND FILM for Layout of Schematic) D5 MMBD914L R19 1Ω R18 1Ω C13 C15 VIN (28V MAX) C2 U T1* 1µH 1:1.42 M1A 36 35 34 33 32 31 3 29 28 27 26 25 24 23 22 21 2 19 C14, VOUT3 12V 12mA R22 1Ω M7 C1, C21, C22 22µF 35V EA PLL LPF PLLIN BOOST 1 TGL1 SW1 TGS1 RUN/SS1 SENSE 1 SENSE 1 1 2 3 R5 4.7k D6 CMDSH-3 R1 4 V PROG1 INTVCC C2 C8 22pF VOUT1 5V 3A LTC1439 LTC1539 I TH1 M1B D2 CMDSH-3 D1 MBRS14 VIN BG1 INTV CC PGND BG2 POR2 C OSC SGND LBI LBO SFB1 R3 1k 1% C4 3.3µF 25V POR2 C3 56pF R13, 1k C28, C29 1µF 1V EA C18,.1µF C24, 4.7µF, 16V C23, 5 6 7 8 9 LB1 GND D3 MBRS14 M5 D4 CMDSH-3 EXTVCC TGS2 SW2 TGL2 BOOST 2 AUXON AUXFB ITH2 VPROG2 M4 C27 V OUT1 V OSENSE2 SENSE 2 SENSE 2 RUN/SS2 AUXDR 1 11 12 13 14 15 16 17 18 LBO R15 1k C16, C19 1µF 1V EA C6, C7, 47pF VOUT2 3.3V 3A L2 1µH C25, C26 22µF 35V EA R12.2Ω 1W C1, R12 1k C9 22pF R1 27Ω R9 47k C12 6.8nF 5V STANDBY (LTC1539) Q1 2N297 R21 1Ω C11 D7 Q2 ZETEX FZT849 R2 1Ω R11 1Ω R2 1Ω VLDO 2.9V/1A 2.6A PEAK OPTIONAL 33µF 6.3V C5 33µF 6.3V R8, 316k,1% C17, 22pF R7 221k 1% GND 1438 TA4 ALL INPUT AND OUTPUT CAPACITORS ARE AVX-TPS SERIES 5.2V TO 28V: SWITCHING FREQUENCY = 2kHz 5V/3A, 3.3V/3A, 2.9V/1A, 2.6A PEAK LINEAR, 12V/2mA M1, M2, M4 AND M5 = SILICONIX, Si4412DY M3, M6 = IRLML283 M7 = INTERNATIONAL RECTIFIER, IRLL14 R4 11.3k 1% Q1 = MOTOROLA, MMBT297ALT1 Q2 = ZETEX, FZT849 T1 = DALE, LPE-6562-A236 L2 = SUMIDA, CDRH127-1MC 4-286
U PCB LAYOUT A D FIL LTC1438/LTC1439 (Gerber files for this circuit board are available. Call the LTC factory.) W Silkscreen Top Silkscreen Bottom Copper Layer 1 Copper Layer 2 Ground Plane Copper Layer 3 Copper Layer 4 4-287
TYPICAL APPLICATION U 3.3V to 2.9V at 3A Low Noise Linear Regulator 5V 6.8nF 47k 27Ω Q1 MMBT297ALTI 1Ω 1Ω 3.3V ZETEX FZT849 (SURFACE MOUNT) 2.9V ON/OFF AUXDR LTC1439 AUXFB AUXON 22pF 316k 1% 221k 1% 2.9V 3A 33µF 2 1438 TA5 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1142/LTC1142HV Dual High Efficiency Synchronous Step-Down Switching Regulators Dual Synchronous, 2V LTC1148/LTC1148HV High Efficiency Step-Down Switching Regulator Controllers Synchronous, 2V LTC1159 High Efficiency Step-Down Switching Regulator Controller Synchronous, 4V, For Logic Threshold FETs LT 1375/LT1376 1.5A, 5kHz Step-Down Switching Regulators High Frequency, Small Inductor, High Efficiency Switchers, 1.5A Switch LTC143 High Power Step-Down Switching Regulator Controller High Efficiency 5V to 3.3V Conversion at Up to 15A LTC1435 Single High Efficiency Low Noise Switching Regulator Controller 16-Pin Narrow SO and SSOP Packages LTC1436/LTC1436-PLL/ High Efficiency Low Noise Synchronous Step-Down Full-Featured Single Controller LTC1437 Switching Regulator Controllers LT151 Constant-Voltage/Constant-Current Battery Charger 1.3A, Li-Ion, NiCd, NiMH, Pb-Acid Charger LTC1538-AUX Dual, Synchronous Controller with AUX Regulator 5V Standby in Shutdown LTC1539 Dual High Efficiency, Low Noise, Synchronous Step-Down 5V Standby in Shutdown Switching Regulator Controller 4-288