Datasheet LTC3707-SYNC (Analog Devices)
| Manufacturer | Analog Devices |
| Description | High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator |
| Pages / Page | 32 / 1 — FEATURES. DESCRIPTION. 180° Phased Controllers Reduce Required Input. … |
| File Format / Size | PDF / 404 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. 180° Phased Controllers Reduce Required Input. Capacitance and Power Supply Induced Noise. OPTI-LOOP
Model Line for this Datasheet
Text Version of Document
LTC3707-SYNC High Effi ciency, 2-Phase Synchronous Step-Down Switching Regulator
FEATURES DESCRIPTION
n
180° Phased Controllers Reduce Required Input
The LTC®3707-SYNC is a high performance dual step-down
Capacitance and Power Supply Induced Noise
switching regulator controller that drives all N-channel n
OPTI-LOOP
®
Compensation Minimizes COUT
synchronous power MOSFET stages. A constant frequency n
Dual N-Channel MOSFET Synchronous Drive
current mode architecture allows phase-lockable frequency n ±
1.5% Output Voltage Accuracy
of up to 300kHz. Power loss and noise due to the ESR of n
Power Good Output Voltage Monitor
the input capacitors are minimized by operating the two n
Phase-Lockable Fixed Frequency 150kHz to 300kHz
controller output stages out of phase. n Wide VIN Range: 4.5V to 28V Operation OPTI-LOOP compensation allows the transient response to n Very Low Dropout Operation: 99% Duty Cycle be optimized over a wide range of output capacitance and n Adjustable Soft-Start Current Ramping ESR values. The precision 0.8V reference and power good n Foldback Output Current Limiting output indicator are compatible with future microprocessor n Latched Short-Circuit Shutdown with Defeat Option generations, and a wide 4.5V to 28V (30V maximum) input n Output Overvoltage Protection supply range encompasses all battery chemistries. n Remote Output Voltage Sense n Low Shutdown I A RUN/SS pin for each controller provides both soft- Q: 20μA n 5V and 3.3V Standby Regulators start and optional timed, short-circuit shutdown. Current n Small 28-Lead Narrow SSOP Package (0.150˝ Wide) foldback limits MOSFET dissipation during short-circuit n Selectable Constant Frequency, Burst Mode® or conditions when overcurrent latchoff is disabled. Output PWM Operation overvoltage protection circuitry latches on the bottom MOSFET until VOUT returns to normal. The FCB mode
APPLICATIONS
pin can select among Burst Mode operation, constant frequency mode and continuous inductor current mode n Notebook and Palmtop Computers, PDAs or regulate a secondary winding. The IC includes a power n Telecom Systems good output pin that indicates when both outputs are within n Portable Instruments 7.5% of their designed set point. n Battery-Operated Digital Devices L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst Mode n DC Power Distribution Systems and OPTI-LOOP are registered trademarks of Linear Technology Corporation. Protected by U.S. Patents including 5481178, 5705919, 5929620, 6144194, 6177787, 6304066, 6580258. V
TYPICAL APPLICATION
IN + C 5.2V TO 28V IN 1μF 4.7μF 22μF D3 D4 CERAMIC 50V VIN PGOOD INTVCC CERAMIC M1 TG1 TG2 M3 L1 CB2, 0.1μF L2 6.3μH BOOST1 BOOST2 6.3μH CB1, 0.1μF SW1 SW2 LTC3707-SYNC D1 M2 BG1 BG2 M4 D2 f PLLIN PGND IN SENSE1+ SENSE2+ RSENSE1 1000pF 1000pF RSENSE2 0.01Ω 0.01Ω SENSE1– SENSE2– VOUT1 VOUT2 5V VOSENSE1 VOSENSE2 3.3V 5A R2 R4 5A 105k ITH1 ITH2 63.4k C C 1% C1 + COUT1 C2 1% COUT RUN/SS1 SGND RUN/SS2 R3 + 47μF R1 220pF 220pF 56mμF 6V 20k R 20k C1 R C C C2 SS1 SS2 6V SP 1% 15k 1% 15k 0.1μF 0.1μF SP M1, M2, M3, M4: FDS6680A 3707 F01
Figure 1. High Effi ciency Dual 5V/3.3V Step-Down Converter
3707sfa 1
FEATURES DESCRIPTION
n
180° Phased Controllers Reduce Required Input
The LTC®3707-SYNC is a high performance dual step-down
Capacitance and Power Supply Induced Noise
switching regulator controller that drives all N-channel n
OPTI-LOOP
®
Compensation Minimizes COUT
synchronous power MOSFET stages. A constant frequency n
Dual N-Channel MOSFET Synchronous Drive
current mode architecture allows phase-lockable frequency n ±
1.5% Output Voltage Accuracy
of up to 300kHz. Power loss and noise due to the ESR of n
Power Good Output Voltage Monitor
the input capacitors are minimized by operating the two n
Phase-Lockable Fixed Frequency 150kHz to 300kHz
controller output stages out of phase. n Wide VIN Range: 4.5V to 28V Operation OPTI-LOOP compensation allows the transient response to n Very Low Dropout Operation: 99% Duty Cycle be optimized over a wide range of output capacitance and n Adjustable Soft-Start Current Ramping ESR values. The precision 0.8V reference and power good n Foldback Output Current Limiting output indicator are compatible with future microprocessor n Latched Short-Circuit Shutdown with Defeat Option generations, and a wide 4.5V to 28V (30V maximum) input n Output Overvoltage Protection supply range encompasses all battery chemistries. n Remote Output Voltage Sense n Low Shutdown I A RUN/SS pin for each controller provides both soft- Q: 20μA n 5V and 3.3V Standby Regulators start and optional timed, short-circuit shutdown. Current n Small 28-Lead Narrow SSOP Package (0.150˝ Wide) foldback limits MOSFET dissipation during short-circuit n Selectable Constant Frequency, Burst Mode® or conditions when overcurrent latchoff is disabled. Output PWM Operation overvoltage protection circuitry latches on the bottom MOSFET until VOUT returns to normal. The FCB mode
APPLICATIONS
pin can select among Burst Mode operation, constant frequency mode and continuous inductor current mode n Notebook and Palmtop Computers, PDAs or regulate a secondary winding. The IC includes a power n Telecom Systems good output pin that indicates when both outputs are within n Portable Instruments 7.5% of their designed set point. n Battery-Operated Digital Devices L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst Mode n DC Power Distribution Systems and OPTI-LOOP are registered trademarks of Linear Technology Corporation. Protected by U.S. Patents including 5481178, 5705919, 5929620, 6144194, 6177787, 6304066, 6580258. V
TYPICAL APPLICATION
IN + C 5.2V TO 28V IN 1μF 4.7μF 22μF D3 D4 CERAMIC 50V VIN PGOOD INTVCC CERAMIC M1 TG1 TG2 M3 L1 CB2, 0.1μF L2 6.3μH BOOST1 BOOST2 6.3μH CB1, 0.1μF SW1 SW2 LTC3707-SYNC D1 M2 BG1 BG2 M4 D2 f PLLIN PGND IN SENSE1+ SENSE2+ RSENSE1 1000pF 1000pF RSENSE2 0.01Ω 0.01Ω SENSE1– SENSE2– VOUT1 VOUT2 5V VOSENSE1 VOSENSE2 3.3V 5A R2 R4 5A 105k ITH1 ITH2 63.4k C C 1% C1 + COUT1 C2 1% COUT RUN/SS1 SGND RUN/SS2 R3 + 47μF R1 220pF 220pF 56mμF 6V 20k R 20k C1 R C C C2 SS1 SS2 6V SP 1% 15k 1% 15k 0.1μF 0.1μF SP M1, M2, M3, M4: FDS6680A 3707 F01
Figure 1. High Effi ciency Dual 5V/3.3V Step-Down Converter
3707sfa 1
