Datasheet LTC3727A-1 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | High Efficiency, 2-Phase Synchronous Step-Down Switching Regulators |
| Pages / Page | 32 / 1 — FEATURES. DESCRIPTION. Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 14V. … |
| File Format / Size | PDF / 341 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 14V. Out-of-Phase Controllers Reduce Required Input
Model Line for this Datasheet
Text Version of Document
LTC3727A-1 High Effi ciency, 2-Phase Synchronous Step-Down Switching Regulators
FEATURES DESCRIPTION
n
Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 14V
The LTC®3727A-1 is a high performance dual step-down n
Out-of-Phase Controllers Reduce Required Input
switching regulator controller that drives all N-channel
Capacitance and Power Supply Induced Noise
synchronous power MOSFET stages. A constant frequency n
OPTI-LOOP
®
Compensation Minimizes COUT
current mode architecture allows phase-lockable frequency n
±
1% Output Voltage Accuracy
of up to 550kHz. 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 250kHz to 550kHz
controller output stages out of phase. n Dual N-Channel MOSFET Synchronous Drive The LTC3727A-1 is an improved version of the LTC3727 n Wide VIN Range: 4V to 36V Operation family of parts. It has smaller output ripple while in the n Very Low Dropout Operation: 99% Duty Cycle drop-out condition and shorter minimum on-time. n Adjustable Soft-Start Current Ramping n Foldback Output Current Limiting OPTI-LOOP compensation allows the transient response to n Output Overvoltage Protection be optimized over a wide range of output capacitance and n Low Shutdown I ESR values. There is a precision 0.8V reference and a power Q: 20μA n Selectable Constant Frequency or Burst Mode® good output indicator. A wide 4V to 30V (36V maximum) Operation input supply range encompasses all battery chemistries. n Small 28-Lead SSOP Package A RUN/SS pin for each controller provides soft-start. Current foldback limits MOSFET heat dissipation during short-circuit
APPLICATIONS
conditions. Output overvoltage protection circuitry protects n Telecom Systems the controller until VOUT returns to normal. n Automotive Systems , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation. n Battery-Operated Digital Devices All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 5929620, 6177787, 6144194, 6100678, 5408150, 6580258, 6304066, 5705919.
TYPICAL APPLICATION
VIN + 18V TO 28V 22μF 1μF 4.7μF 50V CERAMIC V CERAMIC IN PGOOD INTVCC M1 TG1 TG2 M3 0.1μF 8μH BOOST1 BOOST2 15μH 0.1μF SW1 SW2 LTC3727A-1 M2 BG1 BG2 M4 PLLIN PGND SENSE1+ SENSE2+ 1000pF 0.015Ω 1000pF 0.015Ω SENSE1– SENSE2– VOUT1 VOUT2 5V VOSENSE1 VOSENSE2 12V 5A 105k 280k 4A 1% ITH1 ITH2 1% + 220pF + 56μF 47μF RUN/SS1 RUN/SS2 220pF SGND 20k 20k 15V 6V 1% 1% SP SP 15k 15k 0.1μF 0.1μF M1, M2, M3, M4: FDS6680A 3727 F01
Figure 1. High Effi ciency Dual 12V/5V Step-Down Converter
3727a1fa 1
FEATURES DESCRIPTION
n
Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 14V
The LTC®3727A-1 is a high performance dual step-down n
Out-of-Phase Controllers Reduce Required Input
switching regulator controller that drives all N-channel
Capacitance and Power Supply Induced Noise
synchronous power MOSFET stages. A constant frequency n
OPTI-LOOP
®
Compensation Minimizes COUT
current mode architecture allows phase-lockable frequency n
±
1% Output Voltage Accuracy
of up to 550kHz. 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 250kHz to 550kHz
controller output stages out of phase. n Dual N-Channel MOSFET Synchronous Drive The LTC3727A-1 is an improved version of the LTC3727 n Wide VIN Range: 4V to 36V Operation family of parts. It has smaller output ripple while in the n Very Low Dropout Operation: 99% Duty Cycle drop-out condition and shorter minimum on-time. n Adjustable Soft-Start Current Ramping n Foldback Output Current Limiting OPTI-LOOP compensation allows the transient response to n Output Overvoltage Protection be optimized over a wide range of output capacitance and n Low Shutdown I ESR values. There is a precision 0.8V reference and a power Q: 20μA n Selectable Constant Frequency or Burst Mode® good output indicator. A wide 4V to 30V (36V maximum) Operation input supply range encompasses all battery chemistries. n Small 28-Lead SSOP Package A RUN/SS pin for each controller provides soft-start. Current foldback limits MOSFET heat dissipation during short-circuit
APPLICATIONS
conditions. Output overvoltage protection circuitry protects n Telecom Systems the controller until VOUT returns to normal. n Automotive Systems , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation. n Battery-Operated Digital Devices All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 5929620, 6177787, 6144194, 6100678, 5408150, 6580258, 6304066, 5705919.
TYPICAL APPLICATION
VIN + 18V TO 28V 22μF 1μF 4.7μF 50V CERAMIC V CERAMIC IN PGOOD INTVCC M1 TG1 TG2 M3 0.1μF 8μH BOOST1 BOOST2 15μH 0.1μF SW1 SW2 LTC3727A-1 M2 BG1 BG2 M4 PLLIN PGND SENSE1+ SENSE2+ 1000pF 0.015Ω 1000pF 0.015Ω SENSE1– SENSE2– VOUT1 VOUT2 5V VOSENSE1 VOSENSE2 12V 5A 105k 280k 4A 1% ITH1 ITH2 1% + 220pF + 56μF 47μF RUN/SS1 RUN/SS2 220pF SGND 20k 20k 15V 6V 1% 1% SP SP 15k 15k 0.1μF 0.1μF M1, M2, M3, M4: FDS6680A 3727 F01
Figure 1. High Effi ciency Dual 12V/5V Step-Down Converter
3727a1fa 1
