LTC3728 - Dual, 550kHz, 2-Phase Synchronous Step-Down Switching Regulator
- Dual, 180° Phased Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
- OPTI-LOOP Compensation Minimizes COUT
- ±1% Output Voltage Accuracy
- Power Good Output Voltage Indicator
- Phase-Lockable Fixed Frequency 250kHz to 550kHz
- Dual N-Channel MOSFET Synchronous Drive
- Wide VIN Range: 3.5V to 36V Operation
- Very Low Dropout Operation: 99% Duty Cycle
- Adjustable Soft-Start Current Ramping
- Foldback Output Current Limiting
- Latched Short-Circuit Shutdown with Defeat Option
- Output Overvoltage Protection
- Remote Output Voltage Sense
- Low Shutdown IQ : 20µA
- 5V and 3.3V Regulators
- 3 Selectable Operating Modes: Constant-Frequency, Burst Mode Operation and PWM
- Available in 32-Pin 5mm x 5mm QFN and 28-Pin SSOP Packages
AEC-Q100 data available for specific packages
The LTC3728 is a dual high performance step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant-frequency current mode architecture allows phase-lockable frequency of up to 550kHz. Power loss and noise due to the ESR of the input capacitors are minimized by operating the two controller output stages out of phase.
OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The precision 0.8V reference and power good output indicator are compatible with future microprocessor generations, and a wide 3.5V to 30V (36V maximum) input supply range encompasses all battery chemistries.
A RUN/SS pin for each controller provides both softstart and optional timed, short-circuit shutdown. Current foldback limits MOSFET dissipation during short-circuit conditions when overcurrent latchoff is disabled. Output overvoltage protection circuitry latches on the bottom MOSFET until VOUT returns to normal. The FCB mode pin can select among Burst Mode, constant-frequency mode and continuous inductor current mode or regulate a secondary winding. The LTC3728 includes a power good output pin that indicates when both outputs are within 7.5% of their designed set point.
|Vin Range||Vref Accy||Current Limit Latch Off||3.3V LDO Available|
|LTC3728||3.5V to 36V||+/-1%||Yes|
|LTC3728L||4.5V to 28V||+/-1%||Yes||Yes|
|LTC3728LX||4.5V to 28V||+/- 1.5%||Yes||Yes|
|LTC3728L-1||4.5V to 28V||+/- 1.5%||Foldback only||Yes|
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
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Demo BoardsLinear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.
|DC392A-B||LTC3728EUH Demo Board | Dual Output, 5V to 24Vin, 5Vout1 @ 4A, 3.3Vout2 @ 5A||$125.00|
|DC447A||LTC3728EUH | 2-Phase Dual Output Power Supply, Vin = 5V - 14V, Vout1 = 2.5V @ 13A, Vout2 = 1.8V @ 13A||$150.00|
|DC542A||LTC3728EG | Dual 2-Phase, 8V to 24V Input, 5V/3.3V 0A to 12A, 3.3V/2.5V 0A to 12A||$150.00|
Designed for Automotive and Transportation ApplicationsAEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page
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- Notebook and Palmtop Computers
- Telecom Systems
- Portable Instruments
- Battery-Operated Digital Devices
- DC Power Distribution Systems
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