Features and Benefits
- Out-of-Phase Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
- OPTI-LOOP® Compensation Minimizes COUT
- Dual N-Channel MOSFET Synchronous Drive
- ±1% Output Voltage Accuracy
- Power Good Output Voltage Monitor (LTC1628-PG)
- DC Programmed Fixed Frequency 150kHz to 300kHz
- 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 Standby Regulators
- Small 28-Lead SSOP Package
- Selectable Constant Frequency or Burst Mode® Operation
- Available in 5mm × 5mm QFN and 28-Pin SSOP Packages
The LTC1628/LTC1628-PG are high performance dual step-down switching regulator controllers that drive all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows adjustment of the frequency up to 300kHz. 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 soft-start 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 LTC1628-PG includes a power good output pin that replaces the FLTCPL, fault coupling control pin of the LTC1628.
- Notebook and Palmtop Computers, PDAs
- Battery Chargers
- Portable Instruments
- Battery-Operated Digital Devices
- DC Power Distribution Systems
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (7)
DC543A Demo Board for:
LTC1628 High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator
LTC2920 Single/Dual Power Supply Margining Controller
Demonstration circuit 392 is a dual output, step-down, synchronous buck converter featuring either the 150kHz to 300kHz LTC1628EUH controller (DC392A-A), the 250kHz to 550kHz LTC3728EUH (DC392A-B) or 250kHz to 550kHz LTC3728LUH (DC392A-C). It operates with an input voltage range of 7V to 24V and provides 3.3V @ 5A and 5V @ 4A at its output.
DC271A: Demo Board for the LTC1628 High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator.
DC264A: Demo Board for the LTC1628 High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator.
DC265A: Demo Board for the LTC1628 High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator.
DC236C-A: Demo Board for the LTC1628 High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator.
Documentation & Resources
R384 Reliability Data3/26/2018
Design Note 279: Microprocessor Core Supply Voltage Set by I2C Bus without VID Lines8/21/2021
DN265 - Hot Swap Circuit Meets InfiniBand Specification4/4/2014
DN210 - 2-Phase, Dual Switching Regulator Fits in Tight Places3/21/2014
DN249 - LTC1628-SYNC Minimizes Input Capacitors in Multioutput, High Current Power Supplies3/21/2014
Design Solutions 10 - Active Voltage Positioning Reduces Output Capacitors8/21/2007
Design Solutions 9 - 2-Phase DC/DC Controller Reduces Capacitanceand Increases Battery Life in Portable Applications8/21/2007
Design Solutions 8 - 2-Step Power Conversion: Portable Power for the Future8/21/2007
Supply Tracking and Sequencing at Point-of-Load: Easy Design without the Drawbacks of MOSFETs9/1/2005 LT Journal
Low Voltage, High Current DC/DC Power Supply with Load Sharing and Redundancy8/1/2002 LT Journal
SMBus Controls CPU Voltage Regulators without VID Pins9/1/2001 LT Journal
Beware: Worst-Case Specifications Can Be a Reality2/1/2000 LT Journal
LTC1702/LTC1703 Switching Regulator Controllers Set a New Standard for Transient Response9/1/1999 LT Journal
A Third Generation Dual, Opposing-Phase Switching Regulator Controller6/1/1999 LT Journal
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.