Features and Benefits
- No Current Sense Resistors Required
- Out-of-Phase Controllers Reduce Required Input Capacitance
- All N-Channel Synchronous Drive
- VIN Range: 2.75V to 4.5V
- Constant-Frequency Current Mode Operation
- 0.6V ±1.5% Voltage Reference
- Low Dropout Operation: 97% Duty Cycle
- True PLL for Frequency Locking or Adjustment
- Selectable Pulse-Skipping/Continuous Operation
- Tracking Function
- Internal Soft-Start Circuitry
- Power Good Output Voltage Monitor
- Output Overvoltage Protection
- Micropower Shutdown: IQ = 6.5µA
- Tiny Low Profile (4mm × 5mm) QFN and Narrow SSOP Packages
The LTC3836 is a 2-phase dual output synchronous step-down switching regulator controller with tracking that drives external N-channel power MOSFETs using few external components. The constant-frequency current mode architecture with MOSFET VDS sensing eliminates the need for sense resistors and improves efficiency. The power loss and noise due to the ESR of the input capacitance are minimized by operating the two controllers out-of-phase. Pulse-skipping operation provides high efficiency at light loads. The 97% duty cycle capability provides low dropout operation, extending operating time in battery-powered systems.
The operating frequency is selectable from 300kHz to 750kHz, allowing the use of small surface mount inductors and capacitors. For noise sensitive applications, the LTC3836 operating frequency can be externally synchronized from 250kHz to 850kHz.
The LTC3836 features an internal 1ms soft-start that can be extended with an external capacitor. A tracking input allows the second output to track the first during start-up.
The LTC3836 is available in the tiny thermally enhanced (4mm × 5mm) QFN and 28-lead narrow SSOP packages.
- General Purpose 3.3V to 1.X Supplies
- Single Lithium-Ion Powered Devices
- Distributed DC Power 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 (2)
Demonstration circuit 1107 is a 2-phase dual high efficiency synchronous step-down DC/DC converter that features the LTC3836EUFD controller. It operates with a 2.75V to 4.5V input range. and has two outputs: 1.8V @ 7A and 1.2V @ 7A.
Demonstration circuit DC1081 is a dual-output low VIN step-down power supply featuring the LTC3836, a low quiescent current, 2-phase synchronous buck controller. The input voltage is from 2.75V to 4.5V. The demo board has two outputs: 1.8V/12A and 1.2V/12A.
Tools & Simulations
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Models for the following parts are available in LTspice:
Sample & Buy
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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.