Features and Benefits
- Spread Spectrum Operation
- Tracking Function
- No Current Sense Resistors Required
- Out-of-Phase Controllers Reduce Required
- Input Capacitance
- Wide VIN Range: 2.75V to 9.8V
- Current Mode Operation
- 0.6V ±1.5% Voltage Reference
- Low Dropout Operation: 100% Duty Cycle
- Pulse Skipping Operation at Light Loads
- Internal Soft-Start Circuitry
- Power Good Output Voltage Monitor
- Output Overvoltage Protection
- Micropower Shutdown: IQ = 9µA
- Tiny Low Profile (4mm × 4mm) QFN and Narrow SSOP Packages
The LTC3736-1 is a 2-phase dual synchronous stepdown switching regulator controller with tracking that drives external complementary 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. Power loss and noise due to the ESR of the input capacitance are minimized by operating the two controllers out of phase.
A unique spread spectrum architecture randomly varies the LTC3736-1’s switching frequency from 450kHz to 580kHz, significantly reducing the peak radiated and conducted noise on both the input and output supplies, making it easier to comply with electromagnetic interference (EMI) standards.
Pulse skipping operation provides high efficiency at light loads. 100% duty cycle capability provides low dropout operation, extending operating time in battery-powered systems. The high switching frequencies allow for the use of small surface mount inductors and capacitors.
The LTC3736-1 is available in the low profile (0.75mm) 24-pin thermally enhanced (4mm × 4mm) QFN package and 24-lead narrow SSOP packages.
|Max Current Sense Voltage||Burst Mode||Soft Start||Spread Spectrum|
- One or Two Lithium-Ion Powered Devices
- Notebook and Palmtop Computers, PDAs
- Portable Instruments
- 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 (1)
Demonstration circuit 803 is a 2-phase dual synchronous high efficiency step-down DC/DC converter featuring the LTC3736EUF-1 controller.The "-1" version features pulse-skipping (in place of Burst Mode operation) at light loads and optional spread spectrum frequency modulation, and has a tighter voltage reference accuracy over temperature when compared with the LTC3736 "plain" version. The demo board operates with a 2.75V to 8V input voltage range and provides outputs of 2.5V @ 5A and 1.8V @ 5A.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.
Models for the following parts are available in LTspice:
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Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.