LM3687
LM3687 is Step-Down DC-DC Converter manufactured by Texas Instruments.
FEATURES
2DC-DC Converter:
- 750m A Maximum Load Capability
- 1.8MHz PWM Fixed Switching Frequency
(Typ.)
- Automatic PFM/PWM Mode Switching
- 27µA typ. Quiescent Current
- Internal Synchronous Rectification for High
Efficiency
- Internal Soft Start
Dual Rail Linear Regulator:
- Startup Mode
- Load Transients < 25m Vpeak Typ.
- Line Transients < 1m Vpeak Typ.
- Very Low Dropout Voltage: 82m V Typ. at
350m A Load Current
- 0.7V ≤ VIN_LIN ≤ 4.5V
- 10µA Typical IQ from VIN_LIN
- 350m A Maximum Load Capability bined mon Features
:
- 65µA typical Quiescent Current from VBATT if
Both Regulators are Enabled
- 750m A Maximum bined Load Capability in
Post Regulation Setup (DC-DC 400m A + Linear Regulator 350m A)
- 1100m A Maximum Total Load Capability in Independent Mode of Operation (DC-DC: 750m A, Linear Regulator: 350m A)
- Operates from a Single Li-Ion Cell or 3 Cell Ni MH/Ni Cd Batteries
- Only Four Tiny Surface-Mount External ponents Required (One Inductor, Three Ceramic Capacitors)
- Small 9-Bump DSBGA Package
- Over-Temperature, Current Overload and Under-Voltage Protection
APPLICATIONS
- Mobile Phones
- Hand-Held Radios
- Personal Digital Assistants
- Palm-top PCs
- Portable Instruments
- Battery Powered Devices
DESCRIPTION
The LM3687 is a step-down DC-DC converter with an integrated low dropout Linear Regulator optimized for powering ultra-low voltage circuits from a single Li-Ion cell or 3 cell Ni MH/Ni Cd batteries. It provides a dual output with fixed output voltages and bined load current up to 750m A in post regulation mode or 1100m A in independent mode of operation, over an input voltage range from 2.7V to 5.5V. There are several different fixed output voltage binations available (refer to Voltage Options).
The Linear Regulator being driven from the fixed output voltage of the buck converter (post regulation) translates to high...
