LM3671

Features:

·16 µA typical quiescent current
·600 mA maximum load capability
·2 MHz PWM fixed switching frequency (typ)
·Automatic PFM/PWM mode switching
·Available in fixed output voltages and adjustable version
·SOT23-5 package
·Internal synchronous rectification for high efficiency
·Internal soft start
·0.01 µA typical shutdown current
·Operates from a single Li-Ion cell or 3 cell NiMH/NiCd batteries
·Only three tiny surface-mount external components
·required (one inductor, two ceramic capacitors)
·Current overload and Thermal shutdown protection


Application

·Mobile phones
·PDAs
·MP3 players
·W-LAN
·Portable instruments
·Digital still cameras
·Portable Hard disk drives


Pinout




Specifications

VIN Pin: Voltage to GND                                              −0.2V to 6.0V
FB, SW, EN Pin: (GND−0.2V) to                                      (VIN + 0.2V)
Continuous Power Dissipation
(Note 3)
Internally Limited
Junction Temperature (TJ-MAX)                                          +125°C
Storage Temperature Range                             −65°C to +150°C
Maximum Lead Temperature
(Soldering, 10 sec.)                                                              260°C
ESD Rating (Note 4)
Human Body Model:
VIN,GND,SW,FB                                                                     2.0 kV
Human Body Model: EN                                                          500V
Machine Model: All Pins                                                          200V


Description

The LM3671 step-down DC-DC converter is optimized for powering ultra-low voltage circuits from a single Li-Ion cell or 3 cell NiMH/NiCd batteries. It provides up to 600mA load current, over an input voltage range from 2.8V to 5.5V. There are several different fixed voltage output options available as well as an adjustable output voltage version.

The device offers superior features and performance for mobile phones and similar portable applications with complex power management systems. Automatic intelligent switching between PWM low-noise and PFM low-current mode offers improved system control. During full-power operation, a fixed-frequency 2 MHz (typ). PWM mode drives loads from ∼70 mA to 600 mA max. Hysteretic PFM mode extends the battery life through reduction of the quiescent current to 16 µA (typ) at light loads and system standby. Internal synchronous rectification provides high efficiency. In shutdown mode (Enable pin pulled low) the device turns off and reduces battery consumption to 0.01 µA (typ).

The LM3671 is available in a SOT23-5 package with Pb and No Pb (Lead free) versions. A high switching frequency - 2 MHz (typ) - allows use of tiny surface-mount components. Only three external surface-mount components, an inductor and two ceramic capacitors, are required.