LM3673_14 Datasheet, PDF (1/23 Pages) Texas Instruments – 2MHz, 350mA Step-Down DC-DC Converter

LM3673
www.ti.com
SNVS434J – JULY 2006 – REVISED NOVEMBER 2006
LM3673 2MHz, 350mA Step-Down DC-DC Converter
Check for Samples: LM3673
FEATURES
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•2 16 µA typical quiescent current
• 350 mA maximum load capability
• 2 MHz PWM fixed switching frequency (typ)
• Automatic PFM/PWM mode switching
• Available in fixed and adjustable output
voltages
• 5-bump MicroSMD package
• Internal synchronous rectification for high
efficiency
• Internal soft start
• 0.01 µA typical shutdown current
• Operates from a single Li-Ion cell battery
• Only three tiny surface-mount external
components required (one inductor, two
ceramic capacitors)
• Current overload and Thermal shutdown
protection
APPLICATIONS
• Mobile phones
• PDAs
• MP3 players
• W-LAN
• Portable instruments
• Digital still cameras
• Portable Hard disk drives
DESCRIPTION
The LM3673 step-down DC-DC converter is optimized for powering low voltage circuits from a single Li-Ion cell
battery and input voltage rails from 2.7V to 5.5V. It provides up to 350mA load current, over the entire input
voltage range. There are several different fixed voltage output options available as well as an adjustable output
voltage version ranging from 1.1V to 3.3V.
The device offers superior features and performance for mobile phones and similar portable systems. The
LM3673 uses intelligent automatic switching between PWM and PFM for better efficiency. During PWM mode,
the device operates at a fixed-frequency of 2 MHz (typ). Hysteretic PFM mode extends the battery life by
reducing the quiescent current to 16 µA (typ) during light load and standby operation. Internal synchronous
rectification provides high efficiency during PWM mode operation. In shutdown mode, the device turns off and
reduces battery consumption to 0.01 µA (typ).
The LM3673 is available in a tiny 5-bump MicroSMD package in leaded (PB) and lead-free (NO PB) versions. A
high switching frequency of 2 MHz (typ) allows the use of three tiny surface-mount components, an inductor and
two ceramic capacitors.
Typical Application Circuits
V_IN
2.7V to 5.5V
C_IN
4.7 PF
V_IN
1
5
LM3673
GND
2
L1: 2.2 PH
SW
V_OUT
C_OUT
10 PF
EN
3
FB
4
Figure 1. Typical Application Circuit
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2006, Texas Instruments Incorporated