2MHz, 350mA Step-Down DC-DC Converter

Features

• 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

LM3673 WEBENCH® Custom Design/Analyze/Build It/Test It   2.70 <= V in Lower V   <= V in Upper V   <= 5.50 V out 1.00 <= V <= 3.30 I out   A <= 0.35 Ambient Temperature °C <= 100 What are WEBENCH® tools?

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.

Applications

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