LM34914_14 Datasheet, PDF (1/21 Pages) Texas Instruments – Ultra Small 1.25A Step-Down Switching Regulator with Intelligent Current Limit

LM34914
www.ti.com
SNVS453A – MAY 2007 – REVISED DECEMBER 2007
LM34914 Ultra Small 1.25A Step-Down Switching Regulator with Intelligent Current Limit
Check for Samples: LM34914
FEATURES
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•2 Input Voltage Range: 8V to 40V
• Integrated N-Channel buck switch
• Valley current limit varies with V_IN and V_OUT to
reduce excessive inductor current
• On-time is reduced when in current limit
• Integrated start-up regulator
• No loop compensation required
• Ultra-Fast transient response
• Maximum switching frequency: 1.3 MHz
• Operating frequency remains nearly constant
with load current and input voltage variations
• Programmable soft-start
• Precision internal reference
• Adjustable output voltage
• Thermal shutdown
TYPICAL APPLICATIONS
• High Efficiency Point-Of-Load (POL) Regulator
• Non-Isolated Buck Regulator
• Secondary High Voltage Post Regulator
DESCRIPTION
The LM34914 Step-Down Switching Regulator features all the functions needed to implement a low cost,
efficient, buck bias regulator capable of supplying at least 1.25A to the load. To reduce excessive switch current
due to the possibility of a saturating inductor the valley current limit threshold changes with input and output
voltages, and the on-time is reduced when current limit is detected. This buck regulator contains a 44V N-
Channel Buck Switch, and is available in the thermally enhanced 3 mm x 3 mm LLP-10 package. The feedback
regulation scheme requires no loop compensation, results in fast load transient response, and simplifies circuit
implementation. The operating frequency remains constant with line and load variations due to the inverse
relationship between the input voltage and the on-time. The valley current limit results in a smooth transition from
constant voltage to constant current mode when current limit is detected, reducing the frequency and output
voltage, without the use of foldback. Additional features include: VCC under-voltage lock-out, thermal shutdown,
gate drive under-voltage lock-out, and maximum duty cycle limit.
Package
• LLP-10 (3 mm x 3mm)
• Exposed Thermal Pad For Improved Heat Dissipation
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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 © 2007, Texas Instruments Incorporated