LM34910C Datasheet, PDF (1/12 Pages) National Semiconductor (TI) – High Voltage (50V, 1.25A) Step Down Switching Regulator

August 2007
LM34910C
High Voltage (50V, 1.25A) Step Down Switching Regulator
General Description
The LM34910C Step Down Switching Regulator features all
of the functions needed to implement a low cost, efficient,
buck bias regulator capable of supplying 1.25A to the load.
This buck regulator contains a 55V N-Channel Buck Switch,
and is available in the thermally enhanced LLP-10 package.
The hysteretic regulation scheme requires no loop compen-
sation, results in fast load transient response, and simplifies
circuit implementation. The operating frequency remains con-
stant with line and load variations due to the inverse relation-
ship between the input voltage and the on-time. The current
limit detection is set at 1.25A. Additional features include:
VCC under-voltage lockout, thermal shutdown, gate drive un-
der-voltage lockout, and maximum duty cycle limiter.
Features
■ ^{Operating frequency remains constant with load current}
and input voltage
■ ^{Maximum Duty Cycle Limited During Start-Up}
■ ^{Adjustable output voltage}
■ ^{Valley Current Limit At 1.25A}
■ ^{Precision internal reference}
■ ^{Low bias current}
■ ^{Highly efficient operation}
■ ^{Thermal shutdown}
Typical Applications
■ ^{High Efficiency Point-Of-Load (POL) Regulator}
■ ^{Non-Isolated Telecommunication Buck Regulator}
■ ^{Secondary High Voltage Post Regulator}
■ ^{Integrated 55V, N-Channel buck switch}
■ ^{Integrated start-up regulator}
■ ^{Input Voltage Range: 8V to 50V}
■ ^{No loop compensation required}
■ ^{Ultra-Fast transient response}
Package
■ ^{LLP-10 (4 mm x 4 mm)}
■ ^{Exposed Thermal Pad For Improved Heat Dissipation}
Connection Diagram
Ordering Information
Order Number
LM34910CSD
LM34910CSDX
LM34910CSDE
Package Type
LLP-10 (4x4)
LLP-10 (4x4)
LLP-10 (4x4)
10-Lead LLP
30023502
NSC Package Drawing
SDC10A
SDC10A
SDC10A
Supplied As
1000 Units on Tape and Reel
4500 Units on Tape and Reel
250 Units on Tape and Reel
© 2007 National Semiconductor Corporation 300235
www.national.com