LM34919_15 Datasheet, PDF (1/21 Pages) Texas Instruments – Ultra-Small 40-V 600-mA Constant On-Time Buck Switching Regulator

LM34919
www.ti.com
SNOSAY2E – MAY 2007 – REVISED FEBRUARY 2013
Ultra-Small 40-V 600-mA Constant On-Time Buck Switching Regulator
Check for Samples: LM34919
FEATURES
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•2 Integrated N-Channel buck switch
• Integrated start-up regulator
• Input Voltage Range: 8V to 40V
• No loop compensation required
• Ultra-Fast transient response
• Operating frequency remains constant with
load current and input voltage
• Maximum switching frequency: 2.0 MHz
• Maximum Duty Cycle Limited During Start-Up
• Adjustable output voltage
• Valley Current Limit At 0.64A
• Precision internal reference
• Low bias current
• Highly efficient operation
• Thermal shutdown
• 10-Pin DSBGA Package
APPLICATIONS
• High Efficiency Point-Of-Load (POL) Regulator
• Non-Isolated Telecommunication Buck
Regulator
• Secondary High Voltage Post Regulator
DESCRIPTION
The LM34919 Step Down Switching Regulator features all of the functions needed to implement a low cost,
efficient, buck bias regulator capable of supplying 0.6A to the load. This buck regulator contains an N-Channel
Buck Switch, and is available in a 10-pin DSBGA package. The constant on-time 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 lockout, thermal shutdown, gate drive under-voltage
lockout, and maximum duty cycle limiter.
Basic Step Down Regulator
8V - 40V
Input
VIN
VCC
C3
C1
R_ON
LM34919
BST
SHUTDOWN
C6
RON/SD
SS
RTN
SGND
SW
ISEN
FB
C4
L1
D1
R1
R2
V_OUT
R3
C2
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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.
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