Switching Regulator. LM25007 Datasheet

LM25007 Regulator. Datasheet pdf. Equivalent

National Semiconductor LM25007
February 2006
42V, 0.5A Step-Down Switching Regulator
General Description
The LM25007 is a monolithic step-down switching regulator
featuring all of the functions needed to implement a low cost,
efficient, power supply. Capable of driving a 0.5Amp load
over a 9V-42V input voltage range, this device is easy to
apply and is provided in the small MSOP-8 and the thermally
enhanced LLP-8 packages. Ultra-fast transient response is
achieved through the use of a constant on-time architecture
with Vin feed forward. This feature provides an almost con-
stant operating frequency over load and input voltage varia-
tions. The operating frequency can be adjusted with a single
resistor. This architecture is easy to use and tolerant of
component selection. An intelligent current limit is imple-
mented in the LM25007 with forced off time that is inversely
proportional to Vout thus ensuring recovery from fault con-
ditions. The output voltage may be set from 2.5V to >30V. To
improve efficiency in light load applications, the Vcc pin can
be connected to an external voltage source to eliminate the
drop through the internal regulator. Additional features in-
clude: thermal shutdown, Vcc under-voltage lockout, gate
drive under-voltage lockout, and max duty cycle limiter.
n Integrated 0.74 ohm N-Channel MOSFET switch
n Guaranteed 0.5Amp output current
n Ultra-Fast Transient Response
n Up to 800kHz operation
n No control loop compensation required
n Vin feed forward provides constant operating frequency
n 2% accurate 2.5V feedback from -40˚C to 125˚C
n Highly efficient operation
n Intelligent current limit protection
n External shutdown control
n Thermal shutdown
n MSOP-8 and thermally enhanced LLP packages
Typical Applications
n 12VDC and 24VDC distributed rail systems
n 24VAC systems
n Automotive body electronics and telematics
n Industrial systems
n HB-LED constant current source
n MSOP - 8
n LLP - 8 (4mm x 4mm)
Basic Step-Down Regulator
© 2006 National Semiconductor Corporation DS201655

LM25007 Datasheet
Recommendation LM25007 Datasheet
Part LM25007
Description Step-Down Switching Regulator
Feature LM25007; www.DataSheet4U.com February 2006 LM25007 42V, 0.5A Step-Down Switching Regulator LM25007 42V, 0.5.
Manufacture National Semiconductor
Download LM25007 Datasheet

National Semiconductor LM25007
Connection Diagram
8-Lead MSOP, LLP
Ordering Information
Order Number
Package Type
NSC Package Drawing
Typical Application Circuit and Block Diagram
Supplied As
1000 Units on Tape and Reel
3500 Units on Tape and Reel
1000 Units on Tape and Reel
4500 Units on Tape and Reel

National Semiconductor LM25007
Pin Descriptions
Pin Name
1 SW Switching Node
2 BST Boost Boot–strap capacitor input
3 RCL Current Limit OFF time programming pin
4 RTN Circuit Ground
5 FB Feedback Signal from Regulated Output
6 RON/SD On-time set pin
7 VCC Output from the internal high voltage bias
8 VIN Input supply voltage
- EP Exposed pad, underside of the LLP package
Application Information
Power switching node. Connect to the inductor,
bootstrap capacitor, and free-wheeling diode.
An external capacitor is required between the BST
and the SW pins. A 0.01µF ceramic capacitor is
A resistor between this pin and RTN sets the
off-time when current limit is detected. The off-time
is preset to 17 µs if FB = 0V .
This pin is connected to the inverting input of the
internal regulation comparator. The regulation
threshold is 2.5V.
A resistor between this pin and VIN sets the switch
on-time as a function of Vin. The minimum
recommended on-time is 300ns at the maximum
input voltage.
If an auxiliary voltage is available to raise the
voltage on this pin above the regulation setpoint
(7V), the internal series pass regulator will
shutdown, reducing the IC power dissipation. Do not
exceed 14V. This output provides gate drive power
for the internal Buck switch. An internal diode is
provided between this pin and the BST pin. A local
0.1uF decoupling capacitor is recommended.
Recommended operating range: 9V to 42V.
Exposed metal pad on the LLP package underside.
It is recommended to connect this pad to the PC
board ground plane to aid in heat dissipation.
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