0.5A load with excellent line and load regulation. These
an 8-lead DIP and an 8-lead surface mount package.
added.
鈥?/div>
, improved line and load specifications,
fixed-frequency oscillator, Shutdown /Soft-start, error flag
delay and error flag output.
The LM2597/LM2597HV series operates at a switching fre-
quency of 150 kHz thus allowing smaller sized filter compo-
nents than what would be needed with lower frequency
switching regulators. Because of its high efficiency, the cop-
per traces on the printed circuit board are normally the only
heat sinking needed.
A standard series of inductors (both through hole and sur-
face mount types) are available from several different manu-
facturers optimized for use with the LM2597/LM2597HV se-
ries. This feature greatly simplifies the design of
switch-mode power supplies.
Other features include a guaranteed
鹵
4% tolerance on out-
put voltage under all conditions of input voltage and output
load conditions, and
鹵
15% on the oscillator frequency. Ex-
ternal shutdown is included, featuring typically 85 碌A(chǔ)
standby current. Self protection features include a two stage
current limit for the output switch and an over temperature
shutdown for complete protection under fault conditions.
The LM2597HV is for use in applications requiring and input
voltage up to 60V.
Features
n
3.3V, 5V, 12V, and adjustable output versions
n
Adjustable version output voltage range, 1.2V to 37V
(57V for HV version)
鹵
4% max over line and load
conditions
n
Guaranteed 0.5A output current
n
Available in 8-pin surface mount and DIP-8 package
n
Input voltage range up to 60V
n
150 kHz fixed frequency internal oscillator
n
Shutdown /Soft-start
n
Out of regulation error flag
n
Error output delay
n
Bias Supply Pin (V
BS
) for internal circuitry improves
efficiency at high input voltages
n
Low power standby mode, I
Q
typically 85 碌A(chǔ)
n
High Efficiency
n
Uses readily available standard inductors
n
Thermal shutdown and current limit protection
Applications
n
n
n
n
Simple high-efficiency step-down (buck) regulator
Efficient pre-regulator for linear regulators
On-card switching regulators
Positive to Negative converter
Typical Application
(Fixed Output Voltage Versions)
DS012440-1
鈥?/div>
Patent Number 5,382,918.
SIMPLE SWITCHER
廬
and
Switchers Made Simple
廬
are registered trademarks of National Semiconductor Corporation.
漏 2001 National Semiconductor Corporation
DS012440
www.national.com
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