LM2926

Manufacturer Part NumberLM2926
DescriptionLow Dropout Regulator with Delayed Reset
ManufacturerNational Semiconductor
LM2926 datasheet
 
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LM2926/LM2927
Low Dropout Regulator with Delayed Reset
General Description
The LM2926 is a 5V, 500 mA, low dropout regulator with de-
layed reset. The microprocessor reset flag is set low by ther-
mal shutdown, short circuits, overvoltage conditions, drop-
out, and power-up. After the fault condition is corrected, the
reset flag remains low for a delay time determined by the de-
lay capacitor. Hysteresis is included in the reset circuit to
prevent oscillations, and a reset output is guaranteed down
to 3.2V supply input. A latching comparator is used to dis-
charge the delay capacitor, which guarantees a full reset
pulse even when triggered by a relatively short fault condi-
tion. A patented quiescent current reduction circuit drops the
ground pin current to 8 mA at full load when the input-output
differential is 3V or more.
Familiar PNP regulator features such as reverse battery pro-
tection, transient protection, and overvoltage shutdown are
included in the LM2926 making it suitable for use in automo-
tive and battery operated equipment.
The LM2927 is electrically identical to the LM2926 but has a
different pin-out. The LM2927 is pin-for-pin compatible with
the L4947 and TLE4260 alternatives. The LM2926 is
pin-for-pin compatible with the LM2925.
Typical Application
>
*
Required if regulator is located far (
2") from power supply filter.
**C
must be at least 10 µF to maintain stability. May be increased without bound to maintain regulation during transients. Locate as close as possible to
O
the regulator. This capacitor msut be rated over the same operating temperature range as the regulator. The equivalent series resistance (ESR) of this
capacitor is critical; see curve under Typical Performance Characteristics.
Connection Diagrams and Ordering Information
5–Lead TO-220
Front View
Order Number LM2926T
See NS Package Number TO5A
© 1998 National Semiconductor Corporation
DS010759
Features
n 5% output accuracy over entire operating range
n Dropout voltage typically 350 mV at 500 mA output
n Externally programmed reset delay
n Short circuit proof
n Reverse battery proof
n Thermally protected
n LM2926 is pin-for-pin compatible with the LM2925
+
n P
Product Enhancement tested
Applications
n Battery operated equipment
n Microprocessor-based systems
n Portable instruments
DS010759-1
5-Lead TO-220
DS010759-2
Front View
Order Number LM2927T
See NS Package Number TO5A
April 1998
DS010759-14
www.national.com