LM2925T National Semiconductor, LM2925T Datasheet



Manufacturer Part Number
National Semiconductor

Specifications of LM2925T

Regulator Topology
Positive Fixed
Voltage - Output
Voltage - Input
Up to 26V
Voltage - Dropout (typical)
0.82V @ 750mA
Number Of Regulators
Current - Output
Current - Limit (min)
Operating Temperature
-40°C ~ 125°C
Mounting Type
Through Hole
Package / Case
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Other names
© 1998 National Semiconductor Corporation
Low Dropout Regulator with Delayed Reset
General Description
The LM2925 features a low dropout, high current regulator.
Also included on-chip is a reset function with an externally
set delay time. Upon power up, or after the detection of any
error in the regulated output, the reset pin remains in the ac-
tive low state for the duration of the delay. Types of errors de-
tected include any that cause the output to become unregu-
lated: low input voltage, thermal shutdown, short circuit,
input transients, etc. No external pull-up resistor is neces-
sary. The current charging the delay capacitor is very low, al-
lowing long delay times.
Designed primarily for automotive applications, the LM2925
and all regulated circuitry are protected from reverse battery
installations or two-battery jumps. During line transients,
such as a load dump (60V) when the input voltage to the
regulator can momentarily exceed the specified maximum
operating voltage, the 0.75A regulator will automatically shut
down to protect both internal circuits and the load. The
Typical Application Circuit
without bound to maintain regulation during transients. Locate as close as
possible to the regulator. This capacitor must be rated over the same
operating temperature range as the regulator. The equivalent series
resistance (ESR) of this capacitor is critical; see curve.
Required if regulator is located far from power supply filter.
must be at least 10 µF to maintain stability. May be increased
FIGURE 1. Test and Application Circuit
LM2925 cannot be harmed by temporary mirror-image inser-
tion. Familiar regulator features such as short circuit and
thermal overload protection are also provided.
n 5V, 750 mA output
n Externally set delay for reset
n Input-output differential less than 0.6V at 0.5A
n Reverse battery protection
n 60V load dump protection
n −50V reverse transient protection
n Short circuit protection
n Internal thermal overload protection
n Available in plastic TO-220
n Long delay times available
n P
Connection Diagram
Product Enhancement tested
See NS Package Number T05A
Order Number LM2925T
TO-220 5-Lead
April 1998

Related parts for LM2925T

LM2925T Summary of contents

Page 1

... Short circuit protection n Internal thermal overload protection n Available in plastic TO-220 n Long delay times available + n P Product Enhancement tested Connection Diagram TO-220 5-Lead Order Number LM2925T See NS Package Number T05A DS005268-1 April 1998 DS005268-2 www.national.com ...

Page 2

... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Input Voltage Operating Range Overvoltage Protection V OUT Electrical Characteristics = 14V µ 500 mA Parameter Output Voltage −40˚C T Line Regulation Load Regulation ...

Page 3

Reset Output Electrical Characteristics = 14V 0.1 µ 25˚C (Note 4) (unless otherwise specified Parameter Delay Current Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Electrical ...

Page 4

Typical Performance Characteristics Reset Voltage on Power-up DS005268-7 Dropout Voltage DS005268-10 Ripple Rejection DS005268-13 www.national.com (Continued) Delay Time DS005268-8 Line Transient Response DS005268-11 Quiescent Current DS005268-14 4 Reset Pull-up Resistor R10 DS005268-9 Ripple Rejection DS005268-12 Output Voltage DS005268-15 ...

Page 5

Typical Performance Characteristics Quiescent Current DS005268-19 Peak Output Current DS005268-20 Definition of Terms Dropout Voltage: The input-output voltage differential at which the circuit ceases to regulate against further reduction in input voltage. Measured when the output voltage has dropped 100 ...

Page 6

Application Hints (Continued) Capacitors must also be rated at all ambient temperatures expected in the system. Many aluminum type electrolytics will freeze at temperatures less than −30˚C, reducing their effective capacitance to zero. To maintain regulator stability down to −40˚C, ...

Page 7

Circuit Schematic 7 www.national.com ...

Page 8

... National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. 5-Lead TO-220 Power Package (T) Order Number LM2925T NS Package Number T05A 2. A critical component in any component of a life support ...

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