NSC LM1921T Datasheet
LM1921 1 Amp Industrial Switch
LM1921 1 Amp Industrial Switch
February 1995
General Description
The LM1921 Relay Driver incorporates an integrated power
PNP transistor as the main driving element. The advantages
of this over previous integrated circuits employing NPN
power elements are several. Greater output voltages are
available off the same supply for driving grounded loads;
typically 4.5 volts for a 500 mA load from a 5.0 volt supply.
The output can swing below ground potential up to 57 volts
negative with respect to the positive power supply. This can
be used to facilitate rapid decay times in inductive loads.
Also, the IC is immune to negative supply voltages or transients. The inherent Safe Operating Area of the lateral PNP
allows use of the IC as a bulb driver or for capacitive loads.
Familiar integrated circuit features such as short circuit protection and thermal shutdown are also provided. The input
voltage threshold levels are designed to be TTL, CMOS,
and LSTTL compatible over the entire operating temperature range. If several drivers are used in a system, their
inputs and/or outputs may be combined and wired together
if their supply voltages are also common.
Typical Application Circuit
Features
Y
1 Amp output drive
Y
Load connected to ground
Y
Low input-output voltage differential
Y
a
60 volt positive transient protection
Y
b
50 volt negative transient protection
Y
Automotive reverse battery protection
Y
Short circuit proof
Y
Internal thermal overload protection
Y
Unclamped output for fast decay times
Y
TTL, LSTTL, CMOS compatible input
Y
Plastic TO-220 package
Y
100% electrical burn-in
Applications
Y
Relays
Y
Solenoids
Y
Valves
Y
Motors
Y
Lamps
Y
Heaters
*Required for stability
TL/H/5271– 1
FIGURE 1. Test and Application Circuit
Connection Diagram
Front View
Order Number LM1921T
See NS Package Number T05A
C
1995 National Semiconductor Corporation RRD-B30M115/Printed in U. S. A.
TL/H/5271
TL/H/5271– 2
Absolute Maximum Ratings
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Supply Voltage
Operating Range 4.75V to 26V
Overvoltage Protection (100 ms)
b
50V toa60V
Internal Power Dissipation Internally Limited
b
Operating Temperature Range
40§Ctoa125§C
Maximum Junction Temperature 150§C
Storage Temperature Range
b
65§Ctoa150§C
Lead Temp. (Soldering, 10 seconds) 230§C
Electrical Characteristics (V
CC
e
12V, I
OUT
e
500 mA, T
e
J
25§C, V
ON/OFF
e
2V, unless otherwise specified.)
Tested Limits Design Limits
Parameter Conditions Typ
(Note 1) (Note 2)
Units
Min Max Min Max
Supply Voltage
Operational 4.75 26 6 24 V
Survival
Transient 100 ms, 1% Duty Cycle
b
15 60 V
b
50 V
Supply Current
e
V
ON/OFF
V
ON/OFF
Input to Output I
Voltage Drop I
0 0.6 1.5 mA
e
2V I
e
0 mA 6 10 mA
OUT
e
I
250 mA 285 350 mA
OUT
e
I
500 mA 575 700 mA
OUT
e
I
1A 1.3 1.5 A
OUT
e
500 mA 0.5 0.8 V
OUT
e
1A 1.0 V
OUT
Short Circuit Current 1.4 1.0 2.0 A
s
s
6V
V
24V .75 3.0 A
CC
Output Leakage Current V
ON/OFF
e
0 0.1 50 mA
ON/OFF Voltage 1.3 0.8 2.0 V
Threshhold 6VsV
s
24V 0.8 2.0 V
CC
ON/OFF Current 15 10 30 mA
Overvoltage Shutdown 32 26 36 V
Thermal Resistance
junction-case ijc 3
case-ambient ica 50
C/W
§
C/W
§
Inductive Clamp
Output Voltage V
ON/OFF
0, I
OUT
e
100 mA
b
60
b
120
b
45 V
e
Fault Conditions
Output Current
ON/OFF
Floating Pin 5 Open 0.1 50 mA
Ground Floating Pin 3 & Pin 4 Open 0.1 50 mA
Reverse Voltage V
Reverse Transient V
Overvoltage V
Supply Current Pin 1 & Pin 2 Short, No load 10 40 mA
Note 1: Guaranteed and 100% production tested.
Note 2: Guaranteed, not necessarily 100% production tested. Not used to calculate outgoing AQL . Limits are for the temperature range of
eb
15V
CC
eb
50V
CC
ea
60V 0.01 1 mA
CC
b
0.01
b
100 mA
b
1mA
b
40§CsT
j
s
150§C.
DC
2
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