IMP3 7
P
OWER
M
ANAGEMENT
Low Dropout Positive
Voltage Regulators
– 800mA
– 2.5V, 3.0V and 3.3V Output
The IMP37 series of Low Dropout (LDO) three-terminal voltage regula-
tors feature guaranteed low dropout voltages at currents up to 0.8A. The
IMP37 regulator family dropout voltage is guaranteed to be 0.95V or
lower at 0.8A. At 100mA, the maximum dropout voltage is 0.8V.
Compared with “1117” type LDOs, the IMP37 has a 20% lower dropout
voltage.
Three fixed output voltages are offered: 2.5V, 3.0V and 3.3V. Output volt-
ages are factory trimmed to within 1% of the nominal value.
In addition to low dropout voltages, the IMP37 family features greatly
reduced quiescent operating current. The 75µA maximum specification
represents an over 100 times improvement over competitive devices.
Devices are short circuit protected, and a thermal protection circuit shuts
the regulator off should the junction temperature exceed 165°C.
The IMP37 is available in low-profile plastic SOT-223 and TO-263
packages and are pin compatible with fixed “1117” devices.
Key Features
x
Low Dropout Voltage
– 0.8V maximum at 100mA
– 0.95V maximum at 800mA
– 20% lower dropout voltage than “1117”
LDO regulators
x
Guaranteed Low Dropout Voltage at Multiple
Current Levels
x
1% Trimmed 2.5V, 3.0V and 3.3V Outputs
x
Reduced Quiescent Current: 75µA Maximum
x
Short Circuit and Thermal Protection
x
Space Saving SOT-223 Surface Mount Package
x
“1117” Pin Compatible
Applications
x
x
x
x
x
x
High-efficiency linear power supplies
Post regulator for switching supplies
5V to 3.3V linear regulators
USB hubs
Battery chargers
Routers, ISDN/DSL modems
Block Diagram
3
R
CS
2
Input
Out
(Tab)
IMP37
+
–
Current
Limit
Thermal
Protection
Error
Amp
–
+
+
Ref
–
1
GND
37_01.eps
©
1999 IMP, Inc.
408-432-9100/www.impweb.com
1
IMP [ IMP, INC ]
