1
GM1112
1A LOW DROPOUT
PRECISION VOLTAGE REGULATOR
Description
The GM1112 is a positive low dropout
regulator and is available in an adjustable
version and fixed output voltage at 1.2V. All
internal circuitry is designed to operate down
to 800mV input to output differential and the
dropout voltage is fully specified as a function
of load current. On chip trimming adjusts the
reference/output voltage to within
±
1%.
Current limit is also trimmed in order to
minimize the stress on both the regulator and
the power source circuitry under overloaded
conditions.
Features
Fixed Output, 1.2V
Output Current of 1.0A
Dropout Voltage 1.3V max @ 1.0A
Line Regulation 0.2% max.
Load Regulation 0.4% max.
Fast Transient Response
Current Limit Protection
Thermal Shutdown Protection
Application
High Efficiency Linear Regulators
Post Regulators for Switching Supplies
Microprocessor Supply
Battery Powered Equipment
Reference Voltage Sources
Hard Drive Controllers
Battery Chargers
Adjustable Power Supply
Typical Application Circuits
V
IN
V
OUT
GM1112
C1
10µF
C2
10µF
www.gammamicro.com.tw
GM1112
V1.03
1
2
GM1112
1A LOW DROPOUT
PRECISION VOLTAGE REGULATOR
Marking Information and Pin Configurations (Top View)
TO 252
(D-PAK)
TO 220
TO 263
(D
2
-PAK)
SOT223
GM1112
AYWW
GM1112
AYWW
GM1112
AYWW
1. Gnd
GM1112
AYWW
3. V
IN
2. V
OUT
1. Gnd
A: Assembly / Test site code
Y: Year
WW: Week
2. V
OUT
3. V
IN
2. V
OUT
1. Gnd
3. V
IN
2. V
OUT
1. Gnd
3. V
IN
GM1112
V1.03
2
3
GM1112
1A LOW DROPOUT
PRECISION VOLTAGE REGULATOR
Ordering Information
Ordering Number
GM1112ST3T
GM1112ST3R
GM1112TC3T
GM1112TC3R
GM1112TB3T
GM1112TA3T
GM1112TA3R
Package
SOT-223
SOT-223
TO-252
TO-252
TO-220
TO-263
TO-263
Shipping
80 Units/Tube
2,500 Units / Tape & Reel
80 Units/Tube
2,500 Units / Tape & Reel
50 Units/Tube
50 Units/Tube
800 Units / Tape & Reel
Absolute Maximum Ratings
PARAMETER
Input Voltage
SOT-223
Thermal Resistance,
Junction to Case
TO-252 (D PAK)
TO-263 (D
2
PAK)
Operating Junction Temperature
Storage Temperature
T
J
T
stg
θ
JA
SYMBOL
V
IN
RATINGS
15
15.0
6.0
3.0
0 to 150
- 65 to 150
℃
℃
℃/W
UNITS
V
GM1112
V1.03
3
4
GM1112
1A LOW DROPOUT
PRECISION VOLTAGE REGULATOR
Electrical Characteristics
(T
A
= 25℃, unless otherwise noted)
Parameter
Output Voltage
Symbol
V
OUT
Condition
I
OUT
=10mA, V
IN
= 5V
10mA
≤
I
OUT
≤
1.0A,
2.65V
≤
V
IN
≤
7V
I
OUT
=10mA,
2.75V
≤
V
IN
≤
7V
V
IN
= V
OUT
+ 1V
10mA
≤
I
OUT
≤
1.0A
I
OUT
=1A
V
IN
= V
OUT
+ 3V
V
IN
= V
OUT
+ 1V
10mA
≤
I
OUT
≤
1.0A
V
IN
= V
OUT
+ 1.5V
I
OUT
= 10mA
Min
1.18
1.17
Typ
1.20
1.20
0.04
0.2
1.15
Max
1.26
Unit
V
1.27
0.2
0.4
1.3
%/V
%/mA
V
A
13
mA
%/℃
%/W
dB
Line Regulation
Load Regulation
Dropout Voltage
Current Limit
Quiescent Current (Fixed Output
Voltage Versions)
Temperature Coefficient
Thermal Regulation
Ripple Rejection
∆V
OI
∆V
OL
∆V
I
CL
I
Q
1.1
3.1
7
0.005
0.003
T
C
R
A
T
A
=25°C, 30ms pulse
V
IN
= V
OUT
+ 1.5V
I
OUT
= 10mA
60
75
GM1112
V1.03
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5
GM1112
1A LOW DROPOUT
PRECISION VOLTAGE REGULATOR
Application Information
Stability Considerations
A capacitor of 10uF as a minimum is suggested to be connected in the input terminal and to be as
close as to the input source for better stability consideration. See typical application circuit page 1 for
reference.
The output compensation capacitor helps to determine three main characteristics of a linear
regulator's performance: start-up delay, load transient response, and loop stability. The capacitor
value and type is based on cost, availability, size and temperature constraints. A tantalum or aluminum
electrolytic capacitor is preferred, as a film or ceramic capacitor with almost zero ESR can cause
instability. An aluminum electrolytic capacitor is the least expensive type, but when the circuit operates
at low temperatures, both the value and ESR of the capacitor will vary widely. For optimum
performance over the full operating temperature range, a tantalum capacitor is best. A 22µF tantalum
capacitor will work fine in most applications, but with high current regulators such as the GM1112,
higher capacitance values will improve the transient response and stability. Most applications for the
GM1112 involve large changes in load current, so the output capacitor must supply instantaneous load
current. The ESR of the output capacitor causes an immediate drop in output voltage given by:
△V
=
△I
X ESR
In microprocessor applications an output capacitor network of several tantalum and ceramic capacitors
in parallel is commonly used. This reduces overall ESR and minimizes the instantaneous output
voltage drop under transient load conditions. The output capacitor network should be placed as close
to the load as possible for the best results.
GM1112
V1.03
1
5
51mcu
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