GAMMA GM2950

GM2950/GM2951
100mA, LOW DROPOUT
VOLTAGE REGULATORS
Description
Features
The GM2950 and GM2951 is a low power voltage
regulator. This device is an excellent choice for use
in battery powered application such as cordless
telephone, radio control systems, and portable
computers.

High accuracy output voltage

Guaranteed 100mA output

Very low quiescent current

Low dropout voltage

Extremely tight load and line
regulation

Very low temperature coefficient

Needs only 1μF capacitor for stability

Error flag warns of output dropout

Logic-controlled electronic shutdown

Output programmable from 1.24V to
29V
The GM2950/GM2951 features very low quiescent
current (75µA Typ.) and very low drop output
voltage (Typ. 40mV at light load and 380mV at
100mA). This includes a tight initial tolerance of
0.5% typ., extremely good load and line regulation
of 0.05% typ., and very low output temperature
coefficient, making the GM2950/ GM2951 useful as
a low power voltage reference.
The GM2951 is available in 8-pin plastic packages.
The regulator output voltage may be pin-strapped
for a -XX volt or programmed from 1.24 volt to 29
volts with external pair of resistors.
The GM2950 is offered in 3-pin TO-92 package
compatible with other fixed regulator.
Applications

Battery powered systems

Portable consumer equipments

Cordless telephones

Portable Instruments

Radio control systems

Automotive electronics

Portable/Palm top/Notebook computers

SMPS Post regulator

Voltage Reference
Shutdown
n
1V
OUT
VIN 8
2 SENSE
FB 7
3 SD
COUT
3.3μF 100K
4 GND
VIN
VTAP 6
ERROR 5
CIN
Error Output
GND
GND
1
Preliminary Information
GM2951-x.x
VOUT
GM2950/GM2951 V2.00
Typical Application Circuit
GM2950/GM2951
100mA, LOW DROPOUT
VOLTAGE REGULATORS
Marking Information and Pin Configurations (Top View)
GM2950-x.x
TO-92
GM2950G
VV
AYWW
VOUT 1
2 3 VIN
GND
G: Green Product
VV: Output Voltage Codes (05: 5.0V, …12:12V)
A: Assembly/Test Site Code
Y: Year
WW: Week
Marking Information and Pin Configurations (Top View)
GM2951-x.x
SO8
2. Sense
3. SD
GM2950/GM2951 V2.00
4. GND
2
GM2951G
VVAYWW
1. VOUT
8.VIN
7. GND
6. VTAP
5. Error
G: Green Product
VV: Output Voltage Codes (A: Adj, 05: 5.0V, …12:12V)
A: Assembly/Test Site Code
Y: Year
WW: Week
GM2950/GM2951
100mA, LOW DROPOUT
VOLTAGE REGULATORS
Ordering Information
GM2950-x.x
Ordering Number
Output voltage
Package
Shipping
GM2950-3.3T92BG
3.3V
TO-92
1,000 Units/ESD Bag
GM2950-3.3T92RLG
3.3V
TO-92
2,000 Units/Ammo Pack (Tape)
GM2950-5.0T92BG
5.0V
TO-92
1,000 Units/ESD Bag
GM2950-5.0T92RLG
5.0V
TO-92
2,000 Units/Ammo Pack (Tape)
GM2951-3.3S8RG
3.3V
SO-8
2,500 Units/Tape & Reel
GM2951-5.0S8RG
5.0V
SO-8
2,500 Units/Tape & Reel
3
Preliminary Information
GM2950/GM2951 V2.00
GM2951-x.x
GM2950/GM2951
100mA, LOW DROPOUT
VOLTAGE REGULATORS
Absolute Maximum Ratings
PARAMETER
SYMBOL
RATINGS
UNITS
VIN Pin Voltage
VIN
-0.3 to +30
V
FB Pin Voltage
VFB
-1.5 to +30
V
SD Pin Voltage
VSD
-0.3 to +30
V
Error Pin Voltage
VERR
-0.3 to +30
V
TJ
- 40 to +150
°C
TSTG
- 65 to +150
°C
Thermal Resistance, Junction to Ambient (SO8 package)
θJA
180
°C/W
Thermal Resistance, Junction to Ambient (SO8 package)
θJC
45
°C/W
Lead Temperature 1.6mm (1/6 inch) from case for 5
seconds
TLEAD
260
°C
ESD Rating (Human Body Model)
ESD
2
kV
Operating Junction Temperature Range
GM2950/GM2951 V2.00
Storage Temperature
4
GM2950/GM2951
100mA, LOW DROPOUT
VOLTAGE REGULATORS
Block Diagram
VIN
VOUT
Error
Amplifier
60K
1.23V
Reference
GND
GM2950-x.x Block Diagram
FB
VIN
VOUT
SENSE
SD
*
60K
60mV
1.23V
Reference
VTAP
Error
Detection
Comparator
ERROR
GND
GM2951-x.x Block Diagram
* for fixed output voltage option only
5
Preliminary Information
Error
Amplifier
GM2950/GM2951 V2.00
*
GM2950/GM2951
100mA, LOW DROPOUT
VOLTAGE REGULATORS
Electrical Characteristics
(Unless otherwise noted, VIN = VOUT + 1V, IOUT = 100μA, COUT = 1μF,
and TJ = 25°C)
Parameter
Output Voltage
Symbol
VOUT
Output Voltage
Temperature Coefficient
Test Condition
(Note 1)
Min
Typ
Max
TJ = 25°C
0.99VOTYP
VOTYP
1.01VOTYP
-25°C ≤ TJ ≤ 85°C
0.985VOTYP
VOTYP
1.015VOTYP
Full Operating
Temperature
0.98VOTYP
VOTYP
1.02VOTYP
50
150
ppm/°C
(Note 2)
Unit
V
Line Regulation
LNR
VOUT + 1V ≤ VIN ≤ 30V
0.04
0.2
%
Load Regulation (Note 3)
LDR
100μA ≤ IOUT ≤ 100mA
0.1
0.3
%
Dropout Voltage (Note 4)
VD
IOUT = 100μA
50
80
IOUT = 100mA
380
450
IOUT = 100μA
75
120
μA
IOUT = 100mA
3
12
mA
mV
Ground Current
IGND
Dropout Ground Current
IDG
VIN = VOUT – 0.5V,
IOUT = 100μA
110
170
μA
Current Limit
ICL
VOUT = 0V
160
200
mA
0.05
0.2
%/W
Thermal Regulation
TREG
Output Noise, 10Hz to
100KHz
COUT = 1μF
430
COUT = 200μF
160
μVRMS
COUT = 3μF
(Bypass = 0.01, pin 7 to
pin 1, GM2951-x.x Only)
100
GM2951-x.x Only
1.21
GM2950/GM2951 V2.00
Reference Voltage
6
Feedback Pin Bias
Current
Reference Voltage
Temperature Coefficient
Feedback Pin Bias
Current Temperature
Coefficient
VREF
Full Operating
Temperature
1.235
1.185
IFB
1.285
20
(Note 2)
1.26
40
V
nA
50
ppm/°C
0.1
nA/°C
ERROR COMPARAMETER
Output Leakage Current
ILK
VOH = 30V
0.01
1.0
μA
Output Low Voltage
VOL
VIN = 4.5V, IOUT = 400μA
150
250
mV
Upper Threshold Voltage
VTHH
Note 6
Lower Threshold Voltage
VTHL
Note 6
Hysteresis
VHYS
40
60
75
15
mV
95
mV
mV
GM2950/GM2951
100mA, LOW DROPOUT
VOLTAGE REGULATORS
Electrical Characteristics
(Unless otherwise noted, VIN = VOUT + 1V, IOUT = 100μA, COUT = 1μF,
and TJ = 25°C)
Parameter
Symbol
Test Condition
(Note 1)
Min
Typ
Max
Unit
0.7
V
SHUTDOWN INPUT
Input Logic Voltage Low
Regulator ON
Input Logic Voltage Low
Regulator OFF
Shutdown Pin Input
Current
ISD
2
VSD = 2.4V
30
50
VSD = 30V
450
600
3
10
VOUT = 5.0V
Regulator Output Current
in Shutdown (Note 7)
3.3V ≤ VOUT < 5.0V
20
2.0V ≤ VOUT < 3.3V
30
μA
μA
Additional conditions for GM2951 series are the FB tied to V TAP and VOUT Tied to SENSE and VSD ≤ 0.8V
2.
Output or Reference voltage temperature coefficients are defined as the worst case voltage change divided
by the total temperature range.
3.
The Regulation is measured at a constant junction temperature using pulse testing with a low duty cycle.
Changes in the output voltage due to heating effects are covered under the specification for thermal
regulation.
4.
The Dropout voltage is defined as the input-to-output differential, at which the output voltage drops 100mV
below it nominal value measure at 1V differential. At very low values of programmed output voltage, the
minimum input supply voltage (2V) (2.3V over temperature) must be taken into account.
5.
VREF ≤ VOUT ≤ (VIN -1V), 2.3V ≤ VIN ≤ 30V, 100μA ≤ IOUT ≤ 100mA, TJ ≤ TJMAX
6.
Comparator thresholds are expressed in terms of a voltage differential at the FB terminal below the nominal
reference voltage measured at VOUT + 1V input. To express these thresholds in terms of an output voltage
change, multiply by the error amplifier gain = VOUT/VREF = (R1 + R2)/R2. For examples, at a programmed
output voltage of 5V, the Error output is guaranteed to go low when the output drops by 95mV x 5V/1.235V
= 384mV. Thresholds remain constant as a percent of VOUT as VOUT is varied, with the dropout warning
occurring at typically 5% below nominal, 7.5% guaranteed.
7.
VSD ≥ 2V, VIN ≤ 30V, VOUT = 0, the FB pin is tied to VTAP.
7
Preliminary Information
1.
GM2950/GM2951 V2.00
Notes:
GM2950/GM2951
100mA, LOW DROPOUT
VOLTAGE REGULATORS
Application Notes

External Capacitors
For better stability, it recommended to use a 1.0μF or greater capacitor tied between V OUT and
GND. The ESR of about 5Ω or less and resonant frequency above 500KHz are important
parameters in the value of capacitor. The capacitor value can be varied, at lower output current,
less output capacitance is required. For the currents below 10mA, the value of capacitor can
reduced to 0.33μF, and 0.1μF for 1mA.
More output capacitance is needed for GM2951 family at voltage below 5V since it runs the error
amplifier at lower gain. At worst case, 3.3μF or greater must be used for condition of 100mA load
at 1.25v output.
If GM2951 is connected to battery or between AC filter capacitor and input is 10 inches wire then
1μF tantalum or aluminum electrolytic capacitor should be connected between V IN and GND.
Instability can occur if stray capacitor to FB terminal (Pin 7). This could be eliminated by a 100pF
capacitor between VOUT and FB pins and increasing output capacitor to 3.3μF.

Reducing Output Noise
To reduce the AC noise presented at VOUT pins, one of the workable approaches is to reduce the
regulator bandwidth by increasing the output capacitor value. However, this approach is not
relatively efficient. It is recommended to use a bypass capacitor across R1 sine it reduces the
high frequency gain from 4 to unity. With the bypass capacitor, noise no longer scales with output
voltage so the improvements are more efficient.

Programming the Output Voltage
The GM2951 output voltage is programmable from 1.24V to 29V by external resistors shown in
figure below. Compared with fixed output voltage option, Pin 2 and Pin 6 are left open and the
external resistors R1 and R2 set the VOUT by the formula:
VOUT = VREF x (1 + R1/R2)
Where VREF is 1.235V
GM2951-A
GM2950/GM2951 V2.00
VOUT
8
Shutdown
n
1 VOUT
VIN 8
2 SENSE
FB 7
3 SD
COUT
3.3μF
CBYPASS
0.1μF
100K
R1
4 GND
VIN
VTAP 6
ERROR 5
CIN
See Application
Note
Error Output
VREF
GND
R2
GND
GM2950/GM2951
100mA, LOW DROPOUT
VOLTAGE REGULATORS
Package Outline Dimensions – TO 92
3.85 – 4.19
4.7 – 5.2
4.9 – 5.2
12.7 – 14..2
0.4 – 0.55 typ.
1.22 – 1.32
Package Outline Dimensions – SO 8
0.016 – 0.050
(0.406 – 0.270)
0.014 – 0.020
(0.356 – 0.508)
0.050
(1.270)
Typ
.
0.150 – 0.157
(3.810 – 3.988)
8.0°
Max
0.053 – 0.059
(1.346 – 1.753)
Seating Plan
0.004 – 0.010
(0.102 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
9
Preliminary Information
0.228 – 0.244
(5.791 – 6.198)
GM2950/GM2951 V2.00
0.189 – 0.197
(4.800 – 5.004)
GM2950/GM2951
100mA, LOW DROPOUT
VOLTAGE REGULATORS
Ordering Number
GM 2950 - 3.3
APM
Gamma
Micro
Circuit
T yp e
T92
B
Output
Voltage
P a c k a g e T yp e
S h i p p i n g T yp e
3.3 = 3.3V
5.0 = 5.0V
T92: TO 92
ST89: SOT 89
ST23: SOT 23
B: Bag
S8
R
Output
Voltage
P a c k a g e T yp e
S h i p p i n g T yp e
A = Adj
3.3 = 3.3V
5.0 = 5.0V
S8: SO 8
T: Tube
R: Tape & Reel
G
G:Green
RL: Ammo Pack (Tape)
T: Tube
R: Tape & Reel
Ordering Number
GM 2951 - 2.2
APM
Gamma
Micro
Circuit
T yp e
G
Blank :Pb-free
G:Green
Note:
GM2950/GM2951 V2.00
Pb-free products:
10

RoHS compliant and compatible with the current require-ments of IPC/JEDEC J-STD-020.

Suitable for use in Pb-free soldering processes with 100% matte tin (Sn) plating.
Green products:

Lead-free (RoHS compliant)

Halogen free(Br or Cl does not exceed 900ppm by weight in homogeneous material and total of
Br and Cl does not exceed 1500ppm by weight)