Gamma GM431SRAST23RG 2.5v adjustable shunt regulator Datasheet

GM431S
2.5V ADJUSTABLE
SHUNT REGULATOR
Description
Features
The GM431S is a three terminal adjustable
shunt regulator with a specified thermal stability
guaranteed over temperature. The output
voltage can be adjusted to any value between
2.5V (VREF) and 36V by using two external
resistors. Active output circuitry provides a very
sharp turn on characteristic, making the
GM431S an excellent replacement for zener
diodes in many applications such as on board
regulation and adjustable power supplies. The

Sink Current Capability 1mA to 100mA

Fast Turn On Response

Low output noise

0.5%, or 1% reference voltage tolerance

Temperature range -40°C to + 125°C

Available in most advanced Small
SOT23, SOT23, TO92, SOT89 and SO8
packages
The GM431S shunt regulator is available with
two voltage tolerances 0.5%, and 1.0% over full
temperature range and four package options SOT-23, TO-92, SOT-89 and SO-8.
Application
Switching power supplies
Battery-orperated computers
Linear regulator
Computer disk drives
Adjustable supplies
Instrumentation
Logic Symbol
Block Diagram
Cathode
Reference
Cathode
Reference
VREF
Anode
www.gammamicro.com.tw
GM431SV2.01
Anode
1
GM431S
2.5V ADJUSTABLE
SHUNT REGULATORS
Marking Information and Pin Configurations (Top View)
Small SOT23 and SOT23
TO92
Anode
2
SOT89
431Sg
AYWW
431Sg
AYWW
ASxYW
1
Ref
Ref 1
3
Cathode
Ref 1
2
3 Cathode
3 Cathode
2
Anode
Anode
(GM431S)
Anode
2
ASx: Marking Code (see table below)
RSxYW
1
Cathode
RSx: Marking Code (see table below)
3
Ref
g: Grade Code (A: 0.5%, B: 1.0%)
(GM431SR)
A: Assembly/Test Site Code
Y: Year
W: Week code
WW: Week
Ordering Information
GM431SV2.01
Ordering Number
2
Precision
Device Code
Grade
Package
Shipping
GM431SAT92BG
0.5%
A
TO-92
1,000 Units/ESD Bag
GM431SAT92RLG
0.5%
A
TO-92
2,000 Units/Ammo Pack (Tape)
GM431SAST23RG
0.5%
ASA
A
SOT-23
3,000 Units/Tape & Reel
GM431SAST23MRG
0.5%
ASA
A
Small SOT-23
3,000 Units/Tape & Reel
GM431SRAST23RG
0.5%
RSA
A
SOT-23
3,000 Units/Tape & Reel
GM431SAST89RG
0.5%
A
SOT-89
1,000 Units/Tape & Reel
GM431SBT92BG
1.0%
B
TO-92
1,000 Units/ESD Bag
GM431SBT92RLG
1.0%
B
TO-92
2,000 Units/Ammo Pack (Tape)
GM431SBST23RG
1.0%
ASB
B
SOT-23
3,000 Units/Tape & Reel
GM431SBST23MRG
1.0%
ASB
B
Small SOT-23
3,000 Units/Tape & Reel
GM431SRBST23RG
1.0%
RSB
B
SOT-23
3,000 Units/Tape & Reel
GM431BST89RG
1.0%
B
SOT-89
1,000 Units/Tape & Reel
GM431S
2.5V ADJUSTABLE
SHUNT REGULATOR
Absolute Maximum Ratings
PARAMETER
Cathode Voltage
Continuous Cathode Current Range
Reference Input Current Range
Power Dissipation at TA = 25°C
SOT-23
TO-92
SOT-89
Package Thermal Resistance
SOT-23
TO-92
SOT-89
Operating Ambient Temperature Range
Storage Temperature
Lead Temperature (soldering 10 sec.)
SYMBOL
RATINGS
UNITS
VKA
IK
IREF
37
-100 to 150
-50μA to 10mA
V
mA
PD
0.23
0.78
0.8
W
336
132
132
-40 - 125
- 65 to 150
260
JA
TA
°C/W
°C
°C
°C
Recommended Operating Conditions
PARAMETER
Cathode Voltage
Cathode Current
SYMBOL
Min
Max
UNITS
VKA
IK
VREF
1
36
100
V
mA
Equivalent Schematics
Cathode
800
800
20pF
Reference
3.28K
4K
10k
20pF
1K
Anode
GM431SV2.01
2.4K
7.2K
3
GM431S
2.5V ADJUSTABLE
SHUNT REGULATORS
Electrical Characteristics (TA = 25°C unless otherwise specified)
Parameter
Reference
Voltage
Symbol
GM431SA
VREF
GM431SB
VREF Deviation over
Temperature
VREF(DEV)
Condition
VKA = VREF, IK = 10mA,
Test circuit 1
Min
Typ
Max
2487
2500
2513
2475
2500
2525
8
17
Unit
mV
VKA = VREF, IK = 10mA,
TA = 0 to 70°C
VKA = 10V to VREF
-2.7
-1.0
VKA = 36V to 10V
-2
-0.4
mV
Ratio of change in VREF
to change in VKA
VREF/VKA
Reference Input Current
IREF
IK = 10mA, R1 = 10K, R2 = ∞
Test circuit 2
0.5
1.2
µA
IREF Deviation over
Temperature
VREF(DEV)
IK = 10mA, R1 = 10K, R2 = ∞
TA =Full range, Test circuit 2
0.4
1.2
µA
Minimum Cathode
Current
IK(MIN)
VKA = VREF
Test circuit 1
0.4
1.0
mA
Off-state cathode Current
IK(OFF)
VKA = 36V, VREF = 0V
Test circuit 3
0.1
1
µA
Dynamic Impedance
|ZKA|
VKA = VREF, IK = 1mA to 10mA,
f ≤1kHz, Test circuit 1
0.25
0.5
Ω
IK = 10mA
mV/V
Test Circuits
VIN
VKA
IK
VIN
VKA
IK
R1
VIN
VKA
IK(OFF)
IREF
VREF
GM431SV2.01
VREF
4
Test Circuit 1
VKA = VREF
R2
VREF
Test Circuit 2
VKA  VREF
Test Circuit 3
Off-State
GM431S
2.5V ADJUSTABLE
SHUNT REGULATOR
Typical Characteristics
150
Cathode current (mA)
200
800
Cathode current (µA)
1000
600
400
200
0
-200
100
50
0
-50
-100
-400
-0.5
0
0.5 1.0 1.5 2.0 2.5
Cathode Voltage (V)
-150
-2
3.0
3
2.5
0.6
2
0.5
0.4
0.3
0.2
1.5
1
0.5
0.1
0
-40
-20
0 20 40 60 80 100 120
TA Ambient Temperature (˚C)
Figure 6. Reference Input Current vs.
Ambient Temperature
0
0
100K
200K 300K 400K 500K 600K
Frequency (Hz)
Figure 7. Dynamic Impedance
2.500
2.498
2.496
2.494
2.492
2.490
2.488
2.486
-40
-20
0 20 40 60 80 100 120
TA Ambient Temperature (˚C)
Figure 8. Reference Input Voltage vs.
Ambient Temperature
GM431SV2.01
VREF, Reference Input Voltage (V)
1
0
2
Cathode Voltage (V)
Figure 5. Cathode Current vs.
Cathode Voltage
Impedance
IREF, Reference Input Current (mA))
Figure 4. Cathode Current vs.
Cathode Voltage
-1
5
GM431S
2.5V ADJUSTABLE
SHUNT REGULATORS
Design Guide for AC-DC SMPS (Switching Mode Power Supply)
Use of Shunt Regulator in Transformer Secondary side control
This example is applicable to both forward transformers and flyback transformers. A Shunt regulator is
used on the secondary side as an error amplifier, and feedback to the primary side is provided via a
photo-coupler.
Transformer
R1
SBD
R3
GM384X
series
(+)
IF
VF
Phototransistor
IB
Output
VO
R2
C1
Light Emitting
Diode
R5
GM431S
(-)
VREF
R4
Figure 9. Typical Shunt Regulator/ Error Amplifier
Determination of external constants for the Shunt Regulator
DC Characteristic determination: In the application circuit above, R1 and R2 are protection resistors
for the light emitting diode in the photo-coupler, and R2 is a bypass resistor to feed IK Minimum, and
these are determined as shown below. The photo-coupler specification should be obtained separately
from the manufacturer. Using the parameters in this circuit, the following formulas are obtained:
VO – VF - VK
R1 =
IF + IB
VF
R2 =
IB
VK is the GM431S operating voltage, and is set at around 3V, taking into account a margin for
fluctuation. R2 is the current shunt resistance for the 1ight emitting diode, in which a bias current IB of
around 1/5 IF f1ows.
Next, the output voltage can be determined by R3 and R4, and the following formula is obtained:
GM431SV2.01
VO = VREF (
6
R3 + R4
)
R4
VREF = 2.5V Typical
The abSo1ute va1ueS of R3 and R4 are determined by the GM431S reference input current IREF and
the AC characteristics described in the next Section. The IREF va1ue is around 0.7µA Typ.
GM431S
2.5V ADJUSTABLE
SHUNT REGULATOR
AC Characteristic Determination:
This refers to the determination of the gain frequency characteristic of the Shunt regulator as an error
amp1ifier. Taking the configuration in Figure 10, the error amp1ifier characteristic is as Shown in Figure
10.
G1
Gain G (dB)
* fOSC: PWM Switching frequency
G2
When R5= 0
F1
FAC
F2
When R5= 0
fOSC Frequency f (Hz)
Figure 10. GM431S Error Amplification Characteristic
In Figure 17, the following formulas are obtained:
Gain
G1 = G0  50 dB to 60 dB (determined by shunt regulator)
R5
G2 =
R3
Corner frequencies
f1 = 1/
f2 = 1/
pC1G0R3)
pC1R5)
G0 iS the Shunt regulator open-loop gain; this is given by the reciprocal of the reference voltage
fluctuation:
VREF/VKA, and is approximately 50 dB.
R1 =
5V – 1.05V – 3V
= 316Ω
2.5mA + 0.54mA
R2 =
1.05V
0.54mA = 2.1kΩ
Next, assume that R3 = R4 = 10k. This gives a 5V output. If R5 = 3.3 k, and C1 = 0.022 pF, the
following values are found.
G2 = 3.3kΩ / 10kΩ = 0.33 times (-10 dB)
f1 = 1 / (2    0.022µF  316  10 k) = 2.3 (Hz)
f1 = 1 / (2    0.022µF  3.3k) = 2.2 (kHz) 2
GM431SV2.01
Practical Example
Consider the example of a photocoupler, with an internal light emitting diode VF = 1.05 V and IF = 2.5mA,
power supply output vo1tage V2 = 5V, and bias resistance R2 current of approximately 1/5 IF at 0.5mA.
If the Shunt regulator VK = 3V, the following values are found.
7
GM431S
2.5V ADJUSTABLE
SHUNT REGULATORS
Package Outline Dimensions – Small SOT 23
0.012 – 0.020
(0.300 – 0.500)
0.089 – 0.100
(2.250 – 2.550)
0.110 – 0.118
(2.800 – 3.000)
0.012 – 0.020
(0.300 – 0.500)
8°
0.010
(0.250)
0.047 – 0.055
(1.200 – 1.400)
0.022
(0.550)
Ref
0.037
(0.095)
Typ
.
0.071 – 0.079
(1.800 – 2.000)
0.003 – 0.006
(0.080 – 0.150)
0.000 – 0.004
(0.000 – 0.100)
0.035 – 0.045
(0.900 – 1.150)
0.035 – 0.041
(0.900 – 1.105)
GM431SV2.01
Inch
(mm)
8
GM431S
2.5V ADJUSTABLE
SHUNT REGULATOR
Package Outline Dimensions – SOT 23
0.110 – 0.120
(2.80 – 3.04)
0.003 – 0.007
(0.08 – 0.18)
0.013 – 0.017
(0.34 – 0.44)
0.063 – 0.104
(2.11 – 2.62)
0.047 – 0.055
(1.20 – 1.40)
0 - 8° typ
0.075
(1.91) Typ.
0.037
(0.93) Typ.
0.0150 – 0.0200
(0.382 – 0.508)
0.0005 – 0.0040
(0.025 – 0.102)
Package Outline Dimensions – SOT 89
0.173 – 0.181
(4.39 – 4.59)
0.061 REF
1.550 REF
0.084 – 0.090
(2.13 – 2.28)
0.155 – 0.167
(3.94 – 4.24)
0.055 – 0.063
(1.39 – 1.60)
0.014 – 0.017
(0.35 – 0.43)
0.090 – 0.102
(2.28 – 2.59)
8°
0.035 – 0.047
(0.89 – 1.19)
0.016 – 0.023
(0.400 – 0.580)
0.013 – 0.021
(0.320 – 0.520)
0.059 BSC
(1.49) BSC
GM431SV2.01
0.118 BSC
(2.99) BSC
9
GM431S
2.5V ADJUSTABLE
SHUNT 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
0.189 – 0.197
(4.800 – 5.004)
0.228 – 0.244
(5.791 – 6.198)
0.016 – 0.050
(0.406 – 0.270)
GM431SV2.01
0.014 – 0.020
(0.356 – 0.508)
10
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)
GM431S
2.5V ADJUSTABLE
SHUNT REGULATOR
Ordering Number
GM 431S A
APM
Gamma
Micro
Circuit
Type
Output
Accuracy
A: 0.5%
B: 1.0%
GM 431SR A
APM
Gamma
Micro
Circuit
Type
Output
Accuracy
A: 0.5%
B: 1.0%
ST23
R
G
Package Type
Shipping Type
G:Green
T92: TO92
ST23:SOT23
ST23M: Small SOT23
ST89: SOT89
S8: SO8
B: Bag
RL: Ammo Pack (Tape)
T: Tube
R: Tape & Reel
ST23
R
G
Package Type
Shipping Type
T92: TO92
ST23:SOT23
ST23M: Small SOT23
ST89: SOT89
S8: SO8
B: Bag
RL: Ammo Pack (Tape)
T: Tube
R: Tape & Reel
G:Green
Note:
Pb-free products:

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.

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)
GM431SV2.01
Green products:
11
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