SS6431G
Adjustable High-Precision Shunt Regulator
FEATURES
Precision reference voltage.
SS6431G:
2.495V
±0.5%
Sink current capability of 200mA.
Minimum cathode current for regulation of 250µA.
Equivalent full-range temperature coefficient of
50 ppm/°C.
Fast turn-on response.
Low dynamic output impedance of 80 milliohms.
Adjustable output voltage.
Low output noise.
Space saving packages: SOT-89, SOT-23, TO-
92 and SO-8.
DESCRIPTION
The SS6431G is a three-terminal adjustable
precision shunt regulator with guaranteed
temperature stability over the applicable ex-
tended commercial temperature range. The
output voltage may be set at any level greater
than 2.495V (V
REF
) up to 30V merely by se-
lecting two external resistors that act as a
voltage divider network.
This device has a
typical output impedance of 0.08Ω. Active
output circuitry provides a very sharp turn-on
characteristic, making this device an excellent
improved replacement for zener diodes in
many applications.
The precise
±0.5%
reference voltage tolerance
of the SS6431G makes it possible in many
applications to avoid the use of a variable
resistor, consequently saving cost and
eliminating the drift and reliability problems
associated with it.
Pb-free lead finish (second-level interconnect).
APPLICATIONS
Linear regulators.
Adjustable supplies.
Switching power supplies.
Battery operated computers.
Instrumentation.
Computer disk drives.
TYPICAL APPLICATION CIRCUIT
V
IN
+
C1
SS6431G
V
OUT
R3
R1 +
C2
R2
V
OUT
= (1+R1/R2) VREF
Precision Regulator
2/10/2005 Rev.2.10
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SS6431G
ORDERING INFORMATION
SS6431GXXXX
Packing type
TR: Tape and reel
TB: Tube (for SO-8)
Package type
S: Small outline
US: SOT-23
UN: SOT-23
X: SOT-89
Z: TO-92
Example: SS6431GSTR
à
in SO-8 package, with Pb-free
lead finish, shipped on tape and reel.
PIN CONFIGURATION
SO-8 (GS)
TOP VIEW
CATHODE
ANODE
ANODE
NC
1
2
3
4
8 REF
7 ANODE
6 ANODE
5 NC
SOT-23 (GUN)
FRONT VIEW
1: CATHODE
2: VREF
3: ANODE
SOT-23 (GUS)
FRONT VIEW
1: VREF
2: CATHODE
3: ANODE
3
1
3
2
1
2
SOT-89 (GX)
FRONT VIEW
1: VREF
2: ANODE
3: CATHODE
TO-92 (GZ)
FRONT VIEW
1: VREF
2: ANODE
3: CATHODE
1
2
3
1
2
3
ABSOLUTE MAXIMUM RATINGS
Cathode Voltage ........……………...............……………..………...............................30V
Continuous Cathode Current ...................………….……......................
-10mA
~ 250mA
Reference Input Current Range .......…………........……..........…………………… 10mA
Operating Temperature Range, T
A
.......………….........….........…………….
-40°C
~ 85°C
Lead Temperature.......…………..................………………..………………………. 260°C
Storage Temperature.......…………..................……………..……………..
-65°C
~ 150°C
Power Dissipation
(Notes 1, 2)
SOT-89 Package .........…………...... 0.80W
TO-92 Package ….......…………....... 0.78W
Note 1:
TJ, max = 150°C.
Note 2:
Ratings apply to ambient temperature at 25°C.
2/10/2005 Rev.2.10
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SS6431G
TEST CIRCUITS
IN
IN
I
IN
R1
I
REF
I
IN
V
Z
SS6431G
V
Z
I
REF
I
Z
V
REF
SS6431G
I
Z
R2
V
REF
Z
=V
REF
(1+R1/R2)+I
REF
xR1
Fig. 1 Test Circuit for VZ=VREF
Fig. 2 Test Circuit for VZ>VREF
IN
V
Z
I
Z(OFF)
SS6431G
Fig. 3 Test Circuit for off-state Current
ELECTRICAL CHARACTERISTICS
(TA=25°C, unless otherwise specified.)
PARAMETER
Reference Voltage
TEST CONDITIONS
V
Z
=V
REF
,
I
IN
=10mA (Fig.1)
V
Z
= V
REF
, I
IN
=10mA,
T
A
= 0°C~ +70°C (Fig. 1)
T
A
= -40°C~ +85°C (Fig. 1)
Ratio of the Change in Ref-
erence Voltage to the
Change in Cathode voltage
I
Z
=10mA
(Fig. 2)
∆V
Z
=10V-V
REF
∆V
Z
=30V-10V
∆V
REF
∆V
Z
V
DEV
9.0
9.0
-0.5
-0.35
20
50
-2.0
-1.5
mV/V
mV/V
mV
V
REF
2.482
2.495
2.508
V
SYMBOL
MIN.
TYP.
MAX.
UNIT
Deviation of Reference
Input Voltage Over
Temperature
(Note 3)
2/10/2005 Rev.2.10
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SS6431G
ELECTRICAL CHARACTERISTICS
(Continued)
PARAMETER
Reference Input Current
Deviation of Reference Input
Current over Temperature
R1 =10kΩ, R2=
∞
,
I
IN
=10mA (Fig. 2)
TEST CONDITIONS
SYMBOL
MIN.
TYP.
0.8
MAX.
3.5
UNIT
µA
I
REF
R1 =10kΩ, R2=
∞
,
I
IN
=10mA
T
A
=-40°C ~ +85°C (Fig. 2)
V
Z
=V
REF
(Fig. 1)
V
Z
=20V, V
REF
=0V (Fig. 3)
V
Z
=V
REF
F<1kHz (Fig. 1)
αI
REF
I
Z(MIN)
I
Z(OFF)
R
Z
0.3
0.25
0.1
0.08
1.2
0.5
1.0
0.3
µA
mA
µA
Ω
Minimum Cathode current
for Regulation
Off-State Current
Dynamic Output Impedance
(Note 4)
V
MAX
V
DEV
= V
MAX
-V
MIN
V
MIN
Where:
T
2
−
T
1
=full temperature change.
αV
REF
can be positive or negative depending on
whether the slope is positive or negative.
Example: V
DEV
= 9.0mV, V
REF
= 2495mV,
T
2
−
T
1
= 70°C, slope is negative.
α
V
REF
=
T
1
TEMPERATURE
T
2
9.0mV
106
2495mV
70
°
C
= −
50ppm/
°
C
Note 3.
Deviation of reference input voltage, V
DEV
, is de-
fined as the maximum variation of the reference input
voltage over the full temperature range.
The average temperature coefficient of the reference in-
put voltage,
αV
REF
is defined as:
Note 4.
The dynamic output impedance, Rz, is de-
fined as:
R
Z
=
∆
V
Z
∆
I
Z
6
V
MAX
- V
MIN
6
V
DEV
±
±
10
10
V
REF
(at 25
°
C)
V
REF
(at 25
°
C)
ppm
=
∆
V
REF
=
T2
−
T1
T2
−
T1
°
C
When the device is programmed with two external re-
sistors, R1 and R2, (see Fig. 2), the dynamic output
impedance of the overall circuit, is defined as:
r
z
=
∆
V
≅
Rz
1
+
R1
R2
∆
I
[ ]
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SS6431G
TYPICAL PERFORMANCE CHARACTERISTICS
1000
800
600
400
200
0
-200
-400
-600
-1.0
2.58
Reference Voltage (V)
V
Z
=V
REF
T
A
=25°C
2.56
V
Z
=V
REF
I
Z
=10mA
V
REF
=2.535V
I
Z(MIN)
Cathode Current (µA)
2.54
2.52
2.50
2.48
2.46
2.44
2.42
V
REF
=2.495V
V
REF
=2.455V
-20
0
20
40
60
80
100
120
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
2.40
-40
Cathode Voltage (V)
Fig. 4 Cathode Current vs. Cathode Voltage
Temperature (°C)
Fig. 5 Reference Voltage vs. Temperature
1.20
0.28
Reference Input Current (µA)
1.15
1.10
1.05
1.00
0.95
0.90
0.85
0.80
0.75
0.70
-40
Dynamic Impedance (Ω)
R1=10KΩ
R2=∞
I
Z
=10mA
0.24
V
Z
=V
REF
I
Z
=1mA to100mA
F <1KHz
0.20
0.16
0.12
0.08
0.04
-20
0
20
40
60
80
100
120
0.00
-40
-20
0
20
40
60
80
100
120
Temperature (°C)
Fig. 6 Reference Input Current vs. Temperature
Temperature (°C)
Fig. 7 Dynamic Impedance vs. Temperature
Change in Reference Voltage (mV)
0
2.5
-1
Off-State Cathode Current (µA)
2.0
I
Z
=10mA
-2
V
REF
=0V
1.5
T
A
=25°C
V
Z
=30V
-3
1.0
-4
-5
0.5
-6
0
5
10
15
20
25
30
35
40
0.0
-40
-20
0
20
40
60
80
100
120
Cathode Voltage (V)
Fig. 8 Change in Reference Voltage vs. Cathode Voltage
Temperature (°C)
Fig. 9 Off-State Cathode Current vs. Temperature
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