SN431/SNF431
Programmable Voltage Reference
◈
Description
The SN431 series are 3-terminal precision shunt regulators that are programmable over a wide voltage range of
2.495V to 36V with ±0.5%, ±1.0% tolerance. The SN431 series have a low dynamic impedance of 0.15Ω. These
features make the SN431 series an excellent replacement for zener diodes in numerous applications circuits that
require a precision reference voltage.
◈
Features
•
Programmable output voltage from 2.495V to 36V
•
Voltage reference tolerance : ±0.5%, ±1.0%
•
Cathode current capability of 1mA to 100mA
◈
Pin Assignment
(Top View)
A
A
R
R A K
PKG : SOT-89
Apply Device : SN431xF
PKG : SOT-23
Apply Device : SN431xS
PKG : SOT-23
Apply Device : SNF431xS
(Top View)
(Top View)
K
R
K
A
(Top View)
(Marking Side View)
(Marking Side View)
A
R
NC
NC
K
RA K
PKG : SOT-25
Apply Device : SN431xN
PKG : TO-92
Apply Device : SN431x
R A K
PKG : TO-92M
Apply Device : SN431xM
[ K : Cathode,
A: Anode,
R : Reference ]
KSD-I0A013-006
1
SN431/SNF431
◈
Symbol
Cathode(K)
◈
Functional block diagram
Cathode(K)
Reference(R)
+
–
V
REF
=2.495V
Reference(R)
Anode(A)
Anode(A)
◈
Ordering Information
Vref
Tolerance
PKG Type
TO-92
TO-92M
±1%
SOT-23
SOT-23
SOT-25
SOT-89
TO-92
TO-92M
±0.5%
SOT-23
SOT-23
SOT-25
SOT-89
1) SN431x Pin Connection :
3)
□
: Year & Week Code
1. Cathode,
Device Name
SN431A
SN431AM
SN431AS
1)
SNF431AS
2)
SN431AN
SN431AF
SN431B
SN431BM
SN431BS
1)
SNF431BS
2)
SN431BN
SN431BF
2. Reference, 3. Anode
Marking
SN431A
SN431A
4GA□
3)
4KA□
3)
N4A□
3)
SN431A
SN431B
SN431B
4GB□
3)
4KB□
3)
N4B□
3)
SN431B
2) SNF431x Pin Connection : 1. Reference, 2. Cathode, 3. Anode
KSD-I0A013-006
2
SN431/SNF431
◈
Absolute maximum ratings
Characteristic
Cathode to Anode voltage
Cathode current
Reference input current
SOT-23
SOT-25
Power Dissipation
SOT-89
TO-92
TO-92M
Junction Temperature
Operating temperature range
Storage temperature range
[Ta=25℃]
Symbol
V
KA
I
K
I
ref
P
D
(Note1)
P
D
(Note1)
P
D
(Note1)
P
D
(Note2)
P
D
(Note2)
T
J
T
opr
T
stg
Rating
37
150
10
350
400
500
625
400
150
-40 ~ +85
-55 ~ +150
Unit
V
mA
mA
mW
℃
℃
℃
Note 1 : Mounted on a glass epoxy PCB board (25.4 × 25.4mm).T
A
=25℃
Note 2 : T
A
=25℃
◈
Recommended operating conditions
Characteristic
Cathode to Anode voltage
Cathode current
Symbol
V
KA
I
K
Rating
Min.
V
ref
1
Max.
36
100
Unit
V
mA
◈
Electrical Characteristics
(Ta=25
℃
, unless otherwise noted.)
Characteristic
Reference voltage (Fig.1)
Reference input voltage
deviation over temperature
(Fig.1, Note1,2)
Ratio of delta reference input
voltage to delta cathode
voltage (Fig.2)
Reference current (Fig.2)
Reference input current
deviation over temperature
(Fig.2, Note 1,2)
Minimum cathode current
for regulation
Off-state cathode current (Fig.3)
Dynamic impedance (Fig.1, Note3)
Symbol
V
ref
ΔV
ref
ΔV
ref
ΔV
KA
I
ref
ΔI
ref
I
K(MIN)
I
K(off)
Z
KA
Condition
V
KA
=V
ref
, I
K
=10mA
V
KA
=V
ref
, I
K
=10mA
@ -40˚C
≤
Ta
≤
85˚C
I
K
=10mA
V
ref
≤V
KA
≤36V
Min. Typ. Max.
SN431B
SN431A
2.482
2.470
-
2.495
2.508
2.520
30
Unit
V
7
mV
-
-
-
-
-
-
-1.0
1.8
0.4
0.35
2.7
0.15
-2.7
4.0
2.5
1.0
1000
0.5
mV/V
μΑ
μΑ
mΑ
nA
Ω
I
K
=10mA, R1=10KΩ, R2=∞
I
K
=10mA, R1=10KΩ, R2=∞
@ -40˚C
≤
Ta
≤
85˚C
V
KA
=V
ref
V
KA
=36V, V
ref
=0V
V
KA
=V
ref
, f
≤
1.0KHz
1.0mA
≤
I
K
≤
100mA
KSD-I0A013-006
3
SN431/SNF431
Fig. 1 Test circuit for V
KA
=V
ref
Fig. 2 Test circuit for V
KA
>V
ref
Fig. 3 Test circuit for I
K(off)
Input
I
K
V
KA
Input
R1
R2
V
ref
I
K
I
ref
V
KA
Input
V
KA
I
K(off)
V
KA
=
V
ref
×
(1
+
Note.
1. Ambient temperature range: T
LOW
= -40℃, T
High
= 85℃
R
1
)
+
I
ref
×
R
1
R
2
2. The deviation parameters
△V
ref
and
△I
ref
are defined as the difference between the maximum value and minimum value
obtained over the full operating ambient temperature range that applied.
∆V
ref
= V
ref
Max – V
ref
Min
∆Ta
= T
2
– T
1
Ambient Temperature
The average temperature coefficient of the reference input voltage,
α
V
ref
is defined as:
Δ
V
ref
× 10
6
)
ppm
V
ref
(T
a
= 25
℃
)
α
V
ref
(
)=
℃
Δ
T
a
(
Example :
△V
ref
= 30mV and the slope is positive,
△V
ref
@ 25℃ = 2.495V
△Ta
= 70℃
0.03
) × 10
6
ppm
2.495
α
V
ref
(
)=
= 171ppm /
℃
℃
70
(
3. The dynamic impedance Z
KA
is defined as:
Ζ
KA
=
Δ
V
KA
Δ
I
K
When the device is operating with two external resistors, R1 and R2, (refer to Fig.2) the total dynamic impedance of the circuit
is given by:
Ζ
KA '
=
Ζ
KA
× (1 +
R
1
)
R
2
KSD-I0A013-006
4
SN431/SNF431
◈
Electrical Characteristic Curves
Fig.4 V
ref
vs T
A
[%]
0.8
Fig.5 I
ref
vs T
A
Reference Input Current - I
ref
[µA]
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
-60
-40
-20
0
20
40
60
80
100
1.0
0.6
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
-1.0
-60
-40
-20
0
20
40
60
80
100
Reference Voltage Change - V
ref
V
KA
=V
ref
I
K
=10mA
I
K
=10mA
R1=10KΩ
R2=∞
Ambient Temperature - T
A
[℃]
Ambient Temperature - T
A
[℃]
Fig.6 I
KA
vs V
KA
150
125
100
75
50
25
0
-25
-50
-75
-100
-125
-150
-2
800
Fig.7 I
KA
vs V
KA
700
600
500
400
300
200
100
0
-100
-200
-1
0
1
2
3
Cathode Current - I
KA
[mA]
T
A
=25℃
Cathode Current - I
KA
[µA]
V
KA
=V
ref
V
KA
=V
ref
T
A
=25℃
-1
0
1
2
3
Cathode Voltage - V
KA
[V]
Fig.8 I
off
vs T
A
Delta Reference Voltage -
△V
ref
[mV]
Off-State Cathode Current - I
off
[nA]
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
-60
-40
-20
0
20
40
60
80
100
0
-5
-10
-15
-20
-25
0
4
Cathode Voltage - V
KA
[V]
Fig.9
△V
ref
vs V
KA
V
KA
= 36V
V
ref
=0V
I
K
=10mA
T
A
=25℃
8
12
16
20
24
28
32
36
40
Ambient Temperature - T
A
[℃]
Cathode Voltage - V
KA
[V]
KSD-I0A013-006
5
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