WSL
431
Adjustable Precision Shunt Regulator
Features
•
•
•
•
•
•
•
•
Precise Reference Voltage to 2.505V
Guaranteed 0.5%, 1% and 2% Reference
Voltage Tolerance
Sink Current Capability, 1mA to 100mA
Quick Turn-on
Adjustable Output Voltage, Vo = V
ref
to 20V
Low Operational Cathode Current, 150µA
Typical
0.1Ω Typical Output Impedance
SOT-89 , TO-92 and SOT-23 Packages
This device has a typical output impedance of
o.1Ω. Active output circuitry provides a very
sharp turn-on characteristic, making the
WSL431 excellent replacements for zener diodes
in many applications, including on-board
Regulation and adjustable power supplies.
Applications
• Linear Regulators
• Adjustable Power Supply
• Switching Power Supply
REF ANODE
CATHODE
General Description
The WSL431 is a 3 terminal adjustable voltage
reference with specified thermal stability over
applicable commercial temperature ranges.
Output voltage may be set to any value between
Vref (2.505V) and 20V with two external
resistors (see Figure 2).
When used with a photocoupler, the WSL431 is
an ideal voltage reference in isolated feedback
circuits for 2.505V to 12V switching-mode
power supplies.
SOT-89 (Top View)
TO-92
SOT-23 (Top View)
Winson reserves the right to make changes to improve reliability or manufacturability.
©Winson, Jan. 2000 (Rev. C)
WSL
431
Ordering Information
WSL431-XP□□
Elec. Grad
2: 0.5% Reference Voltage Tolerance
3: 1% Reference Voltage Tolerance
4: 2% Reference Voltage Tolerance
Package Code
A: TO-92
C: SOT-23
N: SOT-89
Elec. Grade
Package Code
Symbol
REF
ANODE
CATHODE
Functional Diagram
Winson reserves the right to make changes to improve reliability or manufacturability.
©Winson, Jan. 2000 (Rev. C)
WSL
431
Absolute Maximum Ratings
Symbol
V
KA
I
K
I
ref
T
A
T
J
T
STG
T
SO
Parameter
Cathode voltage
Continuous cathode current range
Reference current range
Ambient temperature range
Junction temperature range
Storage Temperature Range
Lead temperature range, T
s
(Soldering,
10sec)
Rating
26
150
3
0 to 85
0 to 125
-65 to 150
260
Unit
V
mA
mA
˚C
˚C
˚C
˚C
Electrical Characteristics
Symbol
Parameter
V
KA
=Vref, I
K
=10mA.
T
A
= 25˚C (unless otherwise noted)
Test Conditions
Min.
WSL431
Typ.
Max.
Unit
V
ref
∆V
ref
/T
∆V
ref
/∆V
KA
I
ref
∆I
ref
/T
I
K(min)
I
K(off)
Reference Voltage Drift over
Temp. range
Voltage Ration
(open loop gain)
Reference Current
Reference Current Drift
WSL431B
WSL431C
WSL431D
T
A
=0 to 85°C
*1
, I
k
=10mA.
I
K
=10 mA, V
KA
=Vref to 20V
*2
I
K
=10mA,
R
1
=10KΩ, R
2
=open
*2
I
K
=10 mA,
R
1
=10KΩ, R
2
=open, TA=0 to
85°C
*2
V
KA
=Vref
*1
V
KA
=20V, Vref=0V
*3
V
KA
=Vref, IK=1 mA to 100mA,
f=1k Hz*1
2.4925
2.480
2.455
2.505 2.5175
2.505 2.530
2.505 2.555
4
20
- 1.6
0.4
0.4
3.5
1.2
mV
mV/
V
µA
µA
-4
z
KA
Notes:
*1
Min. Cathode Current
Off-state Cathode Current
Dynamic Impedance
-0.4
0.15
0.1
-0.1
0.4
1
mA
µA
Ω
: use Figure 1
*2
: use Figure 2
*3
: use Figure 3
Winson reserves the right to make changes to improve reliability or manufacturability.
©Winson, Jan. 2000 (Rev. C)
WSL
431
Test figures
Figure 1. Test Circuit for V
KA
=V
REF
V
O
=V
KA
=V
REF
Figure 2. Test Circuit for V
KA
<V
REF
,
V
O
=V
KA
=V
REF
×(1+R
1
/R
2
)+I
REF
×R
1
Figure 3. Test Circuit for I
k(off)
Winson reserves the right to make changes to improve reliability or manufacturability.
©Winson, Jan. 2000 (Rev. C)
WSL
431
TYPICAL CHARACTERISTICS
Vref. vs Free-Air Temperature
2.525
2.52
2.515
2.51
0.6
0.5
0.4
2.518 V
2.499 V
2.480 V
Iref vs Free-Air Tem
perature
Vref. (V)
2.505
2.5
2.495
2.49
2.485
2.48
2.475
Iref. (uA)
0.3
0.2
0.1
0
20
30
40
50
60
70
o
80
90
100 110 120
20
30
40
50
60
70
o
80
90
100
110
120
C
C
Ik(off) vs Free-Air Temperature
1.4
1.2
1
0.8
0.6
0.4
0.2
0
-0.2
0
20
40
60
o
Ratio of Delta Vref to Delta Vk vs Temperature
0
10
20
30
40
50
60
70
80
90
100
110
120
-0.5
dVref/dVk (mv/v)
80
C
100
120
140
Ik(off) - (uA)
-1
-1.5
-2
-2.5
-3
-3.5
o
Cathode Current vs Cathode Voltage
800
700
600
500
I
KA
- uA
C
V
KA
=V
ref
T
A
=25°C
400
300
200
100
0
-100
-200
-1
-0.5
0
0.5
1
V
KA
- V
I
min
1.5
2
2.5
3
Winson reserves the right to make changes to improve reliability or manufacturability.
©Winson, Jan. 2000 (Rev. C)
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