Precision Adjustable
Shunt Reference
CL2431
FEATURES
Temperature-Compensated: 30ppm/
o
C
Trimmed 0.5% Bandgap Reference
Internal Amplifier with 100mA Capability
Temperature Range: Extended to 0 to 105
o
C
Low Frequency Dynamic Output Impedance: < 150m
Low Output Noise
SOT-23 Replacement for TL431
DESCRIPTION
ORDERING INFORMATION
Part
Package
Tolerance
Temperature Range
CL2431VS
SOT-23
1.0%
0 to +105
o
C
CL2431AVS
SOT-23
0.5%
0 to +105
o
C
CL2431IVS
SOT-23
1.0%
-40 to +85
o
C
CL2431IAVS
SOT-23
0.5%
-40 to +85
o
C
CORPORATION
CALOGIC CORPORATION,
237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
PIN CONFIGURATION (Top View)
The CL2431 is a three terminal adjustable voltage reference
designed to act as an open-loop error amplifier with a 2.5V
temperature compensated reference. Operating as a low
temperature coefficient zener which is programmable from
V
REF
to 18V with two external resistors while providing a wide
operating current range of 1.0mA to 100mA with a typical
dynamic impedance of 0.15
. As a shunt regulator the
device can be used as either a positive or negative voltage
reference. Active output circuitry provides a very sharp
turn-on characteristic, making the CL2431 an excellent
replacement for low-voltage zener diodes in many
applications, including on-board regulation and adjustable
power supplies.
1J-22
CATHODE
REFERENCE
SOT-23 (VS)
ANODE
CL2431
CORPORATION
ABSOLUTE MAXIMUM RATINGS
SYMBOL
PARAMETER
RATING
UNITS
V
KA
Cathode-Anode Reverse Breakdown
18
V
I
AK
Anode-Cathode Forward Current
1
A
I
KA
Operating Cathode Current
100
mA
I
REF
Reference Input Current
1
mA
P
D
Continuous Power Dissipation at 25
o
C
SOT-23
200
mW
T
J
Junction Temperature
150
o
C
T
STG
Storage Temperature
65 to 150
o
C
T
L
Lead Temperature, Soldering 10 Seconds
300
o
C
Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the device. This is a stress rating
only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification
is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability.
RECOMMENDED CONDITIONS
SYMBOL
PARAMETER
RATING
UNIT
V
KA
Cathode Voltage
V
REF
to 18
V
I
K
Cathode Current
10
mA
TYPICAL THERMAL RESISTANCES
PACKAGE
JA
JC
TYPICAL DERATING
SOT-23
575
o
C/W
150
o
C/W
1.7mW/
o
C
CALOGIC CORPORATION,
237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
1G-36
ANODE (A)
CATHODE (K)
2.5V
REFERENCE (R)
+
FUNCTIONAL BLOCK DIAGRAM
CL2431
CORPORATION
CALOGIC CORPORATION,
237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
0
TEMPERATURE (C)
0.019 mV/C
0.001 %/C
7.6 ppm/C
0.2
2000
0
0
0
mV
%
ppm
5
1J-28
15
30
45
60
75
90 105
10
V
REF
T
TC
in
mV
/
o
C
=
V
REF
(
mV
)
T
A
TC
in
%
/
o
C
=
V
REF
V
REF
at
25
o
C
x 100
T
A
TC
in
ppm
/
o
C
=
V
REF
V
REF
at 25
o
C
x 10
6
T
A
*CALCULATING AVERAGE TEMPERATURE COEFFICIENT (TC)
TEST CIRCUITS
IN
V
KA
V
K
I
1G-38
REF
I
REF
= V
REF
I
IN
V
KA
V
2
R
1
R
REF
(V
)
K
I
1G-39
IN
V
KA
V
K(OFF)
I
1G-40
TEST CIRCUIT 1
TEST CIRCUIT 2
TEST CIRCUIT 3
ELECTRICAL CHARACTERISTICS
Electrical characteristics are guaranteed over full junction temperature range (0 to 105
o
C). Ambient temperature must be derated based on
power dissipation and package thermal characteristics. The conditions are: V
KA
= V
REF
and I
K
= 10mA unless otherwise stated.
SYMBOL
PARAMETER
MIN
TYP
MAX
UNIT
CIRCUIT
TEST CONDITION
V
REF
Reference Voltage
2.490
2.500
2.515
V
1
T
A
= 25
o
C, 0.5% CL2431A
2.470
2.500
2.520
V
1
TA = 25
o
C, 1.0% CL2431
TC
V
REF
with Temp.*
0.6
0.2
mV/
o
C
1
V
REF
V
K
Ratio of Change in V
REF
to
Cathode Voltage
2.7
1.01
mV/V
2
V
REF
to 10V
2
0.4
0.3
10V to 18V
I
REF
Reference Input Current
0.7
4
A
2
I
REF
I
REF
Temp Deviation
0.4
1.2
A
2
Over Temp.
I
K(MIN)
Min I
K
for Regulation
0.4
1
mA
1
I
K(OFF)
Off State Leakage
0.04
250
nA
3
V
REF
= 0V, V
KA
= 18V
Z
KA
Dynamic Output Impedance
0.15
0.5
1
f
1kHz, I
K
= 1 to 100mA
CL2431
CORPORATION
TYPICAL PERFORMANCE CURVES
CALOGIC CORPORATION,
237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
100
0.01
60
1P-43
OFF STATE LEAKAGE
30
0
30
60
90
120
10
1
0.1
CUR
RENT
(
n
A)
V
KA
= 18V
V
REF
= 0V
AMBIENT TEMPERATURE (C)
T
A
O
F
F
S
T
AT
E C
A
T
H
O
D
E
I
Z
off
150
100
2
3
1G-42
HIGH CURRENT OPERATING
CHARACTERISTICS
75
50
25
0
25
50
75
125
100
2
1
0
1
CATHODE VOLTAGE (V)
V
KA
TEMPERATURE RANGE: 55 to 125C
V
KA
= V
REF
CATHODE CURRENT (m
A)
I
K
2.46
60
1J-29
TEMPERATURE COEFFICIENT AS
A FUNCTION OF TRIM VALUE
30
2.47
2.48
2.49
2.50
2.51
2.52
2.53
0
30
60
90
120
V
REF
REFERENCE VOLTAGE (V)
V
KA
= V
REF
I
K
= 10mA
V
REF
= 2.500V AT 25C
AMBIENT TEMPERATURE (C)
T
A
2.45
V
KA
CATHODE VOLTAGE (V)
CATHODE CURRENT (
A)
I
K
900
200
1.0
3.0
1G-41
LOW CURRENT OPERATING
CHARACTERISTICS
1.0
0
2.0
100
800
700
600
500
400
300
200
100
0
125C
55C
25C
V
= V
REF
KA
TEMPERATURE RANGE: 55 to 125C
0
50
0
1J-30
REFERENCE VOLTAGE
LINE REGULATION
3
6
9
12
15
18
10
20
30
40
VOLTAGE (mV)
CHANGE IN REFERENCE
V
REF
CATHODE VOLTAGE (V)
V
KA
25C
75C
125C
I
K
= 10mA
TEMPERATURE RANGE: 55 to 125C
55C
0C
3.0
0
60
1G-45
REFERENCE
INPUT CURRENT
30
0
30
60
90
120
2.5
2.0
1.5
1.0
0.5
CURRENT (
A)
REFERENCE INPUT
I
REF
T
A
AMBIENT TEMPERATURE (C)
R1 = 10k
R2 =
I
K
= 10mA
CL2431
CORPORATION
CALOGIC CORPORATION,
237 Whitney Place, Fremont, California 94539, Telephone: 510-656-2900, FAX: 510-651-3025
TYPICAL PERFORMANCE CURVES (continued)
70
0
10
1G-47
NOISE VOLTAGE
100k
f FREQUENCY (Hz)
60
50
40
30
20
10
10k
1k
100
NOISE VOLTAGE nV/
Hz
V
KA
= V
REF
= 10mA
T
A
= 25C
I
K
0.150
0.0
60
1G-48
LOW FREQUENCY DYNAMIC
OUTPUT IMPEDANCE
30
0
30
60
90
120
0.125
0.100
0.075
0.050
0.025
DYNAMIC IMPEDANCE (
)
Z
KA
V
KA
= V
REF
= 1 TO 100mA
f
1kHz
I
KA
FREE AIR TEMPERATURE
T
A
100
0.01
1k
1G-49
DYNAMIC OUTPUT
IMPEDANCE
10M
f FREQUENCY (Hz)
1M
100k
10k
10
1.0
0.1
DYNAMIC IMPEDANCE (
)
Z
KA
T
A
= 25C
= 1 TO 100mA
I
K
70
0
1k
1J-31
SMALL SIGNAL VOLTAGE GAIN
vs FREQUENCY
10M
f FREQUENCY (Hz)
60
50
40
30
20
10
1M
100k
10k
GAIN (dB)
SMALL SIGNAL VOLTAGE
A
V
I
K
= 10mA
TEMPERATURE RANGE: 55 to 125C
1H-01
K
I
230
GND
OUT
15k
8.25k
9
F
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