UTC TL431
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
1
QW-R103-003,I
PROGRAMMABLE PRECISION
REFERENCE
DESCRIPTION
The UTC TL431 is a three-terminal adjustable regulator
with a guaranteed thermal stability over applicable
temperature ranges. The output voltage may be set to any
value between Vref(approximately 2.5V) and 36 V with two
external resistors. It provides very wide applications,
including shunt regulator, series regulator, switching
regulator, voltage reference and others.
FEATURES
*Programmable output Voltage to 36V.
*Low dynamic output impedance 0.2
.
*Sink current capability of 1.0 to 100mA.
*Equivalent full-range temperature coefficient of 50ppm/
C
typical for operation over full rated operating temperature
range.
TO-92
1
SOP-8
SOT-89
1
1
SOT-25
SOT-23
1
3
2
2
3
5
4
SOP-8 1: Cathode; 2,3,6,7: Anode
8: Ref. ; 4,5: N.C.
TO-92 1: Ref. ; 2: Anode ; 3: Cathode
SOT-89 1: Ref. ; 2: Anode ; 3: Cathode
SOT-23 See MARKING INFORMATION
SOT-25 1,2: NC; 3: Cathode; 4: Ref.; 5: Anode
MARKING INFORMATION (SOT-23)
PART
NUMBER
PIN 1
PIN 2
PIN 3
MARKING
TL431 Cathode Ref Anode 431
TL431-NS Ref Cathode Anode 431N
UTC TL431
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
2
QW-R103-003,I
BLOCK DIAGRAM
2.5V Vref
CATHODE
ANODE
REFERENCE
CATHODE
(K)
ANODE(A)
REFERENCE
(R)
ABSOLUTE MAXIMUM RATINGS
(Operating temperature range applies unless otherwise specified))
PARAMETER SYMBOL
VALUE
UNIT
Cathode Voltage
V
KA
37 V
Cathode Current Range(Continuous)
I
KA
-100 ~ +150
mA
Reference Input Current Range
Iref
-0.05 ~ +10
mA
Operating Junction Temperature
Tj
150
C
Operating Ambient Temperature
Topr
-40 ~ +85
C
Storage Temperature
Tstg
-65 ~ +150
C
RECOMMENDED OPERATING CONDITIONS
PARAMETER SYMBOL MIN
TYP
MAX
UNIT
Cathode Voltage
V
KA
V
REF
36 V
Cathode Current
I
KA
1
100 mA
ELECTRICAL CHARACTERISTICS
(Ta=25
C, unless otherwise specified)
PARAMETER SYMBOL
TEST
CONDITIONS
MIN
TYP
MAX
UNIT
Reference Input Voltage
Vref
V
KA
=V
REF
,I
KA
=10mA
2.470 2.495 2.520 V
Deviation of reference Input Voltage
Over temperature (note 1)
Vref/T V
KA
=V
REF
,I
KA
=10mA
T
MIN
<=T
A<=
T
MAX
4.5 17 mV
Ratio of Change in Reference Input
Voltage to the Change in Cathode
Voltage
Vref /V
KA
I
KA
=10mA
V
KA
=10V~V
REF
V
KA
=36V~10V
-1.0
-0.5
-2.7
-2.0
mV/V
Reference Input Current
Iref
I
KA
=10mA,R1=10k
,R2=
1.5
4
A
Deviation of Reference Input Current
Over Full Temperature Range
Iref/T I
KA
=10mA,R1=10k
,R2=
T
A
=full Temperature
0.4 1.2
A
Minimum Cathode Current for
Regulation
I
KA
(min) V
KA
=V
REF
0.45 1.0 mA
Off-State Cathode Current
I
KA
(OFF) V
KA
=36V,V
REF
=0
0.05
1.0
A
Dynamic Impedance
Z
KA
V
KA
=V
REF
, I
KA
=1 to 100mA
f
1.0kHz
0.15 0.5
Note:T
MIN
=0
C,T
MAX
=+70
C
UTC TL431
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
3
QW-R103-003,I
TYPICAL PERFORMANCE CHARACTERISTICS
-2
-1
0
1
2
3
-100
-75
-50
-25
0
25
50
75
100
125
Cathode Voltage (V)
C
a
t
hode C
u
r
r
ent
(
m
A
)
Fig 1 Cathode Current Vs Cathode Voltage
Ta=25C
V
KA
=V
REF
-1
1
0
2
3
-200
0
400
200
600
800
-2
Cathode Voltage (V)
C
a
t
hode C
u
r
r
ent
(
mA
)
Fig 2 Cathode Current Vs Cathode Voltage
Ta=25C
V
KA
=V
REF
I
KA(min)
0
5
10
15
20
25
30
35
40
0
-5
-10
-15
-20
-25
-30
-35
-40
Cathode Voltage (V)
C
hange I
n
R
e
f
e
r
ence I
N
put
V
o
l
t
age (
m
V
)
Fig 3 Change in Reference Input Voltage
Vs Cathode voltage
I
KA
=100mA
Ta=25C
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
Time (ms)
I
nput
and O
u
t
put
V
o
l
t
age (
V
)
Fig 4 Pulse Response
Ta=25C
2
10
1
10
-1
10
0
10
7
10
6
10
5
10
10
4
10
3
I
m
pedance (
)?
Frequency (Hz)
Fig 5 Dynamic Impedance
Vs Frequency
Ta=25C
I
KA
=0mA to 100mA
-10
0
10
20
30
40
50
60
70
7
10
6
10
5
10
10
4
10
3
Fig 6 Small Signal Voltage Amplification Vs Frequency
V
o
l
t
age A
m
pl
i
f
i
c
at
i
on (
d
B
)
Frequency (Hz)
Ta=25C
I
KA
=10mA
UTC TL431
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
4
QW-R103-003,I
temperature
Fig. 7
re
fe
re
nc
e
v
o
l
t
a
g
e
TO-92
0
20
40
60
80
100
120
140
100p
1n
10n
100n
1
10
CA
T
H
ODE
CURRE
NT
,
I
K
(m
A)
LOAD CAPACITANCE,C
L
A V
KA
=Vref
B V
KA
=5.0V@I
K
=10mA
C V
KA
=10V@I
K
=10mA
D V
KA
=15V@I
K
=10mA
Ta=25
A
B
C
D
TEST CIRCUIT
INPUT
V
KA
V
REF
I
KA
UTC TL431
R1
R2
I
REF
V
KA=
V
REF*(
1
+
R1
/
R2
)+
I
REF*
R1
INPUT
V
KA
V
REF
I
KA
UTC TL431
INPUT
V
KA
I
KA(OFF)
UTC TL431
Fig 8 Test Circuit For V
KA
=V
REF
Fig 9 Test Circuit for V
KA >=
V
REF
Fig 10 Test Circuit For I
KA(OFF)
UTC TL431
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
5
QW-R103-003,I
APPLICATION CIRCUIT
Vi
Vo
V
REF
UTC TL431
R1
R2
Vo=(1+R1/R2)*V
REF
Vi
Vo
V
REF
UTC TL431
R1
R2
Vo=(1+R1/R2)*V
REF
UTC7805
OUT
IN
COMMON
Vi
Vo
V
REF
UTC TL431
R1
R2
Vo=(1+R1/R2)*V
REF
Fig 11 Shutdown Regulator Fig 12 Output Control of a Three Fig 13 Higher-current Shunt Regulator
-Terminal Fixed Regulator
Vi
Vo
UTC TL431
Rs
R
S
=V
REF
/RCL
RCL
Io
Vi
Vo
UTC TL431
Rs
Io
I
O
=V
REF
/R
S
Fig 14 Constant-current Sink Fig 15 Current Limiting or Current Source
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