UTC TL431A
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
1
QW-R103-007,C
PROGRAMMABLE PRECISION
REFERENCE
DESCRIPTION
The UTC TL431A 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 36V 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 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
SOT-23
1
2
3
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 1: Cathode; 2: Ref; 3: Anode
BLOCK DIAGRAM
2.5V Vref
CATHODE
ANODE
REFERENCE
CATHODE
(K)
ANODE(A)
REFERENCE
(R)
UTC TL431A
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
2
QW-R103-007,C
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 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
2.483 2.495 2.507 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 TL431A
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
3
QW-R103-007,C
TYPICAL PERFORMANCE CHARACTERISTICS
-2
-1
0
1
2
3
-100
-75
-50
-25
0
25
50
75
100
125
Cathode Voltage (V)
C
a
thode 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
thode 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 In R
e
fer
enc
e IN
put
Vol
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)
Input and Output Vol
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
Im
pedanc
e (
)?
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
Vol
t
age Am
pl
i
f
i
c
ati
on (
d
B)
Frequency (Hz)
Ta=25C
I
KA
=10mA
UTC TL431A
LINEAR INTEGRATED CIRCUIT
UTC
UNISONIC TECHNOLOGIES CO., LTD.
4
QW-R103-007,C
TEST CIRCUIT
INPUT
V
KA
V
REF
I
KA
UTC TL431A
R1
R2
I
REF
V
KA=
V
REF*(
1
+
R1
/
R2
)+
I
REF*
R1
INPUT
V
KA
V
REF
I
KA
UTC TL431A
INPUT
V
KA
I
KA(OFF)
UTC TL431A
Fig 7 Test Circuit For V
KA
=V
REF
Fig 8 Test Circuit for V
KA >=
V
REF
Fig 9 Test Circuit For I
KA(OFF)
APPLICATION CIRCUIT
Vi
Vo
V
REF
UTC TL431A
R1
R2
Vo=(1+R1/R2)*V
REF
Vi
Vo
V
REF
UTC TL431A
R1
R2
Vo=(1+R1/R2)*V
REF
UTC7805
OUT
IN
COMMON
Vi
Vo
V
REF
UTC TL431A
R1
R2
Vo=(1+R1/R2)*V
REF
Fig 10 Shutdown Regulator Fig 11 Output Control of a Three Fig 12 Higher-current Shunt Regulator
-Terminal Fixed Regulator
Vi
Vo
UTC TL431A
Rs
R
S
=V
REF
/RCL
RCL
Io
Vi
Vo
UTC TL431A
Rs
Io
I
O
=V
REF
/R
S
Fig 13 Constant-current Sink Fig 14 Current Limiting or Current Source
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