Voltage Regulators
AN1432NT
Variable output, low voltage operation shunt regulator
I
Overview
The AN1432NT is a low voltage operation and posi-
tive voltage variable output type shunt regulator. Since the
output voltage is adjustable from approximately 1.275 V to
14 V, it is suitable for a power supply of small-sized 3 V-
system portable equipment.
0.6±0.15
5.0±0.2
Unit: mm
4.0±0.2
(1.0)
5.1±0.2
2.3±0.2
(1.0)
13.5±0.5
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Features
•
High accuracy reference voltage:
1.275 V (allowance:
±2%)
•
Low voltage operation: 1.275 V to 14 V
2.54
0.43
+0.1
–0.05
0.43
+0.1
–0.05
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Applications
•
Office automation equipment and other small-sized por-
table equipment
Note) The value of reference voltage and the package differ from AN1432MS.
2 3 1
SSIP003-P-0000
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Block Diagram
Output
K
1
R
1
Constant current source
I
REF
Ref.
Reference voltage
V
REF
R
2
3
A
V
KA
=
V
REF
(1
+
R
1
)
+
I
REF
· R
1
R
2
2
Error
amplifier
Output
transistor
V
KA
1
AN1432NT
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Pin Descriptions
Pin No.
1
K: Cathode
Description
Voltage Regulators
The pin for the combined use of the power source current supply of IC and the constant
voltage output as the shunt regulator. An excessive current supplied to this pin is bypassed
to the anode pin through the output transistor.
The reference voltage (1.275 V typical) pin. Although the impedance is high under the
normal using conditions, be careful that the impedance drops and current flows into the IC
inside if a current or voltage is forced to apply from the outside.
The constant voltage reference pin of the shunt regulator, and the current from the cathode
and reference flows out. Usually grounded.
2
Reference
3
Anode
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Absolute Maximum Ratings
Parameter
Supply voltage
Reference voltage
Supply current
Reference current
Cathode - anode reverse current
Cathode - reference reverse current
Power dissipation
*2
Operating ambient temperature
*1
Storage temperature
*1
Symbol
V
K
V
REF
I
K
I
REF
−I
KA
−I
KR
P
D
T
opr
T
stg
Rating
14.4
7
20
50
−10
−10
340
−30
to
+85
−55
to
+150
Unit
V
V
mA
µA
mA
mA
mW
°C
°C
Note) 1. Do not apply external currents or voltages to any pins not specifically mentioned.
For circuit currents, '+' denotes current flowing into the IC and '−' denotes current flowing out of the IC.
2. *1: Except for the power dissipation, operating ambient temperature and storage temperature, all ratings are for T
a
=
25°C.
*2: The value at T
a
=
85°C.
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Recommended Operating Range
Parameter
Supply voltage
Symbol
V
CC
Range
V
REF
to 14
Unit
V
Note) The value of reference voltage differs from AN1432MS (surface mounting package).
2
Voltage Regulators
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Electrical Characteristics at T
a
=
25°C
Parameter
Reference voltage
Reference voltage fluctuation 1
Reference voltage fluctuation 2
Reference input current
Minimum cathode current
Off time cathode current
Dynamic impedance
Symbol
V
REF
∆V
REF
/
∆V
KA
∆V
REF
/
∆V
KA
I
REF
I
K min
I
K OFF
Z
KA
Conditions
V
KA
=
V
REF
, I
K
=
10 mA
V
REF
≤
V
KA
≤
5 V,
I
K
=
10 mA
5 V
≤
V
KA
≤
15 V,
I
K
=
10 mA
R
I
=
10 kΩ, I
K
=
10 mA
V
KA
=
V
REF
V
KA
=
15 V, V
REF
=
0 V
V
KA
=
V
REF
, f
≤
1 kHz,
I
K
=
1 mA to 10 mA
Min
Typ
AN1432NT
Max
1.30
3.5
2.0
4.4
350
1.0
0.5
Unit
V
mV/V
mV/V
µA
µA
µA
Ω
1.249 1.275
1.9
1.0
2.5
290
0.1
•
Design reference data
Note) The characteristics listed below are theoretical values based on the IC design and are not guaranteed.
Parameter
Reference voltage change
with temperature
Reference input current change
with temperature
Symbol
∆V
REF
/
∆T
a
∆I
REF
/
∆T
a
Conditions
V
KA
=
V
REF
, I
KA
=
10 mA
0°C
≤
T
a
≤ +70°C
R
1
=10
kΩ, I
K
=
10 mA
0°C
≤
T
a
≤ +70°C
Reference value
3
0.4
Unit
mV
µA
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Application Notes
1. P
D
T
a
curve of SSIP003-P-0000
P
D
T
a
1.0
0.8
Power dissipation P
D
(W)
Independent IC without a heat sink
R
th(j-a)
=
190°C/W
P
D
=
658mW (25°C)
0.6
0.4
0.2
0
0
20
40
60
80 85 100
120
140
160
Ambient temperature T
a
(°C)
3
AN1432NT
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Application Notes (continued)
2. Main Characteristics
V
REF1
temperature characteristic
1.282
1.280
1.278
Voltage Regulators
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REF
temperature characteristic
2.0
1.9
1.8
1.7
V
REF1
(V)
I
REF
(µA)
1.276
1.274
1.272
1.270
1.6
1.5
1.4
1.3
1.2
1.268
1.266
−25
1.1
0
25
50
75
100
1.0
−25
0
25
50
75
100
T
a
(°C)
T
a
(°C)
∆V
REF
temperature characteristic
3.0
180
160
I
K OFF
temperature characteristic
2.5
140
2.0
120
∆V
REF
(mV)
I
K OFF
(nA)
0
25
50
75
100
100
80
60
40
1.5
1.0
0.5
20
0
−25
0
−25
0
25
50
75
100
T
a
(°C)
T
a
(°C)
Z
KA
temperature characteristic
0.6
0.5
0.4
Z
KA
(Ω)
0.3
0.2
0.1
0
−25
0
25
50
75
100
T
a
(°C)
4
Voltage Regulators
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Application Notes (continued)
2. Main Characteristics (continued)
Gain
phase characteristics
60
50
Phase
40
0
−45
−90
Gain
10
0
−135
−180
−225
−270
−315
−360
10
100
1k
10k
100k
1M
10M
AN1432NT
Gain
phase characteristics measurement circuit
220
Ω
10
µF
Phase delay
φ
(
°
)
Voltage gain G
VOL
(dB)
15 kΩ
8.2 kΩ
30
20
I
K
≈
10 mA
Frequency f (Hz)
Ripple rejection ratio
0
−10
Ripple rejection ratio measurement circuit
1 kΩ
10
µF
50
Ω
Out
I
K
≈
10 mA
Ripple rejection ratio RR (dB)
−20
−30
−40
−50
−60
−70
−80
100
1k
10k
100k
1M
Frequency f (Hz)
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Application Circuit Example
This circuit amplifies the error voltage of the secondary side output voltage in the insulation type switching power
supply, then transfers it to the primary side via a photocoupler.
Replaceable with the conventional products (AN1431M, AN1431T).
(Primary side)
(Secondary side)
V
OUT
AN1432NT
To Primary side
control IC
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