Adjustable Precision Shunt Regulator
AP432
This datasheet contains new product information. Advanced Power Electronics Corp. reserves the rights to modify the product specification without notice. No liability is assumed as
a result of the use of this product. No rights under any patent accompany the sale of the product.
1
Features
- Precision reference voltage
B : 1.24V ± 1%
A : 1.24V ± 0.5%
- Sink current capability: 200mA.
- Minimum cathode current for regulation: 150µA
- Equivalent full-range temp coefficient: 30 ppm/oC
- Fast turn-on Response.
- Low dynamic output impedance: 0.2Ω
- Programmable output voltage to 20v
- Low output noise
- Packages: SOT-89, SOT-23, SOT-23-5L, SO-8
and TO-92
General Description
The AP432 are 3-terminal adjustable precision shunt
regulators with guaranteed stable temperature over
the applicable extended commercial temperature
range. The output voltage may be set at any level
greater than 1.24\/ (V REF) up to 20V merely by
selecting two external resistors that act as a voltage
divider network. These devices have a typical output
impedance of 0.2Ω. Active output circuitry provides
very sharp turn-on characteristics, making these
devices excellent improved replacements for Zener
diodes in many applications.
The precise +/- 1% reference voltage tolerance of the
AP432 make it possible in many applications to avoid
the use of a variable resistor, consequently saving cost
and eliminating drift and reliability problems associated
with it.
Ordering Information
A P 4 3 2 X - X - HF
- RoHS & Halogen-FreeCompliant
Package Reference Voltage
M : SO-8
G : SOT-89
T : TO-92
N : SOT-23
Y : SOT-23-5L
Tolerance:
A : 1.24V(+/-) 0.5%
B : 1.24V(+/-)1%
Typical Application Circuit
+
+
R2
R1
V
OUT
V
IN
V
OUT
= (1+R1/R2)V
REF
Precision Regulator
C
in
C
out
AP432
Advanced Power
Electronics Co rp.
200905112
Halogen-Free
Adjustable Precision Shunt Regulator
AP432
Advanced Power Electronics Corp.
www.a-power.com.tw 2
Block Diagram
REF (R)
V
REF
+
-
Anode (A)
Cathode (C)
1.24V
Symbol
Cathode (C)
REF (R)
Anode (A)
Pin Configuration
Order Number Pin Configuration (Top View)
AP432G
(SOT-89)
AP432T
(TO-92)
Order Number
AP432N
(SOT-23)
AP432Y
(SOT-23-5L)
1 REF
2 Anode
3 Cathode
Anode 1
2 REF
3 Cathode
Cathode 1
Anode 2
Anode 3
NC 4 5 NC
6 Anode
7 Anode
8 REF
AP432M
(SO-8)
Pin Configuration (Top View)
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Anode
1
2
5
4
1
3
REF
NC
Cathode
NC
3 Cathode
2 Anode
1 REF
Adjustable Precision Shunt Regulator
AP432
Advanced Power Electronics Corp.
www.a-power.com.tw
3
Absolute Maximum Ratings
Cathode Voltage…………....……..............................…..........……………………………………...……….20V
Continuous cathode current ………………………………......................……………………...-10mA ~ 250mA
Reference input current range ……………………...….………....................………………………………10mA
Operating temperature range ............……………………………………………………………… -20 oC ~ 85oC
Lead Temperature……………….…………….…..……………………..………………..……........260oC
Storage Temperature ……………………..............…......………………….......……...........-65oC ~ 150oC
Power Dissipation (Notes 1. 2) SOT-89 .……………..……..……………………...........….... 0. 80W
TO-92.....…………….………………………....……….. ..... 0.78W
SOT-23 …………………..…..…………………………….…. 0.25W
SOT-25...……………………..………….……………………..0.25W
SOP-8...………………….……………………………..……… 0.6W
Note 1: TJ, max =150oC. .
Note 2: Ratings apply to ambient temperature at 25oC.
Electrical Characteristics (Ta=25oC, unless otherwise specified.)
Parameter Test conditions Symbo
l Min. Typ. Max. Unit
-B 1.227 1.252
Reference Voltage
VKA = Vref,
I KA = 10mA
(Fig.1) -A VREF 1.233 1.24 1.246V
Deviation of Reference Input Voltage
over Temperature (Note 3)
VKA = VREF , IKA = 10mA ,
Ta = full range (Fig.1) VREF 3.0 20 mV
Ratio of the Change in Reference
Voltage to the Change in Cathode
Voltage
IKA = 10mA
(Fig.2) VKA = 20 ~VREF
KA
REF
V
V
∆
∆
-1.4 -2.0 mV/V
Reference Input Current R1 = 10KΩ,R2 = ∞
IKA= 10mA (Fig.2) IREF 1.4 3.5 µA
Deviation of Reference Input Current
over Temperature
R1 = 10KΩ,R2 = ∞
IKA = 10mA
Ta = Full range (Fig.2)
αIREF 0.4 1.2 µA
Minimum Cathode Current for
Regulation VKA = VREF (Fig.1) IKA(min) 0.15 0.3 mA
Off-state Current VKA = 20V , VREF = 0V (Fig.3) IKA(off) 0.1 1.0 µA
Dynamic Output Impedance (Note 4) V KA = VREF
Frequency
≤
1KHz (Fig.1) KA
Z 0.2 0.5 Ω
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Adjustable Precision Shunt Regulator
AP432
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www.a-power.com.tw
4
V
MAX
V
MIN
T
I
T
2
TEMPERATURE
V
DEV
= V
MAX
- V
MIN
Note 3. Deviation of reference input voltage, VDEV, is defined as the maximum variation of the reference over
the full temperature range.
The average temperature coefficient of the reference input voltage αVREF is defined as:
12
6
C)(25
REF
DEV
REF TT
10)
V
V
(
V
−
×
°
=
α
……………………..……………….. ( )
C
ppm
°
Where:
T2 – T1 = full temperature change.
αVREF can be positive or negative depending on whether the slope is positive or negative.
Note 4. The dynamic output impedance, RZ, is defined as:
KA
KA
KA I
V
Z∆
∆
=
When the device is programmed with two external resistors R1 and R2 (see Figure 2.), the dynamic output
impedance of the overall circuit, is defined as:
)(≈
R2
R1
1Z
i
v
'
ZKAKA +
∆
∆
=
Test Circuits
Input
V
REF
V
KA
I
KA
Fig1. Test Circuit for V
KA
= V
REF
IN
V
REF
R1
R2
I
REF
I
KA
V
KA
Fig2. Test circuit for V
KA
＞
V
REF
IN
V
KA
I
Z(OFF)
Fig3. Test Circuit for off-state Current
R1I)
R2
R1
(1VV
REFREFKA
⋅++=
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Adjustable Precision Shunt Regulator
AP432
Advanced Power Electronics Corp.
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5
Typical Performance Characteristics
+
-
+
-
Output
GND
15KΩ
8.25KΩ
9µF
I
KA
232Ω
TEST CIRCUIT FOR VOLTAGE AMPLIFICATION
SMALL-SIGNAL VOLTAGE AMPLIFICATION vs. FREQUENCY
0
10
20
30
40
50
60
1K 10K 100K 1M 10M
f-Frequency-Hz
A
V-Small Signal Voltage Amplification (dB)
I
KA
=10mA
T
A
=25
o
C
+
-
IKA
GND
Output
1KΩ
50Ω
TEST CIRCUIT FOR REFERENCE IMPEDANCE
REFERENCE IMPEDANCE vs. FREQUENCY
0.1
1
10
100
1K 10K 100K 1M 10M
f-Frequency-Hz
∣ZKA∣—Reference Impedance —Ω
I
KA
=10mA
T
A
=25
o
C
+
-
150O
IKA
V
BATT
C
L
TEST CIRCUIT FOR CURVE A
+
-
C
L
R1=10KO
R2
IKA
150O
V
BATT
TEST CIRCUIT FOR CURVE B, C, AND D
The areas under the curves represent conditions that may cause the
device to oscillate. For curves B, C, and D, R2 and V+ were adjusted
to establish the initial V
KA
and I
KA
conditions with C
L
=0.V
BATT
and
C
L
were then adjusted to determine the ranges of stability.
STABILITY BOUNDARY CONDITIONS
†
0
10
20
30
40
50
60
70
80
90
100
0.001 0.01 0.1 1 10
C
L
-Load Capacitance-µF
I
KA
-Cathode Current-m
A
A
V
KA
=V
ref
B V
KA
=5V
C V
KA
=10V
D V
KA
=15V
A
B
C
D
Stable
Stable
TA=25
o
C
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Adjustable Precision Shunt Regulator
AP432
Advanced Power Electronics Corp.
www.a-power.com.tw
6
Application Examples
V
IN
+
Low Limit V
REF
(1 + R1B/R2B) +V
BE
High Limit V
REF
(1 + R1A/R2A)
R1A R1B
R2A R2B V
BE
Output ON when
Low Limint
＜
V
IN
＜
High Limit
Fig.10 Over-Voltage / Under-Voltage Protection Circuit
V
IN
R
CL
I
OUT
I
OUT
= V
REF
/ R
CL
Fig.6 Current Limiter or Current Source
I
OUT
V
IN
I
OUT
= V
REF
/ R
S
R
S
Fig.7 Constant-Current Sink
Fig.4 Voltage Monitor Fig.5 Delay Timer
V
OUT
= (1 + R1/R2) ×V
REF
V
IN
R1
R2
Fig.8 Higher-Current Shunt Regulator
V
OUT
V
IN
PUSE
R1
R2
L
IMIT
(1 + R1/R2) ×V
REF
Fig.9 Crow Bar
V
OUT
V
IN
ON
OFF
R
+
V
IN
Delay = RC x ln( V
IN
-V
REF
)
LED on when Low Limit
＜
V
IN
＜
High Limit
Low Limit
≈
V
REF
(1+R1B/R2B)
High Limit
≈
V
REF
(1+R1A/R2A)
R1A
R2A
V
IN
R1B
R2B
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