SmartSwitch
TM
General Description
The AHK432 is a low voltage adjustable shunt refer-
ence with thermal stability guaranteed over the full
industrial temperature range. This 3-terminal regula-
tor has an output voltage range that extends from
V
REF
(1.24V) to 20V, giving designers outstanding
flexibility in the development of power supplies and
instrumentation. With a low operating current of
60A, the AHK432 is well suited for battery-powered
portable electronic applications. It also has a sharp
turn-on characteristic and a dynamic resistance of
only 50m
W
making it an excellent replacement for
zener diodes in low tempco designs.
The AHK432 is available in the surface-mount 3 or
5 pin SOT-23, as well as the through hole TO-92.
Three voltage tolerance options are offered in each
package: 0.5%, 1%, and 2%.
Features
Wide output voltage range (1.24 to 20V)
Operating current from 60A to 100mA
Low dynamic output resistance of 50m
0.5% trimmed voltage reference
10mV typ. V
REF
deviation, from -40 to +105C
Surface mount 3 or 5 pin SOT-23 or through-
hole 3 pin TO-92 packages
Applications
Notebook computers
Isolated feedback in switching power supplies
Adjustable and programmable supplies
Linear regulators (External Reference)
Instrumentation
Medical Electronics*
Global voltage reference for multiple power
supplies
AHK432
Adjustable Low Voltage Shunt Regulator
Preliminary
Information
432.2001.11.0.96
1
Typical Application
R
L
IN
OUT
R2
R1
AHK432
Adjustable regulator:
OUT = V
REF
R1 + R2
R2
PowerManager
TM
Absolute Maximum Ratings
(T
A
=25C unless otherwise noted)
Note: Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at con-
ditions other than the operating conditions specified is not implied. Only one Absolute Maximum rating should be applied at any one time.
Electrical Characteristics
(T
J
=25C unless otherwise noted)
AHK432 0.5%
AHK432 1.0%
AHK432 2.0%
Symbol
Description
Conditions
min
typ
max
min
typ
Max min
typ
max Units
V
Z
=V
REF
T
A
=25C 1.234 1.240 1.246 1.228 1.240 1.252 1.215 1.240 1.265
V
V
REF
Reference
I
Z
=10mA
Voltage
(test circuit 1)
T
A
=-40
1.222
1.258 1.215
1.265 1.200
1.280
to +105C
V
DEV
V
REF
Temp
T
A
=-40 to +105C,
10
25
10
25
10
25
mV
Deviation
V
Z
=V
REF
, I
Z
=10mA
(test circuit 1)
V
REF
/
V
Z
Ratio of
I
Z
=10mA,
-1.0
-2.7
-1.0
-2.7
-1.0
-2.7
mV/V
Change in V
REF
V
Z
=16V to V
REF
to Change in
(test circuit 2)
Cathode Voltage
I
REF
Reference
R1=10k
,
0.15
0.5
0.15
0.5
0.15
0.5
A
Input Current
R2=
, I
Z
=10mA
(test circuit 2)
I
REF(DEV)
I
REF
Temp
T
A
=-40 to +105C
0.1
0.4
0.1
0.4
0.1
0.4
A
Deviation
R1=10k
, R2=
,
I
Z
=10mA
(test circuit 2)
I
Z(OFF)
Off State
V
REF
=0V
V
Z
=6V
0.04
0.1
0.04
0.1
0.04
0.1
A
Cathode Current
(test circuit 3)
V
Z
=16V
0.04
0.5
0.04
0.5
0.04
0.5
R
Z
Dynamic
f<1kHz, V
Z
=V
REF
,
0.05
0.2
0.05
0.2
0.05
0.2
Output
I
Z
=100mA to 100mA
Impedance
(test circuit 1)
I
Z(MIN)
Minimum
V
Z
=V
REF
60
80
60
80
60
80
A
Operating
(test circuit 1)
Current
Symbol
Description
Value
Units
V
Z
Cathode Voltage
20
V
I
Z
Continuous Cathode Current
100
mA
I
REF
Reference Current
3
mA
T
J
Operating Junction Temperature Range
-40 to 150
C
JA
Maximum Thermal Resistance
TO-92
160
C/W
SOT-23-3, SOT-23-5
410
P
D
Maximum Power Dissipation
TO-92
780
mW
SOT-23-3, SOT-23-5
300
T
LEAD
Maximum Soldering Temperature (at Leads)
260
C
AHK432
Adjustable Low Voltage Shunt Regulator
2
432.2001.11.0.96
Typical Characteristics
(Unless otherwise noted, T
A
= 25C, I
Z
= 10mA)
Ratio of
V
REF
/
V
Z
vs. Temperature
-600
-500
-400
-300
-200
-100
0
-50
-25
0
25
50
75
100
125
Junction Temperature (
C)
Ratio
(
V/V)
I
Z
=10mA
dV
Z
=V
REF
to 16V
Cathode Current vs. Temperature
0
10
20
30
40
50
60
70
80
-50
-25
0
25
50
75
100
125
Junction Temperature (
C)
Cathode Current (nA)
V
Z
=5V
V
REF
=0V
(Off-state)
Reference Current vs. Temperature
0
20
40
60
80
100
120
140
160
180
-50
-25
0
25
50
75
100
125
Junction Temperatur e (
C)
Re
f
e
r
e
n
c
e
C
urre
nt
(nA)
I
Z
=10mA
R
1
=10k
R
2
=Open
Reference Voltage vs. Temperature
1.232
1.236
1.24
1.244
1.248
1.252
-50
-25
0
25
50
75
100
125
Junction Temperature (
C)
Re
fer
e
nce V
o
ltage (V
)
I
Z
=10mA
Cathode Current vs. Cathode Voltage
-200
-150
-100
-50
0
50
100
150
200
-1
-0.5
0
0.5
1
1.5
Cathode Voltage (V)
Cathode Current (
A)
Cathode Current vs. Cathode Voltage
-15
-10
-5
0
5
10
15
-1
-0.5
0
0.5
1
1.5
Cathode Voltage ( V)
Cathode Current (mA)
AHK432
Adjustable Low Voltage Shunt Regulator
4
432.2001.11.0.96
AHK432
Adjustable Low Voltage Shunt Regulator
432.2001.11.0.96
5
(Unless otherwise noted, T
A
= 25C, I
Z
= 10mA)
Test Circuit for Stability
R2
AHK432
C
L
I
Z
1k
R1=10k
Stability Boundary
0
20
40
60
80
100
10.E+0
100.E+0
1.E+3
10.E+3
100.E+3
1.E+6
10.E+6
Load Capacitance (pF)
Cu
rre
n
t
(
m
A
)
Stable
Stable
Unstable
V
REF
=V
Z
Test Circuit for Voltage
Gain and Phase
V
IN
V
OUT
8.25k
13.7k
AHK432
5V
169
Gain and Phase vs. Frequency
-20
0
20
40
60
80
100
120
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
Frequency (Hz)
G
a
in (dB
)
-30
0
30
60
90
120
150
180
Impedance vs. Frequency
0.01
0.1
1
10
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
Frequency ( Hz )
Impedance (
)
Cathode Impedance vs. Temperature
-4 %
0%
4%
8%
12%
16%
-50
-25
0
25
50
75
100
125
Junction Temperature (
C)
N
o
rmaliz
ed Impedance
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