ZHT431
Adjustable precision Zener shunt regulator
Description
The ZHT431 is a three terminal adjustable
shunt regulator offering excellent temperature
stability and output current handling capability
up to 100mA. The device offers extended
operating temperature range working from -55
to +125°C. The output voltage may be set to
any chosen voltage between 2.5 and 20 volts
by selection of two external divider resistors.
The devices can be used as a replacement for
zener diodes in many applications requiring an
improvement in zener performance.
Features
•
•
•
•
•
•
•
•
Surface mount SOT223 and SOT23
packages
2% and 1% tolerance
Maximum temperature coefficient
67 ppm/°C
Temperature compensated for operation
over the full temperature range
Programmable output voltage
50 A to 100mA current sink capability
Low output noise
Wide temperature range -55 to +125°C
Applications
•
•
•
•
Series and shunt regulator
Voltage monitor
Over voltage / under voltage protection
Switch mode power supplies
Pinout information
V
REF
GND
GND
V
Z
SOT223
Pinout - Top view
SOT23
Pinout - Top view
V
Z
GND
V
REF
Ordering information
Order reference
ZHT431C01L
ZHT431C01STOB
ZHT431C01STZ
ZHT431C02L
ZHT431C02STOB
ZHT431C02STZ
ZHT431F01TA
ZHT431F02TA
ZHT431G01TA
ZHT431G02TA
Tolerance Package Part mark Status
Reel size Quantity
(%)
(inches)
per reel
1
TO92 ZHT43101 Obsolete
Loose
4000
1
TO92 ZHT43101 Obsolete
12.5
1500
1
TO92 ZHT43101 Obsolete Concertina
1500
2
TO92 ZHT43102 Obsolete
Loose
4000
2
TO92 ZHT43102 Obsolete
12.5
1500
2
TO92 ZHT43102 Obsolete Concertina
1500
1
SOT23
43C
Released
7
3000
2
SOT23
43D
Released
7
3000
1
SOT223 ZHT43101 Released
7
1000
2
SOT223 ZHT43102 Released
7
1000
Tape
width
-
-
-
-
-
-
8mm
8mm
12mm
12mm
Issue 5 - October 2006
© Zetex Semiconductors plc 2006
1
www.zetex.com
ZHT431
Schematic diagram
V
Z
V
REF
Gnd
Absolute maximum rating
Cathode voltage (V
Z
)
Cathode current
Operating temperature
Storage temperature
20V
150mA
-55 to 125°C
-55 to 150°C
Power dissipation (T
amb
=25°C)
(T
jmax
= 150°C)
SOT23
TO92
SOT223
Recommended operating conditions
Min.
Cathode voltage
Cathode current
V
REF
50µA
Max.
20V
100mA
330mW
780mW
2W
Issue 5 - October 2006
© Zetex Semiconductors plc 2006
2
www.zetex.com
ZHT431
Electrical characteristics test conditions (unless otherwise stated):T
amb
=25°C
Symbol Parameter
Min.
V
REF
V
DEV
∆V
REF
----------------
-
∆V
Z
Value
Typ.
2.50
2.50
10
-1.85
-1.0
0.12
0.04
Max.
2.55
2.525
30
-2.7
-2.0
1.0
0.2
2%
2.45
Units Conditions
V
V
mV
I
L
=10mA (Fig.1),
V
Z
=V
REF
I
L
=10mA, V
Z
=V
REF
T
amb
=full range (Fig1)
Reference voltage
1% 2.475
Deviation of reference input
voltage over temperature
Ratio of the change in
reference voltage to the
change in cathode voltage
mV/V V
Z
from V
REF
to 10V
I
Z
=10mA (Fig.2)
mv/V V
Z
from 10V to 20V
I
Z
=10mA (Fig.2)
A
A
R1=10k, R2=O/C,
l
L
=10mA (Fig.2)
R1=10k, R2=O/C,
I
L
=10mA T
amb
=full
range (Fig.2)
V
Z
=V
REF
(Fig.1)
V
Z
=20V, V
REF
=0V(Fig.3)
V
Z
=V
REF
(Fig.1), f=0Hz,
I
C
=1mA to 100mA
I
REF
I
REF
Reference input current
Deviation of reference input
current over temperature
Minimum cathode current
for regulation
Off-state current
Dynamic output impedance
I
Zmin
I
Zoff
R
Z
35
50
0.1
0.75
A
A
Deviation of reference input voltage, V
DEV
, is defined as the maximum variation of the reference
input voltage over the full temperature range.
The average temperature coefficient of the reference input voltage, V
REF
is defined as:
V
DEV
x
1000000
ppm
-
V
REF
⎛
------------
⎞
=
-----------------------------------------
-
⎝ °C ⎠
V
REF
(
T1
–
T2
)
The dynamic output impedance, R
Z
, is defined as:
R
Z
V
max
∆
V
Z
=
---------
-
∆
I
Z
V
min
V
dev
= V
max
- V
min
When the device is programmed with two externalresistors, R1
and R2, (fig 2) , the dynamic outputimpedance of the overall
circuit, R’, is defined as:
R
′
T1
Temperature
T2
=
R
Z
(
1 +
R1
)
------
-
R2
Issue 5 - October 2006
© Zetex Semiconductors plc 2006
3
www.zetex.com
ZHT431
Typical characteristics
Issue 5 - October 2006
© Zetex Semiconductors plc 2006
4
www.zetex.com
ZHT431
Typical characteristics
60
Open Loop Voltage Gain (dB)
V
Z
I
Z
40
230
15k
9µF
20
+
8k25
-
0
100
1k
10k
100k
1M
Frequency (Hz)
I
Z
= 10mA,
T
A
= 25°C
Gain v Frequency
Test Circuit for Open Loop Voltage Gain
220
3.0
Repetitive pulse
Input Monitor
V
Z
Voltage Swing (V)
2.0
Single pulse
1.0
V
Z
Pulse
Generator
50
0
5.0
0
0
0.2
0.4
INPUT
0.6
0.8
1.0
Time (µs)
T
A
= 25°C
Pulse Response
100
Test Circuit for Pulse Response
150
Input
V
Z
Cathode Current (mA)
80
STABLE
60
STABLE
I
Z
10k
40
20
0
10p
100p
1000p
0.01
µ
0.1
µ
1
µ
Load Capacitance (F)
V
ref
< V
Z
< 20, I
Z
= 10mA, T
A
= 25°C
Stability Boundary Conditions
Test Circuit for Stability Boundary Conditions
4-31
Issue 5 - October 2006
© Zetex Semiconductors plc 2006
5
www.zetex.com
