Not Recommended for New Design
Please Use ZR431LF01 /02
ADJUSTABLE PRECISION
ZENER SHUNT REGULATOR
ZR2431
ISSUE 3 DECEMBER 1997
DEVICE DESCRIPTION
FEATURES
The ZR2431 is a three terminal adjustable
s hu n t r e g u l a t or o f f e r i n g e xc el l e nt
temperature stability and output current
handling capability up to 25mA. The output
voltage may be set to any chosen voltage
between 1.24 and 15 volts by selection of
two external divider resistors.
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•
•
•
•
The devices can be used as a replacement
for zener diodes in many applications
r e qu i r i n g a n i mpr o ve me nt i n z e ner
performance.
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•
•
The ZR2431 is particularly used in the
feedback control loop of switch mode power
supplies. In this application the device 1.24
volt reference enables the generation of low
voltage supplies, typically 3.3 volts or 3 volts.
Surface mount SOT23, SOT223, SOT89
and SO8 packages
TO92 package
2.5% and 1% tolerance
Maximum temperature coefficient 52
ppm/°C
Temperature compensated for
operation over the full temperature
range
Programmable output voltage
100µA to 25mA current sink capability
Low output noise
APPLICATIONS
•
•
•
•
•
Shunt regulator
Series regulator
Voltage monitor
Over voltage/ under voltage protection
Switch mode power supplies
SCHEMATIC DIAGRAM
VZ
Vref
Gnd
4-154
Not Recommended for New Design
Please Use ZR431LF01 /02
ZR2431
ABSOLUTE MAXIMUM RATING
Power Dissipation (Tamb=25°C,
Tjmax=150°C)
SOT23
330mW
SOT223
2W
SO8
780mW
TO92
780mW
SOT89
1.5W
Cathode Voltage (VZ)
15V
Cathode Current
50mA
Operating Temperature
-40 to 85°C
Storage Temperature
-55 to 125°C
Recommended Operating Conditions
Min Max
Cathode Voltage
VREF 15V
Cathode Current
100µA 25mA
ELECTRICAL CHARACTERISTICS
TEST CONDITIONS (Unless otherwise stated):Tamb=25°C
VALUE
SYMBOL MIN TYP MAX UNITS CONDITIONS
PARAMETER
Reference Voltage
2.5% Vref
1.0%
1.209 1.24 1.271 V
1.228 1.24 1.252
IL=10mA (Fig1), VZ=Vref
Deviation of Reference Input Vdev
Voltage over Temperature
4.0
8.0
mV
IL=10mA, VZ=Vref
Ta=full range (Fig1)
Ratio of the change in
∆Vref
Reference Voltage to the
∆VZ
Change in Cathode Voltage
0.5
2.0
mV/V
VZ from Vref to 10V
IZ=10mA (Fig2)
0.02 0.11 0.4
µA
R1=10k, R2=O/C, lL=10mA (Fig2)
Deviation of Reference Input ∆Iref
Current over Temperature
0.02 0.2
µA
R1=10k, R2=O/C, IL=10mA
Ta=full range (Fig2)
Minimum Cathode
Current for Regulation
IZmin
30
100
µA
†
Off-state Current
IZoff
10
30
µA
VZ=15V, Vref =0V (Fig3)
Ω
VZ=Vref (Fig1), f=0Hz, IL=10mA
Reference Input Current
Iref
Dynamic Output Impedance RZ
0.25 2
Deviation of reference input voltage, Vdev, 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, Vref is defined as:
Vmax
Vdev x 1000000
Vref (ppm ⁄ °C)=
Vref (T1−T2)
The dynamic output impedance, Rz, is
∆VZ
defined as:
RZ =
∆IZ
Vmin
When the device is programmed with two
external resistors, R1 and R2, (fig 2) , the
dynamic output impedance of the overall
Vdev = Vmax - Vmin
circuit, R’, is defined as:
R1
R’=Rz (1+ )
R2
† With a capacitance of greater than 100pF
between cathode and anode, minimum
cathode current must be 0.2mA.
T1
Temperature
T2
4-155
Not Recommended for New Design
Please Use ZR431LF01 /02
ZR2431
Change in Reference Output Voltage(mV)
TYPICAL CHARACTERISTICS
TYPICAL CHARACTERISTICS
140
Vref = Vz
Iz=10mA
Reference Current (nA)
130
120
110
100
90
80
-40
-20
0
20
40
60
80
Temperature (°C)
26
Iz = 10mA
1
0
-1
-2
-3
-4
-5
0
10
15
Change in Vref v Cathode Voltage
10
Vref = Vz
1mA
24
22
20
18
16
14
-40
-20
0
20
40
60
80
10mA
1
0.1
100
Temperature (°C)
10k
100k
Dynamic Impedance v Frequency
2.0
1.244
1.242
Power Dissipation (W)
Iz=10mA
1.240
1.238
1.236
1.234
1.232
-40
1k
Frequency (Hz)
Cathode Current v Temperature
Reference Voltage (V)
5
Cathode Voltage (V)
Vref = Vz
Dynamic Impedance (Ω)
Minimum Cathode Current(µA)
Reference Current v Temperature
2
SOT 89
SOT 223
1.0
SO8/TO92
SOT23
0
-20
0
20
40
60
80
25
Temperature (°C)
50
75
85
Ambient Temprature (°C)
Reference Voltage v Temperature
Power Dissipation Derating
4-156
100
Not Recommended for New Design
Please Use ZR431LF01 /02
ZR2431
TYPICAL CHARACTERISTICS
60
VZ
Open Loop Voltage Gain (dB)
Iz = 10mA
50
40
240Ω
10µF
30
+
20
47k
-
10
0
100
10k
1k
100k
1M
Frequency (Hz)
IZ = 10mA, TA = 25°C
Test Circuit for Open Loop Voltage Gain
Gain v Frequency
120Ω
Input Monitor
Single
Pulse
2.0
Voltage Swing (V)
IZ
47k
VZ
Vz
1.0
Repetitive
Pulse
Pulse
Generator
0
5.0
50Ω
2.5
INPUT
0
TA = 25°C
0
100
200
300
400
500
Time (us)
Test Circuit for Pulse Response
Pulse Response
Vref < VZ < 20, IZ = 10mA, TA = 25°C
Cathode Current(mA)
30
Input
150Ω
VZ
25
STABLE
IZ
20
10k
15
STABLE
UNSTABLE
10
100µF
5
0
10p
100p
1n
10n
.1µ
1µ
10µ
Load Capacitance(F)
Stablity Boundary Conditions
Test Circuit for Stability
Boundary Conditions
4-157
Not Recommended for New Design
Please Use ZR431LF01 /02
ZR2431
DC TEST CIRCUITS
IL
Input
VZ
IL
Input
IZ
R1
I ref
VZ
IZ
1µF
R2
VZ
I zoff
I ref
1µF
Vref
Input
1µF
Vref
Fig 1 – Test Circuit for Vz=Vref Fig 2 – Test Circuit for Vz>Vref
4-158
Fig 3 – Test Circuit for Off
State current
Not Recommended for New Design
Please Use ZR431LF01 /02
ZR2431
APPLICATION CIRCUITS
V+
Vout
V+
Vout
R1
R1
Vref
Vref
R2
Vout =
R2
R1
1+
Vref
Vout =
R2
1+
R1
Vref
R2
SHUNT REGULATOR
HIGHER CURRENT SHUNT REGULATOR
V+
ZSR***
V+
Vout
Out
In
Common
30
R1
0.01µF
Vref
R1
R2
Vout
Vref
R2
Vout MIN = Vref + Vreg
Vout =
1+
R1
Vref
R2
Vout =
1+
R1
Vref
R2
OUTPUT CONTROL OF A
THREE TERMINAL FIXED REGULATOR
SERIES REGULATOR
V+
V+
R1A
OUTPUT
R1B
Vref
INPUT
V on
2V
Vref
V off = V+
R2A
V TH = 2.5V
R2B
Low limit =
High limit =
SINGLE SUPPLY COMPARATOR
WITH TEMPERATURE
COMPENSATED THRESHOLD
1+
R1B
Vref
R2B
1+
R1A
Vref
R2A
OVER VOLTAGE / UNDER VOLTAGE
PROTECTION CIRCUIT
4-159
OUTPUT
Not Recommended for New Design
Please Use ZR431LF01 /02
ZR2431
CONNECTION DIAGRAMS
SO8 Package Suffix – N8
SOT223 Package Suffix – G
Top View
Top View –
Pin 4 floating or connected to pin 2
SOT23 Package Suffix – F
TO92 Package Suffix – C
Top View
Bottom View
SOT89 Package Suffix – Z
ORDERING INFORMATION
Top View
4-160
Part Number
Package
Tol
%
Part Mark
ZR2431N802
SO8
2.5
ZR243102
ZR2431N801
SO8
1
ZR243101
ZR2431G02
SOT223
2.5
ZR243102
ZR2431G01
SOT223
1
ZR243101
ZR2431F02
SOT23
2.5
24D
ZR2431F01
SOT23
1
24E
ZR2431Z02
SOT89
2.5
24D
ZR2431Z01
SOT89
1
24E
ZR2431C02
TO92
2.5
ZR243102
ZR2431C01
TO92
1
ZR243101