Issue 7 - April 2008 1 www.zetex.com
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ZTLV431
1.24V Cost effective shunt regulator
Description
Ordering information
The ZTLV431 is a three terminal adjustable
shunt regulator offering excellent temperature
stability and output current handling capability
up to 20mA. The output voltage may be set to
any chosen voltage between 1.24 volts and 10
volts by selection of two external divider
resistors.
The ZTLV431 can be used as a replacement for
zener diodes in many applications requiring an
improvement in zener performance.
The ZTLV431 is available as standard as an
A grade which has an initial tolerance of 1%
and covers the -40°C to 125°C temperature
range as standard.
Features
• Low voltage operation VREF = 1.24V
• Temperature range -40 to 125°C
• Reference voltage tolerance at 25°C
• 1% ZTLV431A
• Typical temperature drift
• 4 mV (0°C to 70°C)
• 6 mV (-40°C to 85°C)
• 11mV (-40°C to 125°C
•100␮A minimum cathode current
•0.25⍀ typical output impedance
• Adjustable output voltage 1.24V to 10V
Applications
• Opto-coupler linearization
• Linear regulators
• Improved Zener
• Variable reference
Pin connections
Tol. Order code Package Part mark Status Reel size
(inches)
Tape width
(mm)
Quantity
per reel
1% ZTLV431AFTA SOT23 S1A Active 7” (180mm) 8 3,000
3Ref
ZTLV431_F (SOT23)
(top view)
Cathode 2
1 Anode
ZTLV431
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Absolute maximum ratings
Operation above the absolute maximum rating may cause device failure. Operation at the
absolute maximum ratings, for extended periods, may reduce device reliability.
Unless otherwise stated voltages specified are relative to the ANODE pin.
Package thermal data
Recommended operating conditions
Cathode voltage (VKA) 10V
Continuous cathode current (IKA) -20 to 20mA
Reference input current range (IREF) -0.05 to 3mA
Operating junction temperature -40 to 150°C
Storage temperature -55 to 150°C
Package ⍜JA PDIS
TA =25°C
SOT23 380°C/W 330 mW
SOT23F 160°C/W 780 mW
Min. Max. Units
VKA cathode voltage VREF 10 V
IKA cathode current 0.1 15 mA
TA operating ambient temperature range -40 125 °C
ZTLV431
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Electrical characteristics (electrical characteristics over recommended operating
conditions, TA = 25°C, KKA = VREF
, IKA = 10mA unless otherwise stated)
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:
The dynamic output impedance, ZKA, is defined as:
When the device is programmed with two externalresistors, R1
and R2, (fig 2) , the dynamic output impedance of the overall
circuit, Z’, is defined as:
Symbol Parameter Conditions Min. Typ. Max. Units
VREF Reference voltage
ZTLV431A 1.228 1.24 1.252
V
TA = -40 to 85°C ZTLV431A 1.215 1.265
T
A
= -40 to 125°C
ZTLV431A 1.209 1.271
VREF(dev)
Deviation of reference
voltage over full
temperature range
TA = 0 to 70°C 4 12
mV
TA = -40 to 85°C 6 20
T
A
= -40 to 125°C
11 31
Ratio of change in
reference voltage to
the change in cathode
voltage
V
KA
from V
REF
to
I
KA
= 10mA
6V -1.5 -2.7
mV/V
10V -1.5 -2.7
IREF
Reference input current
IKA = 10mA, R1 = 10k⍀., R2 = OC 0.1 0.5 µA
IREF(dev)
IREF deviation over full
temperature range
IKA = 10mA,
R1 = 10k⍀,
R2 = OC
TA = 0 to 70°C 0.05 0.3
µA
TA = -40 to 85°C 0.1 0.4
T
A
= -40 to 125°C
0.15 0.5
IKMIN Minimum cathode
current for regulation
VKA = VREF
T
A
= -40 to 125°C
55 100 µA
IK(OFF) Off-state current VKA = 10V, VREF =0V 10 30 µA
zKA Dynamic output
impedance
VKA = VREF
, f = <1kHz,
IK = 0.1 to 15mA
0.25 0.4 ⍀
ΔVREF
ΔVKA
-----------------
V
max
V
min
T1 T2
V
dev
=V
max
-V
min
Temperature
VREF
ppm
°C
------------- ⎠
⎞
⎝
⎛VDEV x1000000
VREF T1T2
–()
------------------------------------------
=
ZKA
ΔVK
ΔIK
----------=
Z′ZKAxR
R
+
()=
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Typical characteristics
Power dissipation (mW)
Ambient temperature (°C)
Power dissipation derating
350
300
250
200
150
100
50
-40 -25 -10 -5 20 35 50 65 80 95 110 125
Reference Current v Temperature
80
-40 -25 -10 5 20 35 50 65 80 95 110 125
90
100
110
120
130
140
Temperature (°C)
Reference Current (nA)
Minimum cathode current vs temperature
16
-40 -25 -10 5 20 35 50 65 80 95 110 125
18
20
22
24
26
Temperature (°C)
Minimum cathode current (µA)
Dynamic impedance vs frequency
0.1
0.1 1 10 100
1
10
100
Frequency (kHz)
Dynamic Impedance (Ω)
V
REF
= V
KA
I
K
= 1mA
I
K
= 10mA
Change in reference voltage vs Cathode voltage
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
0186420
Cathode voltage (V)
Change in reference voltage (mV)
Reference voltage vs Temperature
1.232
-42 -25 -10 5 20 35 50 65 80 95 110 125
1.234
1.236
1.238
1.24
1.242
1.244
Temperature (°C)
Reference voltage (V)
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Typical characteristics
Stability boundary conditions
0
0.01 0.1 1 10 100 1000 10000
5
10
15
20
25
30
Load capacitance (nF)
Cathode current (mA)
Open loop gain vs frequency
00 1 10 100
10
20
30
40
50
60
Frequency (kHz)
Open loop gain (dB)
Pulse response
-2.5
0 50 100 150 200 250 300 350 400 450 500
0
2.5
5
Time (μs)
Input Voltage swing (V)
0
1
2
Output voltage swing (V)
V
KA
V
IN
Single
pulse
Repetitive
pulse
ZTLV431
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Typical characteristics
Pin connections - preview status devices
1Ref
ZTLV431_FF (SOT23F)
(top view)
Cathode 2
3 Anode
Preview
ZTLV431
Issue 7 - April 2008 7 www.zetex.com
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Package outline - SOT23
Note: Controlling dimensions are in millimeters. Approximate dimensions are provided in inches
Dim. Millimeters Inches Dim. Millimeters Inches
Min. Max. Min. Max. Min. Max. Min. Max.
A - 1.12 - 0.044 e1 1.90 NOM 0.075 NOM
A1 0.01 0.10 0.0004 0.004 E 2.10 2.64 0.083 0.104
b 0.30 0.50 0.012 0.020 E1 1.20 1.40 0.047 0.055
c 0.085 0.20 0.003 0.008 L 0.25 0.60 0.0098 0.0236
D 2.80 3.04 0.110 0.120 L1 0.45 0.62 0.018 0.024
e0.95 NOM0.037 NOM-----
E
e
L
e1
D
A
c
E1
L1
A1
b
3 leads
ZTLV431
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© Zetex Semiconductors plc 2008
Definitions
Product change
Zetex Semiconductors reserves the right to alter, without notice, specifications, design, price or conditions of supply of any product or
service. Customers are solely responsible for obtaining the latest relevant information before placing orders.
Applications disclaimer
The circuits in this design/application note are offered as design ideas. It is the responsibility of the user to ensure that the circuit is fit for
the user’s application and meets with the user’s requirements. No representation or warranty is given and no liability whatsoever is
assumed by Zetex with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights
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tort (including negligence), breach of statutory duty, restriction or otherwise) for any damages, loss of profit, business, contract,
opportunity or consequential loss in the use of these circuit applications, under any circumstances.
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approval of the Chief Executive Officer of Zetex Semiconductors plc. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body
or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the
labeling can be reasonably expected to result in significant injury to the user.
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cause the failure of the life support device or to affect its safety or effectiveness.
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For the latest information on technology, delivery terms and conditions and prices, please contact your nearest Zetex sales office.
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ESD (Electrostatic discharge)
Semiconductor devices are susceptible to damage by ESD. Suitable precautions should be taken when handling and transporting devices.
The possible damage to devices depends on the circumstances of the handling and transporting, and the nature of the device. The extent
of damage can vary from immediate functional or parametric malfunction to degradation of function or performance in use over time.
Devices suspected of being affected should be replaced.
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Product status key:
“Preview” Future device intended for production at some point. Samples may be available
“Active” Product status recommended for new designs
“Last time buy (LTB)” Device will be discontinued and last time buy period and delivery is in effect
“Not recommended for new designs”
Device is still in production to support existing designs and production
“Obsolete” Production has been discontinued
Datasheet status key:
“Draft version” This term denotes a very early datasheet version and contains highly provisional information, which
may change in any manner without notice.
“Provisional version” This term denotes a pre-release datasheet. It provides a clear indication of anticipated performance.
However, changes to the test conditions and specifications may occur, at any time and without notice.
“Issue” This term denotes an issued datasheet containing finalized specifications. However, changes to
specifications may occur, at any time and without notice.
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