Loading...Zetex (Now Diodes) ZR431LC01L, ZR431LC02L, ZR431LF01TA, ZR431LF02TA Schematic [ru]
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ZR431L
Adjustable precision shunt regulator
Summary
Description
The ZR431L is a three terminal adjustable shunt regulator offering excellent temperature stability and output current handling capability up to 25mA. The output voltage may be set to any chosen voltage between 1.24 and 10 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.
The ZR431L 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.
Features
•2.5% and 1% tolerance
• Max. temperature coefficient 50 ppm/°C
• Temperature compensated for operation over -40 to 85°C
•100mA to 25mA current sink capability
•Surface mount SOT23 package
Applications
•Switch mode power supplies
•Shunt regulator
•Series regulator
•Voltage monitor
•Over voltage / under voltage protection
Ordering information
Device |
Pack |
Part mark |
Status |
Quantity |
Reel size |
TOL % |
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per reel |
(inches) |
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ZR431LF01TA |
SOT23 |
43M |
Active |
3000 |
7 |
1 |
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ZR431LF02TA |
SOT23 |
43L |
Active |
3000 |
7 |
2.5 |
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ZR431LC01STOB |
TO92 |
ZR431L01 |
Obsolete |
1500 |
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1 |
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ZR431LC02STOB |
TO92 |
ZR431L02 |
Obsolete |
1500 |
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2.5 |
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ZR431LC01L |
TO92 |
ZR431L01 |
Obsolete |
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Loose |
1 |
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ZR431LC02L |
TO92 |
ZR431L02 |
Obsolete |
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Loose |
2.5 |
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Issue 3 - April 2008 |
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1 |
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www.zetex.com |
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© Zetex Semiconductors plc 2008
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ZR431L |
Absolute maximum ratings |
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Parameter |
Symbol |
Limit |
Unit |
Cathode voltage |
VZ |
10 |
V |
Cathode current |
|
50 |
mA |
Storage temperature |
TSTG |
-55 to 105 |
°C |
Junction temperature |
TJ |
-40 to 125 |
°C |
Power dissipation (at Tamb = 25°C unless otherwise stated) |
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Package |
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Value |
Unit |
SOT23 |
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330 |
mW |
Recommended operating conditions |
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Parameter |
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Min. |
Max. |
Cathode voltage |
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VREF |
10V |
Cathode current |
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100 A |
25mA |
Operating temperature |
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-40°C |
85°C |
Issue 3 - April 2008 |
2 |
www.zetex.com |
© Zetex Semiconductors plc 2008
ZR431L
Block diagram
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:
Vref( ppmIC) = Vdevx1000000
Vref (T1 −T2)
The dynamic output impedance, Rz, is defined as:
RZ |
= |
VZ |
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IZ |
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When the device is programmed with two external resistors, R1 and R2, (fig 2), the dynamic output impedance of the overall circuit, R’, is defined as:
R'= RZ (1+ RR12)
Issue 3 - April 2008 |
3 |
www.zetex.com |
© Zetex Semiconductors plc 2008
ZR431L
Electrical characteristics (at Tamb = 25°C unless otherwise stated)
Parameter |
Symbol |
Min. |
Typ. |
Max. |
Unit |
Conditions |
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Reference Voltage 2.5% |
Vref |
1.209 |
1.24 |
1.271 |
V |
IL = 10mA (Fig1), VZ = Vref |
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1.0% |
V |
1.228 |
1.24 |
1.252 |
V |
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ref |
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Deviation of Reference |
Vdev |
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4.0 |
8.0 |
mV |
IL = 10mA, VZ = Vref |
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Input Voltage over |
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Ta = full range (Fig 1) |
Temperature |
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Ratio of the change in |
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Vref |
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0.5 |
2.0 |
mV/V |
VZ from Vref to 10V |
Reference Voltage to the |
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IZ = 10mA (Fig2) |
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change in Cathode |
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VZ |
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Voltage) |
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Reference Input Current |
Iref |
0.02 |
0.11 |
0.4 |
A |
R1 = 10k, R2 = O/C, |
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lL = 10mA (fig2) |
Deviation of Reference |
Iref |
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0.02 |
0.2 |
A |
R1 = 10k, R2 = O/C, |
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Input Current over |
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IL = 10mA Ta = full |
Temperature |
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range (Fig2) |
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Minimum Cathode |
IZmin |
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30 |
100 |
A |
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Current for Regulation |
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Off-state Current |
IZoff |
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10 |
30 |
A |
VZ = 10V, Vref = 0V |
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(Fig3) |
Dynamic Output |
RZ |
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0.25 |
2 |
Ω |
VZ = Vref(Fig1), f = 0Hz, |
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Impedance |
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IL = 10mA |
DC Test circuits
Fig 1 - Test Circuit for VZ = Vref Fig 2 - Test Circuit for VZ > Vref Fig 3 - Test Circuit for Off State current
Issue 3 - April 2008 |
4 |
www.zetex.com |
© Zetex Semiconductors plc 2008