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TL431LI-Q1
TL432LI-Q1
SNVSBA4A – MAY 2019 – REVISED NOVEMBER 2019
TL431LI-Q1 / TL432LI-Q1 Programmable Shunt Regulator With Optimized Reference
Current
1 Features
3 Description
•
•
The TL431LI-Q1 is a three-terminal adjustable shunt
regulator, with specified thermal stability over
applicable automotive, commercial, and military
temperature ranges. The output voltage can be set to
any value between Vref (approximately 2.495 V) and
36 V with two external resistors. The device has a
typical output impedance of 0.3 Ω. Its active output
circuitry provides a very sharp turn-on characteristic,
making it an excellent replacement for Zener diodes
in many applications, such as onboard regulation,
adjustable power supplies, and switching power
supplies. This device is a pin-to-pin alternative to the
industry standard TL431-Q1 with optimized Iref and
IIdev performance. The lower Iref and IIdev values of the
TL431LI-Q1 enable designers to achieve higher
system accuracy and lower leakage current. The
TL432LI-Q1 has exactly the same functionality and
electrical specifications as the TL431LI-Q1, but has a
different pinout for the DBZ package.
1
•
•
•
•
•
•
•
•
•
Qualified for automotive applications
AEC-Q100 qualified with the following results:
– Device temperature grade 1: –40°C to +125°C
ambient operating temperature
– Device temperature grade 0: –40°C to +150°C
ambient operating temperature
Reference voltage tolerance at 25°C
– 0.5% (B grade)
– 1% (A grade)
Minimum typical output voltage: 2.495 V
Adjustable output voltage: Vref to 36 V
27 mV maximum temperature drift for grade 1
34 mV maximum temperature drift for grade 0
0.3-Ω typical output impedance
Sink-current capability
– Imin = 0.6 mA (max)
– IKA = 15 mA (max)
Reference input current IREF: 0.4 μA (max)
Deviation of reference input current over
temperature, II(dev): 0.3 μA (max)
2 Applications
•
•
•
•
•
•
•
•
•
•
Inverter and motor control
DC/DC converter
LED lighting
On-board charger (OBC)
Infotainment and cluster
Engine management actuator
Transmission
Power steering
Powertrain exhaust sensor
Alternator starter
The TL431LI-Q1 is offered in two grades, with initial
tolerances (at 25°C) of 0.5% and 1%, for the B and A
grade, respectively. The TL431LI-Q1 is also available
in two temperature grades: grade 1 (denoted by a 'Q'
in the part number), and grade 0 (denoted by a 'E' in
the part number), which represent maximum ambient
operating temperatures of 125°C and 150°C
respectively. The TL43xLI-Q1 is characterized for
operation from –40°C to 125°C for grade 1, and
–40°C to 150°C for grade 0, and its low output drift
versus temperature ensures good stability over the
entire temperature range.
Device Information(1)
PART NUMBER
TL43xLI-Q1
PACKAGE (PIN)
SOT-23 (3)
BODY SIZE (NOM)
2.90 mm x 1.30 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Simplified Schematic
VKA
Input
IKA
Vref
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
TL431LI-Q1
TL432LI-Q1
SNVSBA4A – MAY 2019 – REVISED NOVEMBER 2019
www.ti.com
Table of Contents
1
2
3
4
5
6
7
8
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Device Comparison Table.....................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
3
4
7.1
7.2
7.3
7.4
7.5
7.6
4
4
4
4
5
6
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
Typical Characteristics ..............................................
Parameter Measurement Information .................. 9
8.1 Temperature Coefficient............................................ 9
8.2 Dynamic Impedance ............................................... 10
9
Detailed Description ............................................ 11
9.1 Overview ................................................................. 11
9.2 Functional Block Diagram ....................................... 11
9.3 Feature Description................................................. 12
9.4 Device Functional Modes........................................ 12
10 Applications and Implementation...................... 13
10.1 Application Information.......................................... 13
10.2 Typical Applications .............................................. 13
10.3 System Examples ................................................. 22
11 Power Supply Recommendations ..................... 25
12 Layout................................................................... 25
12.1 Layout Guidelines ................................................. 25
12.2 Layout Example .................................................... 25
13 Device and Documentation Support ................. 26
13.1
13.2
13.3
13.4
13.5
13.6
13.7
13.8
Device Support......................................................
Documentation Support ........................................
Related Links ........................................................
Receiving Notification of Documentation Updates
Support Resources ...............................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
26
26
26
26
26
27
27
27
14 Mechanical, Packaging, and Orderable
Information ........................................................... 27
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Original (May 2019) to Revision A
•
2
Page
Changed device status from Advance Information to Production Data ................................................................................. 1
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5 Device Comparison Table
DEVICE PINOUT
INITIAL ACCURACY
OPERATING FREE-AIR TEMPERATURE (TA)
TL431LI-Q1
TL432LI-Q1
A: 1% B: 0.5%
Q: -40°C to 125°C
E: -40°C to 150°C
6 Pin Configuration and Functions
TL431LI-Q1 DBZ Package
3-Pin SOT-23
Top View
CATHODE
TL432LI-Q1 DBZ Package
3-Pin SOT-23
Top View
1
3
REF
ANODE
1
3
ANODE
2
REF
CATHODE
2
Pin Functions
PIN NUMBER
NAME
TL431LI-Q1
TL432LI-Q1
DBZ
DBZ
TYPE
DESCRIPTION
ANODE
3
3
O
Common pin, normally connected to ground
CATHODE
1
2
I/O
Shunt current/Voltage input
REF
2
1
I
Threshold relative to common anode
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7 Specifications
7.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
MIN
VKA
Cathode Voltage (2)
IKA
Continuos Cathode Current Range
II(ref)
Reference Input Current
TJ
Tstg
(1)
(2)
MAX
UNIT
37
V
–10
18
mA
–5
10
mA
Operating Junction Temperature Range
–40
150
C
Storage Temperature Range
–65
150
C
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
All voltage values are with respect to ANODE, unless otherwise noted.
7.2 ESD Ratings
VALUE
Electrostatic
discharge
V(ESD)
(1)
Human body model (HBM), per AEC Q100-002 (1)
±4000
Charged-device model (CDM), per AEC Q100-011
±1000
UNIT
V
AEC Q100-002 indicates that HBM stressing shall be in accordance with the ANSI/ESDA/JEDEC JS-001 specification
7.3 Recommended Operating Conditions
VKA
Cathode Voltage
IKA
Continuous Cathode Current Range
TA
Operating Free-Air Temperature (1)
(1)
MIN
MAX
UNIT
VREF
36
V
0.6
15
mA
TL43xLIxQ
–40
125
C
TL43xLIxE
–40
150
C
Maximum power dissipation is a function of TJ(max), θJA, and TA. The maximum allowable power dissipation at any allowable ambient
temperature is PD = (TJ(max) – TA)/θJA. Operating at the absolute maximum TJ can affect reliability. Please see the Semiconductor and IC
Package Thermal Metrics Application Report for more information.
7.4 Thermal Information
TL43xLI
THERMAL METRIC
(1)
DBZ
UNIT
3 PINS
RθJA
Junction-to-ambient thermal resistance
371.7
C/W
RθJC(top)
Junction-to-case (top) thermal resistance
145.9
C/W
RθJB
Junction-to-boardthermal resistance
104.7
C/W
ψJT
Junction-to-top characterization resistance
23.9
C/W
ψJB
Junction-to-board characterization resistance
102.9
C/W
(1)
4
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics Application
Report.
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7.5 Electrical Characteristics
over recommended operating conditions, TA = 25°C (unless otherwise noted)
PARAMETER
TEST CIRCUIT
Vref
Reference Voltage
VI(dev)
Deviation of reference
input voltage over full
temperature range (1)
See Figure 14
VKA = Vref, IKA = 1 mA
ΔVref /
ΔVKA
Ratio of change in
reference voltage to the
change in cathode
voltage
See Figure 15
IKA = 1 mA
Iref
Reference Input Current See Figure 15
II(dev)
Deviation of reference
input current over full
temperature range (1)
Imin
Minimum cathode
current for regulation
Ioff
Off-state cathode
current
|ZKA|
(1)
(2)
Dynamic Impedance
See Figure 14
TEST CONDITIONS
(2)
VKA = Vref, IKA = 1 mA
MIN
TYP MAX
UNIT
TL43xLIAx devices
2470 2495 2520
mV
TL43xLIBx devices
2483 2495 2507
mV
TL43xLIxQ devices
10
27
mV
TL43xLIxE devices
14
34
mV
–1.4
–2.7
mV/V
–1
–2
mV/V
IKA = 1 mA, R1 = 10kΩ, R2 = ∞
0.2
0.4
µA
See Figure 15
IKA = 1 mA, R1 = 10kΩ, R2 = ∞
0.1
0.3
µA
See Figure 14
VKA = Vref
0.6
mA
See Figure 16
VKA = 36 V, Vref = 0
0.1
1
µA
See Figure 14
VKA = Vref, IKA = 1 mA to 15 mA
0.3
0.75
Ω
ΔVKA = 10 V - Vref
ΔVKA = 36 V - 10 V
The deviation parameters VI(dev) and II(dev) are defined as the differences between the maximum and minimum values obtained over the
rated temperature range. For more details on VI(dev) and how it relates to the average temperature coefficient, see the Temperature
Coefficient section.
The dynamic impedance is defined by |ZKA| = ΔVKA/ΔIKA. For more details on |ZKA| and how it relates to VKA, see the Temperature
Coefficient section.
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7.6 Typical Characteristics
Data at high and low temperatures are applicable only within the recommended operating free-air temperature
ranges of the various devices.
0.5
2520
IKA = 1 mA
Iref - Reference Current - µA
Vref - Reference Voltage - mV
Vka = Vref
2515 IKA = 1 mA
2510
2505
2500
2495
2490
2485
0.4
0.3
0.2
0.1
2480
2475
-50
0
-50
-25 0
25 50 75 100 125 150
TA - Free-Air Temperature - °C
Book
Figure 1. Reference Voltage versus Free-Air Temperature
Figure 2. Reference Current versus Free-Air Temperature
0.064
12
9
6
3
0
VKA = 36 V
0.056 VREF = 0 V
0.048
0.04
0.032
0.024
0.016
0.008
0
-50
-3
0
0.5
1
1.5
2
2.5
VKA - Cathode Voltage -V
3
D003
Figure 4. Off-State Cathode Current
versus Free-Air Temperature
VKA = 3 V to 36 V
-0.4
'Vref / 'VKA = mV/V
-0.45
-0.5
-0.55
-0.6
-0.65
-0.7
-0.75
-0.8
-50
-25
0
25 50 75 100 125 150
Temperature (°C)
D006
Figure 5. Ratio of Delta Reference Voltage to Delta Cathode
Voltage versus Free-Air Temperature
AV - Small-Signal Voltage Amplification - dB
Figure 3. Cathode Current versus Cathode Voltage
-0.35
-25 0
25 50 75 100 125 150
TA - Free-Air Temperature - °C
75
200
Gain
Phase
60
160
45
120
30
80
15
40
0
100
1k
10k
100k
f - Frequency - Hz
1M
Phase - Degrees
VKA = Vref
TA = 25°C
Ioff - Off-State Cathode Current - PA
IKA - Cathode Current - mA
15
6
-25 0
25 50 75 100 125 150
TA - Free-Air Temperature - °C
0
10M
Gain
Figure 6. Small-Signal Voltage Amplification
versus Frequency
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Typical Characteristics (continued)
IKA = 10 mA
TA = 25°C
Output
IKA
15 kΩ
232 Ω
9 µF
+
−
8.25 kΩ
|ZKA| - Reference Impedance - Ohms
100
10
5
3
2
1
0.5
0.3
0.2
0.1
1k
GND
Figure 7. Test Circuit for Voltage Amplification
IKA = 1 mA
50 T = 25°C
A
30
20
10k
100k
f - Frequency - Hz
1M
Figure 8. Reference Impedance versus Frequency
6
1 kΩ
Output
Input and Output Voltage - V
Input
IKA
50 Ω
−
+
GND
TA = 25qC
5
4
3
Output
2
1
0
-1
1
2
3
4
t - Time - Ps
5
6
7
puls
Figure 10. Pulse Response
Figure 9. Test Circuit for Reference Impedance
15
220 Ω
50 Ω
GND
IKA - Cathode Current - mA
Output
Pulse
Generator
f = 100 kHz
0
12
Stable Region
9
6
3
0
0.001
Figure 11. Test Circuit for Pulse Response
A VKA = Vref
B VKA = 5 V
C VKA = 10 V
0.01
0.1
1
CL - Load Capacitance - µF
10
Copy
TL43
The areas under the curves represent conditions that may cause the
device to oscillate. For curves B and C, R2 and V+ are adjusted to
establish the initial VKA and IKA conditions, with CL = 0. VBATT and CL
then are adjusted to determine the ranges of stability.
Figure 12. Stability Boundary Conditions for All TL431LI-Q1,
TL432LI-Q1 Devices
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Typical Characteristics (continued)
150 Ω
IKA
+
VBATT
CL
−
TEST CIRCUIT FOR CURVE A
IKA
R1 = 10 kΩ
150 Ω
CL
+
R2
VBATT
−
TEST CIRCUIT FOR CURVES B, C, AND D
Figure 13. Test Circuits for Stability Boundary Conditions
8
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8 Parameter Measurement Information
VKA
Input
IKA
Vref
Figure 14. Test Circuit for VKA = Vref
Input
VKA
IKA
R1
Iref
R2
Vref
R1 ö
æ
VKA = Vref ç 1 +
÷ + Iref × R1
R2 ø
è
Figure 15. Test Circuit for VKA > Vref
Input
VKA
Ioff
Figure 16. Test Circuit for Ioff
8.1 Temperature Coefficient
The deviation of the reference voltage, Vref, over the full temperature range is known as VI(dev). The parameter of
VI(dev) can be used to find the temperature coefficient of the device. The average full-range temperature
coefficient of the reference input voltage, αVref, is defined as:
αVref is positive or negative, depending on whether minimum Vref or maximum Vref, respectively, occurs at the
lower temperature. The full-range temperature coefficient is an average and therefore any subsection of the rated
operating temperature range can yield a value that is greater or less than the average. For more details on
temperature coefficient, refer to the Voltage Reference Selection Basics White Paper.
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8.2 Dynamic Impedance
'VKA
'IKA . When the device is operating with two external resistors
The dynamic impedance is defined as
'V
z'
'I , which is approximately equal to
(see Figure 15), the total dynamic impedance of the circuit is given by
R1 ·
§
ZKA ¨ 1
¸
© R2 ¹ .
ZKA
Itest
P/
IKA (mA)
The VKA of the TL431LI-Q1 can be affected by the dynamic impedance. The TL431LI-Q1 test current Itest for VKA
is specified in the Electrical Characteristics. Any deviation from Itest can cause deviation on the output VKA.
Figure 17 shows the effect of the dynamic impedance on the VKA.
IKA
IKA(min)
0
VKA (V)
Ps
Figure 17. Dynamic Impedance
10
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9 Detailed Description
9.1 Overview
This standard device has proven ubiquity and versatility across a wide range of applications, ranging from power
to signal path. This is due to its key components containing an accurate voltage reference and op amp, which
are very fundamental analog building blocks. TL43xLI-Q1 is used in conjunction with its key components to
behave as a single voltage reference, error amplifier, voltage clamp or comparator with integrated reference.
TL43xLI-Q1 can be operated and adjusted to cathode voltages from 2.495 V to 36 V, making this part optimal for
a wide range of end equipments in industrial, auto, telecom and computing. In order for this device to behave as
a shunt regulator or error amplifier, >0.6mA (Imin(max)) must be supplied in to the cathode pin. Under this
condition, feedback can be applied from the Cathode and Ref pins to create a replica of the internal reference
voltage.
Various reference voltage options can be purchased with initial tolerances (at 25°C) of 0.5% (denoted by B), and
1% (denoted by A). TL431LI-Q1 and TL432LI-Q1 are both functionally the same, but have different pinout
options.
9.2 Functional Block Diagram
CATHODE
+
REF
_
Vref
ANODE
Figure 18. Equivalent Schematic
CATHODE
REF
ANODE
Figure 19. Detailed Schematic
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9.3 Feature Description
TL43xLI-Q1 consists of an internal reference and amplifier that outputs a sink current based on the difference
between the reference pin and the virtual internal pin. The sink current is produced by the internal Darlington
pair, shown in Figure 19. A Darlington pair is used for this device to be able to sink a maximum current of 15 mA.
When operated with enough voltage headroom (≥ 2.495 V) and cathode current (IKA), TL43xLI-Q1 forces the
reference pin to 2.495 V. However, the reference pin can not be left floating, as it needs IREF ≥ 0.4 µA (see the
Specifications). This is because the reference pin is driven into an npn, which needs base current in order
operate properly.
When feedback is applied from the Cathode and Reference pins, TL43xLI-Q1 behaves as a Zener diode (refer to
Figure 23 for a circuit example), regulating to a constant voltage dependent on current being supplied into the
cathode. This is due to the internal amplifier and reference entering the proper operating regions. The same
amount of current needed in the above feedback situation must be applied to this device in open loop, servo, or
error amplifying implementations for it to be in the proper linear region giving TL43xLI-Q1 enough gain.
Unlike many linear regulators, TL43xLI-Q1 is internally compensated to be stable without an output capacitor
between the cathode and anode. However, if it is desired to use an output capacitor, Figure 12 can be used as a
guide to assist in choosing the correct capacitor to maintain stability.
9.4 Device Functional Modes
9.4.1 Open Loop (Comparator)
When the cathode/output voltage or current of TL43xLI-Q1 is not being fed back to the reference/input pin in any
form, this device is operating in open loop. With proper cathode current (Ika) applied to this device, TL43xLI-Q1
has the characteristics shown in Figure 18. With such high gain in this configuration, TL43xLI-Q1 is typically used
as a comparator. Since the reference is integrated, TL43xLI-Q1 is the preferred choice when users are trying to
monitor a certain level of a single signal. Refer to the Using the TL431 as a Voltage Comparator Application
Report for more details on open loop comparator applications on the TL431LI-Q1.
9.4.2 Closed Loop
When the cathode/output voltage or current of TL43xLI-Q1 is being fed back to the reference/input pin in any
form, this device is operating in closed loop. The majority of applications involving TL43xLI-Q1 use it in this
manner to regulate a fixed voltage or current. The feedback enables this device to behave as an error amplifier,
computing a portion of the output voltage and adjusting it to maintain the desired regulation. This is done by
relating the output voltage back to the reference pin in a manner to make it equal to the internal reference
voltage, which can be accomplished through resistive or direct feedback.
12
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10 Applications and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
10.1 Application Information
As this device has many applications and setups, there are many situations that this data sheet can not
characterize in detail. The linked application notes help the designer make the best choices when using this part.
Designing with the Improved TL431LI Application Note provides a deeper understanding of this accuracy of the
device in a flyback optocoupler application. Setting the Shunt Voltage on an Adjustable Shunt Regulator
Application Note assists designers in setting the shunt voltage to achieve optimum accuracy for this device.
10.2 Typical Applications
10.2.1 Comparator With Integrated Reference
Vsup
Rsup
Vout
CATHODE
R1
VIN
RIN
REF
VL
+
R2
2.5V
ANODE
Figure 20. Comparator Application Schematic
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Typical Applications (continued)
10.2.2 Design Requirements
For this design example, use the parameters listed in Table 1 as the input parameters.
Table 1. Design Parameters
DESIGN PARAMETER
EXAMPLE VALUE
Input Voltage Range
0 V to 5 V
Input Resistance
10 kΩ
Supply Voltage
24 V
Cathode Current (Ik)
5 mA
Output Voltage Level
~2 V – VSUP
Logic Input Thresholds VIH/VIL
VL
10.2.3 Detailed Design Procedure
When using TL43xLI-Q1 as a comparator with reference, determine the following:
• Input voltage range
• Reference voltage accuracy
• Output logic input high and low level thresholds
• Current source resistance
10.2.3.1 Basic Operation
In the configuration shown in Figure 20, TL43xLI-Q1 behaves as a comparator, comparing the VREF pin voltage
to the internal virtual reference voltage. When provided a proper cathode current (IK), TL43xLI-Q1 has enough
open loop gain to provide a quick response. This can be seen in Figure 21 where the RSUP = 10 kΩ (IKA = 500
µA) situation responds much slower than RSUP = 1 kΩ (IKA = 5 mA). With the TL43xLI-Q1 max operating current
(IMIN) being 1 mA, operation below that can result in low gain, leading to a slow response.
10.2.3.1.1 Overdrive
Slow or inaccurate responses can also occur when the reference pin is not provided enough overdrive voltage.
This is the amount of voltage that is higher than the internal virtual reference. The internal virtual reference
voltage is within the range of 2.495 V ±(0.5% or 1.0%), depending on which version is being used. The more
overdrive voltage provided, the faster the TL43xLI-Q1 responds.
For applications where TL43xLI-Q1 is being used as a comparator, it is best to set the trip point to greater than
the positive expected error (that is +1.0% for the A version). For fast response, setting the trip point to >10% of
the internal VREF suffices.
For minimal voltage drop or difference from Vin to the ref pin, TI recommends to use an input resistor
