ATL43x 2.5V Low Iq Adjustable Precision Shunt Regulator datasheet (Rev. E)

Document overview

  • Manufacturer or author: Texas Instruments, Incorporated [SLVSCV5,E]
  • PDF pages: 31

Technical content

ATL43x 2.5V Low Iq Adjustable Precision Shunt Regulator

1 Features

  • Adjustable Regulated Output of 2.5V to 36V
  • Very-Low Operating Current – IKA(min) = 35µA (Maximum) – IREF = 150nA (Maximum)
  • Internally Compensated for Stability – Stable With No Capacitive Load
  • Reference Voltage Tolerances at 25°C – 0.5% for B Grade – 1% for A Grade
  • Typical Temperature Drift – 5mV (–40°C to +85°C); I Version – 6mV (–40°C to +125°C); Q Version
  • Extended Cathode Current Range 35µA to 100mA
  • Low Output Impedance of 0.3Ω (Maximum)

2 Applications

  • Secondary Side Regulation in Flyback SMPSs
  • Industrial, Computing, Consumer, and Portables
  • Adjustable Voltage and Current Referencing
  • Power Management
  • Power Isolation
  • Zener Replacement

3 Description

The ATL431 and ATL432 are three-terminal adjustable shunt regulator s, with specified thermal stability over applicable automotive, commercial, and industrial temperature ranges. The output voltage can be set to any value between Vref (approximately 2.5V) and 36V, with two external resistors. These devices have a typical output impedance of 0.05 Ω. Active output circuitry provides a very sharp turn- on characteristic, making these devices excellent replacements for Zener diodes in many applications, such as onboard regulation, adjustable power supplies, and switching power supplies. The ATL43x has > 20x improvement cathode current range over its TL43x predecessor. It also is stable with a wider range of load capacitance types and values. ATL431 and ATL432 are the exact same parts but with different pinouts and order numbers. The ATL43x is offered in two grades, with initial tolerances (at 25°C) of 0.5%, 1%, for the B and A grade, respectively. In addition, low output drift vs temperature ensures consistent voltage regulation over the entire temperature range. The ATL43xxI devices are characterized for operation from –40°C to +85°C, and the ATL43xxQ devices are characterized for operation from –40°C to +125°C. Device Information PART NUMBER PACKAGE(1) BODY SIZE (NOM) (2) ATL431 ATL432 SOT (3) 2.90mm × 1.60mm (1) For all available packages, see the orderable addendum at the end of the data sheet. (2) The package size (length × width) is a nominal value and includes pins, where applicable. Vref Input VKA IKA Copyright © 2017, Texas Instruments Incorporated Simplified Schematic CKA(PF) IKA(PA) 0.0001 0.001 0.01 0.1 1 10 100 1000 2000 STABLE D001 Stability Region for VKA = 15V ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 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.

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13 Mechanical, Packaging, and Orderable

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4 Pin Configuration and Functions

3 ANODE

Figure 4-1. ATL431 DBZ Package 3-Pin SOT-23 Top View 1REF 2CATHODE Figure 4-2. ATL432 DBZ Package 3-Pin SOT-23 Top View Table 4-1. Pin Functions PIN I/O DESCRIPTION NAME NO. ATL431x ATL432x CATHODE 1 2 I/O Shunt Current/Voltage input REF 2 1 I Threshold relative to common anode ANODE 3 3 O Common pin, normally connected to ground

5 Specifications

5.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1) MIN MAX UNIT VKA Cathode voltage(2) 40 V IKA Continuous cathode current –100 150 mA II(ref) Reference input current –0.05 10 mA TJ Operating virtual junction temperature –40 150 °C Tstg Storage temperature –65 150 °C (1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. (2) All voltage values are with respect to ANODE, unless otherwise noted.

5.2 ESD Ratings

V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±1000 (1) JEDEC document JEP155 states that 500V HBM allows safe manufacturing with a standard ESD control process. (2) JEDEC document JEP157 states that 250V CDM allows safe manufacturing with a standard ESD control process.

5.3 Recommended Operating Conditions

VKA Cathode voltage Vref 36 V IKA Cathode current .035 100 mA TA Operating free-air temperature I Grade –40 85 Q Grade –40 125 www.ti.com ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 Copyright © 2024 Texas Instruments Incorporated Submit Document Feedback 3 Product Folder Links: ATL431 ATL432

5.4 Thermal Information

THERMAL METRIC(1) ATL43x UNITDBZ (SOT-23)

3 PINS

RθJA Junction-to-ambient thermal resistance 331.8 °C/W RθJC(top) Junction-to-case (top) thermal resistance 106.5 °C/W RθJB Junction-to-board thermal resistance 64.6 °C/W ψJT Junction-to-top characterization parameter 4.9 °C/W ψJB Junction-to-board characterization parameter 62.9 °C/W (1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.

5.5 Electrical Characteristics, ATL431Ax, ATL432Ax

over recommended operating conditions, TA = 25°C (unless otherwise noted) PARAMETER TEST CIRCUIT TEST CONDITIONS MIN TYP MAX UNIT Vref Reference voltage Figure 6-1 VKA = Vref, IKA = 1mA 2475 2500 2525 mV VI(dev) Deviation of reference input voltage over full temperature range, see section Figure 6-1 VKA = Vref, IKA = 1mA, ATL43xAI; TA = -40°C to 85°C 5 15 mV ATL43xAQ; TA = -40°C to 125°C 6 34 ΔVref / ΔVKA Ratio of change in reference voltage to the change in cathode voltage Figure 6-2 IKA = 1mA ΔVKA = 10V − Vref –0.4 –2.7 mV/V ΔVKA = 36V − 10V –0.1 –2 Iref Reference input current Figure 6-2 IKA = 1mA, R1 = 10kΩ, R2 = ∞ 30 150 nA II(dev) Deviation of reference input current over full temperature range, see section Figure 6-2 IKA = 1mA, R1 = 10kΩ, R2 = ∞ 20 50 nA Imin Minimum cathode current for regulation Figure 6-1 Figure 5-5 VKA = Vref 20 35 µA Ioff Off-state cathode current Figure 6-3 VKA = 36V, Vref = 0 0.05 0.2 µA |zKA| Dynamic impedance, see section Figure 6-1 VKA = Vref, f ≤ 1 kHz, IKA = 1 mA to 100 mA 0.05 0.3 Ω

5.6 Electrical Characteristics, ATL431Bx, ATL432Bx

over recommended operating conditions, TA = 25°C (unless otherwise noted) PARAMETER TEST CIRCUIT TEST CONDITIONS MIN TYP MAX UNIT Vref Reference voltage Figure 6-1 VKA = Vref, IKA = 1mA 2487 2500 2512 mV VI(dev) Deviation of reference input voltage over full temperature range, see section Figure 6-1 VKA = Vref, IKA = 1mA ATL43xBI; TA = –40°C to 85°C 5 15 mV ATL43xBQ; TA = –40°C to 125°C 6 34 ΔVref / ΔVKA Ratio of change in reference voltage to the change in cathode voltage Figure 6-2 IKA = 1mA ΔVKA = 10V − Vref –0.4 –2.7 mV/V ΔVKA = 36V − 10V –0.1 –2 Iref Reference input current Figure 6-2 IKA = 1mA, R1 = 10kΩ, R2 = ∞ 30 150 nA II(dev) Deviation of reference input current over full temperature range, see section Figure 6-2 IKA = 1mA, R1 = 10kΩ, R2 = ∞ 20 50 nA Imin Minimum cathode current for regulation Figure 6-1 Figure 5-5 VKA = Vref 20 35 µA Ioff Off-state cathode current Figure 6-3 VKA = 36V, Vref = 0 0.05 0.2 µA |zKA| Dynamic impedance, see section Figure 6-1 VKA = Vref, f ≤ 1 kHz, IKA = 1 mA to 100 mA 0.05 0.3 Ω ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 www.ti.com

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5.7 Typical Characteristics

Data at high and low temperatures are applicable only within the recommended operating free-air temperature ranges of the various devices. TA (qC) Vref (mV) -40 -20 0 20 40 60 80 100 120 140 2475 2480 2485 2490 2495 2500 2505 2510 2515 2520 Vref = 2485mV Vref = 2500mV Vref = 2504mV IKA=1mA Figure 5-1. Reference Voltage vs Free-Air Temperature TA (qC) IREF (PA) -40 -20 0 20 40 60 80 100 120 140 0.008 0.016 0.024 0.032 0.04 Figure 5-2. Reference Current vs Free-Air Temperature VKA = VREF (V) IKA (mA) -100 -80 -60 -40 -20 100 D001 Figure 5-3. Cathode Current vs Cathode Voltage VKA = VREF (V) IKA (PA) 0 0.5 1 1.5 2 2.5 3 D001 TA = -40qC TA = 25qC TA = 85qC TA = 125qC Figure 5-4. Cathode Current vs Cathode Voltage VKA = VREF (V) IKA (PA) Ik(min) Figure 5-5. Cathode Current vs Cathode Voltage TA (qC) IOFF (PA) -40 -20 0 20 40 60 80 100 120 140 0.04 0.08 0.12 0.16 0.2 Figure 5-6. Off-State Cathode Current vs Free-Air Temperature www.ti.com ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 Copyright © 2024 Texas Instruments Incorporated Submit Document Feedback 5 Product Folder Links: ATL431 ATL432

5.7 Typical Characteristics (continued)

Data at high and low temperatures are applicable only within the recommended operating free-air temperature ranges of the various devices. Vka (V) 'Vref (mV) 0 5 10 15 20 25 30 35 40 -5.5 -4.5 -3.5 -2.5 -1.5 -0.5 IKA=1mA Figure 5-7. Delta Reference Voltage vs Cathode Voltage Temperature (qC) 'Vref/'Vka (mV) -40 -20 0 20 40 60 80 100 120 140 -0.5 -0.45 -0.4 -0.35 -0.3 -0.25 -0.2 -0.15 -0.1 D001 Vref to 10V 10V to 36V IKA=1mA Figure 5-8. Delta Reference Voltage vs Cathode Voltage Frequency (Hz) Noise (nV/—Hz) 10 100 1000 10000 600 660 720 780 840 900 D001 IKA = 1mA Figure 5-9. Noise Voltage ±20 100 120 140 160 180 10 100 1000 10000 100000 1000000 Gain (dB) and Phase (ƒ) Frequency (Hz) Gain Phase C001 Figure 6-4 used for this measurement. IKA=1mA Figure 5-10. Small-Signal Voltage Amplification vs Frequency Frequency (Hz) Output Impedance (:) 100 1000 10000 100000 1000000 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.1 1.2 Figure 6-5 used for this measurement. Figure 5-11. Output Impedance vs Frequency TA (qC) Output Impedance (:) -40 -20 0 20 40 60 80 100 120 140 0.02 0.04 0.06 0.08 0.1 Figure 6-5 used for this measurement. Figure 5-12. DC Output Impedance vs Temperature ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 www.ti.com

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Data at high and low temperatures are applicable only within the recommended operating free-air temperature ranges of the various devices. IKA = 100µA Figure 6-7 used for this measurement. Figure 5-13. Pulse Response CKA(PF) IKA(PA) 0.0001 0.001 0.01 0.1 1 10 100 1000 2000 STABLE D001 Unstable STABLE ESR < 20mΩ Figure 6-6 used to verify stability. Figure 5-14. Low IKA (VKA = 2.5V) Stability Boundary Conditions All ATL43xx Devices CKA(PF) IKA(PA) 0.0001 0.001 0.01 0.1 1 10 100 1000 2000 STABLE D001 Unstable STABLE ESR < 20mΩ Figure 6-6 used to verify stability. Figure 5-15. Low IKA (VKA = 5.0V) Stability Boundary Conditions All ATL43xx Devices CKA(PF) IKA(PA) 0.0001 0.001 0.01 0.1 1 10 100 1000 2000 STABLE D001 Unstable STABLE ESR < 20mΩ Figure 6-6 used to verify stability. Figure 5-16. Low IKA (VKA = 10.0V) Stability Boundary Conditions All ATL43xx Devices CKA(PF) IKA(PA) 0.0001 0.001 0.01 0.1 1 10 100 1000 2000 STABLE D001 ESR < 20mΩ Figure 6-6 used to verify stability. Figure 5-17. Low IKA (VKA = 15.0V) Stability Boundary Conditions All ATL43xx Devices CKA(uF) IKA(mA) 0.0001 0.001 0.01 0.1 1 10 100 Stable D001 Unstable ESR < 20mΩ Figure 6-6 used to verify stability. Figure 5-18. High IKA (VKA = 2.5V) Stability Boundary Conditions All ATL43xx Devices www.ti.com ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 Copyright © 2024 Texas Instruments Incorporated Submit Document Feedback 7 Product Folder Links: ATL431 ATL432

Data at high and low temperatures are applicable only within the recommended operating free-air temperature ranges of the various devices. CKA(uF) IKA(mA) 0.0001 0.001 0.01 0.1 1 10 100 Stable D001 Unstable ESR < 20mΩ Figure 6-6 used to verify stability. Figure 5-19. High IKA (VKA = 5.0V) Stability Boundary Conditions All ATL43xx Devices CKA(uF) IKA(mA) 0.0001 0.001 0.01 0.1 1 10 100 Stable D001 Unstable ESR < 20mΩ Figure 6-6 used to verify stability. Figure 5-20. High IKA (VKA = 10.0V) Stability Boundary Conditions All ATL43xx Devices CKA(uF) IKA(mA) 0.0001 0.001 0.01 0.1 1 10 100 Stable D001 ESR < 20mΩ Figure 6-6 used to verify stability. Figure 5-21. High IKA (VKA = 15.0V) Stability Boundary Conditions All ATL43xx Devices ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 www.ti.com

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6 Parameter Measurement Information

The deviation parameters V ref(dev) and I ref(dev) are defined as the differences between the maximum and minimum values obtained over the rated temperature range. The average full-range temperature coefficient of the reference input voltage αVref is defined as: SPACE SPACE αVref is positive or negative, depending on whether minimum V ref or maximum V ref, respectively, occurs at the lower temperature. The dynamic impedance is defined as: ∆ IKA ∆ VKA |z | =KA SPACE When the device is operating with two external resistors (see Figure 6-2), the total dynamic impedance of the circuit is given by: ∆ I ∆ V|z'| = which is approximately equal to R1|z |KA (1 + ( SPACE Vref Input VKA IKA Figure 6-1. Test Circuit for VKA = Vref Ir ef IKA VKAInput Vref KA ref ref R1V = V 1 + + I × R1R2 /c230 /c246 /c231 /c247 /c232 /c248 Figure 6-2. Test Circuit for VKA > Vref Ioff VKAInput Figure 6-3. Test Circuit for Ioff 2.5 k IK= 1mA 15 kQ 15 kQ VDC = 7.57 V 100 µF Figure 6-4. Test Circuit for Phase and Gain Measurement www.ti.com ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 Copyright © 2024 Texas Instruments Incorporated Submit Document Feedback 9 Product Folder Links: ATL431 ATL432

F Figure 6-5. Test Circuit for Reference Impedance (ZKA) >250Ÿ Vbat IK CL >250Ÿ Vbat IK R1 = 10NŸ CL Figure 6-6. Test Circuit for Stability Boundary Conditions 50 Ÿ Pulse Generator F = 100kHz GND OUTPUT IK 25NŸ Figure 6-7. Test Circuit for Pulse Response ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 www.ti.com

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7 Detailed Description

7.1 Overview

The ATL43x is a low power counterpart to TL431 and TLV431, having lower minimum cathode current ( Ik(min) = 35µA). Like the TL431, the ATL43x is used in conjunction with it's key components to behave as a single voltage reference, error amplifier, voltage clamp, or comparator with integrated reference. The ATL43x can be operated and adjusted to cathode voltages from 2.5V to 36V, this part is an excellent choice for a wide range of end equipments in industrial, auto, telecom and computing. For this device to behave as a shunt regulator or error amplifier, > 35µA (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% and 1.0%. These reference options are denoted by B (0.5%) and A (1.0%) after the ATL43x. The ATL43xxI devices are characterized for operation from –40°C to +85°C, and the ATL43xxQ devices are characterized for operation from –40°C to +125°C.

7.2 Functional Block Diagram

Copyright © 2017, Texas Instruments Incorporated Vref CATHODE ANODE REF

7.3 Feature Description

ATL43x 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 an internal Darlington pair. When operated with enough voltage headroom ( ≥ 2.5V) and cathode current (I KA), ATL43x forces the reference pin to 2.5V. However, the reference pin can not be left floating, as it needs Iref ≥ 0.1µA (please see the Functional Block Diagram). 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, ATL43x behaves as a Zener diode, 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 required in the above feedback situation must be applied to this device in open-loop, servo, or error amplifying implementations for the current to be in the proper linear region to give the ATL43x enough gain. Unlike many linear regulators, ATL43x 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 5-14 through Figure 5-21 can be used as a guide to assist in choosing the correct capacitor to maintain stability. www.ti.com ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 Copyright © 2024 Texas Instruments Incorporated Submit Document Feedback 11 Product Folder Links: ATL431 ATL432

7.4 Device Functional Modes

7.4.1 Open Loop (Comparator)

When the cathode/output voltage or current of ATL43x is not being fed back to the reference/input pin in any form, this device is operating in open loop. With such high gain in this configuration, the ATL43x is typically used as a comparator. Due to the integrated reference, the ATL43x allows users to monitor a certain level of a single signal.

7.4.2 Closed Loop

When the cathode/output voltage or current of ATL43x is being fed back to the reference/input pin in any form, this device is operating in closed loop. The majority of applications involving the ATL43x 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 via resistive or direct feedback. ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 www.ti.com

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8 Application and Implementation

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, as well as validating and testing their design implementation to confirm system functionality.

8.1 Application Information

Figure 8-1 shows the ATL43x used in a 24-V isolated flyback supply. The output of the regulator, plus the forward voltage drop of the optocoupler LED (2.5 + 0.7 = 3.2V), determine the minimum voltage that can be regulated in an isolated supply configuration. Regulated voltage as low as 5.0Vdc is possible in the topology shown in Figure 8-1. The 431 family of devices are prevalent in these applications, being designers go-to choice for secondary side regulation. Due to this prevalence, this section will further go on to explain operation and design in both states of the ATL43x that this application sees: open-loop (Comparator + Vref) and closed-loop (Shunt Regulator). The key benefit in isolated supplies for the ATL43x is the no load power savings gained by the > 20x decrease in I Kmin from TL431. More information about this and other benefits can be found in Designing with the "Advanced" TL431, ATL431 (SLVA685). Further information about system stability and using a ATL43x device for compensation can be found in Compensation Design With TL431 for UCC28600 (SLUA671). Copyright © 2017, Texas Instruments Incorporated Gate Drive VCC VFB Controller Current Sense GND VI 120 V Vo=24 V ATL431 Ibias Figure 8-1. Flyback With Isolation Using ATL43x as Voltage Reference and Error Amplifier It is important to consider the cathode voltage ramp rate when using ATL431 or ATL432 in overvoltage protection or other voltage monitoring applications, in optocoupler configurations, or any configuration where a power supply may ramp the cathode voltage quickly while ATL431 or ATL432 is meant to be in operation. For fast cathode current ramp rates, inaccurate responses may occur which can trip voltage monitoring circuits when www.ti.com ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 Copyright © 2024 Texas Instruments Incorporated Submit Document Feedback 13 Product Folder Links: ATL431 ATL432

an overvoltage or undervoltage condition has not actually been met. When designing with ATL431 or ATL432, it is recommended that the ramp rate of the cathode voltage remain below 0.0125V/µs to mitigate potential inaccuracies. For voltage monitoring or other applications where a ramp rate faster than 0.0125 V/µs is required, please consider other high-performance, pin-to-pin devices from TI: ATL431LI, TLA431, or TL431.

8.2 Typical Applications

8.2.1 Comparator With Integrated Reference (Open-Loop)

Copyright © 2017, Texas Instruments Incorporated 2.5V CATHODE ANODE REFVIN Vout Vsup Rsup VL RIN Figure 8-2. Comparator Application Schematic

8.2.1.1 Design Requirements

For this design example, use the parameters listed in Table 8-1 as the input parameters. Table 8-1. Design Parameters DESIGN PARAMETER EXAMPLE VALUE Input voltage range 0V to 3.3V Input resistance 100kΩ Supply voltage 5V Cathode current (IK) 50µA High output voltage level (Vin < 2.5V) Vsup Low output voltage (Vin > 2.5V) ~2V

8.2.1.2 Detailed Design Procedure

When using the ATL43x 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

8.2.1.2.1 Basic Operation

In the configuration shown in Figure 8-2, the ATL43x behaves as a comparator, comparing the V ref pin voltage to the internal virtual reference voltage. When provided a proper cathode current (I k), ATL43x have enough ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 www.ti.com

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open-loop gain to provide a quick response. With the maximum operating current (I min) of ATL43x being 35µA, operation below that can result in low gain; leading to a slow response.

8.2.1.2.2 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 will be within the range of 2.5V ± (0.5% or 1.0%) depending on which version is being used. The more overdrive voltage provided, the faster the ATL43x responds. For applications where ATL43x 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 should suffice. Figure 8-3 shows the transition from V OH to VOL based on the input voltage and can be used as a guide for selecting the overdrive voltage. For minimal voltage drop or difference from Vin to the ref pin, TI recommends using an input resistor < 1M Ω to provide Iref.

8.2.1.2.3 Output Voltage and Logic Input Level

In order for ATL43x to properly be used as a comparator, the logic output must be readable by the receiving logic device. This is accomplished by knowing the input high and low level threshold voltage levels, typically denoted by VIH and VIL. As seen in Figure 8-3 , the output low level voltage for ATL43x in open-loop/comparator mode is ~2V, which is sufficient for some ≥ 5-V supplied logic. However, would not work for 3.3-V and 1.8-V supplied logic. To accommodate this, a resistive divider can be tied to the output to attenuate the output voltage to a voltage legible to the receiving low voltage logic device. The output high voltage for ATL43x is approximately V sup due to ATL43x being open-collector. If V sup is much higher than the receiving maximum input voltage tolerance of the logic, the output must be attenuated to accommodate the reliability of the outgoing logic. When using a resistive divider on the output, ensure that the sum of the resistive divider (R1 and R2 in Figure 8-2) is much greater than Rsup so that the resistive divider does not interfere with the ability of the ATL43x to pull close to Vsup when turning off. ATL43x requires an input resistance in this application in order to source the reference current (I ref) needed from this device to be in the proper operating regions while turning on. The actual voltage seen at the ref pin will be: Vref = Vin – Iref × Rin (1) Because Iref can be as high as 0.15µA, TI recommendsusing a resistance small enough that will mitigate the error that Iref creates from Vin. Also, the input resistance must be set high enough as to not surpass the absolute maximum of 10mA. www.ti.com ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 Copyright © 2024 Texas Instruments Incorporated Submit Document Feedback 15 Product Folder Links: ATL431 ATL432

8.2.1.3 Application Curve

VIN (V) VOUT (V) 1.5 1.75 2.25 2.5 2.75 3.25 3.5 3.75 4.25 4.5 4.75 5.25 5.5 D001 RIN = 100kΩ VSUP = 5.0V RSUP = 10kΩ Figure 8-3. Open-Loop (Comparator Mode) VOUT vs VIN

8.2.2 Shunt Regulator/Reference

VO ( R1 VREF 0.1% 0.1% ATL431 = 1 + VREF) CL Copyright © 2017, Texas Instruments Incorporated Figure 8-4. Shunt Regulator Schematic

8.2.2.1 Design Requirements

For this design example, use the parameters listed in Table 8-2 as the input parameters. Table 8-2. Design Parameters DESIGN PARAMETER EXAMPLE VALUE Reference initial accuracy 1.0% Supply voltage 48V Cathode current (IK) 50µA Output voltage level 2.5V to 36V Load capacitance 1nF Feedback resistor values (R1 and R2) 10kΩ

8.2.2.2 Detailed Design Procedure

When using the ATL43x as a Shunt Regulator, determine the following:

  • Input voltage range
  • Temperature range
  • Total accuracy
  • Cathode current
  • Reference initial accuracy
  • Output capacitance ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 www.ti.com

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8.2.2.2.1 Programming Output/Cathode Voltage

To program the cathode voltage to a regulated voltage a resistive bridge must be shunted between the cathode and anode pins with the mid point tied to the reference pin. This can be seen in Figure 8-4, with R1 and R2 being the resistive bridge. The cathode/output voltage in the shunt regulator configuration can be approximated by the equation shown in Figure 8-4. The cathode voltage can be more accurately determined by taking in to account the cathode current: VO = (1 + R1 / R2) × Vref – Iref × R1 (2) For this equation to be valid, the ATL43x must be fully biased so that it has enough open-loop gain to mitigate any gain error. This can be done by meeting the I min spec denoted in Electrical Characteristics, ATL431Ax, ATL432Ax table. www.ti.com ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 Copyright © 2024 Texas Instruments Incorporated Submit Document Feedback 17 Product Folder Links: ATL431 ATL432

8.2.2.2.2 Total Accuracy

When programming the output above unity gain (V KA = V ref), ATL43x is susceptible to other errors that may effect the overall accuracy beyond Vref. These errors include:

  • R1 and R2 accuracies
  • VI(dev) – Change in reference voltage over temperature
  • ΔVref / ΔVKA – Change in reference voltage to the change in cathode voltage
  • |zKA| – Dynamic impedance, causing a change in cathode voltage with cathode current Worst case cathode voltage can be determined taking all of the variables in to account. Setting the Shunt Voltage on an Adjustable Shunt (SLVA445), assists designers in setting the shunt voltage to achieve optimum accuracy for this device.

8.2.2.2.3 Stability

Though the ATL43x is stable with no capacitive load, the device that receives the output voltage of the shunt regulator could present a capacitive load that is within the ATL43x region of stability, shown in Figure 5-14 through Figure 5-21. Also, designers can use capacitive loads to improve the transient response or for power supply decoupling. Figure 5-14 through Figure 5-21 should be used as a guide for capacitor selection and compensation. It is characterized using ceramic capacitors with very-low ESR. When it is desirable to use a capacitor within the unstable region, higher ESR capacitors can be used to stabilize ATL43x or an external series resistance can be added. For more information and guidance on ESR values, see Designing with the "Advanced" TL431, ATL431 (SLVA685). Unlike the TL431, the stability boundary is characterized and determined with resistors 250 Ω and greater. Which is designed for low cathode current applications.

8.2.2.3 Application Curves

IKA = 50µA Figure 8-5. ATL43x Start-Up Response IKA = 1mA Figure 8-6. ATL43x Start-Up Response ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 www.ti.com

18 Submit Document Feedback Copyright © 2024 Texas Instruments Incorporated

Product Folder Links: ATL431 ATL432

9 Power Supply Recommendations

When using the ATL43x in a flyback supply (see Figure 8-1), it is often common for designers to place the bias resistor between the Anode of the Opto-Coupler and the output voltage (V O = 24V). However, this makes the ATL43x more susceptible to EOS/ESD damage. Therefore, TI recommends placing the bias resistor between the Cathodes of the Opto-Coupler and the ATL43x, as shown in Figure 8-1. For further explanation, see Designing with the "Advanced" TL431, ATL431 (SLVA685). When using the ATL43x as a Linear Regulator to supply a load, designers will typically use a bypass capacitor on the output/cathode pin. Be sure that the capacitance is within the stability criteria shown in Figure 5-14 through Figure 5-21. To not exceed the maximum cathode current, be sure that the supply voltage is current limited. Also, be sure to limit the current being driven into the Ref pin, as not to exceed the absolute maximum rating. For applications shunting high currents, pay attention to the cathode and anode trace lengths, adjusting the width of the traces to have the proper current density.

10 Layout

10.1 Layout Guidelines

Place decoupling capacitors as close to the device as possible. Use appropriate widths for traces when shunting high currents to avoid excessive voltage drops.

10.2 Layout Example

(TOP VIEW) REF CA THODE ANODE Rsup Rref Vsup CL Vin GND GND Figure 10-1. DBZ Layout Example www.ti.com ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 Copyright © 2024 Texas Instruments Incorporated Submit Document Feedback 19 Product Folder Links: ATL431 ATL432

11 Device and Documentation Support

11.1 Receiving Notification of Documentation Updates

To receive notification of documentation updates, navigate to the device product folder on ti.com. Click on Notifications to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document.

11.2 Support Resources

TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight from the experts. Search existing answers or ask your own question to get the quick design help you need. Linked content is provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use.

11.3 Trademarks

TI E2E™ is a trademark of Texas Instruments. All trademarks are the property of their respective owners.

11.4 Electrostatic Discharge Caution

This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.

11.5 Glossary

TI Glossary This glossary lists and explains terms, acronyms, and definitions. ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 www.ti.com

20 Submit Document Feedback Copyright © 2024 Texas Instruments Incorporated

Product Folder Links: ATL431 ATL432

NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision D (October 2016) to Revision E (December 2024) Page Changes from Revision C (September 2015) to Revision D (October 2016) Page

  • Changed Small-Signal Voltage Amplification vs Frequency with an updated graph to provide additional data. 5 Changes from Revision B (May 2015) to Revision C (September 2015) Page Changes from Revision A (April 2015) to Revision B (May 2015) Page Changes from Revision * (March 2013) to Revision A (April 2015) Page

13 Mechanical, Packaging, and Orderable Information

The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. www.ti.com ATL431, ATL432 SLVSCV5E – MARCH 2015 – REVISED DECEMBER 2024 Copyright © 2024 Texas Instruments Incorporated Submit Document Feedback 21 Product Folder Links: ATL431 ATL432

www.ti.com 31-Oct-2025 PACKAGING INFORMATION Orderable part number Status (1) Material type (2) Package | Pins Package qty | Carrier RoHS (3) Lead finish/ Ball material (4) MSL rating/ Peak reflow (5) Op temp (°C) Part marking (6) ATL431AIDBZR Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU | NIPDAUAG Level-1-260C-UNLIM -40 to 85 (ZCKS, ZCR3) ATL431AIDBZR.A Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU Level-1-260C-UNLIM -40 to 85 (ZCKS, ZCR3) ATL431AQDBZR Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU | NIPDAUAG Level-1-260C-UNLIM -40 to 125 (ZCLS, ZCS3) ATL431AQDBZR.A Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU Level-1-260C-UNLIM -40 to 125 (ZCLS, ZCS3) ATL431BIDBZR Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU | NIPDAUAG Level-1-260C-UNLIM -40 to 85 (ZCMS, ZCT3) ATL431BIDBZR.A Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU Level-1-260C-UNLIM -40 to 85 (ZCMS, ZCT3) ATL431BQDBZR Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU | NIPDAUAG Level-1-260C-UNLIM -40 to 125 (ZCJS, ZCU3) ATL431BQDBZR.A Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU Level-1-260C-UNLIM -40 to 125 (ZCJS, ZCU3) ATL432AIDBZR Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU | NIPDAUAG Level-1-260C-UNLIM -40 to 85 (ZCNS, ZCV3) ATL432AIDBZR.A Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU Level-1-260C-UNLIM -40 to 85 (ZCNS, ZCV3) ATL432AQDBZR Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU | NIPDAUAG Level-1-260C-UNLIM -40 to 125 (ZCOS, ZCW3) ATL432AQDBZR.A Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU Level-1-260C-UNLIM -40 to 125 (ZCOS, ZCW3) ATL432BIDBZR Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU | NIPDAUAG Level-1-260C-UNLIM -40 to 85 (ZCPS, ZCX3) ATL432BIDBZR.A Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU Level-1-260C-UNLIM -40 to 85 (ZCPS, ZCX3) ATL432BQDBZR Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU | NIPDAUAG Level-1-260C-UNLIM -40 to 125 (ZCQS, ZCY3) ATL432BQDBZR.A Active Production SOT-23 (DBZ) | 3 3000 | LARGE T&R Yes NIPDAU Level-1-260C-UNLIM -40 to 125 (ZCQS, ZCY3) (1) Status: For more details on status, see our product life cycle. (2) Material type: When designated, preproduction parts are prototypes/experimental devices, and are not yet approved or released for full production. Testing and final process, including without limitation quality assurance, reliability performance testing, and/or process qualification, may not yet be complete, and this item is subject to further changes or possible discontinuation. If available for ordering, purchases will be subject to an additional waiver at checkout, and are intended for early internal evaluation purposes only. These items are sold without warranties of any kind. (3) RoHS values: Yes, No, RoHS Exempt. See the TI RoHS Statement for additional information and value definition. (4) Lead finish/Ball material: Parts may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two lines if the finish value exceeds the maximum column width. (5) MSL rating/Peak reflow: The moisture sensitivity level ratings and peak solder (reflow) temperatures. In the event that a part has multiple moisture sensitivity ratings, only the lowest level per JEDEC standards is shown. Refer to the shipping label for the actual reflow temperature that will be used to mount the part to the printed circuit board. Addendum-Page 1

www.ti.com 31-Oct-2025 (6) Part marking: There may be an additional marking, which relates to the logo, the lot trace code information, or the environmental category of the part. Multiple part markings will be inside parentheses. Only one part marking contained in parentheses and separated by a "~" will appear on a part. If a line is indented then it is a continuation of the previous line and the two combined represent the entire part marking for that device. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 2

PACKAGE MATERIALS INFORMATION www.ti.com 23-Apr-2026 TAPE AND REEL INFORMATION Reel Width (W1) REEL DIMENSIONS A0B0K0WDimension designed to accommodate the component lengthDimension designed to accommodate the component thicknessOverall width of the carrier tapePitch between successive cavity centersDimension designed to accommodate the component width TAPE DIMENSIONSK0 P1B0WA0Cavity QUADRANT ASSIGNMENTS FOR PIN 1 ORIENTATION IN TAPE Pocket QuadrantsSprocket HolesQ1Q1Q2Q2Q3Q3Q4Q4User Direction of Feed P1ReelDiameter *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Reel Diameter (mm) Reel Width W1 (mm) (mm) (mm) (mm) (mm) W (mm) Pin1 Quadrant Pack Materials-Page 1

PACKAGE MATERIALS INFORMATION www.ti.com 23-Apr-2026 Device Package Type Package Drawing Pins SPQ Reel Diameter (mm) Reel Width W1 (mm) (mm) (mm) (mm) (mm) W (mm) Pin1 Quadrant Pack Materials-Page 2

PACKAGE MATERIALS INFORMATION www.ti.com 23-Apr-2026 TAPE AND REEL BOX DIMENSIONS Width (mm) W LH *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) ATL431AIDBZR SOT-23 DBZ 3 3000 180.0 180.0 18.0 ATL431AIDBZR SOT-23 DBZ 3 3000 210.0 185.0 35.0 ATL431AQDBZR SOT-23 DBZ 3 3000 183.0 183.0 20.0 ATL431AQDBZR SOT-23 DBZ 3 3000 180.0 180.0 18.0 ATL431AQDBZR SOT-23 DBZ 3 3000 210.0 185.0 35.0 ATL431BIDBZR SOT-23 DBZ 3 3000 210.0 185.0 35.0 ATL431BIDBZR SOT-23 DBZ 3 3000 183.0 183.0 20.0 ATL431BIDBZR SOT-23 DBZ 3 3000 180.0 180.0 18.0 ATL431BQDBZR SOT-23 DBZ 3 3000 180.0 180.0 18.0 ATL431BQDBZR SOT-23 DBZ 3 3000 210.0 185.0 35.0 ATL432AIDBZR SOT-23 DBZ 3 3000 210.0 185.0 35.0 ATL432AIDBZR SOT-23 DBZ 3 3000 180.0 180.0 18.0 ATL432AQDBZR SOT-23 DBZ 3 3000 210.0 185.0 35.0 ATL432AQDBZR SOT-23 DBZ 3 3000 180.0 180.0 18.0 ATL432AQDBZR SOT-23 DBZ 3 3000 183.0 183.0 20.0 ATL432BIDBZR SOT-23 DBZ 3 3000 180.0 180.0 18.0 ATL432BIDBZR SOT-23 DBZ 3 3000 210.0 185.0 35.0 ATL432BQDBZR SOT-23 DBZ 3 3000 210.0 185.0 35.0 Pack Materials-Page 3

PACKAGE MATERIALS INFORMATION www.ti.com 23-Apr-2026 Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) ATL432BQDBZR SOT-23 DBZ 3 3000 180.0 180.0 18.0 Pack Materials-Page 4

www.ti.com PACKAGE OUTLINE C 0.20

0.08 TYP

0.25 2.64 2.10

1.12 MAX

0.10

0.01 TYP

3X 0.5 0.3 0.6

0.2 TYP

1.9 0.95 0 -8 TYP 4X 0 -15 4X 4 -15 A 3.04 2.80 B1.4 1.2 (0.95) (0.15) (0.125) SOT-23 - 1.12 mm max heightDBZ0003A SMALL OUTLINE TRANSISTOR 4214838/F 08/2024 NOTES: 1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing per ASME Y14.5M. 2. This drawing is subject to change without notice. 3. Reference JEDEC registration TO-236, except minimum foot length. 4. Support pin may differ or may not be present. 5. Body dimensions do not include mold flash, protrusions, or gate burrs. Mold flash, protrusions, or gate burrs shall not exceed 0.25mm per side

0.2 C A B

0.1 C SCALE 4.000

www.ti.com EXAMPLE BOARD LAYOUT

0.07 MAX

0.07 MIN

3X (1.3) 3X (0.6) (2.1) 2X (0.95) (R0.05) TYP 4214838/F 08/2024 SOT-23 - 1.12 mm max heightDBZ0003A SMALL OUTLINE TRANSISTOR NOTES: (continued) 5. Publication IPC-7351 may have alternate designs. 6. Solder mask tolerances between and around signal pads can vary based on board fabrication site. SYMM LAND PATTERN EXAMPLE SCALE:15X PKG SOLDER MASK OPENING METAL UNDER SOLDER MASK SOLDER MASK DEFINED METALSOLDER MASK OPENING NON SOLDER MASK DEFINED (PREFERRED) SOLDER MASK DETAILS

www.ti.com EXAMPLE STENCIL DESIGN (2.1) 2X(0.95) 3X (1.3) 3X (0.6) (R0.05) TYP SOT-23 - 1.12 mm max heightDBZ0003A SMALL OUTLINE TRANSISTOR 4214838/F 08/2024 NOTES: (continued) 7. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate design recommendations. 8. Board assembly site may have different recommendations for stencil design. SOLDER PASTE EXAMPLE BASED ON 0.125 THICK STENCIL SCALE:15X SYMM PKG

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