TL431AIDBVR - 2.495V-36V Adjustable Shunt Reference, 1% | Texas Instruments
料号： TL431AIDBVR ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $0.42 | $0.42 |
| 10 | $0.36 | $3.60 |
| 100 | $0.24 | $24.00 |
| 500 | $0.18 | $90.00 |
| 1,000 | $0.14 | $140.00 |
| 3,000 | $0.11 | $330.00 |
TL431AIDBVR 概述
A shunt voltage reference is a two-terminal (plus reference pin) device that maintains a constant voltage across its terminals by shunting excess current to ground, analogous to a Zener diode but with programmable breakdown voltage. Shunt references form a sub-category of voltage references within the broader voltage regulator hierarchy (voltage reference -> shunt regulator -> analog reference circuit -> signal chain IC), and they are foundational building blocks for power supply feedback, ADC reference rails, comparator thresholds, and error amplifiers in isolated and non-isolated converter topologies.
Key features of the TL431AIDBVR include a 2.495V reference voltage (Vref) with 1% initial accuracy at 25C, an operating cathode current range of 1 mA to 100 mA, typical dynamic impedance of 0.2 ohm at 1 kHz, and an operating temperature range of -40C to +85C. The SOT-23-5 surface-mount package offers a compact footprint while exposing the reference, anode, and cathode pins in a standardized layout used industry-wide across second-source vendors.
The TL431 architecture uses a buried-Zener bandgap reference cell feeding an on-chip op-amp that drives a pass transistor, producing a sharp knee in the I-V curve and excellent thermal stability. According to the manufacturer datasheet, the device exhibits typical output impedance of 0.2 ohm over 1 kHz and a wideband noise figure suitable for switch-mode power supply feedback loops and audio threshold detection.
Typical applications include SMPS secondary-side regulation, isolated flyback error amplifier reference, adjustable Zener replacement, voltage monitoring and reset circuits, and precision current limiting. The SOT-23-5 form factor is well suited for high-density DC-DC converter boards and compact adapter designs.
When designing with the TL431AIDBVR, ensure the cathode current stays between 1 mA and 100 mA across all load and line conditions, including start-up transients. Place the device close to the opto-coupler or error-amplifier input to minimize loop-area noise pickup, and use a bypass capacitor on the reference pin if the application requires low AC noise.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
直接替换替代料： TL431AIDBVR ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： TL431AIDBVR （相同外形与封装尺寸） ——差异在于 Package, MSL Level, Minimum Cathode Current for Regulation, Operating Temperature Range, Reference Voltage (Vref).
快速对比工具——选择替代料号进行并排对比：
TL431AIDBVT
✅ 直接替换📋 参考替代料（不在目录中）
TL431AQDBVRQ1
✅ 直接替换📋 参考替代料（不在目录中）
TL431ACDBZR
✅ 直接替换✓ 有现货
$0.07 / 个
查看数据手册 →TL431AIDBVR
✅ 直接替换✓ 有现货
$0.11 / 个
查看数据手册 →TL431A-SOT23-5
✅ 直接替换📋 参考替代料（不在目录中）
TL431A-SOT23
✅ 直接替换📋 参考替代料（不在目录中）
TL431AIDBVR 规格参数
| Reference Type | Adjustable Shunt Voltage Reference |
| Initial Tolerance (A Grade) | ±1% at 25°C |
| Reference Voltage (Vref) | 2.495 V nominal |
| Adjustable Output Voltage Range | 2.495 V to 36 V |
| Maximum Cathode Current (IK) | 100 mA |
| Minimum Cathode Current (Imin) | 1 mA |
| Typical Dynamic Impedance | 0.2 ohm at 1 kHz |
| 工作温度范围 | -40°C to +85°C |
| 封装 | SOT-23-5 (DBV) |
| 安装类型 | Surface Mount |
| 引脚数量 | 5 |
| Grade | A (1% tolerance) |
| MSL 等级 | 1 (unlimited floor life) |
| RoHS 状态 | Compliant |
| Lead-Free / Halogen-Free | Yes (per TI product page) |
TL431AIDBVR 引脚配置
| 引脚 1 | NC / Reference option — No Connect or alternate reference pin (verify against datasheet revision) |
| 引脚 2 | Reference (REF) — Voltage reference input; connects to resistor divider |
| 引脚 3 | Anode (A) — Anode terminal; connects to ground |
| 引脚 4 | Cathode (K) — Cathode terminal; main current-carrying pin |
| 引脚 5 | NC / Cathode option — No Connect or alternate cathode pin (verify against datasheet revision) |
典型应用
TL431AIDBVR 适用于 6 应用s: Switch-Mode Power Supply (SMPS) Feedback, Adjustable Zener Diode Replacement, Voltage Monitoring and Reset Circuit, Battery Charger Reference and Termination Control, ADC and DAC Reference Rail, Industrial Process Control and Instrumentation.
Switch-Mode Power Supply (SMPS) Feedback
The TL431AIDBVR serves as the secondary-side reference and error amplifier in isolated and non-isolated SMPS topologies such as flyback, forward, and buck converters. Its 2.495V reference, ±1% initial tolerance, and 0.2 ohm dynamic impedance enable tight output voltage regulation across line and load variations. The device is paired with an opto-coupler (e.g., PC817) to close the feedback loop across the isolation barrier, replacing discrete Zener+op-amp solutions. The SOT-23-5 package fits compact adapter and high-density converter designs where board area is at a premium.
推荐
Adjustable Zener Diode Replacement
The TL431AIDBVR functions as a programmable two-terminal Zener replacement, allowing the breakdown voltage to be set anywhere from 2.495V to 36V via external resistor divider. Unlike a discrete Zener, the TL431 offers sharper knee characteristics, lower dynamic impedance (0.2 ohm vs Zener's tens of ohms), and tighter tolerance (±1% A grade). The 100 mA cathode current capability handles higher-power clamping and bias applications than typical Zener diodes. Engineers frequently use it for overvoltage protection rails, precision clamping, and adjustable voltage reference rails in industrial instrumentation.
推荐
Voltage Monitoring and Reset Circuit
The TL431AIDBVR implements precision voltage monitoring and microprocessor reset generation when combined with a comparator or by directly driving a reset line. Its 2.495V reference can be scaled up via resistor divider to monitor rails such as 3.3V, 5V, or 12V with ±1% accuracy. The 1 mA minimum cathode current and sharp transfer characteristic produce clean, hysteresis-free reset edges. The SOT-23-5 package suits space-constrained IoT, embedded, and industrial control designs where a small-footprint supervisor is required.
推荐
Battery Charger Reference and Termination Control
In linear and switch-mode battery charger designs, the TL431AIDBVR provides the precision voltage reference for charge termination detection. The 2.495V reference combined with a resistor divider sets the float voltage for single-cell Li-ion, NiMH, or lead-acid battery stacks, with ±1% accuracy ensuring safe termination thresholds. The 100 mA cathode current drives opto-isolated feedback to primary-side controllers in isolated charger designs. The SOT-23-5 footprint enables compact USB charger, power bank, and portable device charger implementations.
推荐
ADC and DAC Reference Rail
The TL431AIDBVR can serve as a low-cost adjustable reference for low-to-medium resolution ADCs and DACs, providing 2.495V-36V programmable output with ±1% initial tolerance. Although its 0.2 ohm dynamic impedance and noise performance are not on par with dedicated low-noise references like the REF5025, it is suitable for 8-bit and 10-bit data-acquisition systems where cost dominates. Designers often buffer the output with an op-amp (e.g., OPA227) to drive the reference pin of successive-approximation ADCs without loading the TL431 reference node.
推荐
Industrial Process Control and Instrumentation
In industrial process control loops, the TL431AIDBVR provides stable threshold references for comparators, current loops (4-20 mA), and signal conditioning circuits. The -40°C to +85°C operating temperature and ±1% tolerance suit factory automation, sensor transmitters, and PLC analog input modules. Its 36V cathode-anode rating handles 24V industrial bus rails with adequate headroom for transient protection. The SOT-23-5 SMD package supports automated assembly in high-volume industrial product lines.
推荐
推荐产品汇总
工程参考数据： TL431AIDBVR ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | TL431AIDBVT | TL431AQDBVRQ1 | TL431ACDBZR | TL431AIDBVR (onsemi) | TL431A-SOT23-5 | TL431A-SOT23 |
|---|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | onsemi | Diodes Incorporated | Nexperia |
| Package | SOT-23-5 (DBV) | SOT-23-5 (DBV) - same | SOT-23-5 (DBV) - same | SOT-23-5 (DBZ) - similar family | SOT-23-5 - same | SOT-23-5 - same | SOT-23-5 - same |
| Reference Voltage (Vref) | 2.495 V | 2.495 V | 2.495 V | 2.495 V | 2.495 V | 2.495 V | 2.495 V |
| Initial Tolerance | ±1% (A grade) | ±1% (A grade) | ±1% (A grade) | ±1% (A grade) | ±1% (A grade) | ±1% (A grade) | ±1% (A grade) |
| Maximum Cathode Current | 100 mA | 100 mA | 100 mA | 100 mA | 100 mA | 100 mA | 100 mA |
| Adjustable Output Range | 2.495 V to 36 V | 2.495 V to 36 V | 2.495 V to 36 V | 2.495 V to 36 V | 2.495 V to 36 V | 2.495 V to 36 V | 2.495 V to 36 V |
| Operating Temperature | -40°C to +85°C | -40°C to +85°C | -40°C to +125°C (automotive) | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C |
| Automotive Grade (AEC-Q100) | No | No | Yes | No | No | No | No |
关键差异点
- Wide second-source availability across multiple manufacturers （对比 TL431AIDBVR (onsemi))
- Automotive-grade variant available in same package （对比 TL431AQDBVRQ1)
- Industry-standard reference voltage and tolerance （对比 TL431A-SOT23-5 (Diodes Inc.))
设计说明
The cathode current must stay between 1 mA and 100 mA across all load, line, and start-up conditions. Below 1 mA the TL431 exits regulation and the reference voltage collapses; above 100 mA the device overheats. Always calculate worst-case IK at minimum load (IK = (VIN - VREF)/Rpullup - I_divider) and maximum load. For start-up, the IK path must provide at least 1 mA before the output reaches regulation - a common bug is undersizing the cathode pull-up resistor.
Place the TL431AIDBVR close to the opto-coupler or error-amplifier input to minimize the feedback loop area, which reduces noise injection and improves transient response. Keep the REF pin traces short and away from switching nodes; a 100 pF to 1 nF bypass capacitor on REF may be added in noisy environments but is not always required. The SOT-23-5 thermal pad should be soldered to a copper pour (even if small) to improve thermal dissipation at high IK.
The TL431AIDBVR has a typical dynamic impedance of 0.2 ohm at 1 kHz, but this rises at higher frequencies due to the internal op-amp bandwidth. For SMPS feedback loops operating above 10 kHz crossover, account for reduced loop gain at high frequencies. The device exhibits a noise voltage of approximately 50 nV/sqrt(Hz) above 1 kHz, which is suitable for general-purpose regulation but not for low-noise precision references - buffer with an op-amp if driving a precision ADC reference.
合规信息
RoHS compliant and lead-free per TI product page. AEC-Q100 qualification not applicable for the standard TL431AIDBVR - choose TL431AQDBVRQ1 for automotive.
