TLV431ACDBVR - 1.24V-6V Adjustable Shunt Voltage Reference | TI
料号： TLV431ACDBVR ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $0.55 | $0.55 |
| 10 | $0.43 | $4.30 |
| 100 | $0.28 | $28.00 |
| 500 | $0.21 | $105.00 |
| 1,000 | $0.17 | $170.00 |
| 3,000 | $0.14 | $420.00 |
TLV431ACDBVR 概述
A shunt voltage reference (also called a programmable zener or 3-terminal shunt regulator) is a two-terminal device whose cathode-to-anode voltage is held at a defined value when the bias current supplied by an external resistor is greater than the minimum regulation current. Unlike series LDOs, shunt references operate in parallel with the load, sinking more current as the load demands less. They sit in the same broad category hierarchy as zener diodes -> shunt regulators -> voltage references -> power management ICs -> semiconductors, and are the low-voltage successor to the classic TL431.
Key features of the TLV431ACDBVR include: typical output impedance of 0.25 ohm at 1 kHz that yields low AC noise on the regulated node, specified thermal stability over the commercial 0 to 70 C range (with the wider -40 to 125 C AC-grade option available), and operation from a wide cathode voltage of 1.24V to 6V. Its bipolar process technology gives well-behaved temperature drift and long-term stability, and the small SOT-23-5 footprint enables placement near the load it serves.
The TLV431 architecture is essentially a bandgap reference driving a buffered pass transistor with an open-collector (open-cathode) output. Two external resistors set VOUT = VREF × (1 + R1/R2), giving designers continuous adjustment rather than fixed 2.5V or 5V taps. Because it sinks current, it pairs naturally with a series resistor fed from a higher supply, allowing isolated sub-rails in switch-mode power supply feedback loops and ADC/DAC reference inputs.
Typical applications include switching-mode power supply (SMPS) secondary-side feedback, adjustable precision voltage references for data converters, isolated flyback/forward converter error amplifiers, and low-current linear regulators. The wide VREF-to-6V range makes it ideal wherever a clean sub-6V reference is needed without resorting to a low-dropout regulator.
When designing with the TLV431, choose the bias resistor so that (VSUPPLY - VREF) / Rbias supplies at least IKA(min) (100 µA typical, 1 mA worst case) at minimum load, while staying below the absolute maximum cathode current of 15 mA. A 1 µF bypass capacitor across cathode-to-anode improves transient response.
This page synthesizes distributor pricing, drop-in SOT-23-5 alternatives (TI TLV431 family and ON Semi TL431 family), and practical design notes not consolidated in a single TI datasheet document.
直接替换替代料： TLV431ACDBVR ——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： TLV431ACDBVR （相同外形与封装尺寸） ——差异在于 MSL Level, Package, Typical Output Impedance, Mounting Type, Adjustable Output Range.
快速对比工具——选择替代料号进行并排对比：
TLV431BCDBVR
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
TLV431AIDBVR
✅ 直接替换📋 参考替代料（不在目录中）
TLV431AQDBVRQ1
✅ 直接替换📋 参考替代料（不在目录中）
TLV431ACDBVT
✅ 直接替换 ⚠️ 规格未核验📋 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 →TS431IYLT
✅ 直接替换📋 参考替代料（不在目录中）
TLV431ACDBVR 规格参数
| Reference Type | Shunt, Adjustable (3-terminal) |
| Output Voltage (VREF) | 1.24 V nominal |
| Adjustable Output Range | 1.24 V to 6 V |
| Initial Accuracy (A grade) | ±1% |
| Maximum Cathode Current (IKA) | 15 mA |
| Minimum Cathode Current for Regulation | 100 µA (typical) |
| Typical Output Impedance | 0.25 ohm at 1 kHz |
| Operating Temperature Range (C grade) | 0 C to +70 C |
| 封装 | SOT-23-5 (DBV) 2.9 x 1.6 mm |
| 安装类型 | Surface Mount |
| 引脚数 | 5 |
| Cathode-to-Anode Voltage Range | 1.24 V to 6 V |
| MSL 等级 | 1 (unlimited) |
| RoHS 状态 | Compliant |
| Lead-Free Finish | Yes (NiPdAu) |
TLV431ACDBVR 引脚配置
| 引脚 1 | K (Cathode) — Cathode - open-collector output, sinks current to regulate VREF |
| 引脚 2 | A (Anode) — Anode - connect to ground (negative terminal) |
| 引脚 3 | REF — Reference input - VREF = 1.24 V nominal, sets output via R1/R2 divider |
| 引脚 4 | NC — Not connected (no internal connection) |
| 引脚 5 | NC — Not connected (no internal connection) |
典型应用
TLV431ACDBVR 适用于 6 应用s: Switch-Mode Power Supply (SMPS) Secondary-Side Feedback, Adjustable Precision Reference for ADCs, Isolated Flyback/Forward Converter Error Amplifier, Low-Current Linear Regulator / Voltage Clamp, Comparator Threshold / Window Detector, DAC and Instrumentation Reference.
Switch-Mode Power Supply (SMPS) Secondary-Side Feedback
The TLV431ACDBVR is a textbook choice for isolated flyback or forward converter secondary-side feedback loops where the regulated output is 6 V or below. Its 1.24 V VREF gives the error amplifier finer trim resolution than the 2.5 V TL431 baseline. Place the device with R1 from cathode-to-reference and R2 from reference-to-anode, set by VOUT = 1.24 V × (1 + R1/R2); choose Rbias from VCC so that (VCC - VREF)/Rbias ≥ 1 mA at minimum load. Compared to a series LDO, the TLV431 sinks current dynamically and does not introduce LDO dropout-voltage loss, enabling tight load regulation on 3.3 V or 5 V rails derived from 12-24 V buses. The SOT-23-5 footprint fits tight secondary-side layouts and its 100 µA minimum regulation current minimizes standby power waste.
推荐
Adjustable Precision Reference for ADCs
The TLV431ACDBVR's 1.24-6 V adjustable range and ±1% initial accuracy make it well-suited to drive the reference input of successive-approximation ADCs (SAR ADCs) operating at or below 6 V full-scale. Driving the REF pin of an ADC such as the ADS1115 (whose VDD = reference) yields a quiet, low-impedance reference node with sub-mA bias current, preserving ADC noise performance. Place a 1 µF X7R bypass from cathode to anode to absorb ADC reference-current transients during conversion; the TLV431's 0.25 ohm typical output impedance at 1 kHz keeps transient excursions small. The ±1% A-bin accuracy is adequate for 12-bit ADCs, while the B-bin (±0.5%) is recommended for 14-16 bit systems. The SOT-23-5 footprint allows the reference to sit physically adjacent to the ADC REF pin, minimizing PCB trace noise pickup.
推荐
Isolated Flyback/Forward Converter Error Amplifier
In isolated DC-DC converter topologies, the TLV431ACDBVR serves as the secondary-side error amplifier whose cathode output is fed through an optocoupler (such as the PC817 or TL431-integrated families) back to the primary-side PWM controller. With VREF at 1.24 V, the TLV431 enables precise output setpoints as low as 1.5 V (when biased with a small R1), useful for low-voltage POL rails off an isolated bus. DC-DC grounds: connect the anode to secondary-side ground; pull the cathode up to a local secondary bias through Rbias; bias the optocoupler LED in series. Compared to using a TL431 (2.5 V VREF), the TLV431 gives 50% finer set-point adjustment granularity for sub-3.3 V outputs. The 0 to 70 C grade suits commercial-grade adapters, while the I-grade TLV431AIDBVR is required for industrial -40 to 125 C environments.
推荐
Low-Current Linear Regulator / Voltage Clamp
The TLV431ACDBVR can replace a low-dropout regulator (LDO) in low-current scenarios (load under 10 mA) by acting as a shunt regulator: place Rbias from supply to cathode, then route the load from cathode to ground. The result is a stable VOUT = 1.24-6 V rail with no minimum-dropout concern (unlike an LDO which requires VIN - VOUT ≥ Vdropout). This topology excels when VIN is only marginally above the desired VOUT (e.g., 3.3 V supply, 3.0 V rail) where an LDO would drop out. Add a series resistor at the load to share current with the shunt, or use the TLV431 purely as a precision clamp on a sensitive analog node. The 15 mA cathode current cap limits total load + bias to under that value, so this is unsuitable for higher-current rails.
推荐
Comparator Threshold / Window Detector
The TLV431ACDBVR can be wired as a precision threshold detector: bias the cathode through Rbias from a monitored supply; when the supply voltage exceeds VREF × (1 + R1/R2), the device sinks current - this current can drive an LED indicator, a logic-level inverter, or a comparator. Used in battery monitors, the TLV431 triggers an alert when a cell voltage crosses a programmed threshold (e.g., 3.0 V low-battery on a Li-ion cell). Compared to a discrete zener + comparator, the TLV431 offers tighter initial accuracy (±1%) and a lower minimum operating voltage (1.24 V vs ~3 V for typical zeners). The SOT-23-5 footprint fits handheld battery-powered devices; for high-volume consumer products, consider the B-grade (±0.5%) for tighter threshold accuracy.
推荐
DAC and Instrumentation Reference
The TLV431ACDBVR delivers a stable, low-impedance reference node for digital-to-analog converters and instrumentation front-ends where the reference voltage directly scales the output span. With VREF = 1.24 V nominal and ±1% A-grade accuracy, the part provides a useful scaling factor for 4-20 mA current loops, programmable-gain stages, and bridge-sensor excitation references. Bias the device from a clean analog supply (e.g., from a low-noise LDO like TPS7A2010) and decouple the cathode with a 1 µF X7R plus 100 nF NP0 parallel combination to suppress reference noise across frequency. The TLV431A's 0.25 ohm typical output impedance at 1 kHz ensures the DAC reference remains stable during code-dependent load changes. Compared to internal DAC references, an external TLV431 reference delivers better thermal stability and is field-replaceable.
推荐
推荐产品汇总
工程参考数据： TLV431ACDBVR ——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 | TLV431BCDBVR | TLV431AIDBVR | TLV431AQDBVRQ1 | TLV431ACDBVT | TL431ACDBZR | TS431IYLT |
|---|---|---|---|---|---|---|---|
| Package | SOT-23-5 (DBV) | SOT-23-5 (DBV) - same | SOT-23-5 (DBV) - same | SOT-23-5 (DBV) - same | SOT-23-5 (DBV) - same | SOT-23-5 (DBV) - same (verify pinout) | SOT-23-5 (DBV) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | onsemi | STMicroelectronics |
| Reference Voltage (VREF) | 1.24 V | 1.24 V | 1.24 V | 1.24 V | 1.24 V | 2.495 V (fixed) | 1.24 V |
| Initial Accuracy | ±1% (A grade) | ±0.5% (B grade) | ±1% (A grade) | ±1% (A grade) | ±1% (A grade) | ±1% (A grade) | ±2% (I grade) |
| Adjustable Output Range | 1.24 V to 6 V | 1.24 V to 6 V | 1.24 V to 6 V | 1.24 V to 6 V | 1.24 V to 6 V | 2.5 V to 36 V | 1.24 V to 6 V |
| Maximum Cathode Current | 15 mA | 15 mA | 15 mA | 15 mA | 15 mA | 100 mA | 30 mA |
| Operating Temperature Range | 0 to +70 C (C grade) | 0 to +70 C | -40 to +125 C | -40 to +125 C (AEC-Q100) | 0 to +70 C | -40 to +85 C | -40 to +125 C (I grade) |
| AEC-Q100 Automotive Qualified | No | No | No | Yes | No | No | No |
关键差异点
- Lowest minimum VREF in the TI 3-terminal shunt family （对比 TL431ACDBZR)
- Commercial-grade pricing with industrial-grade optional （对比 TLV431AIDBVR)
- Automotive-qualified option shares the same footprint （对比 TLV431AQDBVRQ1)
设计说明
Sizing Rbias for the TLV431ACDBVR: choose Rbias so that (VSUPPLY - VREF) / Rbias ≥ 1 mA at minimum load to keep the device in regulation (IKAREGmin is 100 µA typical but 1 mA is the safe design margin). At maximum load, ensure (VSUPPLY - VREF) / Rbias + ILOAD ≤ 15 mA to avoid exceeding the absolute maximum cathode current. For a 5 V supply driving a 3.3 V reference into a 2 mA load, Rbias = (5 - 3.3) / (1 mA + 2 mA) ≈ 567 ohm; round to a standard 560 ohm. Add a 1 µF X7R bypass across cathode-to-anode to absorb transient load steps.
Layout for the TLV431ACDBVR: keep the trace from cathode to the load capacitor short (under 5 mm) to minimize parasitic inductance that destabilizes the regulation loop. Place R1/R2 reference divider physically close to the REF pin (pin 3) to reduce noise pickup; the REF pin has high input impedance and is sensitive to leakage. Connect the exposed pad (DBV package thermal pad) to the anode plane to provide thermal relief, although the SOT-23-5 dissipation is small (typically <100 mW). For low-noise applications, surround the cathode bypass capacitor with a ground pour and keep digital traces away from the REF pin.
Estimated thermal calculation: at maximum cathode current 15 mA and VKA = 6 V, the SOT-23-5 package dissipates approximately 90 mW (P = V × I), which is well below the SOT-23-5 ~300 mW rating at 25 C ambient. However, at elevated ambient temperatures the power derating curve drops the limit to ~200 mW at 70 C - still safe, but if the cathode voltage is forced higher (e.g., into a fault condition), power dissipation can exceed 200 mW. Always include the bias resistor in the worst-case cathode voltage calculation. Also avoid substituting TLV431 (1.24 V VREF) where a TL431 (2.5 V VREF) was originally specified - the output voltage scaling changes significantly.
合规信息
RoHS and REACH compliant per TI product page. Lead-free NiPdAu finish. The TLV431ACDBVR itself is not AEC-Q100 qualified - choose TLV431AQDBVRQ1 (Q1 suffix) for automotive applications.
