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Texas Instruments TLVH431BCDBZT
- Part No.:
- TLVH431BCDBZT
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TLVH431BCDBZT.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,703
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Product details
Overview
TLVH431BCDBZT from Texas Instruments is a low-voltage adjustable precision shunt regulator in SOT-23-3 package, featuring 1.24 V reference voltage (±0.5% at 25°C), 100 μA minimum cathode current for regulation, and operation from –40°C to +125°C. It replaces Zener diodes in secondary-side flyback SMPS feedback loops and serves as an integrated-reference comparator in power-rail monitoring circuits.
For engineers reviewing the TLVH431BCDBZT datasheet, TLVH431BCDBZT pinout, TLVH431BCDBZT application, or TLVH431BCDBZT equivalent, key selection criteria include reference tolerance grade (B = 0.5%), cathode current range (100 μA–70 mA), dynamic impedance (0.25 Ω typical), thermal stability across industrial/automotive temperature ranges, and compatibility with optocoupler-based isolated feedback topologies.
Technical Context
The TLVH431BCDBZT implements a precision bandgap reference and high-gain transconductance amplifier in a 3-terminal shunt configuration. Its internal architecture forces the REF pin to 1.24 V when sufficient cathode current (≥100 μA) flows and feedback is applied between CATHODE and REF terminals.
In open-loop mode, it functions as a comparator with built-in 1.24 V threshold; in closed-loop mode, it acts as an error amplifier regulating output voltage via external resistor divider. The device is internally compensated and stable without output capacitance, though phase margin vs. capacitive load is characterized up to 100 nF.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 1.24 V ±0.5% at 25°C - sets precise regulation point for feedback networks |
| Min Cathode Current | 100 μA - minimum sink current required to maintain regulation accuracy |
| Output Impedance | 0.25 Ω typical - enables tight voltage regulation under varying load conditions |
| Operating Temp Range | –40°C to +125°C - supports automotive and industrial environments without derating |
| Cathode Voltage Range | 1.24 V to 18 V - allows adjustable output from near-supply rails up to 18 V |
| Reference Input Current | 0.1–0.5 μA - ultra-low bias current minimizes resistor-divider loading error |
| Dynamic Impedance | 0.25 Ω @ f ≤ 1 kHz, IK = 0.1–70 mA - ensures stable loop response in SMPS compensation |
Pinout & Package
SOT-23-3 package (2.92 mm × 1.30 mm body size), surface-mount, lead-free, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current input/output | Sinks regulated current; connects to feedback node or optocoupler LED anode in isolated supplies |
| REF (Pin 2) | Reference input | Senses divided output voltage; requires ≥0.1 μA bias current; must not be left floating |
| ANODE (Pin 3) | Common return path | Typically connected to system ground or power rail common; forms reference potential for REF pin |
Key Features
| Feature | Design Value |
|---|---|
| Low-voltage operation | Starts regulating at 1.24 V - enables use in 1.8 V, 2.5 V, and 3.3 V systems where TL431 cannot function |
| B-grade tolerance | ±0.5% VREF at 25°C - reduces calibration overhead in precision ADC references and voltage monitors |
| Wide cathode current range | 100 μA to 70 mA - supports both ultra-low-power standby modes and full-load regulation |
| Ultra-low reference current | 0.1–0.5 μA - permits use of high-value resistor dividers (>1 MΩ), minimizing quiescent power loss |
| High-temperature rating | Specified to +125°C - qualified for under-hood automotive and industrial motor-control applications |
Applications
| Adjustable Voltage Reference for Data Converters | Secondary-Side Regulation in Flyback SMPS |
|---|---|
Use Scenario: Provides stable reference for 12–16-bit SAR and delta-sigma ADCs in battery-powered instrumentation. IC Role / Device Role / Timing Role: Precision shunt reference establishing VREF node; replaces discrete Zener + op-amp combos. Use Value: 0.5% initial tolerance and <31 mV VREF deviation over –40°C to +125°C ensure consistent LSB scaling across temperature. |
Use Scenario: Error amplifier and voltage reference in isolated 3.3 V/5 V flyback converters using optocoupler feedback. IC Role / Device Role / Timing Role: Closed-loop shunt regulator comparing scaled output voltage to internal 1.24 V reference. Use Value: Enables regulation down to ~2.7 V output (1.24 V + opto LED VF) - critical for low-voltage digital supply rails. |
| Zener Diode Replacement | Voltage Monitoring for Power Rails |
Use Scenario: Replaces 1.2–2.5 V Zener diodes in on-board LDO pre-regulation and bias networks. IC Role / Device Role / Timing Role: Adjustable shunt clamp with sharp turn-on characteristic and low leakage (<0.1 μA off-state). Use Value: 0.25 Ω dynamic impedance delivers superior regulation vs. Zeners (typically >10 Ω), reducing output ripple by >95%. |
Use Scenario: Monitors 1.8 V, 2.5 V, or 3.3 V core rails for brownout detection in microcontroller reset circuits. IC Role / Device Role / Timing Role: Open-loop comparator with integrated 1.24 V reference; triggers reset when rail drops below threshold. Use Value: Eliminates external reference IC and comparator; 100 μA min cathode current allows direct connection to rail via single pull-up resistor. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLVH431ACDBZT | 1% reference tolerance (A grade) vs. 0.5% (B grade); otherwise identical electrical specs and pinout | Suitable where ±1% regulation accuracy suffices, e.g., non-precision power sequencing | Select TLVH431ACDBZT to reduce cost when tighter tolerance is unnecessary |
| TLVH432BCDBZT | Same B-grade tolerance and specs, but reversed pinout: REF/ANODE/CATHODE instead of CATHODE/REF/ANODE | Requires PCB layout revision; used where alternate pin assignment simplifies routing in dense layouts | Choose TLVH432BCDBZT only if board redesign is acceptable and pinout optimization is prioritized |
Compared with TLVH431ACDBZT, TLVH431BCDBZT provides 2× tighter reference tolerance for precision feedback, while TLVH432BCDBZT offers identical performance in a mechanically compatible but electrically re-pinned variant - neither is pin-compatible without layout changes.
Availability
TLVH431BCDBZT is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, and precision data acquisition systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TLVH431BCDBZT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.
The TLVH431 family was designed as a low-voltage, high-accuracy replacement for TL431 in isolated feedback, voltage monitoring, and precision reference applications - targeting systems operating below 2.5 V where legacy shunt regulators fail.
FAQ
What is the reference voltage tolerance of TLVH431BCDBZT at 25°C?
The TLVH431BCDBZT has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal VREF with min/max values of 1.234 V and 1.246 V. This B-grade tolerance is confirmed in Section 5.7 of the TI datasheet and applies specifically to the TLVH431BCDBZT variant. The tolerance widens to ±31 mV over the full –40°C to +125°C range.
Can TLVH431BCDBZT operate with cathode voltages below 2.5 V?
Yes, TLVH431BCDBZT is explicitly designed for low-voltage operation starting at 1.24 V - its minimum cathode voltage is VREF itself. Unlike TL431 (2.5 V min), TLVH431BCDBZT regulates stably at 1.8 V, 2.5 V, and 3.3 V rails, making it suitable for modern low-voltage SMPS and battery-powered systems. Operation down to 1.24 V is validated across temperature and load conditions per TI's recommended operating conditions.
What is the minimum cathode current required for regulation in TLVH431BCDBZT?
The TLVH431BCDBZT requires a minimum cathode current of 100 μA to maintain regulation accuracy, as specified in Section 5.5 (IK(min)) of the datasheet. Below this threshold, gain drops significantly and VREF deviates. This value is tested at full temperature range and is lower than TL431's 1 mA requirement - enabling ultra-low-power standby modes in always-on systems.
Is TLVH431BCDBZT pin-compatible with TLVH432BCDBZT?
No, TLVH431BCDBZT is not pin-compatible with TLVH432BCDBZT. While both use SOT-23-3 packages, TLVH431BCDBZT has CATHODE/REF/ANODE pinout (Pin 1/2/3), whereas TLVH432BCDBZT uses REF/ANODE/CATHODE (Pin 1/2/3). Swapping them without PCB modification will cause functional failure. The datasheet explicitly states TLVH432 is offered "with different pinouts" for identical packages.
Does TLVH431BCDBZT require an output capacitor for stability?
No, TLVH431BCDBZT is internally compensated and stable without an output capacitor between CATHODE and ANODE. This eliminates mandatory external capacitance in most shunt regulator configurations. However, if a capacitor is added for noise filtering or transient response, TI provides phase-margin vs. capacitive-load curves (Figures 5-15 to 5-17) to guide selection - stability is maintained up to 100 nF depending on cathode voltage.
TLVH431BCDBZT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 1.24V
- Voltage - Output (Max):
- 18 V
- Current - Output:
- 70 mA
- Tolerance:
- ±0.5%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 100 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
TLVH431BCDBZT FAQ
1.How can I place an order for TLVH431BCDBZT through Aetrix?
Please submit a Request for Quotation (RFQ) for TLVH431BCDBZT on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for TLVH431BCDBZT reliable?
The price and inventory of TLVH431BCDBZT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TLVH431BCDBZT is usually 5 days.
3.What payment methods are accepted for TLVH431BCDBZT?
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4.How is shipping managed for TLVH431BCDBZT?
TLVH431BCDBZT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TLVH431BCDBZT order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for TLVH431BCDBZT?
For technical support, including TLVH431BCDBZT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TLVH431BCDBZT requirements.
6.How does Aetrix verify that TLVH431BCDBZT is sourced from the original manufacturer or authorized distributors?
All TLVH431BCDBZT products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TLVH431BCDBZT meets industry standards.
7.What is the process for return or replacement of TLVH431BCDBZT?
All TLVH431BCDBZT units undergo pre-shipment inspection (PSI). If there is an issue with TLVH431BCDBZT, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The TLVH431BCDBZT part is unused and in its original packaging.
Return procedure for TLVH431BCDBZT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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