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Texas Instruments TLVH431AQDBZT
- Part No.:
- TLVH431AQDBZT
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
TLVH431AQDBZT.pdf
- Description:
- IC VREF SHUNT ADJ 1% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:948
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Product details
Overview
TLVH431AQDBZT from Texas Instruments is a low-voltage adjustable precision shunt regulator in SOT-23-3 package, featuring 1.24 V reference voltage (±1% at 25°C), 100 μA to 70 mA cathode current range, and operation from –40°C to +125°C. It functions as a programmable Zener replacement or error amplifier in isolated flyback SMPS feedback loops.
For engineers reviewing the TLVH431AQDBZT datasheet, TLVH431AQDBZT pinout, TLVH431AQDBZT application, or TLVH431AQDBZT equivalent, key selection criteria include reference tolerance grade (A = 1%), thermal stability over automotive temperature range, cathode current headroom for optocoupler drive, and SOT-23-3 footprint compatibility with legacy TL431-based designs.
Technical Context
The TLVH431AQDBZT implements a bandgap-referenced error amplifier with Darlington output stage, enabling precise shunt regulation down to 1.24 V. Its internal 1.24 V reference is stable across –40°C to +125°C with typical dynamic impedance of 0.25 Ω and reference voltage deviation ≤31 mV over full temperature range.
In closed-loop configuration, it compares external resistor-divided cathode voltage against its internal reference to sink cathode current and maintain regulation. In open-loop mode, it operates as a comparator with integrated reference, requiring ≥100 μA cathode current to ensure sufficient gain and sharp turn-on behavior.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 1.24 V ±1% at 25°C - sets minimum adjustable output voltage and defines accuracy baseline for resistor-divider programming. |
| Cathode Current Range | 100 μA to 70 mA - supports low-power monitoring (e.g., rail sensing) and robust optocoupler LED drive in isolated supplies. |
| Operating Temperature | –40°C to +125°C - qualified for automotive under-hood and industrial control applications without derating. |
| Dynamic Impedance | 0.25 Ω typical - ensures tight regulation under load transients; total circuit impedance scales with external resistor values. |
| Reference Input Current | 0.1–0.5 μA - enables high-impedance feedback networks without significant divider loading error. |
| Output Voltage Range | VREF to 18 V - achieved via two external resistors; supports 3.3 V, 5 V, 12 V, and custom rails in compact power designs. |
| Thermal Stability | ≤31 mV VREF deviation over –40°C to +125°C - corresponds to <100 ppm/°C average TC, critical for precision references. |
Pinout & Package
SOT-23-3 package (2.92 mm × 1.30 mm body size) with gull-wing leads; thermally enhanced for 206°C/W junction-to-ambient resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current input / regulated output node | Connects to supply rail being monitored or optocoupler anode; sinks current to maintain VREF at REF pin. |
| REF (Pin 2) | Reference input / feedback sense node | Must be connected to resistor divider midpoint; draws only 0.1–0.5 μA, minimizing divider power loss. |
| ANODE (Pin 3) | Common return / ground reference | Typically tied to system ground or negative rail; serves as voltage reference point for both REF and CATHODE terminals. |
Key Features
| Feature | Design Value |
|---|---|
| Low-voltage operation | Regulates down to 1.24 V - enables direct use in 1.8 V, 2.5 V, and 3.3 V systems where standard TL431 (2.5 V) cannot function. |
| Automotive-grade temperature range | –40°C to +125°C operation - supports AEC-Q100-qualified designs without external compensation or derating. |
| Ultra-low reference current | 0.1–0.5 μA max - permits use of >1 MΩ feedback dividers, reducing quiescent current in battery-powered applications. |
| Stable without output capacitor | Internally compensated - eliminates need for cathode-to-anode capacitor in most configurations, simplifying layout and BOM. |
| Zener diode replacement | 100 μA minimum cathode current - achieves sharp knee and low leakage (<0.1 μA off-state), outperforming discrete Zeners in precision. |
Applications
| Secondary-Side Regulation | Voltage Monitoring |
|---|---|
Use Scenario: Isolated 3.3 V flyback converter with optocoupler feedback loop. IC Role / Device Role / Timing Role: Precision shunt regulator and error amplifier on secondary side, comparing output voltage against internal 1.24 V reference. Use Value: Enables regulation of output voltages as low as 2.7 V (1.24 V + opto LED drop), with <1% initial accuracy and minimal temperature drift. |
Use Scenario: Real-time monitoring of 5 V and 12 V power rails in automotive ECU. IC Role / Device Role / Timing Role: Adjustable threshold detector comparing rail voltage to programmable reference via resistor divider. Use Value: Provides fail-safe undervoltage detection with 100 μA cathode current headroom and guaranteed operation at –40°C. |
| Comparator with Integrated Reference | Adjustable Voltage Reference |
Use Scenario: Overvoltage protection circuit triggering at 4.2 V for Li-ion charging path. IC Role / Device Role / Timing Role: Open-loop comparator using internal 1.24 V reference and external resistor network to set trip point. Use Value: Eliminates need for external reference IC or precision resistor network; achieves <1% trip accuracy across automotive temperature range. |
Use Scenario: Programmable reference for 12-bit SAR ADC in industrial data acquisition module. IC Role / Device Role / Timing Role: Stable, low-drift voltage source setting full-scale input range (e.g., 0–2.5 V or 0–5 V). Use Value: Delivers 0.25 Ω dynamic impedance and <31 mV VREF drift over –40°C to +125°C, ensuring ADC linearity and offset stability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLVH431BQDBZT | 0.5% reference tolerance (vs. 1% for TLVH431AQDBZT); otherwise identical electrical specs and pinout. | Required where tighter initial accuracy is needed for calibration-critical systems (e.g., metrology, precision DACs). | Select TLVH431BQDBZT when reference accuracy dominates system error budget; same SOT-23-3 footprint and thermal profile. |
| TLVH432AQDBZT | Different pinout: REF on Pin 1, CATHODE on Pin 2, ANODE on Pin 3 - incompatible with TLVH431AQDBZT PCB layout. | Used when design requires alternate routing or compatibility with TLVH432-specific reference schematics. | Choose TLVH432AQDBZT only if board layout accommodates reversed REF/CATHODE pins; no electrical advantage over TLVH431AQDBZT. |
Compared with TLVH431AQDBZT, TLVH431BQDBZT offers higher initial accuracy at same cost and thermal performance, while TLVH432AQDBZT provides identical functionality but demands PCB redesign due to inverted pin assignment - making TLVH431AQDBZT optimal for new designs prioritizing layout reuse and AEC-Q100-compliant 1% tolerance.
Availability
TLVH431AQDBZT is available at Aetrix Electronics and suitable for automotive power management, industrial SMPS feedback, and precision voltage monitoring applications requiring stable component supply across extended temperature ranges.
Supply support for TLVH431AQDBZT 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 company specializing in analog, embedded processing, and power management technologies, with leadership in precision analog ICs for industrial and automotive markets.
The TLVH431 family was designed specifically for low-voltage shunt regulation in isolated power supplies and precision monitoring systems, addressing the gap between standard TL431 (2.5 V) and ultra-low-voltage references.
FAQ
What is the reference voltage tolerance of TLVH431AQDBZT at 25°C?
The TLVH431AQDBZT has a reference voltage tolerance of ±1% at 25°C, corresponding to a 1.24 V nominal value ranging from 1.228 V to 1.252 V. This A-grade tolerance is specified in Section 5.6 of the TI datasheet and applies across all package variants including the SOT-23-3 DBZ form factor used by TLVH431AQDBZT.
Can TLVH431AQDBZT replace TL431 in existing designs?
TLVH431AQDBZT can replace TL431 in many designs but requires verification of cathode voltage headroom and feedback network scaling. Unlike TL431 (2.5 V reference), TLVH431AQDBZT operates down to 1.24 V and draws only 0.1–0.5 μA at the REF pin, enabling lower-power resistor dividers. Its SOT-23-3 footprint differs from TL431's TO-92 or SOIC-8, so mechanical compatibility must be confirmed.
What is the minimum cathode current required for regulation in TLVH431AQDBZT?
The TLVH431AQDBZT requires a minimum cathode current of 100 μA to maintain regulation, as specified in Section 5.5 of the datasheet. Below this threshold, open-loop gain drops significantly, causing poor regulation accuracy and delayed response. This value is guaranteed over the full –40°C to +125°C operating range and is critical when sizing optocoupler LED current in flyback converters.
Does TLVH431AQDBZT require an output capacitor for stability?
No, TLVH431AQDBZT is internally compensated and does not require an output capacitor between cathode and anode for basic stability. The datasheet confirms stable operation without external capacitance in standard shunt regulator configurations. However, if a capacitive load is added (e.g., for noise filtering), Figures 5-15 through 5-17 provide phase margin guidance to avoid oscillation.
How does the TLVH431AQDBZT pinout differ from TLVH432AQDBZT?
TLVH431AQDBZT uses Pin 1 = CATHODE, Pin 2 = REF, Pin 3 = ANODE. TLVH432AQDBZT reverses Pins 1 and 2: Pin 1 = REF, Pin 2 = CATHODE, Pin 3 = ANODE. This difference is explicitly documented in Figures 4-4 and 4-5 of the datasheet. PCB layouts for TLVH431AQDBZT are not compatible with TLVH432AQDBZT without trace modification.
TLVH431AQDBZT 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:
- ±1%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 100 µA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
TLVH431AQDBZT FAQ
1.How can I place an order for TLVH431AQDBZT through Aetrix?
Please submit a Request for Quotation (RFQ) for TLVH431AQDBZT 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 TLVH431AQDBZT reliable?
The price and inventory of TLVH431AQDBZT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TLVH431AQDBZT is usually 5 days.
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TLVH431AQDBZT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TLVH431AQDBZT 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 TLVH431AQDBZT?
For technical support, including TLVH431AQDBZT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TLVH431AQDBZT requirements.
6.How does Aetrix verify that TLVH431AQDBZT is sourced from the original manufacturer or authorized distributors?
All TLVH431AQDBZT 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 TLVH431AQDBZT meets industry standards.
7.What is the process for return or replacement of TLVH431AQDBZT?
All TLVH431AQDBZT units undergo pre-shipment inspection (PSI). If there is an issue with TLVH431AQDBZT, 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 TLVH431AQDBZT part is unused and in its original packaging.
Return procedure for TLVH431AQDBZT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TLVH431AQDBZT Tags
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