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Texas Instruments TLVH431BQLP
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- Part No.:
- TLVH431BQLP
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
TLVH431BQLP.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,064
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Product details
Overview
TLVH431BQLP from Texas Instruments is a low-voltage adjustable precision shunt regulator in TO-92 package, featuring 0.5% reference voltage tolerance at 25°C, 1.24 V nominal reference voltage, –40°C to +125°C operating temperature range, and 100 μA minimum cathode current for regulation. It serves as an integrated voltage reference and error amplifier in isolated flyback SMPS feedback loops.
For engineers reviewing the TLVH431BQLP datasheet, TLVH431BQLP pinout, TLVH431BQLP application, or TLVH431BQLP equivalent, key selection criteria include reference accuracy over temperature, cathode current headroom for stability in optocoupler-coupled feedback, dynamic impedance under load, and compatibility with 3.3 V/5 V system rails requiring sub-2.5 V references.
Technical Context
The TLVH431BQLP implements a bandgap-referenced error amplifier with internal 1.24 V reference and Darlington output stage, enabling precise shunt regulation down to 1.24 V. Its open-loop comparator mode supports voltage monitoring without external reference, while closed-loop operation with resistive divider feedback achieves stable output voltage from 1.24 V to 18 V.
It operates with cathode-to-anode voltage as low as 1.24 V and supports continuous cathode current from 100 μA to 70 mA. Thermal stability is specified across –40°C to +125°C (Q-grade), and typical dynamic impedance is 0.25 Ω at 10 mA, ensuring tight regulation under varying load conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (VREF) | 1.24 V ±0.5% at 25°C - enables accurate low-voltage setpoints in feedback networks |
| Operating Temperature Range | –40°C to +125°C - qualified for automotive and industrial environments requiring extended thermal robustness |
| Min Cathode Current (IK(min)) | 100 μA - ensures regulation starts reliably in ultra-low-power flyback bias circuits |
| Dynamic Impedance (|zKA|) | 0.25 Ω typical - minimizes output voltage deviation under fast load transients |
| Cathode Voltage Range (VKA) | 1.24 V to 18 V - supports wide-output-range shunt regulation without external components |
| Reference Input Current (Iref) | 0.1–0.5 μA - reduces divider resistor power loss and improves high-impedance sensing accuracy |
| Output Leakage (IK(off)) | 0.02–0.1 μA at VKA = 18 V - ensures minimal standby current in always-on monitoring applications |
Pinout & Package
TLVH431BQLP uses a 3-pin TO-92 package (4.30 mm × 4.30 mm body) with through-hole mounting. Pin 1 is CATHODE, Pin 2 is ANODE, and Pin 3 is REF - no NC or substrate pins present in this variant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current input / regulated output node | Connects to feedback network output or optocoupler LED anode; sinks current to maintain VREF at Pin 3 |
| ANODE (Pin 2) | Common return / ground reference | Must be connected to system ground or lowest potential node; defines voltage reference for cathode and ref terminals |
| REF (Pin 3) | Feedback input / threshold sense node | Monitors divided output voltage; device regulates when voltage at this pin equals 1.24 V ±0.5% |
Key Features
| Feature | Design Value |
|---|---|
| Low-voltage operation | Starts regulation at 1.24 V cathode-to-anode - enables use in 1.8 V, 2.5 V, and 3.3 V systems where TL431 cannot function |
| 0.5% initial reference tolerance (B grade) | Reduces need for post-manufacturing calibration in precision power supplies and data converter references |
| Stable without output capacitor | Internally compensated design eliminates mandatory cathode-to-anode bypass capacitor - simplifies layout and improves reliability |
| Ultra-low reference input current | 0.1–0.5 μA max - permits use of high-value feedback resistors (>1 MΩ), minimizing quiescent current in battery-powered monitors |
| Sharp turn-on characteristic | High open-loop gain enables clean comparator action for rail voltage supervision with hysteresis-free thresholds |
Applications
| Isolated Flyback Secondary Regulation | Voltage Monitoring for Power Rails |
|---|---|
Use Scenario: Used with optocoupler in secondary-side feedback loop of 3.3 V isolated flyback converter to regulate output tightly across line/load/temperature. IC Role / Device Role / Timing Role: Acts as combined voltage reference and error amplifier - compares scaled output against internal 1.24 V reference and adjusts optocoupler LED current. Use Value: Enables regulation down to ~2.7 V output (1.24 V + opto VF), supporting modern low-voltage rails without sacrificing accuracy or stability. | Use Scenario: Monitors 5 V or 3.3 V main power rail in industrial PLC or automotive ECU to trigger fault flag if voltage drops below threshold. IC Role / Device Role / Timing Role: Functions as comparator with integrated reference - REF pin tied to resistor divider, CATHODE pulled up to monitored rail via current source. Use Value: Eliminates need for external precision reference; 0.5% tolerance ensures detection within ±25 mV of 5 V nominal, meeting IEC 61000-4-11 immunity requirements. |
| Adjustable Voltage Reference for Data Converters | Zener Diode Replacement in On-Board Regulation |
Use Scenario: Provides programmable reference voltage for 12-bit SAR ADC in sensor signal chain, set to 2.048 V using 1% metal-film resistors. IC Role / Device Role / Timing Role: Serves as precision shunt reference - configured in closed loop with R1/R2 divider to generate stable, low-noise VREF independent of supply ripple. Use Value: 0.25 Ω dynamic impedance and <10 μVPP low-frequency noise ensure <0.5 LSB error contribution at full scale, exceeding ADC manufacturer's reference recommendations. | Use Scenario: Replaces 2.4 V Zener diode in local 3.3 V LDO pre-regulator circuit to improve temperature drift and leakage performance. IC Role / Device Role / Timing Role: Operates as active shunt regulator - sinks excess current when input exceeds setpoint, maintaining constant voltage at LDO input. Use Value: Reduces temperature coefficient from ±5000 ppm/°C (Zener) to ±100 ppm/°C (TLVH431BQLP), cutting output drift by >95% over –40°C to +125°C. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLVH431BILP | Same electrical specs but rated for –40°C to +85°C (I-grade); TO-92 package identical | Not qualified for full automotive temperature range; suitable for commercial/industrial ambient-limited designs | Select TLVH431BILP only if end-equipment ambient does not exceed 85°C and cost sensitivity outweighs Q-grade qualification |
| TLVH431BDCKR | SC-70-6 package (2.0 mm × 1.25 mm); same B-grade tolerance and Q-temp rating; includes two NC pins | Requires PCB redesign for surface-mount assembly; smaller footprint enables space-constrained portable devices | Choose TLVH431BDCKR when board area is critical and reflow-compatible packaging is preferred over through-hole TO-92 |
Compared with TLVH431BILP and TLVH431BDCKR, TLVH431BQLP uniquely combines Q-grade temperature qualification (–40°C to +125°C) with through-hole TO-92 mechanical robustness and legacy compatibility - making it optimal for high-reliability industrial controls and automotive body electronics where serviceability and thermal margin are prioritized over miniaturization.
Availability
TLVH431BQLP is available at Aetrix Electronics and suitable for isolated flyback SMPS design, precision voltage monitoring, data converter reference generation, and on-board shunt regulation requiring stable component supply across automotive and industrial temperature ranges.
Supply support for TLVH431BQLP 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 and embedded processing solutions, with deep expertise in precision analog, power management, and interface technologies.
The TLVH431 family was designed specifically for low-voltage shunt regulation and integrated reference applications in isolated power supplies, voltage supervisors, and data acquisition systems - addressing limitations of legacy TL431 in sub-2.5 V domains.
FAQ
What is the reference voltage tolerance of TLVH431BQLP at 25°C?
The TLVH431BQLP has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal value with min/max bounds of 1.234 V and 1.246 V. This B-grade specification is confirmed in Section 5.7 of the official TI datasheet SLVS555N and applies strictly to the TLVH431BQLP variant across its TO-92 packaging and Q-temperature qualification.
Can TLVH431BQLP operate with cathode voltage below 2.5 V?
Yes, TLVH431BQLP is explicitly designed for low-voltage operation starting at 1.24 V cathode-to-anode voltage - significantly lower than the 2.5 V minimum required by TL431. This enables direct use in 1.8 V, 2.5 V, and 3.3 V systems. The device maintains regulation down to 1.24 V as long as minimum cathode current (100 μA) is supplied and temperature remains within –40°C to +125°C.
What is the minimum cathode current required for regulation in TLVH431BQLP?
The minimum cathode current required for stable regulation in TLVH431BQLP is 100 μA at 25°C, with a maximum of 150 μA across the full –40°C to +125°C temperature range. This value is specified in Section 5.5–5.7 of the TI datasheet and is critical for ensuring sufficient open-loop gain in feedback configurations such as optocoupler-based flyback controllers.
Does TLVH431BQLP require an output capacitor for stability?
No, TLVH431BQLP is internally compensated and stable without an output capacitor between cathode and anode - a key differentiator from many linear regulators. However, if an output capacitor is added for noise filtering or transient response enhancement, Figures 5-15 to 5-17 in the datasheet provide phase-margin guidance for selecting values up to 10 nF depending on cathode voltage and load conditions.
How does TLVH431BQLP differ from TLVH432 variants?
TLVH431BQLP and TLVH432 variants share identical electrical specifications but differ in pinout: TLVH431BQLP uses CATHODE–ANODE–REF (Pin 1–2–3), while TLVH432 packages reverse REF and ANODE. This pinout difference prevents direct substitution without PCB modification. TLVH431BQLP's TO-92 pinout is standardized per Figure 4-3, and no TLVH432 variant is offered in TO-92 packaging.
TLVH431BQLP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA)
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Obsolete
- 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:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
TLVH431BQLP FAQ
1.How can I place an order for TLVH431BQLP through Aetrix?
Please submit a Request for Quotation (RFQ) for TLVH431BQLP 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 TLVH431BQLP reliable?
The price and inventory of TLVH431BQLP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TLVH431BQLP is usually 5 days.
3.What payment methods are accepted for TLVH431BQLP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TLVH431BQLP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TLVH431BQLP?
TLVH431BQLP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TLVH431BQLP 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 TLVH431BQLP?
For technical support, including TLVH431BQLP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TLVH431BQLP requirements.
6.How does Aetrix verify that TLVH431BQLP is sourced from the original manufacturer or authorized distributors?
All TLVH431BQLP 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 TLVH431BQLP meets industry standards.
7.What is the process for return or replacement of TLVH431BQLP?
All TLVH431BQLP units undergo pre-shipment inspection (PSI). If there is an issue with TLVH431BQLP, 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 TLVH431BQLP part is unused and in its original packaging.
Return procedure for TLVH431BQLP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TLVH431BQLP Tags
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TL431AIDBZR
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TL431BQDBZR
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AZ431LBNTR-G1
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LM4040D20IDBZR
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LM4041DIM3-ADJ/NOPB
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LM4040DIM3X-2.5/NOPB
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AZ431LANTR-G1
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