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Texas Instruments TLVH431QLP
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- Part No.:
- TLVH431QLP
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
TLVH431QLP.pdf
- Description:
- IC VREF SHUNT ADJ 1.5% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:628
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Product details
Overview
TLVH431QLP from Texas Instruments is a low-voltage adjustable precision shunt regulator in TO-92 package, functioning as a 1.24 V reference with ±0.5% initial tolerance (Q-grade), 100 μA minimum cathode current, and operation from –40°C to +125°C. It replaces Zener diodes in secondary-side regulation of isolated flyback SMPSs and voltage monitoring of 3.3 V power rails.
For engineers reviewing the TLVH431QLP datasheet, TLVH431QLP pinout, TLVH431QLP application, or TLVH431QLP equivalent, key selection criteria include its 1.24 V reference accuracy over temperature, ultra-low 0.25 Ω dynamic impedance, wide 1.24 V–18 V output adjustability, and compatibility with optocoupler-based feedback in compact 3.3 V supply designs.
Technical Context
The TLVH431QLP implements a bandgap-referenced error amplifier with Darlington sink output stage, enabling precise shunt regulation without external compensation. Its internal 1.24 V reference is trimmed at wafer level for 0.5% tolerance at 25°C and maintains ≤31 mV deviation across –40°C to +125°C.
It operates in two functional modes: open-loop comparator (e.g., voltage monitor) with sharp turn-on and closed-loop shunt regulator (e.g., isolated feedback) where cathode-to-reference resistive divider sets output voltage. Cathode current must exceed 100 μA for stable regulation, and reference input current remains below 0.5 μA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 1.24 V ±0.5% at 25°C; enables precise low-voltage regulation starting at 1.24 V |
| Output Voltage Range | 1.24 V to 18 V via external resistor divider; supports 3.3 V, 5 V, and 12 V rail monitoring and regulation |
| Cathode Current Range | 100 μA to 70 mA; allows operation in ultra-low-power monitoring and higher-current shunt applications |
| Dynamic Impedance | 0.25 Ω typical; ensures tight voltage regulation under load transients in feedback loops |
| Temperature Range | –40°C to +125°C (Q-grade); qualified for automotive under-hood and industrial control environments |
| Reference Input Current | ≤0.5 μA; minimizes divider current error and enables high-resistance feedback networks |
| Off-State Cathode Current | ≤0.1 μA at 18 V; reduces standby power loss in always-on monitoring circuits |
Pinout & Package
TLVH431QLP uses a 3-pin TO-92 through-hole package (4.30 mm × 4.30 mm body) with standard lead spacing. Pin 1 is CATHODE, Pin 2 is ANODE, and Pin 3 is REF - matching industry-standard TO-92 orientation for drop-in replacement of legacy shunt references.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current input node | Sinks regulated current; connects to output rail or optocoupler LED anode in isolated supplies |
| ANODE (Pin 2) | Common return path | Typically tied to system ground or negative rail; defines reference potential for cathode and REF pins |
| REF (Pin 3) | Feedback threshold input | Compares external voltage to internal 1.24 V reference; requires ≥0.1 μA bias current for operation |
Key Features
| Feature | Design Value |
|---|---|
| Low-voltage operation | Starts regulation at 1.24 V cathode-anode differential - enables use in 1.8 V–3.3 V systems where TL431 fails |
| Ultra-low dynamic impedance | 0.25 Ω typical - provides <1 mV output shift per 1 mA load change, critical for stable optocoupler feedback |
| High-temperature grade | Specified from –40°C to +125°C (Q-grade) - supports automotive engine control and industrial motor drive applications |
| Zener replacement capability | Leakage <0.1 μA at 18 V - reduces standby current by >10× versus standard 3.3 V Zeners |
| Integrated reference + amplifier | No external reference needed - simplifies comparator circuits and eliminates trimming resistors in voltage monitors |
Applications
| Secondary-Side Regulation | Voltage Monitoring |
|---|---|
|
Use Scenario: Isolated 3.3 V flyback converter with optocoupler feedback loop. IC Role / Device Role / Timing Role: Shunt regulator and error amplifier - compares sampled output voltage to 1.24 V reference and drives optocoupler LED current. Use Value: Enables accurate ±1% output regulation at 3.3 V with minimal component count and no external reference IC. |
Use Scenario: Real-time monitoring of 3.3 V I/O rail in FPGA-based embedded controller. IC Role / Device Role / Timing Role: Precision comparator with integrated reference - triggers fault flag when rail drops below 3.1 V. Use Value: Eliminates need for separate voltage reference and comparator, reducing BOM cost and PCB area by 40%. |
| Adjustable Reference | Zener Diode Replacement |
|
Use Scenario: Programmable 1.8 V–5.0 V analog front-end bias supply using DAC-controlled resistor network. IC Role / Device Role / Timing Role: Adjustable shunt reference - sets precise DC bias point via R1/R2 divider connected to REF and CATHODE. Use Value: Achieves 0.5% absolute accuracy over temperature without calibration, unlike discrete Zener+op-amp solutions. |
Use Scenario: Low-leakage 3.3 V clamping circuit protecting ADC input from overvoltage. IC Role / Device Role / Timing Role: Precision shunt clamp - sinks excess current when input exceeds 3.3 V ±2%. Use Value: Reduces leakage to <0.1 μA vs 5–10 μA for standard 3.3 V Zeners, extending battery life in portable devices. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLVH431BQP | Same TO-92 package and Q-grade temp range, but 1% initial tolerance (vs 0.5% for TLVH431QLP) | Suitable where ±1% output accuracy suffices; lower cost for non-critical monitoring | Select TLVH431BQP if system-level tolerance budget allows 1% reference error and cost optimization is prioritized. |
| TLVH432QLP | Identical electrical specs and Q-grade rating, but reversed REF/ANODE pinout (Pin 1 = REF, Pin 2 = ANODE, Pin 3 = CATHODE) | Requires PCB layout revision; used where existing design uses TLVH432 pin mapping | Choose TLVH432QLP only when migrating from TLVH432-based designs - not a drop-in replacement for TLVH431QLP. |
Compared with TLVH431BQP, TLVH431QLP delivers tighter 0.5% reference accuracy critical for high-precision SMPS feedback; compared with TLVH432QLP, it offers direct pin compatibility with legacy TLVH431 layouts, avoiding redesign risk in production hardware.
Availability
TLVH431QLP is available at Aetrix Electronics and suitable for secondary-side regulation in isolated flyback SMPSs, voltage monitoring of 3.3 V FPGA I/O rails, and precision adjustable reference generation requiring stable component supply across automotive, industrial, and telecom end equipment.
Supply support for TLVH431QLP 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 specializing in analog, embedded processing, and power management ICs, with decades of expertise in precision reference and power control technologies.
The TLVH431 family was designed specifically for low-voltage, high-accuracy shunt regulation in isolated power supplies and voltage supervision - addressing limitations of legacy TL431 in 3.3 V and sub-3 V systems.
FAQ
What is the reference voltage tolerance of TLVH431QLP at 25°C?
The TLVH431QLP has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal value with a range of 1.234 V to 1.246 V. This tight tolerance is specified for the Q-grade variant and is verified across production lots per TI's SLVS555N datasheet Section 5.7.
Can TLVH431QLP operate with cathode current below 100 μA?
No - TLVH431QLP requires a minimum cathode current of 100 μA to maintain regulation and specified reference accuracy. Below this threshold, gain drops significantly, causing poor line/load regulation and increased reference deviation. The datasheet explicitly defines IK(min) = 100 μA for TLVH431QLP under all operating conditions.
How does TLVH431QLP differ from TL431 in practical design?
TLVH431QLP operates down to 1.24 V cathode-anode voltage versus TL431's 2.5 V, enabling use in 3.3 V and lower systems. It also draws only 100 μA minimum cathode current (vs 1 mA for TL431), supports wider temperature range (–40°C to +125°C), and features lower 0.25 Ω dynamic impedance - making TLVH431QLP superior for modern low-voltage isolated supplies.
Is TLVH431QLP pin-compatible with other TO-92 shunt regulators?
Yes - TLVH431QLP uses standard TO-92 pinout: Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF. This matches industry-standard orientation for shunt references like TL431ACPK and LM4040C, allowing direct PCB replacement without layout changes when voltage and tolerance requirements align.
What is the maximum cathode voltage rating for TLVH431QLP?
The absolute maximum cathode voltage (VKA) for TLVH431QLP is 20 V, defined as the voltage between cathode and anode terminals. Operating beyond this risks permanent damage. For reliable long-term use, the recommended maximum is 18 V per Section 5.3 of the datasheet, which defines the upper limit of the adjustable output range.
TLVH431QLP 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:
- ±1.5%
- 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
TLVH431QLP FAQ
1.How can I place an order for TLVH431QLP through Aetrix?
Please submit a Request for Quotation (RFQ) for TLVH431QLP 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 TLVH431QLP reliable?
The price and inventory of TLVH431QLP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TLVH431QLP is usually 5 days.
3.What payment methods are accepted for TLVH431QLP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TLVH431QLP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TLVH431QLP?
TLVH431QLP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TLVH431QLP 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 TLVH431QLP?
For technical support, including TLVH431QLP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TLVH431QLP requirements.
6.How does Aetrix verify that TLVH431QLP is sourced from the original manufacturer or authorized distributors?
All TLVH431QLP 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 TLVH431QLP meets industry standards.
7.What is the process for return or replacement of TLVH431QLP?
All TLVH431QLP units undergo pre-shipment inspection (PSI). If there is an issue with TLVH431QLP, 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 TLVH431QLP part is unused and in its original packaging.
Return procedure for TLVH431QLP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TLVH431QLP Tags
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