Texas Instruments TLV431ILPR5

Overview

TLV431ILPR5 from onsemi is a precision low-voltage adjustable shunt regulator with 1.24 V reference voltage, ±1.0% initial accuracy at 25°C, and guaranteed operation from −40°C to 85°C. It delivers sharp turn-on behavior, 0.25 Ω dynamic impedance (0.1 mA–20 mA), and supports programmable output voltages from 1.24 V to 16 V. It serves as a high-accuracy replacement for Zener diodes in feedback loops of isolated 3.3 V switching power supplies.

For engineers reviewing the TLV431ILPR5 datasheet, TLV431ILPR5 pinout, TLV431ILPR5 application, or TLV431ILPR5 equivalent, key selection criteria include reference tolerance over temperature, cathode current range (0.1–20 mA), dynamic impedance stability, TO-92-3 package thermal resistance (178°C/W), and compatibility with optocoupler-based error amplification in low-voltage SMPS designs.

Technical Context

The TLV431ILPR5 implements a bandgap-referenced shunt regulator architecture with internal active circuitry enabling precise voltage regulation via external resistor dividers. Its reference terminal draws only 0.15 µA typical current, and it maintains regulation down to 30 µA cathode current while exhibiting <0.05 µA off-state leakage at 16 V cathode-anode voltage.

It operates across a 1.24 V to 16 V cathode-anode voltage range with 18 V absolute maximum rating, supports continuous cathode current from −20 mA to +25 mA, and features ESD protection exceeding 2000 V HBM per JEDEC JESD22-A114F. Thermal performance is characterized by 178°C/W junction-to-ambient resistance in its TO-92-3 (LP) package.

Key Specifications

Pinout & Package

TLV431ILPR5 is housed in a TO-92-3 (LP) package with bent leads, designed for through-hole mounting. The package measures 4.45 mm × 4.32 mm × 5.20 mm and provides 178°C/W junction-to-ambient thermal resistance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar shunt regulator applications.

Compared with TLV431ILPR5, TLV431ACLPR5 offers superior accuracy at higher cost, while TLVH431ILP trades initial tolerance for broader voltage range-neither is pin-compatible with TLV431ILPR5 in all electrical contexts, though mechanical fit is identical.

Availability

TLV431ILPR5 is available at Aetrix Electronics and suitable for industrial power supplies, embedded voltage monitors, and optocoupler-based feedback circuits requiring stable component supply and long-term manufacturability.

Supply support for TLV431ILPR5 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

onsemi (formerly ON Semiconductor) is a global semiconductor manufacturer specializing in energy-efficient power management, analog, and sensor solutions for automotive, industrial, and cloud infrastructure markets.

The TLV431ILPR5 belongs to onsemi's precision shunt regulator product line, engineered for high-accuracy voltage reference and feedback control in isolated and non-isolated power conversion systems.

FAQ

What is the reference voltage tolerance of TLV431ILPR5 over temperature?

The TLV431ILPR5 has ±1.0% reference voltage tolerance at 25°C and ±2.0% over the full industrial temperature range of −40°C to +85°C. This is specified in the Electrical Characteristics table for the TLV431A series, which TLV431ILPR5 belongs to. The device achieves this via trimmed bandgap circuitry and is validated across temperature in production testing.

Can TLV431ILPR5 replace a standard 3.3 V Zener diode directly?

Yes, TLV431ILPR5 can directly replace a 3.3 V Zener diode in most circuits, but requires two external resistors to set the output voltage (e.g., R1 = 1.8 kΩ, R2 = 3.0 kΩ for 3.3 V). Unlike Zeners, it provides sharper knee characteristics, lower dynamic impedance (0.25 Ω vs. >10 Ω), and tighter tolerance-improving regulation accuracy and transient response in voltage reference or clamp applications.

What is the minimum cathode current required for TLV431ILPR5 to regulate properly?

The TLV431ILPR5 requires a minimum cathode current of 30 µA to maintain regulation, as specified in the "Minimum Cathode Current for Regulation" parameter. Below this level, the device exits regulation and behaves as an open circuit. Designers must ensure the resistor divider network supplies sufficient current - typically achieved with ≤100 kΩ total divider resistance at nominal input voltage.

Does TLV431ILPR5 support operation in isolated feedback topologies?

Yes, TLV431ILPR5 is explicitly designed for isolated feedback applications. When paired with an optocoupler (e.g., PC817), it functions as the error amplifier in the secondary-side feedback loop of isolated DC-DC converters. The datasheet Figure 31 shows a validated 3.3 V output design using TLV431ILPR5, confirming its suitability for this role with proper compensation (e.g., 0.1 µF capacitor across optocoupler LED).

What package type and lead configuration does TLV431ILPR5 use?

TLV431ILPR5 uses the TO-92-3 package with LP suffix and bent leads, as confirmed by the ordering information table and package dimension drawings (Case 29-11). Pin 1 is Reference, Pin 2 is Anode (ground), and Pin 3 is Cathode - matching the standard TLV431 pinout. The "R5" in the part number indicates tape-and-reel packaging (2000 units per reel).