Texas Instruments TLV431BILPRE3

Overview

TLV431BILPRE3 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, ±0.5% initial tolerance at 25°C, 0.25 Ω typical dynamic impedance, and operation down to 1.24 V cathode-anode voltage - used as an integrated reference in isolated flyback feedback loops, Zener replacement circuits, and voltage monitoring systems.

For engineers reviewing the TLV431BILPRE3 datasheet, TLV431BILPRE3 pinout, TLV431BILPRE3 application, or TLV431BILPRE3 equivalent, this page delivers verified electrical specs, SC-70 package details, functional mode distinctions (open-loop comparator vs closed-loop shunt regulation), thermal performance data, and real-world design considerations for secondary-side SMPS control and low-voltage threshold detection.

Technical Context

The TLV431BILPRE3 implements a bandgap-referenced error amplifier with Darlington output stage, enabling precise shunt regulation from 1.24 V to 6 V via two external resistors. Its internal architecture supports both open-loop comparator operation (with integrated 1.24 V reference) and closed-loop error amplification - critical for optocoupler-coupled feedback in 3.3 V/5 V isolated DC-DC converters.

It operates with as little as 55 µA minimum cathode current for regulation and maintains stability without external compensation capacitors, though phase margin vs. capacitive load curves (Figures 5-19–5-21) guide safe output capacitance selection up to 1 nF. Temperature drift is specified at 4 mV (0°C to 70°C), 6 mV (–40°C to 85°C), and 11 mV (–40°C to 125°C).

Key Specifications

Pinout & Package

TLV431BILPRE3 is packaged in a 6-pin SC-70 (DCK) outline measuring 2.0 mm × 1.5 mm - offering 40% smaller footprint than SOT-23-3. The package features a substrate connection on Pin 2 that must be tied to the anode or left floating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431AILPRE3, TLV431BILPRE3 provides tighter initial reference accuracy for precision feedback loops; compared with TLVH431ILP, it offers superior space efficiency and lower quiescent current but sacrifices maximum cathode voltage and current capability.

Availability

TLV431BILPRE3 is available at Aetrix Electronics and suitable for isolated flyback power supplies, battery voltage monitors, and low-voltage Zener replacement circuits requiring stable component supply and guaranteed long-term manufacturability.

Supply support for TLV431BILPRE3 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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets.

The TLV431x family was designed specifically to replace TL431 in low-voltage, low-power applications - targeting 3.3 V/5 V isolated SMPS, portable equipment, and space-constrained systems needing sub-2 V reference capability.

FAQ

What is the reference voltage tolerance of TLV431BILPRE3 at 25°C?

The TLV431BILPRE3 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a V_REF range of 1.234 V to 1.246 V. This tighter tolerance than TLV431A (±1%) or TLV431 (±1.5%) makes TLV431BILPRE3 suitable for high-accuracy feedback loops in precision power supplies and sensor interfaces where minimal setpoint error is critical.

Can TLV431BILPRE3 operate with a cathode-to-anode voltage below 1.24 V?

No - TLV431BILPRE3 requires a minimum cathode-to-anode voltage (V_KA) of 1.24 V to maintain regulation. Below this, the internal reference and amplifier cannot bias correctly. The device datasheet specifies V_KA range as 1.24 V to 6 V, and operation outside this range may result in unpredictable output or failure to regulate. TLV431BILPRE3 is not rated for sub-1.24 V operation.

What is the minimum cathode current required for TLV431BILPRE3 to regulate properly?

The TLV431BILPRE3 requires a minimum cathode current (I_K(min)) of 55 µA to enter and sustain regulation, as specified in Section 5.7 of the datasheet. This value applies across the full industrial temperature range (–40°C to 85°C). Supplying less than 55 µA may cause loss of regulation, increased output impedance, or delayed turn-on - especially critical in low-power battery applications.

Does TLV431BILPRE3 require an external compensation capacitor?

No - TLV431BILPRE3 is internally compensated and remains stable without an external output capacitor between cathode and anode. However, if an output capacitor is used (e.g., for noise filtering), Figures 5-19 through 5-21 in the datasheet define safe capacitive load ranges (up to ~1 nF depending on V_KA) to maintain ≥45° phase margin. Adding excessive capacitance can induce oscillation.

How does TLV431BILPRE3 differ from TL431 in practical design?

TLV431BILPRE3 differs from TL431 in three key ways: (1) lower reference voltage (1.24 V vs 2.5 V), enabling regulation in 1.8 V–3.3 V systems; (2) lower minimum cathode current (55 µA vs 1 mA), supporting ultra-low-power designs; and (3) smaller SC-70 package (2.0 mm × 1.5 mm) versus TL431's TO-92 or SOIC-8. These differences make TLV431BILPRE3 ideal for modern compact, low-voltage power architectures where TL431 cannot function.