Texas Instruments TLV431BCLPRE3

Overview

TLV431BCLPRE3 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 SMPS feedback loops, Zener replacement circuits, and voltage monitoring systems.

For engineers reviewing the TLV431BCLPRE3 datasheet, TLV431BCLPRE3 pinout, TLV431BCLPRE3 application, or TLV431BCLPRE3 equivalent, key selection considerations include its SC-70 (DCK) package footprint, 55–100 µA minimum cathode current requirement, 4–11 mV reference drift over temperature, ultra-low 0.1–0.5 µA reference terminal current, and compatibility with optocoupler-based secondary-side regulation in 3.3 V and lower-output power supplies.

Technical Context

The TLV431BCLPRE3 implements a bandgap-referenced error amplifier with Darlington output stage, enabling precise shunt regulation via external resistor divider feedback between cathode and reference pins. Its internal architecture supports both open-loop comparator mode (with integrated 1.24 V threshold) and closed-loop shunt regulation mode without requiring external compensation.

It operates across industrial temperature range (–40°C to +85°C), delivers stable regulation from 1.24 V to 6 V output, and maintains 0.25 Ω dynamic impedance up to 15 mA cathode current - critical for tight voltage control in low-headroom, high-efficiency DC/DC feedback paths.

Key Specifications

Pinout & Package

TLV431BCLPRE3 is packaged in ultra-small SC-70 (DCK) outline: 2.0 mm × 1.5 mm footprint, 6-pin configuration with exposed thermal pad (not electrically connected). Pin 1 = CATHODE, Pin 3 = REF, Pin 6 = ANODE; Pins 2, 4, 5 are NC (no internal connection).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431ACLPE3, TLV431BCLPRE3 provides tighter reference accuracy for precision feedback loops; compared with TLVH431ILP, it offers superior board-area efficiency and lower quiescent current at the expense of voltage and current headroom.

Availability

TLV431BCLPRE3 is available at Aetrix Electronics and suitable for isolated flyback SMPS designs, voltage monitoring circuits, and Zener diode replacement applications requiring stable component supply, consistent parametric performance, and long-term manufacturability.

Supply support for TLV431BCLPRE3 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 TLV431 family was designed specifically for low-voltage, high-accuracy shunt regulation in space- and power-constrained applications - targeting secondary-side feedback in compact AC/DC adapters, battery monitoring, and precision reference subsystems.

FAQ

What is the operating temperature range for TLV431BCLPRE3?

The TLV431BCLPRE3 is specified for industrial operation from –40°C to +85°C (TLV431BI grade). Its reference voltage drift is limited to 6 mV across this range, and minimum cathode current remains ≤100 µA. This makes TLV431BCLPRE3 suitable for automotive cabin electronics, industrial PLCs, and outdoor power equipment where ambient temperatures exceed commercial limits.

Can TLV431BCLPRE3 replace a standard 3.3 V Zener diode?

Yes, TLV431BCLPRE3 can directly replace a 3.3 V Zener diode when configured with R1 and R2 resistors to set V_OUT = 1.24 V × (1 + R1/R2). Unlike Zeners, TLV431BCLPRE3 offers ±0.5% initial tolerance, 6 mV tempco, and 0.25 Ω dynamic impedance - resulting in significantly tighter regulation and lower voltage droop under load. No additional components are required beyond the two external resistors.

What is the minimum cathode current needed for regulation in TLV431BCLPRE3?

The TLV431BCLPRE3 requires a minimum cathode current (I_K(min)) of 55 µA at 25°C, rising to 100 µA at +85°C. Below this threshold, the device exits regulation and behaves as an open circuit. Designers must ensure the external bias network - including optocoupler LED or load resistor - delivers sufficient current across all operating conditions to maintain TLV431BCLPRE3 in active regulation.

Does TLV431BCLPRE3 require an output capacitor for stability?

No, TLV431BCLPRE3 is internally compensated and remains stable without an output capacitor between cathode and anode. This eliminates capacitor-related failures and saves board space. However, if a capacitive load is added (e.g., for noise filtering), stability must be verified using TI's phase margin vs. capacitive load curves (Figures 5-19 to 5-21); TLV431BCLPRE3 supports up to ~1 nF without oscillation at V_KA = 5 V.

How does the SC-70 package of TLV431BCLPRE3 compare to SOT-23-3 versions?

The TLV431BCLPRE3 uses the SC-70 (DCK) package - 2.0 mm × 1.5 mm - which is 40% smaller than the SOT-23-3 (DBZ) variant (2.92 mm × 2.37 mm). While both share functional pinout equivalence (CATHODE/REF/ANODE), the SC-70 has 6 pins (3 active, 3 NC) versus 3 pins on SOT-23-3. The smaller footprint benefits ultra-compact power modules, but requires attention to thermal relief and solder paste volume during reflow.