Texas Instruments TLV431BCLPR

Overview

TLV431BCLPR from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, 0.5% initial tolerance at 25°C, and operation from 1.24 V to 6 V output range. It delivers 0.25 Ω typical dynamic impedance, 80 µA typical cathode current, and supports secondary-side regulation in isolated flyback SMPSs.

For engineers reviewing the TLV431BCLPR datasheet, TLV431BCLPR pinout, TLV431BCLPR application, or TLV431BCLPR equivalent, key selection considerations include its SC-70 package footprint, thermal drift of 4 mV (0°C to 70°C), ultra-low I_REF (0.1–0.5 µA), and compatibility with optocoupler-based feedback in 3.3 V/3 V power supplies.

Technical Context

The TLV431BCLPR operates as a 3-terminal adjustable shunt reference with an internal bandgap reference and high-gain NPN-based error amplifier. Its functional modes include open-loop comparator operation (with integrated 1.24 V reference) and closed-loop shunt regulation via resistive feedback between cathode and reference pins.

It achieves stable regulation without external compensation capacitors due to internal frequency compensation, and its sharp turn-on characteristic enables precise Zener replacement in low-voltage applications. The device requires ≥55 µA minimum cathode current for regulation across its full temperature range (–40°C to 125°C for TLV431BQ variant).

Key Specifications

Pinout & Package

TLV431BCLPR is packaged in a 6-pin SC-70 (DCK) package measuring 2.0 mm × 1.5 mm - 40% smaller than SOT-23-3 - with exposed pad not electrically connected. Pin 1 is CATHODE, Pin 3 is REFERENCE, Pin 6 is ANODE; Pins 2 and 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 TLV431ACLPR, TLV431BCLPR offers tighter reference accuracy for precision regulation; compared with TLVH431ILP, it provides superior board-area efficiency and lower system-level noise but lacks high-voltage headroom.

Availability

TLV431BCLPR is available at Aetrix Electronics and suitable for isolated flyback SMPSs, voltage monitoring circuits, Zener-replacement regulators, and adjustable current sources requiring stable component supply and long-term manufacturability.

Supply support for TLV431BCLPR 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 specializing in analog and embedded processing technologies, with leadership in precision analog ICs and power management solutions.

The TLV431 family was designed specifically for low-voltage, high-accuracy shunt regulation in space-constrained and thermally demanding applications - including telecom, industrial power supplies, and automotive subsystems.

FAQ

What is the reference voltage tolerance of TLV431BCLPR at 25°C?

The TLV431BCLPR 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 tight tolerance is specified in Section 5.7 of the TI datasheet SLVS139Z and applies exclusively to the TLV431B grade. The TLV431BCLPR maintains this accuracy across its SC-70 package variant and supports precision feedback in applications such as 3.3 V isolated SMPSs.

Can TLV431BCLPR replace a standard Zener diode?

Yes, TLV431BCLPR is explicitly designed as a high-performance Zener diode replacement. Its 0.25 Ω dynamic impedance, sharp turn-on characteristic, and 1.24 V reference enable superior regulation accuracy and stability compared to discrete Zeners. Unlike Zeners, TLV431BCLPR supports adjustable output voltages up to 6 V using two external resistors and operates reliably with cathode currents as low as 55 µA - making it ideal for low-power and precision biasing applications.

What is the minimum cathode current required for regulation in TLV431BCLPR?

The TLV431BCLPR requires a minimum cathode current (I_K(min)) of 55 µA to maintain regulation, with a maximum of 100 µA across its full operating temperature range (–40°C to 125°C). This value is confirmed in Section 5.7 of the datasheet and is critical for ensuring proper amplifier biasing and loop stability. Supplying less than 55 µA may result in degraded regulation accuracy or loss of control in feedback configurations.

Does TLV431BCLPR require an external compensation capacitor?

No, TLV431BCLPR does not require an external output capacitor for stability due to its internally compensated architecture. As stated in Section 7.3 of the datasheet, the device remains stable without added capacitance between cathode and anode. However, if an output capacitor is used for filtering, Figure 5-19 provides phase margin guidance to avoid oscillation - especially with capacitive loads exceeding 1 nF in high-frequency applications.

What package type is used for TLV431BCLPR and how does it compare to SOT-23-3?

TLV431BCLPR uses the SC-70 (DCK) package - a 6-pin surface-mount outline measuring 2.0 mm × 1.5 mm. Per TI's package documentation, this footprint is 40% smaller than the standard SOT-23-3 package. While both packages support similar thermal performance (R_θJA = 87°C/W for DCK vs 206°C/W for DBZ), the SC-70 offers superior board-area efficiency and is optimized for high-density DC/DC modules and portable electronics where space is constrained.