Texas Instruments TLV431BCDCKR

Overview

TLV431BCDCKR 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 TLV431BCDCKR datasheet, TLV431BCDCKR pinout, TLV431BCDCKR application, or TLV431BCDCKR equivalent, this page delivers verified electrical specs, SC-70 package details, functional mode distinctions (open-loop comparator vs. closed-loop shunt regulation), and real-world design implications for secondary-side regulation and low-voltage referencing.

Technical Context

The TLV431BCDCKR 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 reference is trimmed to 0.5% accuracy at 25°C and exhibits 4 mV max drift over 0°C to 70°C (TLV431BC grade).

In open-loop mode, it functions as a comparator with integrated 1.24 V reference and ~1 V output low level; in closed-loop configuration with cathode-to-reference feedback, it achieves stable shunt regulation with <100 µA minimum cathode current and no external compensation capacitor required.

Key Specifications

Pinout & Package

TLV431BCDCKR uses the DCK (SC-70-6) package: 2.0 mm × 1.5 mm footprint, 0.95 mm height, 6-pin surface-mount outline with exposed thermal pad (not electrically connected). Pin 1 = CATHODE, Pin 3 = REF, Pin 6 = ANODE; Pins 2, 4, 5 are NC or substrate tie (must connect to ANODE or leave open per datasheet).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431BCDCKR, TLV431ACDCKR trades 0.5% precision for lower unit cost, while TLVH431IDBVR expands operational range at the expense of package compatibility and quiescent current - neither is pin-compatible, but both serve adjacent design requirements in the same system families.

Availability

TLV431BCDCKR is available at Aetrix Electronics and suitable for isolated SMPS feedback, precision voltage monitoring, and low-voltage Zener replacement applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for TLV431BCDCKR 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- and power-constrained applications - targeting isolated DC/DC converters, voltage supervisors, and reference-intensive instrumentation.

FAQ

What is the reference voltage tolerance of TLV431BCDCKR at 25°C?

The TLV431BCDCKR 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 grade ('B') is confirmed in Section 5.7 of the TI datasheet SLVS139Z and applies specifically to the TLV431BC variant packaged in SC-70 (DCK). The tolerance remains stable across the 0°C to 70°C operating range with ≤4 mV total drift.

Can TLV431BCDCKR replace a standard 3.3 V Zener diode?

Yes, TLV431BCDCKR can directly replace a 3.3 V Zener diode when configured with R1 and R2 to set V_OUT = 3.3 V using the formula V_OUT = V_REF × (1 + R1/R2). Its 0.25 Ω dynamic impedance, ±0.5% tolerance, and 4 mV temperature drift over 0°C–70°C provide significantly better regulation accuracy and stability than typical 5% Zener diodes, especially under varying load or temperature conditions.

What is the minimum cathode current required for regulation in TLV431BCDCKR?

The TLV431BCDCKR requires a minimum cathode current (I_K(min)) of 55 µA to 100 µA depending on temperature - 55 µA typical at 25°C and up to 100 µA at 70°C (Section 5.7, TI SLVS139Z). This ultra-low requirement enables operation in micropower systems where traditional TL431 (1 mA min) would fail, such as battery-backed voltage monitors or energy-harvesting regulators.

Does TLV431BCDCKR require an output capacitor for stability?

No, TLV431BCDCKR is internally compensated and does not require an external output capacitor between cathode and anode for basic shunt regulation stability. This is explicitly stated in Section 7.3 of the datasheet. However, if a capacitive load is added (e.g., for noise filtering), Figure 5-19 provides phase margin guidance to avoid oscillation - stability depends on load capacitance and V_KA, not on mandatory capacitor use.

What are the valid operating voltage ranges for TLV431BCDCKR?

TLV431BCDCKR operates with cathode-to-anode voltage (V_KA) from 1.24 V to 6 V, as specified in Section 5.3 (Recommended Operating Conditions). It cannot regulate below 1.24 V, and absolute maximum V_KA is 7 V (Section 5.1). The device draws reference current (I_REF) of 0.1–0.5 µA and supports cathode currents from 0.1 mA to 15 mA within this voltage window.