Texas Instruments TLV431CDBZRG4

Overview

TLV431CDBZRG4 from Texas Instruments is a low-voltage adjustable precision shunt regulator in SC-70 (DCK) package, featuring 1.24 V reference voltage, ±1.5% initial tolerance at 25°C, and operation down to 1.24 V cathode-anode voltage. It delivers 0.25 Ω typical dynamic impedance and supports adjustable output from 1.24 V to 6 V using two external resistors - ideal for secondary-side regulation in compact 3.3 V flyback SMPS designs.

For engineers reviewing the TLV431CDBZRG4 datasheet, TLV431CDBZRG4 pinout, TLV431CDBZRG4 application, or TLV431CDBZRG4 equivalent, key selection considerations include its 0°C to 70°C temperature range (TLV431C grade), ultra-small 2.0 mm × 1.5 mm SC-70 footprint, low 80 µA typical cathode current requirement, and integrated reference functionality enabling Zener replacement and comparator use without external references.

Technical Context

The TLV431CDBZRG4 implements a bandgap-based reference with an internal NPN Darlington output stage, operating as a 3-terminal adjustable shunt regulator. Its closed-loop behavior relies on feedback from cathode to reference pin to force the reference terminal to 1.24 V, enabling precise voltage or current regulation via external resistor networks.

In open-loop mode, it functions as a comparator with built-in 1.24 V threshold, requiring ≥55 µA minimum cathode current for stable switching response. Thermal drift is specified at 4 mV over 0°C to 70°C, and it remains stable without output capacitance due to internal compensation - unlike many linear regulators.

Key Specifications

Pinout & Package

TLV431CDBZRG4 is housed in a 6-pin SC-70 (DCK) package measuring 2.0 mm × 1.5 mm - 40% smaller than SOT-23-3 - with thermal pad exposed on bottom for enhanced dissipation. Pin 1 is CATHODE, Pin 3 is REFERENCE, Pin 6 is ANODE; Pins 2, 4, and 5 are NC (no internal connection).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431CDBZRG4, TLV431ACDBZRG4 offers improved accuracy at same footprint and thermal profile, while TLVH431IDBVR trades compactness for extended voltage range and current capability - making each suitable for distinct trade-offs between precision, size, and operating envelope.

Availability

TLV431CDBZRG4 is available at Aetrix Electronics and suitable for isolated flyback SMPS regulation, voltage monitoring, and adjustable reference applications requiring stable component supply, consistent parametric performance, and long-term industrial availability.

Supply support for TLV431CDBZRG4 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 leader delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and consumer markets.

The TLV431 family was designed as a low-voltage, precision alternative to the TL431, targeting space-constrained and low-power applications including isolated power supplies, battery monitors, and sensor signal conditioning.

FAQ

What is the reference voltage tolerance of TLV431CDBZRG4 at 25°C?

The TLV431CDBZRG4 has a ±1.5% reference voltage tolerance at 25°C, corresponding to a 1.24 V nominal V_REF with a range of 1.222 V to 1.258 V. This tolerance applies specifically to the TLV431C grade and is confirmed in Section 5.5 of the official TI datasheet SLVS139Z. The TLV431CDBZRG4 maintains this specification across its 0°C to 70°C operating range.

Which package type does TLV431CDBZRG4 use, and what are its dimensions?

TLV431CDBZRG4 uses the SC-70 (DCK) package, a 6-pin surface-mount outline measuring 2.0 mm × 1.5 mm. This ultra-small footprint is 40% smaller than standard SOT-23-3 packages and includes an exposed thermal pad on the bottom for improved heat dissipation. Pin configuration follows TI's DCK mechanical drawing, with CATHODE on Pin 1, REFERENCE on Pin 3, and ANODE on Pin 6.

Can TLV431CDBZRG4 replace a Zener diode, and how does its performance compare?

Yes, TLV431CDBZRG4 is explicitly designed as a precision Zener diode replacement. It provides sharper turn-on, lower dynamic impedance (0.25 Ω typical vs >10 Ω for most Zeners), and superior temperature stability (4 mV drift over 0°C–70°C). Unlike passive Zeners, TLV431CDBZRG4 requires only 55–80 µA minimum cathode current and supports adjustable output from 1.24 V to 6 V using two resistors - enabling far greater flexibility and accuracy.

What is the minimum cathode current required for regulation in TLV431CDBZRG4?

The TLV431CDBZRG4 requires a minimum cathode current (I_K(min)) of 55 µA to enter and maintain regulation, with a typical value of 80 µA at 25°C. This parameter is validated across the full 0°C to 70°C operating range and is critical for designing bias networks in low-power applications such as battery monitors or always-on voltage supervisors. Below this threshold, regulation accuracy degrades and open-loop gain drops significantly.

Does TLV431CDBZRG4 require an external output capacitor for stability?

No, TLV431CDBZRG4 is internally compensated and remains stable without an external output capacitor between cathode and anode - a key advantage over many linear regulators. This eliminates capacitor-related BOM cost, layout area, and potential instability from ESR/ESL effects. However, if an output capacitor is added for noise filtering, Figure 5-19 in the TI datasheet provides phase margin guidance to ensure stability across capacitive loads up to 1 nF.