Texas Instruments TLV431BIDBVRG4

Overview

TLV431BIDBVRG4 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 0.5% initial reference voltage tolerance (1.24 V at 25°C), 0.25 Ω typical dynamic impedance, and operation down to 1.24 V cathode-anode voltage. It regulates output voltages from 1.24 V to 6 V using two external resistors and serves as a Zener replacement or error amplifier in isolated flyback SMPS feedback loops.

For engineers reviewing the TLV431BIDBVRG4 datasheet, TLV431BIDBVRG4 pinout, TLV431BIDBVRG4 application, or TLV431BIDBVRG4 equivalent, key selection criteria include reference accuracy over temperature (±6 mV from –40°C to 85°C), ultra-low 80 µA typical cathode current requirement, SC-70 package footprint (2.0 mm × 1.5 mm), and compatibility with optocoupler-based secondary-side regulation in 3.3 V systems.

Technical Context

The TLV431BIDBVRG4 implements a bandgap-referenced error amplifier driving an NPN Darlington sink output stage. Its internal reference is trimmed to 1.24 V ±0.5% at 25°C and exhibits 6 mV max deviation across –40°C to 85°C industrial range. The device operates open-loop as a comparator with integrated reference or closed-loop as a shunt regulator, requiring ≥55 µA minimum cathode current for regulation.

It features internal compensation for stability without an output capacitor, supports resistive feedback configurations, and delivers sharp turn-on characteristics due to active output circuitry. The SC-70 (DCK) package enables high-density PCB layouts while maintaining thermal resistance of 87°C/W junction-to-ambient.

Key Specifications

Pinout & Package

TLV431BIDBVRG4 is packaged in the ultra-small SC-70 (DCK) outline measuring 2.0 mm × 1.5 mm - 40% smaller than SOT-23-3 - with 6 pins and a substrate-connected pin requiring connection to ANODE or left open.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431BIDBVRG4, TLV431BIDBVT offers identical performance in a larger, simpler 3-pin package but forfeits thermal control via substrate connection; TLVH431AILPR extends voltage and current capability at the cost of accuracy and package size - making TLV431BIDBVRG4 optimal for compact, precision 3.3 V–5 V isolated regulation.

Availability

TLV431BIDBVRG4 is available at Aetrix Electronics and suitable for isolated flyback SMPS regulation, precision voltage monitoring, and Zener diode replacement requiring stable component supply, consistent parametric performance, and long-term manufacturability in industrial and computing applications.

Supply support for TLV431BIDBVRG4 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 delivering analog and embedded processing solutions, with leadership in precision analog, power management, and signal chain technologies.

The TLV431 family is designed for low-voltage, high-accuracy shunt regulation in space-constrained power systems - targeting secondary-side feedback in 3.3 V/5 V isolated DC/DC converters, voltage supervision, and comparator applications requiring integrated reference stability.

FAQ

What is the reference voltage tolerance of TLV431BIDBVRG4 at 25°C?

The TLV431BIDBVRG4 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal VREF with a min/max 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 only to the TLV431B grade - distinct from TLV431A (±1%) and TLV431 (±1.5%). The value is trimmed during production and verified per unit.

Can TLV431BIDBVRG4 operate with a cathode-anode voltage below 1.24 V?

No, TLV431BIDBVRG4 requires a minimum cathode-anode voltage (VKA) of 1.24 V to enter regulation - this is its reference voltage and absolute lower bound for functional operation. Below 1.24 V, the device remains in cutoff with off-state cathode current ≤0.1 µA. Operation at exactly 1.24 V is valid only if minimum cathode current (55 µA) is supplied, as confirmed in Section 5.3 Recommended Operating Conditions.

What is the purpose of Pin 2 (Substrate) on TLV431BIDBVRG4?

Pin 2 on TLV431BIDBVRG4 is the substrate connection, which must be either connected to the ANODE pin or left electrically floating - it must never be tied to ground, signal, or any other potential. This requirement is explicitly stated in Figure 4-5 and Table 4-1 of the datasheet to prevent latch-up and ensure thermal stability. Failure to follow this violates absolute maximum ratings and may cause permanent damage.

How does TLV431BIDBVRG4 achieve stability without an output capacitor?

TLV431BIDBVRG4 achieves intrinsic stability through internal compensation of its error amplifier stage, eliminating the need for an external cathode-to-anode capacitor. This is confirmed in Section 7.3 Feature Description, which states "unlike many linear regulators, TLV431 is internally compensated to be stable without an output capacitor." Stability boundaries versus capacitive load are quantified in Figures 5-19 to 5-21 for design verification when optional capacitance is added.

Is TLV431BIDBVRG4 pin-compatible with TL431 or TLVH431?

No, TLV431BIDBVRG4 is not pin-compatible with TL431 (SOT-23-3, 3-pin) or TLVH431 (SOT-89-3 or TO-92-3). TLV431BIDBVRG4 uses a 6-pin SC-70 (DCK) package with dedicated NC and substrate pins - physically and functionally distinct. Substitution requires PCB redesign. The datasheet explicitly lists TLVH431 as a separate product family with wider VKA range and alternate pinouts, confirming no mechanical or electrical interchangeability.