Texas Instruments TLV431BCDBVR

Overview

TLV431BCDBVR 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 down to 1.24 V cathode-anode voltage. It delivers 0.25 Ω typical dynamic impedance, 80 µA typical minimum cathode current, and supports output voltage adjustment from 1.24 V to 6 V using two external resistors - widely used in isolated flyback secondary-side regulation for 3.3 V SMPS.

For engineers reviewing the TLV431BCDBVR datasheet, TLV431BCDBVR pinout, TLV431BCDBVR application, or TLV431BCDBVR equivalent, this page provides verified technical context, SC-70 package details, functional mode distinctions (open-loop comparator vs. closed-loop shunt regulation), real-world stability boundaries, and validated alternative options for voltage reference and error amplifier roles in power management circuits.

Technical Context

The TLV431BCDBVR implements a bandgap-referenced transconductance amplifier driving a Darlington sink output stage, enabling precise shunt regulation without external compensation. Its internal reference is trimmed to 1.24 V ±0.5% 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 reference and sharp turn-on; in closed-loop configuration with resistive feedback between cathode and reference pins, it acts as an adjustable shunt regulator or error amplifier - supporting stable operation up to 15 mA cathode current and compatible with optocoupler-based isolation schemes.

Key Specifications

Pinout & Package

TLV431BCDBVR is housed in an ultra-small SC-70 (DCK) package measuring 2.0 mm × 1.5 mm - 40% smaller footprint than SOT-23-3. The 6-pin configuration includes dedicated CATHODE, REF, ANODE, NC, and substrate connection terminals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431ACDBVR, TLV431BCDBVR offers tighter reference accuracy for high-precision feedback; compared with TLVH431IDBVR, it trades off voltage/current headroom for optimized low-voltage performance and lower quiescent current - making TLV431BCDBVR ideal for compact, battery-aware 3.3 V systems.

Availability

TLV431BCDBVR is available at Aetrix Electronics and suitable for isolated flyback regulation, voltage monitoring, and Zener replacement applications requiring stable component supply, consistent parametric performance, and long-term industrial availability.

Supply support for TLV431BCDBVR 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, power management, and signal chain solutions.

The TLV431 family was designed specifically for low-voltage, high-accuracy shunt regulation and reference applications - targeting space-constrained, energy-efficient power supplies and sensing interfaces in industrial, computing, and communications equipment.

FAQ

What is the reference voltage tolerance of TLV431BCDBVR at 25°C?

The TLV431BCDBVR has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal value with min/max bounds of 1.234 V and 1.246 V. This grade ('B') is confirmed in Section 5.7 of the TI datasheet SLVS139Z and distinguishes it from TLV431ACDBVR (±1%) and base TLV431 (±1.5%). TLV431BCDBVR maintains this precision across its specified operating temperature range.

Can TLV431BCDBVR replace a standard Zener diode in a 3.3 V regulator circuit?

Yes, TLV431BCDBVR is a direct, high-performance replacement for low-voltage Zener diodes in 3.3 V applications. With its 1.24 V reference, 0.25 Ω dynamic impedance, and adjustable output up to 6 V, it provides superior accuracy, lower temperature drift, and sharper turn-on than discrete Zeners. TLV431BCDBVR requires only two external resistors for voltage setting and operates reliably at cathode currents as low as 55 µA - far below typical Zener knee currents.

What is the correct pin configuration for TLV431BCDBVR in SC-70 (DCK) package?

TLV431BCDBVR in SC-70 (DCK) package has six pins: Pin 1 = CATHODE, Pin 2 = Substrate (connect to ANODE or leave open), Pin 3 = REF, Pin 4 = NC, Pin 5 = NC, Pin 6 = ANODE. This mapping is defined in Table 4-1 and Figure 4-5 of the TI datasheet SLVS139Z. Pins 4 and 5 are unconnected; Pin 2 must not be left floating without connection to ANODE due to substrate coupling requirements.

Does TLV431BCDBVR require an output capacitor for stability?

No, TLV431BCDBVR is internally compensated and does not require an output capacitor for basic shunt regulator stability. Its architecture allows stable operation with purely resistive feedback - unlike many op-amp-based references. However, if a capacitive load is added (e.g., for noise filtering), Figure 5-19 in the datasheet provides phase margin vs. capacitive load guidance to avoid oscillation, especially at higher cathode voltages (e.g., 5 V).

How does TLV431BCDBVR function in open-loop comparator mode?

In open-loop mode, TLV431BCDBVR compares voltage at the REF pin to its internal 1.24 V reference and sinks cathode current when REF exceeds that threshold - acting as a comparator with integrated reference. It requires ≥55 µA cathode current to maintain sufficient gain; output swings from ~1 V (low) to near V_KA (high, open-collector). TLV431BCDBVR is commonly used this way in overvoltage/undervoltage detection circuits without external components.