Texas Instruments TLV431AIDBZR

Overview

TLV431AIDBZR from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, 1% initial tolerance at 25°C, and operation from 1.24 V to 6 V output range. It delivers 0.25 Ω typical dynamic impedance and 80 µA typical minimum cathode current, serving as a Zener diode replacement in isolated flyback SMPS feedback loops and on-board voltage monitoring circuits.

For engineers reviewing the TLV431AIDBZR datasheet, TLV431AIDBZR pinout, TLV431AIDBZR application, or TLV431AIDBZR equivalent, key selection considerations include its SC-70 (DCK) package footprint, temperature-stable 1.24 V reference, cathode current requirements for regulation, and open-loop comparator functionality with integrated reference.

Technical Context

The TLV431AIDBZR implements a three-terminal shunt-regulator architecture with an internal bandgap reference and high-gain NPN-based error amplifier driving a Darlington sink output stage. Its functional modes include closed-loop regulation (with resistive feedback from cathode to reference) and open-loop comparator operation (with reference pin driven externally).

It operates with ≥1.24 V cathode-to-anode voltage headroom and requires ≥55 µA cathode current for regulation across –40°C to 125°C (Q-grade), achieving ±4 mV reference drift over 0°C–70°C and maintaining stability without external compensation capacitors.

Key Specifications

Pinout & Package

TLV431AIDBZR uses the SC-70 (DCK) 6-pin package with substrate-connected pin 2. Pin 2 must be connected to the anode or left floating; pins 4 and 5 are no-connect (NC). The device has three active terminals: cathode (pin 1), reference (pin 3), and anode (pin 6).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431BIDBZR, TLV431AIDBZR trades 0.5% tolerance for lower cost in non-critical referencing; compared with TLVH431IDBVR, it offers smaller footprint and lower quiescent current but limited to 6 V and 15 mA cathode current - making it optimal for compact, low-voltage, cost-sensitive power supervision.

Availability

TLV431AIDBZR is available at Aetrix Electronics and suitable for isolated flyback SMPS design, voltage monitoring systems, and Zener-replacement bias networks requiring stable component supply and long-term manufacturability.

Supply support for TLV431AIDBZR 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 for industrial, automotive, and communications markets.

The TLV431x family was designed specifically as a low-voltage, low-power alternative to the TL431, targeting space-constrained and energy-efficient applications such as isolated DC/DC converters and precision voltage supervision.

FAQ

What is the reference voltage tolerance of TLV431AIDBZR at 25°C?

The TLV431AIDBZR has a reference voltage tolerance of ±1% at 25°C, meaning its 1.24 V nominal reference falls between 1.228 V and 1.252 V under standard test conditions. This tolerance is confirmed in Section 5.6 of the TI datasheet SLVS139Z and applies specifically to the TLV431A grade in the SC-70 package. TLV431AIDBZR maintains this specification across its rated operating temperature ranges.

Can TLV431AIDBZR be used as a comparator, and what are the key requirements?

Yes, TLV431AIDBZR can operate in open-loop comparator mode with integrated reference. Key requirements include supplying ≥55 µA cathode current, ensuring the reference pin voltage exceeds 1.24 V by ≥10% for fast response, and using a pull-up resistor on the cathode to define logic-high level. The TLV431AIDBZR's high open-loop gain and sharp turn-on make it suitable for undervoltage lockout and overvoltage detection without external components.

What is the minimum cathode current required for regulation in TLV431AIDBZR?

The TLV431AIDBZR requires a minimum cathode current of 55 µA to maintain regulation, as specified in Section 5.6 of the datasheet under IK(min) for TLV431AC/AI grades. This value holds across its full operating temperature range (–40°C to 125°C for Q-grade variants). Below this threshold, the device may exit regulation and exhibit degraded reference accuracy or delayed turn-on in comparator mode.

Does TLV431AIDBZR require an external compensation capacitor?

No, TLV431AIDBZR is internally compensated and does not require an external output capacitor for stability in standard shunt regulator configurations. Its architecture ensures phase margin >45° across load and capacitive conditions per Figure 5-19–5-21 in the datasheet. However, if large capacitive loads (>1 nF) are present at the cathode, stability analysis using those figures is recommended before final layout.

How does the SC-70 package of TLV431AIDBZR compare to SOT-23-3 in size and thermal performance?

The SC-70 (DCK) package of TLV431AIDBZR measures 2.0 mm × 1.5 mm, offering a 40% smaller footprint than the SOT-23-3 (2.92 mm × 2.37 mm). Thermally, its junction-to-ambient resistance (RθJA) is 87°C/W - significantly lower than SOT-23-3's 206°C/W - enabling higher power dissipation in compact layouts. Both packages share compatible solder reflow profiles, but TLV431AIDBZR's SC-70 requires fine-pitch placement capability.