Texas Instruments TLV431ACDBZR

Overview

TLV431ACDBZR 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, 80 µA typical minimum cathode current, and supports secondary-side regulation in isolated flyback SMPSs.

For engineers reviewing the TLV431ACDBZR datasheet, TLV431ACDBZR pinout, TLV431ACDBZR application, or TLV431ACDBZR equivalent, this page provides verified electrical parameters, SC-70 package details, functional mode distinctions (open-loop comparator vs. closed-loop shunt regulator), and real-world design implications for voltage monitoring and Zener replacement.

Technical Context

The TLV431ACDBZR implements a bandgap-referenced NPN-based error amplifier with internal Darlington sink output, enabling precise voltage regulation via external resistor feedback between cathode and reference pins. Its architecture supports both open-loop comparator operation (with integrated 1.24 V threshold) and closed-loop shunt regulation without requiring external compensation capacitors.

It operates with ≥1.24 V cathode-to-anode voltage headroom and requires ≥55 µA cathode current for regulation across its full temperature range (–40°C to 85°C for TLV431AI variant). The device exhibits 4 mV max reference drift over 0°C to 70°C and 6 mV over –40°C to 85°C, with 0.15–0.5 µA reference terminal current.

Key Specifications

Pinout & Package

TLV431ACDBZR is housed in an ultra-small SC-70 (DCK) package measuring 2.0 mm × 1.5 mm - 40% smaller footprint than SOT-23-3 - with thermal resistance R_θJA = 87°C/W and R_θJC(top) = 259°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431BIDBZR, TLV431ACDBZR trades 0.5% tolerance for lower unit cost and identical thermal performance; compared with TLVH431ACDBVR, it offers smaller SC-70 footprint and lower quiescent current but limits maximum cathode voltage to 6 V.

Availability

TLV431ACDBZR is available at Aetrix Electronics and suitable for isolated flyback SMPS regulation, voltage monitoring circuits, Zener diode replacement, and comparator-based threshold detection requiring stable component supply and guaranteed long-term sourcing.

Supply support for TLV431ACDBZR 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-constrained and energy-efficient applications - including isolated DC/DC converters, battery monitors, and portable electronics.

FAQ

What is the reference voltage tolerance of TLV431ACDBZR at 25°C?

The TLV431ACDBZR has a reference voltage tolerance of ±1% at 25°C, meaning its V_REF falls within 1.228 V to 1.252 V under nominal conditions. This is confirmed in Section 5.6 of the TI datasheet SLVS139Z. The 'A' suffix denotes the 1% grade, distinct from the 0.5% TLV431B and 1.5% base TLV431 variants. TLV431ACDBZR maintains this specification across its SC-70 package variant.

Can TLV431ACDBZR operate with a cathode voltage below 1.24 V?

No - TLV431ACDBZR requires a minimum cathode-to-anode voltage (V_KA) of 1.24 V to enter regulation. Below this threshold, the internal amplifier cannot bias correctly and the device remains in cutoff. The datasheet specifies V_KA ≥ V_REF (1.24 V) in Recommended Operating Conditions (Section 5.3), and Figure 5-4 confirms zero cathode current below 1.24 V. TLV431ACDBZR is not functional as a sub-1.24 V reference.

What is the minimum cathode current required for regulation in TLV431ACDBZR?

TLV431ACDBZR requires a minimum cathode current (I_K(min)) of 55 µA to maintain regulation at room temperature, rising to 80 µA across its full operating range of –40°C to 85°C. This value is specified in Section 5.6 (Electrical Characteristics for TLV431A) of the datasheet. Supplying less than 55 µA risks loss of regulation accuracy and increased output impedance - critical in low-power battery applications where TLV431ACDBZR is commonly deployed.

Does TLV431ACDBZR require an external output capacitor for stability?

No - TLV431ACDBZR is internally compensated and stable without an external output capacitor between cathode and anode. This is explicitly stated in Section 7.3 ("Feature Description") of the datasheet. While capacitive loads up to 1 nF can be tolerated (per Figure 5-19), adding a capacitor is unnecessary for basic shunt regulation and may degrade transient response. TLV431ACDBZR's 0.25 Ω dynamic impedance inherently provides sufficient phase margin in standard feedback configurations.

How does TLV431ACDBZR differ from TL431 in practical design?

TLV431ACDBZR differs from TL431 primarily in three ways: (1) lower 1.24 V reference voltage (vs. 2.5 V), enabling use in 1.8 V–3.3 V systems; (2) lower 80 µA typical minimum cathode current (vs. 1 mA for TL431), improving efficiency in low-power designs; and (3) SC-70 packaging (vs. TO-92 or SOIC), reducing footprint by >60%. These differences make TLV431ACDBZR the preferred choice for modern compact, low-voltage power supplies where TL431 cannot operate.