Texas Instruments TLV431CDBZR

Overview

TLV431CDBZR from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, ±1.5% 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 TLV431CDBZR datasheet, TLV431CDBZR pinout, TLV431CDBZR application, or TLV431CDBZR equivalent, key selection considerations include its SC-70 package footprint, temperature-stable 1.24 V reference, low IK(min) requirement for low-power biasing, and compatibility with optocoupler-based feedback in 3.3 V and lower-output isolated power supplies.

Technical Context

The TLV431CDBZR operates as a 3-terminal adjustable shunt reference with an internal bandgap reference and high-gain NPN-based error amplifier. Its functional modes include open-loop comparator operation (with integrated 1.24 V threshold) and closed-loop shunt regulation via external resistor divider feedback between cathode and reference pins.

It achieves stable regulation without output capacitance due to internal compensation, and its cathode-anode voltage (VKA) range of 1.24 V–6 V enables use in low-voltage systems where legacy TL431 devices cannot operate. The device's 0.25 Ω dynamic impedance and sharp turn-on characteristic support precise voltage clamping and fast response in monitoring and error-amplifier roles.

Key Specifications

Pinout & Package

TLV431CDBZR uses the SC-70 (DCK) 6-pin package with 2.0 mm × 1.5 mm body size and gull-wing leads. Pin 1 is CATHODE, Pin 3 is ANODE, and Pin 6 is REFERENCE; Pins 2, 4, and 5 are no-connect (NC) terminals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431CDBZR, TLV431ACDBZR offers tighter initial accuracy without trade-offs in size or power, while TLVH431IDBVR trades SC-70 compactness for broader voltage/current capability-making it suitable only when TLV431CDBZR's 6 V/15 mA limits are exceeded.

Availability

TLV431CDBZR is available at Aetrix Electronics and suitable for isolated flyback SMPS regulation, precision voltage monitoring, and low-voltage Zener replacement requiring stable component supply across industrial, computing, and telecom end equipment.

Supply support for TLV431CDBZR 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 was designed specifically for low-voltage, high-accuracy shunt regulation and integrated reference applications-targeting space-constrained, energy-efficient power supplies and intelligent sensing systems.

FAQ

What is the reference voltage tolerance of TLV431CDBZR at 25°C?

The TLV431CDBZR has a reference voltage tolerance of ±1.5% at 25°C, corresponding to a VREF range of 1.21 V to 1.27 V. This tolerance is specified in the Electrical Characteristics table for TLV431C grade devices and applies under standard test conditions (VKA = VREF, IK = 10 mA). The TLV431CDBZR part number explicitly denotes the "C" grade, confirming this 1.5% specification.

Can TLV431CDBZR be used in place of a Zener diode?

Yes, TLV431CDBZR functions as an active, adjustable Zener diode replacement with superior performance: it offers 0.25 Ω dynamic impedance (vs. 10–100 Ω for typical Zeners), ±1.5% initial accuracy (vs. ±5% for standard Zeners), and sharp turn-on behavior. Unlike passive Zeners, TLV431CDBZR requires only 80 µA minimum cathode current and supports output voltages from 1.24 V to 6 V via external resistors-enabling precise, low-power clamping in modern low-voltage systems.

What is the operating temperature range for TLV431CDBZR?

The TLV431CDBZR is rated for operation from 0°C to 70°C (commercial temperature range), as indicated by the "C" suffix in its part number. Its reference voltage deviation over this full range is guaranteed at ≤12 mV, and minimum cathode current remains ≤80 µA. This range is validated per TI's SLVS139Z datasheet and aligns with the TLV431C grade specifications in Section 5.5.

Does TLV431CDBZR require an output capacitor for stability?

No, TLV431CDBZR does not require an output capacitor for basic stability-it is internally compensated and operates stably without one across its full operating range. However, if an output capacitor is added (e.g., for noise filtering), Figure 5-19 in the TI datasheet provides phase margin vs. capacitive load guidance to avoid oscillation. Stability boundaries depend on VKA and load conditions, but the core design eliminates mandatory external capacitance-a key advantage over many op-amp-based references.

How is the output voltage set for TLV431CDBZR in shunt regulator configuration?

The output voltage of TLV431CDBZR is set using two external resistors (R1 and R2) in a voltage divider between cathode and anode, with the reference pin connected to the divider midpoint. The formula is VO = VREF × (1 + R1/R2) + Iref × R1, where VREF = 1.24 V and Iref ≤ 0.5 µA. For most designs, the Iref × R1 term is negligible, yielding VO ≈ 1.24 V × (1 + R1/R2). This allows precise adjustment from 1.24 V up to 6 V while maintaining regulation with ≥80 µA cathode current.