Texas Instruments TLV431CDBVT

Overview

TLV431CDBVT 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 3.3 V systems.

For engineers reviewing the TLV431CDBVT datasheet, TLV431CDBVT pinout, TLV431CDBVT application, or TLV431CDBVT equivalent, key selection criteria include reference accuracy over 0°C to 70°C, ultra-small SC-70 package footprint, low cathode current requirement, and stability without external compensation in closed-loop configurations.

Technical Context

The TLV431CDBVT implements a 3-terminal adjustable shunt reference architecture with an internal bandgap reference and NPN-based error amplifier driving a Darlington sink output stage. Its open-loop comparator mode enables voltage monitoring with integrated 1.24 V threshold, while closed-loop operation with resistive feedback achieves precise voltage or current regulation.

It operates with ≥1.24 V cathode-to-anode voltage (VKA), requires ≥55 µA cathode current for regulation, and maintains stable performance across 0°C to 70°C ambient temperature. The device is internally compensated and does not require an output capacitor for stability in standard shunt regulator configurations.

Key Specifications

Pinout & Package

TLV431CDBVT is housed in a 6-pin SC-70 (DCK) package measuring 2.0 mm × 1.5 mm - 40% smaller than SOT-23-3 - with exposed substrate pad requiring connection to ANODE or left floating per TI specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431ACDBVT, TLV431CDBVT trades 0.5% accuracy for lower cost in commercial-temperature applications; versus TLVH431IDBVR, it offers smaller SC-70 size and lower IQ but sacrifices voltage headroom and current capacity.

Availability

TLV431CDBVT is available at Aetrix Electronics and suitable for isolated flyback SMPSs, voltage monitoring circuits, Zener replacement designs, and comparator-based threshold detection requiring stable component supply and commercial-temperature grade performance.

Supply support for TLV431CDBVT 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 TLV431x family was designed specifically for low-voltage, low-power shunt regulation and integrated reference applications in space-constrained industrial, computing, and telecom power systems.

FAQ

What is the reference voltage tolerance of TLV431CDBVT at 25°C?

The TLV431CDBVT has a reference voltage tolerance of ±1.5% at 25°C, corresponding to a VREF range of 1.222 V to 1.258 V. This tolerance applies specifically to the 'C' grade variant and is confirmed in Section 5.5 of the TI SLVS139Z datasheet. TLV431CDBVT maintains this specification across its rated 0°C to 70°C operating temperature range.

Which package type does TLV431CDBVT use, and what are its dimensions?

TLV431CDBVT uses the SC-70 (DCK) package, a 6-pin surface-mount outline measuring 2.0 mm × 1.5 mm. Per TI's Package Information table, this footprint is 40% smaller than SOT-23-3. Pin 2 is the substrate connection and must be tied to ANODE or left open; pins 4 and 5 are NC. The DCK package is explicitly listed for TLV431B variants including TLV431CDBVT in the official orderable addendum.

Can TLV431CDBVT replace a standard Zener diode, and what advantages does it offer?

Yes, TLV431CDBVT is widely used as a Zener diode replacement. It provides superior performance: 0.25 Ω typical dynamic impedance versus >10 Ω for discrete Zeners, ±1.5% initial tolerance versus ±5% for common Zeners, and sharp turn-on characteristics enabled by active amplification. Unlike passive Zeners, TLV431CDBVT regulates down to 1.24 V and supports adjustable outputs up to 6 V using two external resistors-making it ideal for modern low-voltage rails.

What is the minimum cathode current required for regulation in TLV431CDBVT?

The TLV431CDBVT requires a minimum cathode current (IK(min)) of 55 µA to 80 µA to maintain regulation, as specified in Section 5.5 of the datasheet for the TLV431C grade. This low current requirement enables use in ultra-low-power applications such as battery-backed monitoring circuits or standby-mode power supplies where traditional shunt regulators would draw excessive quiescent current.

Does TLV431CDBVT require an external output capacitor for stability in shunt regulator configurations?

No, TLV431CDBVT is internally compensated and does not require an external output capacitor between CATHODE and ANODE for stability in standard closed-loop shunt regulator configurations. This is explicitly stated in Section 7.3 of the datasheet. However, if an output capacitor is added for filtering, Figure 5-19 provides phase margin vs capacitive load data to ensure stability-particularly important when driving capacitive loads exceeding 1 nF.