Texas Instruments TLV431CDBVR

Overview

TLV431CDBVR from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, ±1.5% initial tolerance at 25°C, 0.25 Ω typical dynamic impedance, 80 µA typical minimum cathode current, and operation from 1.24 V to 6 V output range. It serves as a Zener replacement or error amplifier in isolated flyback SMPS feedback loops.

For engineers reviewing the TLV431CDBVR datasheet, TLV431CDBVR pinout, TLV431CDBVR application, or TLV431CDBVR equivalent, key selection factors include its SC-70 package footprint, temperature-stable 1.24 V reference, low IK(min) for low-power regulation, and compatibility with optocoupler-based secondary-side control in 3.3 V systems.

Technical Context

The TLV431CDBVR implements a bandgap-referenced transconductance amplifier driving a Darlington sink output stage. Its internal reference is trimmed to 1.24 V with ±1.5% accuracy at 25°C and exhibits 4 mV max drift over 0°C to 70°C - the commercial-grade temperature range for the 'C' suffix variant.

It operates in two distinct functional modes: open-loop comparator (with integrated 1.24 V threshold) and closed-loop shunt regulator (using external resistive feedback between cathode and reference pins). Stability is internally compensated, eliminating mandatory output capacitance but requiring attention to capacitive load when used with optocouplers.

Key Specifications

Pinout & Package

TLV431CDBVR is housed in an ultra-small SC-70 (DCK) package measuring 2.0 mm × 1.5 mm - 40% smaller than SOT-23-3 - with 6 terminals. Pin 1 is CATHODE, Pin 3 is REFERENCE, and Pin 6 is ANODE; Pins 2, 4, and 5 are no-connect (NC) or substrate tie points per TI's mechanical drawing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431CDBVR, TLV431ACDBVR offers improved accuracy for cost-sensitive commercial designs, while TLV431BIDBVR adds both tighter tolerance and extended temperature capability - making it suitable for harsher environments without altering PCB layout.

Availability

TLV431CDBVR 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 consistent parametric performance.

Supply support for TLV431CDBVR 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 as a low-voltage, low-power alternative to the TL431 for applications needing sub-2.5 V reference capability - targeting compact, efficient, and cost-effective voltage regulation in consumer, computing, and communications systems.

FAQ

What is the reference voltage tolerance of TLV431CDBVR at 25°C?

The TLV431CDBVR has a reference voltage tolerance of ±1.5% at 25°C, meaning its VREF falls between 1.222 V and 1.258 V under nominal conditions. This tolerance applies specifically to the 'C' grade variant and is confirmed in Section 5.5 of the TI datasheet SLVS139Z. The TLV431CDBVR maintains this specification across its commercial temperature range (0°C to 70°C).

Can TLV431CDBVR replace a standard Zener diode in a 3.3 V regulator?

Yes, TLV431CDBVR can directly replace a Zener diode in a 3.3 V shunt regulator configuration. With its 1.24 V reference and external resistor divider, it achieves precise 3.3 V output while offering far better temperature stability (4 mV drift over 0°C–70°C), lower dynamic impedance (0.25 Ω), and sharper turn-on than discrete Zeners. The TLV431CDBVR also eliminates Zener leakage and voltage spread issues common in low-voltage Zener families.

What is the minimum cathode current required for regulation in TLV431CDBVR?

The TLV431CDBVR requires a minimum cathode current (IK(min)) of 80 µA typical to maintain regulation, as specified in Section 5.5 of the datasheet. This value is valid across its full operating temperature range (0°C to 70°C). Supplying less than this may result in degraded regulation accuracy or loss of feedback control - especially critical in low-power or battery-operated TLV431CDBVR implementations.

Does TLV431CDBVR require an output capacitor for stability?

No, TLV431CDBVR does not require an output capacitor for basic stability due to internal compensation - a key advantage over many linear regulators. However, when used with optocouplers in isolated flyback topologies, capacitive loading on the cathode node can affect phase margin. Figure 5-19 in the TLV431CDBVR datasheet provides guidance for selecting safe capacitor values to avoid oscillation.

What package type is used for TLV431CDBVR and how many pins does it have?

TLV431CDBVR uses the SC-70 (DCK) package, a 6-pin surface-mount outline measuring 2.0 mm × 1.5 mm. Of the six terminals, only three are functional: Pin 1 (CATHODE), Pin 3 (REFERENCE), and Pin 6 (ANODE); Pins 2, 4, and 5 are no-connect (NC) or substrate ties. This ultra-compact package delivers 40% smaller footprint than SOT-23-3 while maintaining full TLV431CDBVR functionality.