Texas Instruments TLV431BCDBZTG4

Overview

TLV431BCDBZTG4 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, 0.5% initial tolerance at 25°C, and operation down to 1.24 V cathode-anode voltage. It delivers 0.25 Ω typical dynamic impedance, 80 µA typical minimum cathode current, and supports output voltage adjustment from 1.24 V to 6 V using two external resistors-ideal for secondary-side regulation in isolated 3.3 V flyback SMPSs.

For engineers reviewing the TLV431BCDBZTG4 datasheet, TLV431BCDBZTG4 pinout, TLV431BCDBZTG4 application, or TLV431BCDBZTG4 equivalent, key selection criteria include reference accuracy over temperature (±4 mV from 0°C to 70°C), ultra-small SC-70 package footprint, open-loop comparator capability with integrated reference, and compatibility with optocoupler-based feedback loops in space-constrained power supplies.

Technical Context

The TLV431BCDBZTG4 implements a three-terminal shunt-regulator architecture with an internal bandgap reference and NPN-based error amplifier driving a Darlington sink output stage. Its functional modes include closed-loop regulation (shunt reference/error amplifier) and open-loop comparator operation-both requiring ≥55 µA cathode current for stable gain.

It operates without external compensation due to internal frequency compensation, supports cathode voltages from 1.24 V to 6 V, and maintains <0.25 Ω dynamic impedance across 0.1 mA–15 mA cathode current range at ≤1 kHz. The device is specified for 0°C to 70°C ambient (TLV431BC grade) and features 2000 V HBM ESD rating.

Key Specifications

Pinout & Package

TLV431BCDBZTG4 is housed in a 6-pin SC-70 (DCK) package with 2.0 mm × 1.5 mm body size and gull-wing leads. Pin 1 is CATHODE, Pin 3 is REFERENCE, and Pin 6 is ANODE; Pins 2, 4, and 5 are NC (no internal connection).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431ACDBZTG4, TLV431BCDBZTG4 provides tighter reference accuracy for precision regulation; compared with TLVH431ACDBZR, it offers smaller footprint and lower power consumption but sacrifices voltage range and current drive-making TLV431BCDBZTG4 optimal for space-constrained, low-voltage, high-accuracy shunt regulation.

Availability

TLV431BCDBZTG4 is available at Aetrix Electronics and suitable for isolated flyback SMPSs, voltage monitoring circuits, and low-voltage Zener replacement applications requiring stable component supply, consistent parametric performance, and long-term manufacturability.

Supply support for TLV431BCDBZTG4 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 personal electronics markets.

The TLV431 family was designed as a low-voltage, precision alternative to the TL431 for applications demanding 1.24 V reference, ultra-low cathode current, and compact packaging-targeting isolated power supplies, portable devices, and space-constrained embedded systems.

FAQ

What is the reference voltage tolerance of TLV431BCDBZTG4 at 25°C?

The TLV431BCDBZTG4 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal reference with a range of 1.234 V to 1.246 V. This tight tolerance is confirmed in Section 5.7 of the TI datasheet and applies specifically to the 'B' grade variant in the TLV431BC temperature grade (0°C to 70°C). TLV431BCDBZTG4 maintains this specification across its full operating temperature range with ±4 mV deviation.

Can TLV431BCDBZTG4 replace a standard Zener diode?

Yes, TLV431BCDBZTG4 can directly replace low-voltage Zener diodes (1.24 V to 6 V range) with significant advantages: it offers 0.25 Ω dynamic impedance versus typical Zener values >10 Ω, ±0.5% initial tolerance versus 5% for standard Zeners, and ±4 mV temperature drift over 0°C–70°C. Unlike Zeners, TLV431BCDBZTG4 requires no minimum current to regulate and provides sharp turn-on characteristics due to its active amplifier architecture.

What is the minimum cathode current required for regulation in TLV431BCDBZTG4?

The TLV431BCDBZTG4 requires a minimum cathode current of 55 µA to maintain regulation, as specified in Section 5.7 of the TI datasheet under IK(min) for TLV431B grade. This value is typical at 25°C and increases to 80 µA maximum across the full 0°C–70°C operating range. Operation below this threshold results in degraded gain and unstable regulation behavior.

Which package does TLV431BCDBZTG4 use, and how does it compare to SOT-23-3?

TLV431BCDBZTG4 uses the SC-70 (DCK) package-a 6-pin gull-wing surface-mount package measuring 2.0 mm × 1.5 mm. It is 40% smaller in footprint than the SOT-23-3 package (2.92 mm × 2.37 mm), enabling higher component density. Though pin-count differs, TLV431BCDBZTG4's SC-70 pinout (CATHODE–REF–NC–NC–NC–ANODE) is functionally compatible with 3-pin variants when unused pins are left unconnected per TI layout guidelines.

Does TLV431BCDBZTG4 require an external output capacitor for stability?

No, TLV431BCDBZTG4 does not require an external output capacitor for stability because it is internally compensated, as stated in Section 7.3 of the TI datasheet. This allows direct cathode-to-anode connection in most shunt regulator configurations. However, if an output capacitor is used (e.g., for noise filtering), Figure 5-19 in the datasheet provides phase margin vs capacitive load curves to ensure stability-particularly important when driving capacitive loads >1 nF.