Texas Instruments TLVH431BCDBZTG4

Overview

TLVH431BCDBZTG4 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 0.5% initial reference voltage tolerance at 25°C, 1.24 V nominal reference voltage, and operation down to 1.24 V cathode-anode voltage. It delivers stable regulation across –40°C to +125°C, supports cathode current from 100 μA to 70 mA, and features 0.25 Ω typical dynamic impedance-enabling accurate secondary-side feedback in isolated 3.3 V flyback SMPS designs.

For engineers reviewing the TLVH431BCDBZTG4 datasheet, TLVH431BCDBZTG4 pinout, TLVH431BCDBZTG4 application, or TLVH431BCDBZTG4 equivalent, key selection considerations include its B-grade (0.5%) reference accuracy, SOT-23-3 (DBZ) package pin compatibility with TLVH432 variants, ultra-low minimum cathode current requirement, and verified stability without output capacitance in closed-loop shunt configurations.

Technical Context

The TLVH431BCDBZTG4 implements a precision bandgap reference and high-gain NPN-based error amplifier in a 3-terminal shunt topology. Its internal architecture forces the REF pin to 1.24 V when sufficient cathode current (≥100 μA) flows and feedback is applied, enabling adjustable output voltage from 1.24 V to 18 V via two external resistors.

Unlike the TL431, it operates at lower headroom (down to 1.24 V), achieves sharper turn-on due to active output circuitry, and maintains thermal stability over industrial and automotive temperature ranges (–40°C to +125°C). The DBZ package variant uses CATHODE–REF–ANODE pinout (Pin 1–2–3), distinct from TLVH432's REF–CATHODE–ANODE arrangement.

Key Specifications

Pinout & Package

SOT-23-3 (DBZ) package: 2.92 mm × 1.30 mm body, gull-wing leads, JEDEC MO-178AC compliant. Pin 1 = CATHODE, Pin 2 = REF, Pin 3 = ANODE. Anode is common terminal, typically connected to system ground or return path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431ACDBZTG4 and TLVH432BCDBZTG4, TLVH431BCDBZTG4 offers the tightest initial reference accuracy in the standard DBZ pinout configuration-making it optimal for high-precision feedback paths where layout reuse and minimal calibration effort are priorities.

Availability

TLVH431BCDBZTG4 is available at Aetrix Electronics and suitable for secondary-side SMPS regulation, precision voltage monitoring, and adjustable reference generation requiring stable component supply across automotive, industrial, and telecom end equipment.

Supply support for TLVH431BCDBZTG4 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 leader delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, precision, and power efficiency.

The TLVH431 family was designed specifically for low-voltage, high-accuracy shunt regulation in isolated power supplies and precision analog systems-addressing limitations of legacy TL431 devices in modern low-voltage architectures.

FAQ

What is the reference voltage tolerance of TLVH431BCDBZTG4 at 25°C?

The TLVH431BCDBZTG4 has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal V_REF with min/max values of 1.234 V and 1.246 V. This B-grade precision is confirmed in Section 5.7 of the TI datasheet SLVS555N and applies specifically to the BC (commercial) and BI (industrial) temperature variants. TLVH431BCDBZTG4 maintains this tolerance across its rated operating range.

Does TLVH431BCDBZTG4 require an output capacitor for stability?

No, TLVH431BCDBZTG4 is internally compensated and remains stable without an output capacitor between cathode and anode. This is explicitly stated in Section 7.3 of the datasheet and validated in Figure 5-15 through 5-17 for capacitive loads up to 10 nF. Adding a capacitor is optional and only recommended for specific noise-reduction or phase-margin tuning scenarios-not for basic stability.

What is the minimum cathode current required for regulation in TLVH431BCDBZTG4?

The minimum cathode current (I_K(min)) for regulation in TLVH431BCDBZTG4 is 100 μA at 25°C, with a maximum of 120 μA over the full –40°C to +125°C range. This value is specified in Sections 5.5–5.7 and enables operation in ultra-low-power applications such as battery voltage supervisors and energy-harvesting circuits where current budgets are constrained.

How does the pinout of TLVH431BCDBZTG4 differ from TLVH432 variants?

TLVH431BCDBZTG4 uses a CATHODE–REF–ANODE pinout (Pin 1–2–3) in the SOT-23-3 (DBZ) package, whereas TLVH432BCDBZTG4 uses REF–CATHODE–ANODE (Pin 1–2–3). This difference is documented in Figures 4-4 and 4-5 of the datasheet and means the two are not pin-compatible-direct substitution requires PCB layout revision to avoid functional failure.

Can TLVH431BCDBZTG4 replace a Zener diode in low-leakage applications?

Yes, TLVH431BCDBZTG4 serves as a high-performance Zener replacement with off-state cathode current (I_K(off)) as low as 0.02 μA at 18 V and sharp turn-on characteristics. Its active circuitry provides lower leakage, tighter voltage tolerance, and better temperature stability than discrete Zeners-making it ideal for voltage clamping, threshold detection, and on-board regulation where leakage current must be minimized.