Texas Instruments TLVH431ACDBVT

Overview

TLVH431ACDBVT from Texas Instruments is a low-voltage adjustable precision shunt regulator in SOT-23-3 (DBZ) package, functioning as a 1.24 V reference with 1% initial tolerance at 25°C, 100 μA minimum cathode current for regulation, 0.25 Ω typical dynamic impedance, and operation from –40°C to +125°C. It replaces Zener diodes in secondary-side feedback of isolated 3.3 V flyback SMPSs.

For engineers reviewing the TLVH431ACDBVT datasheet, TLVH431ACDBVT pinout, TLVH431ACDBVT application, or TLVH431ACDBVT equivalent, key selection criteria include reference voltage accuracy over temperature, cathode current range (100 μA–70 mA), output impedance stability, open-loop comparator capability, and compatibility with optocoupler-based isolated regulation circuits.

Technical Context

The TLVH431ACDBVT implements a precision bandgap reference (1.24 V) paired with a high-gain NPN-based error amplifier and Darlington sink output stage. Its internal architecture enables stable closed-loop shunt regulation or open-loop comparator operation without external compensation.

It operates with cathode-to-anode voltage from 1.24 V to 18 V and supports two functional modes: closed-loop regulation (via resistive divider feedback from cathode to REF) and open-loop threshold detection (REF referenced to external signal). Thermal drift is specified at ±31 mV over –40°C to +125°C for the Q-grade variant.

Key Specifications

Pinout & Package

SOT-23-3 (DBZ) package: 2.92 mm × 1.30 mm body, 3-pin surface-mount, gull-wing leads, anode-connected substrate.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431ACDBVT, TLVH431BCDBVT offers higher initial accuracy without trade-offs in temperature drift or current range, while TLVH432ACDBVT provides identical performance in a mechanically incompatible pinout-making the former a direct upgrade and the latter a layout-dependent alternative.

Availability

TLVH431ACDBVT is available at Aetrix Electronics and suitable for isolated SMPS feedback, precision ADC references, power-rail monitoring, and Zener-replacement circuits requiring stable component supply across automotive, industrial, and telecom end equipment.

Supply support for TLVH431ACDBVT 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 specializing in analog, embedded processing, and power management ICs, with decades of expertise in precision reference and power control solutions.

The TLVH431 family was designed specifically for low-voltage, high-accuracy shunt regulation in space-constrained and thermally demanding applications-including isolated DC-DC converters, battery monitors, and sensor signal chains.

FAQ

What is the minimum cathode current required for regulation in TLVH431ACDBVT?

The TLVH431ACDBVT requires a minimum cathode current of 100 μA to maintain regulation across its full operating temperature range (–40°C to +125°C). This value is specified in the Electrical Characteristics table under IK(min) and is critical for ensuring stable reference voltage output in low-power designs such as battery-backed systems or always-on monitoring circuits. Below this threshold, the device may exit regulation and exhibit increased VREF deviation.

Can TLVH431ACDBVT replace a standard Zener diode in a 3.3 V rail clamp application?

Yes, TLVH431ACDBVT can directly replace a 3.3 V Zener diode with significant advantages: it provides 1% initial accuracy (vs. ±5% typical for Zeners), 0.25 Ω dynamic impedance (vs. 10–100 Ω for Zeners), and off-state cathode current ≤0.1 μA (vs. >10 μA for most Zeners). In a rail clamp configuration, connect CATHODE to the 3.3 V rail, ANODE to ground, and REF to a resistor divider setting VOUT = 3.3 V. No external op-amp or reference is needed.

What is the pin configuration of TLVH431ACDBVT and how does it differ from TLVH432 variants?

TLVH431ACDBVT uses SOT-23-3 (DBZ) package with Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF. This differs from TLVH432ACDBVT, which has Pin 1 = REF, Pin 2 = CATHODE, Pin 3 = ANODE. The pinout reversal means TLVH432 variants are not physically or electrically interchangeable without PCB modification. Always verify pin mapping using Figure 4-4 (TLVH431 DBZ) and Figure 4-5 (TLVH432 DBZ) in the official datasheet.

Does TLVH431ACDBVT require an output capacitor for stability?

No, TLVH431ACDBVT is internally compensated and remains stable without an output capacitor between CATHODE and ANODE - a key advantage over many op-amp-based references. However, if an output capacitor is added (e.g., for noise filtering), stability depends on capacitive load value and cathode voltage; Figures 5-15 through 5-17 in the datasheet provide phase-margin guidance for 1.25 V, 2.5 V, and 5 V operating points to avoid oscillation.

What temperature range is guaranteed for TLVH431ACDBVT?

TLVH431ACDBVT is rated for operation from –40°C to +125°C (Q-grade), with all electrical specifications - including VREF tolerance, dynamic impedance, and cathode current limits - guaranteed across this full industrial and automotive junction temperature range. This is confirmed in Section 5.3 Recommended Operating Conditions and Table 5.5 TLVH43x Electrical Characteristics, where "TLVH431AQ" denotes the Q-grade variant used in the ACDBVT ordering code.