Texas Instruments TLVH431ACDCKT

Overview

TLVH431ACDCKT from Texas Instruments is a low-voltage adjustable precision shunt regulator in SC-70 package, providing 1.24 V reference voltage with ±0.5% initial tolerance at 25°C, 100 μA to 70 mA cathode current range, and operation from –40°C to +125°C. It serves as an integrated voltage reference and error amplifier in isolated flyback SMPS feedback loops, replacing Zener diodes in low-leakage on-board regulation.

For engineers reviewing the TLVH431ACDCKT datasheet, TLVH431ACDCKT pinout, TLVH431ACDCKT application, or TLVH431ACDCKT equivalent, key selection criteria include reference accuracy over temperature, minimum cathode current for regulation (100 μA), dynamic impedance (0.25 Ω), SC-70 footprint compatibility, and open-loop comparator functionality with built-in 1.24 V reference.

Technical Context

The TLVH431ACDCKT implements a precision bandgap reference and high-gain transconductance 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 between CATHODE and REF, enabling adjustable output voltage from 1.24 V to 18 V via two external resistors.

In open-loop mode, it functions as a comparator with integrated reference: the REF pin compares against the internal 1.24 V threshold, sinking cathode current when REF voltage exceeds that value. The device is internally compensated and stable without an output capacitor, though capacitive load stability depends on cathode voltage and load conditions per TI's phase margin curves.

Key Specifications

Pinout & Package

TLVH431ACDCKT is housed in a 6-pin SC-70 (DCK) package with 2.00 mm × 1.25 mm body size. Pin 2 is substrate-connected and must be tied to ANODE or left floating; pins 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 TLVH431BIDCKT and TLVH432ACDCKR, TLVH431ACDCKT uniquely combines Q-grade temperature range (–40°C to +125°C), SC-70 footprint, and standard TLVH431 pinout - making it the optimal choice for thermally demanding, space-constrained isolated power applications requiring guaranteed performance at maximum junction temperature.

Availability

TLVH431ACDCKT is available at Aetrix Electronics and suitable for isolated flyback SMPS design, low-voltage rail monitoring, and precision ADC reference applications requiring stable component supply and long-term manufacturability.

Supply support for TLVH431ACDCKT 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 and embedded processing solutions, with deep expertise in precision analog, power management, and signal chain technologies.

The TLVH431 family was designed specifically for low-voltage, high-accuracy shunt regulation in isolated power supplies and compact voltage-monitoring systems - addressing limitations of legacy TL431 devices in modern 1.8 V–3.3 V architectures.

FAQ

What is the minimum cathode current required for regulation in TLVH431ACDCKT?

The TLVH431ACDCKT 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 datasheet's Electrical Characteristics table under IK(min) for the Q-grade variant. Below this threshold, gain drops significantly, causing poor reference accuracy and unstable regulation behavior - especially critical in low-power optocoupler biasing.

Can TLVH431ACDCKT replace a standard Zener diode in low-leakage applications?

Yes, TLVH431ACDCKT is explicitly designed as a Zener diode replacement with superior performance: off-state cathode current is only 0.02–0.1 μA (vs. 1–10 μA for typical Zeners), dynamic impedance is 0.25 Ω (vs. 5–50 Ω), and temperature coefficient is <92 ppm/°C (vs. 500–2000 ppm/°C). Its SC-70 package also offers better thermal coupling and long-term stability than glass or plastic Zeners.

What is the function of Pin 2 (ANODE) in the TLVH431ACDCKT SC-70 package?

In TLVH431ACDCKT, Pin 2 is the ANODE terminal - the common reference node typically connected to ground or circuit return. Critically, it is also the substrate connection point and must either be tied directly to the ANODE net or left electrically floating. Leaving it unconnected or tying it elsewhere risks latch-up or parametric shift due to substrate bias effects.

How does TLVH431ACDCKT achieve stability without an output capacitor?

TLVH431ACDCKT incorporates internal frequency compensation, eliminating the need for an external cathode-to-anode capacitor in most configurations. Its open-loop gain rolls off predictably, and phase margin remains >45° across the 0.1–100 kHz range per Figure 5-11. However, with large capacitive loads (>10 nF), stability depends on cathode voltage - consult Figures 5-15 to 5-17 for safe CL limits at 1.25 V, 2.5 V, and 5 V VKA.

What distinguishes TLVH431ACDCKT from TLVH432ACDCKR?

TLVH431ACDCKT and TLVH432ACDCKR share identical electrical specifications and SC-70 packaging, but differ in pinout: TLVH431ACDCKT uses CATHODE–ANODE–REF (Pins 1–2–3), while TLVH432ACDCKR uses REF–CATHODE–ANODE. This makes them electrically compatible but mechanically incompatible - PCB layout must be redesigned to accommodate the swapped pin assignments.