Texas Instruments TLVH431AQDCKR

Overview

TLVH431AQDCKR from Texas Instruments is a low-voltage adjustable precision shunt regulator in SC-70 package, functioning as a 1.24 V reference with ±0.5% initial tolerance at 25°C, 100 μA minimum cathode current for regulation, and 0.25 Ω typical dynamic impedance. It enables precise voltage monitoring and secondary-side regulation in isolated 3.3 V flyback SMPS designs.

For engineers reviewing the TLVH431AQDCKR datasheet, TLVH431AQDCKR pinout, TLVH431AQDCKR application, or TLVH431AQDCKR equivalent, key selection factors include its 1.24 V reference accuracy over –40°C to +125°C, ultra-small SC-70 footprint (2.00 mm × 1.25 mm), and compatibility with optocoupler-based feedback loops requiring stable low-voltage references.

Technical Context

The TLVH431AQDCKR 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 cathode current exceeds 100 μA and cathode-to-anode voltage is ≥1.24 V, enabling closed-loop regulation via external resistor dividers.

It operates in two distinct functional modes: open-loop comparator mode (with integrated 1.24 V threshold) and closed-loop shunt regulator mode (with error amplification and sink-current output). Unlike linear regulators, it requires no external compensation capacitor for stability across its full 100 μA–70 mA cathode current range.

Key Specifications

Pinout & Package

TLVH431AQDCKR uses the 6-pin SC-70 (DCK) package with nominal body size 2.00 mm × 1.25 mm. 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 TLVH431AQDCKR, TLVH431ACDCKR trades 0.5% accuracy for cost savings in non-critical applications, while TLVH432AQDBVR offers identical performance in a thermally superior but mechanically incompatible SOT-23-5 package-neither is pin-compatible, requiring layout revision for substitution.

Availability

TLVH431AQDCKR is available at Aetrix Electronics and suitable for automotive power management, industrial sensor signal conditioning, and compact DC-DC converter designs requiring stable component supply across extended temperature ranges.

Supply support for TLVH431AQDCKR 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 for industrial, automotive, and communications markets.

The TLVH431 product line delivers low-voltage, high-accuracy shunt references optimized for isolated power supply feedback, precision voltage monitoring, and comparator functions in space-constrained and thermally demanding environments.

FAQ

What is the reference voltage tolerance of TLVH431AQDCKR at 25°C?

The TLVH431AQDCKR has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 1.24 V nominal value with a range of 1.234 V to 1.246 V. This B-grade accuracy is specified in Section 5.7 of the TI datasheet SLVS555N and applies exclusively to the 'Q' temperature grade (–40°C to +125°C) variant. The TLVH431AQDCKR maintains this tolerance across its full operating temperature range with a maximum deviation of ±31 mV.

Can TLVH431AQDCKR operate with cathode-to-anode voltage below 2.5 V?

Yes, TLVH431AQDCKR is specifically designed for low-voltage operation starting at 1.24 V cathode-to-anode voltage, unlike the TL431 which requires ≥2.5 V. It regulates stably down to its reference voltage (1.24 V) with ≥100 μA cathode current, making it suitable for 1.8 V, 2.5 V, and 3.3 V systems. This capability is confirmed in the "Low-voltage operation" feature list and Figure 5-3 of the TLVH431AQDCKR datasheet.

What is the purpose of Pin 2 on the TLVH431AQDCKR SC-70 package?

Pin 2 on the TLVH431AQDCKR is the substrate connection, internally tied to the ANODE terminal. Per TI's Pin Functions table and Figure 4-2, it must be connected to the ANODE net on the PCB or left electrically floating-never left unconnected or tied to a different potential. This connection ensures proper thermal conduction and prevents latch-up in the Darlington output stage, directly impacting long-term reliability in high-temperature operation.

How does TLVH431AQDCKR differ from TLVH432AQDCKR?

The TLVH431AQDCKR and TLVH432AQDCKR share identical electrical specifications, temperature ratings, and SC-70 packaging, but differ in pinout configuration: TLVH431AQDCKR places REF on Pin 3 and ANODE on Pin 2, while TLVH432AQDCKR swaps these (REF on Pin 2, ANODE on Pin 3). This difference is explicitly stated in the "TLVH432 provides alternative pinouts" feature and Figure 4-5, making them functionally equivalent but not pin-compatible replacements.

Is an external capacitor required for stability with TLVH431AQDCKR?

No, TLVH431AQDCKR is internally compensated and stable without an external output capacitor between CATHODE and ANODE under standard operating conditions (100 μA–70 mA cathode current). However, if capacitive loading is introduced-such as in optocoupler-driven feedback loops-Figures 5-15 through 5-17 in the datasheet provide phase-margin guidance for selecting appropriate capacitor values to maintain stability across varying VKA and temperature conditions.