Nexperia USA Inc. TL431QDBZR-QR

Overview

TL431QDBZR-QR from Nexperia is a three-terminal adjustable precision shunt regulator with 0.5 % reference voltage tolerance (2483–2507 mV at 10 mA, 25 °C), 36 V cathode-anode voltage rating, and 1–100 mA sink current capability. It operates across –40 °C to +125 °C and is AEC-Q100 Grade 1 qualified for automotive feedback loops in isolated DC-DC converters.

For engineers reviewing the TL431QDBZR-QR datasheet, TL431QDBZR-QR pinout, TL431QDBZR-QR application, or TL431QDBZR-QR equivalent, key selection criteria include reference accuracy grade, thermal drift (±17 mV over –40 °C to +125 °C), dynamic impedance (0.2 Ω typical), off-state leakage (<0.5 μA), and SOT23 package compatibility with high-density PCB layouts.

Technical Context

The TL431QDBZR-QR implements an internal bandgap reference, error amplifier, and NPN output stage to regulate voltage via external resistor divider feedback at the REF pin. Its sharp turn-on characteristic and low output impedance enable precise shunt regulation without external compensation in most configurations.

It functions as a programmable 2.495 V reference with gain-controlled cathode current control - not a passive Zener - allowing stable operation from 2.495 V up to 36 V output. The device maintains <0.5 % initial Vref accuracy and supports isolated feedback topologies by referencing ground-referred signals to high-side outputs via optocoupler-coupled REF input.

Key Specifications

Pinout & Package

SOT23-3 plastic surface-mounted package (3.0 × 1.4 × 1.1 mm); standard pinning configuration per Table 3 and Figure 27.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDBZR-Q, TL431QDBZR-QR adds +125 °C operation and automotive qualification; compared with TL431BIDBZR-Q, it retains standard pinning and extends upper temperature limit by 40 °C - critical for engine bay placement.

Availability

TL431QDBZR-QR is available at Aetrix Electronics and suitable for automotive power conversion, precision current sinking, and isolated feedback loop design requiring stable component supply across extended temperature ranges.

Supply support for TL431QDBZR-QR 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

Nexperia is a global semiconductor expert focused on high-volume, high-reliability logic, analog, and discrete components, with core strengths in automotive-qualified parts and efficient manufacturing.

The TL431-Q family targets automotive and industrial power management applications, delivering AEC-Q100 qualified shunt regulation with grade-specific accuracy and extended temperature operation.

FAQ

What is the maximum cathode-anode voltage for continuous operation?

The TL431QDBZR-QR has a recommended maximum cathode-anode voltage of 36 V under normal operating conditions per Table 8. Its absolute maximum rating is 37 V (Table 6), but sustained operation above 36 V risks exceeding thermal limits and violating safe operating area constraints, especially at elevated ambient temperatures.

Does TL431QDBZR-QR require an external capacitor on the REF pin?

A 100 pF capacitor is recommended at the REF pin in isolated SMPS feedback applications (Figure 26) to suppress high-frequency noise coupling from the primary side. In non-isolated shunt regulator configurations, no capacitor is required - the device remains stable with purely resistive feedback due to its low reference input current and internal compensation.

How does the mirrored pinning variant differ from TL431QDBZR-QR?

TL431QDBZR-QR uses standard SOT23 pinning: Pin 1 = K (cathode), Pin 2 = REF, Pin 3 = A (anode). Mirrored variants like TL431BMFDT-Q swap Pins 1 and 2 (REF/K/A), making them incompatible without PCB layout revision. The marking code "CC%" confirms standard pinning for TL431QDBZR-QR per Table 5.

Can TL431QDBZR-QR replace a Zener diode directly?

Yes - TL431QDBZR-QR can replace Zener diodes in shunt regulation roles, but requires two external resistors to set output voltage and a minimum cathode current of 0.4 mA (typical) to maintain regulation. Unlike Zeners, it offers programmability, tighter tolerance, lower impedance, and guaranteed operation down to 2.495 V - enabling more accurate, lower-power designs.