Diodes Incorporated ZTL431BE5TA

Overview

ZTL431BE5TA from Diodes Incorporated is a 0.5%-tolerance, adjustable precision shunt regulator in SOT25 package, delivering 2.5V reference voltage with ±0.013V initial accuracy at +25°C, 0.2Ω typical dynamic output impedance, and 1mA–100mA sink current capability; used for voltage regulation, opto-coupler linearization, and overvoltage protection in industrial power supplies.

For engineers reviewing the ZTL431BE5TA datasheet, ZTL431BE5TA pinout, ZTL431BE5TA application, or ZTL431BE5TA equivalent, key selection criteria include reference voltage tolerance (0.5% B-grade), cathode voltage range (2.5–20V), thermal stability (−40°C to +125°C), and SOT25 package compatibility with high-density PCB layouts.

Technical Context

The ZTL431BE5TA operates as a three-terminal programmable shunt regulator where the reference input (REF) senses voltage via external resistor dividers, the anode (A) connects to ground or low-side return, and the cathode (K) sinks regulated current into the supply rail. Its internal bandgap reference and error amplifier enable precise feedback control without external op-amps.

It achieves stable regulation across −40°C to +125°C ambient temperature with ≤34mV reference deviation over full range, <2.5μA reference input current variation, and maintains <0.5Ω dynamic output impedance up to 100kHz-critical for closed-loop feedback in isolated DC-DC converters and voltage monitors.

Key Specifications

Pinout & Package

SOT25 (5-pin SC-74A) package with exposed thermal pad; compact 2.8mm × 2.9mm footprint, 1.1mm height, and 0.95mm pitch; optimized for thermal dissipation up to 500mW at +25°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431BIDBVR and AS431BZTR-E1, ZTL431BE5TA offers superior thermal robustness (125°C ambient), SOT25's enhanced thermal dissipation (500mW vs. 330mW), and dedicated substrate pin (Pin 5) for improved noise immunity in high-noise motor drive systems.

Availability

ZTL431BE5TA is available at Aetrix Electronics and suitable for industrial power supplies, automotive battery management systems, and test equipment requiring stable component supply with guaranteed long-term continuity and RoHS-compliant sourcing.

Supply support for ZTL431BE5TA 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management, signal integrity, and protection solutions for industrial, automotive, and computing markets.

ZTL431BE5TA belongs to Diodes' precision shunt regulator product line, engineered specifically for high-accuracy, wide-temperature feedback control in isolated power conversion and voltage monitoring applications.

FAQ

What is the maximum cathode-to-anode voltage for ZTL431BE5TA?

The absolute maximum cathode voltage (V_{K A}) is 20V relative to the anode pin. Operation above this level risks permanent device failure. The recommended operating range is 2.5V to 20V, with stable regulation maintained across the full range when external resistors are correctly selected per the datasheet divider equations.

Can ZTL431BE5TA replace a standard 2.5V zener diode directly?

Yes-it functions as a drop-in replacement for 2.5V zeners in most cases, offering superior temperature stability (±34mV over −40°C to +125°C vs. ±100mV for typical zeners), lower dynamic impedance (0.2Ω vs. 10–50Ω), and tighter initial tolerance (0.5% vs. 5–10%). No circuit changes are needed beyond confirming cathode-anode polarity and current limits.

Why does ZTL431BE5TA have five pins when only three are electrically active?

Pins 1 (Anode), 2 (Cathode), and 3 (Reference) are functional; Pin 4 is no-connect, and Pin 5 connects internally to the silicon substrate. Pin 5 improves mechanical stability and thermal conduction in the SOT25 package and may be left floating or tied to Pin 1-this configuration reduces noise coupling and enhances reliability in high-vibration environments.

Is external capacitor required for stability with ZTL431BE5TA?

Yes-a minimum 4.7nF capacitor between cathode and anode is recommended to ensure stability across all capacitive loads and operating conditions. This prevents oscillation in opto-coupled feedback loops and maintains phase margin >45°, especially when driving >100pF gate capacitance or long PCB traces.