Diodes Incorporated ZTL431AE5TA

Overview

ZTL431AE5TA from Diodes Incorporated is a three-terminal adjustable precision shunt regulator in SOT25 package, delivering 2.5V reference voltage with ±1% initial tolerance at +25°C, 0.2Ω typical dynamic output impedance, and 1mA–100mA sink current capability. It operates across –40°C to +125°C and replaces standard zener diodes in feedback loops of linear regulators, opto-coupler-based isolated power supplies, and overvoltage protection circuits.

For engineers reviewing the ZTL431AE5TA datasheet, ZTL431AE5TA pinout, ZTL431AE5TA application, or ZTL431AE5TA equivalent, this page provides verified pin assignments for SOT25, confirmed thermal derating (250°C/W), stable operation up to 20V cathode-anode voltage, and design-meaningful specifications including reference deviation (≤34mV over –40°C to +125°C) and off-state leakage (<0.5μA).

Technical Context

The ZTL431AE5TA implements a bandgap-based reference core with internal error amplifier and NPN output stage, enabling precise voltage regulation via external resistor divider between cathode and reference pins. Its low 0.2Ω dynamic impedance ensures minimal output voltage variation under load transients.

Stability is achieved with ≥4.7nF anode-to-cathode capacitance; the device exhibits defined gain-phase behavior up to 1MHz and remains stable across capacitive loads from 10pF to 100nF per manufacturer characterization. It supports programmable output voltages from 2.5V to 20V using R1/R2 divider networks.

Key Specifications

Pinout & Package

Package: SOT25 (5-pin SC-74A), surface-mount, lead-free, RoHS-compliant. Pin 1 = Anode, Pin 2 = Cathode, Pin 3 = Reference, Pin 4 = NC (internally unconnected), Pin 5 = Anode (tied internally to Pin 1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDBVR and AS431ASTU, ZTL431AE5TA offers superior thermal robustness (–40°C to +125°C), lower dynamic impedance (0.2Ω vs. 0.35Ω), and tighter reference stability (≤34mV vs. ±50mV), making it optimal for automotive power management and precision industrial feedback loops.

Availability

ZTL431AE5TA is available at Aetrix Electronics and suitable for opto-coupler linearization, linear regulator feedback, and overvoltage protection circuits requiring stable component supply, long-term lifecycle assurance, and AEC-Q200-aligned reliability.

Supply support for ZTL431AE5TA 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 semiconductor company specializing in discrete, analog, and mixed-signal ICs, with emphasis on high-reliability power management and signal integrity solutions.

ZTL431AE5TA belongs to Diodes' precision shunt regulator product line, engineered for automotive-grade feedback accuracy, extended temperature operation, and drop-in replacement of legacy TL431 designs in safety-critical power systems.

FAQ

What is the maximum cathode-anode voltage for ZTL431AE5TA?

The absolute maximum cathode-anode voltage (VKA) is 20V. Operation beyond this risks permanent damage. The recommended operating range is VREF (2.5V) to 20V. This limit is strictly enforced by internal junction breakdown characteristics and is validated per DS33263 Rev. 17–2 Section "Absolute Maximum Ratings".

Can ZTL431AE5TA replace a standard 2.5V zener diode directly?

Yes-it functions as a 2.5V zener substitute but with significantly improved performance: ±1% initial tolerance (vs. ±5–10% for zeners), 0.2Ω dynamic impedance (vs. 10–100Ω), and stable operation from –40°C to +125°C. External resistor divider is required only when setting voltages above 2.5V.

Is pin 4 (NC) required to be grounded or left floating?

Pin 4 must be left floating-no connection to PCB trace, ground, or any net. It is internally unconnected; grounding or routing to adjacent signals may cause parasitic coupling or ESD path issues. Diodes Incorporated's AP02001 pad layout guidelines explicitly prohibit connection.

Does ZTL431AE5TA require an external capacitor for stability?

Yes-a minimum 4.7nF capacitor between anode and cathode is required for guaranteed stability across all operating conditions. This value is derived from empirical phase-margin testing in DS33263 Figure 4 and prevents oscillation when driving capacitive loads or long PCB traces.