Diodes Incorporated AS431BKTR-G1

Overview

AS431BKTR-G1 from Diodes Incorporated is a three-terminal adjustable precision shunt regulator with 1.0% reference voltage tolerance, 2.5V to 36V programmable output, 0.15Ω typical dynamic impedance, and operation from –40°C to +125°C. It replaces Zener diodes in switching power supplies, battery chargers, and precision voltage references where thermal stability and low output impedance are critical.

For engineers reviewing the AS431BKTR-G1 datasheet, AS431BKTR-G1 pinout, AS431BKTR-G1 application, or AS431BKTR-G1 equivalent, key selection criteria include cathode current range (1–100 mA), temperature coefficient (20 ppm/°C typical), reference voltage deviation (≤16 mV over –40°C to +125°C), and compatibility with capacitive loads up to 100 µF without oscillation.

Technical Context

The AS431BKTR-G1 implements a bandgap-based precision reference core with internal error amplifier and NPN pass transistor, enabling sharp turn-on and stable regulation across full load and temperature ranges. Its architecture supports both shunt regulation and current-source configurations via external resistor networks.

It operates as a two-input comparator driving an output transistor: the REF pin senses voltage against an internal 2.5V bandgap reference, while the cathode sustains regulated voltage by sinking adjustable current. The device maintains stability under capacitive loads up to 100 µF and exhibits <0.5 mV/V cathode voltage sensitivity (∆VREF/∆VKA).

Key Specifications

Pinout & Package

AS431BKTR-G1 is packaged in SOT25 - a 5-pin surface-mount package with exposed thermal pad, RoHS-compliant and halogen-free "Green" molding compound. Pin 2 is internally connected to substrate and must be tied to ANODE or left floating per layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431BIDBVR and KIA431AP, AS431BKTR-G1 offers superior thermal stability (20 ppm/°C vs. 35–50 ppm/°C), smaller SOT25 footprint, and extended 36V cathode rating - making it optimal for compact, high-reliability industrial power supplies.

Availability

AS431BKTR-G1 is available at Aetrix Electronics and suitable for switching power supplies, battery chargers, and precision voltage reference circuits requiring stable component supply, long-term lifecycle support, and RoHS-compliant "Green" packaging.

Supply support for AS431BKTR-G1 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-performance, high-reliability components for power management, signal integrity, and protection applications.

The AS431 belongs to Diodes' precision reference product line, engineered specifically for high-stability shunt regulation in industrial, computing, and consumer power systems where Zener replacement and tight thermal drift are mandatory.

FAQ

What is the maximum cathode voltage rating for AS431BKTR-G1?

The absolute maximum cathode-to-anode voltage (VKA) is 40 V, but the recommended operating maximum is 36 V. Exceeding 36 V risks violating the specified ∆VREF/∆VKA performance limit and may cause reference voltage shift beyond datasheet guarantees. Operation at 40 V is only permissible for short-duration transients under controlled conditions.

Can AS431BKTR-G1 replace a Zener diode directly in existing designs?

Yes - AS431BKTR-G1 can directly replace Zener diodes in shunt regulator configurations using the same two-resistor divider network. However, the REF pin requires connection to the divider midpoint (not ground), and the ANODE must tie to system ground. Layout must isolate REF from noise sources due to its high-impedance input.

Does AS431BKTR-G1 require an external capacitor for stability?

No external capacitor is required for basic stability. The device remains stable with output capacitance up to 100 µF without oscillation, as verified in the datasheet's stability boundary plots. A 100 nF ceramic capacitor between REF and ANODE is recommended only for high-noise environments to suppress RF pickup on the sensitive reference node.

What does the "G1" suffix indicate in AS431BKTR-G1?

The "G1" suffix denotes Diodes Incorporated's "Green" compliance: fully RoHS-compliant (2015/863/EU), halogen- and antimony-free (<900 ppm Br/Cl, <1000 ppm Sb), and manufactured with lead-free plating and environmentally optimized molding compound - meeting strict environmental requirements for automotive and industrial end equipment.