Diodes Incorporated AP431SHBZTR-G1

Overview

AP431SHBZTR-G1 from Diodes Incorporated is a 3-terminal adjustable precision shunt regulator with 2.495V reference voltage (±1% tolerance at +25°C), 50μA typical minimum cathode current for regulation, and 36V maximum cathode voltage. It replaces Zener diodes in feedback loops of switching power supplies, USB chargers, and voltage adapters where low-power operation and thermal stability across –40°C to +125°C are required.

For engineers reviewing the AP431SHBZTR-G1 datasheet, AP431SHBZTR-G1 pinout, AP431SHBZTR-G1 application, or AP431SHBZTR-G1 equivalent, this device offers verified low-I_K(min) performance, stable regulation under capacitive loads up to 100µF, and compatibility with standard TL431-based PCB layouts while enabling >30% reduction in standby power in adapter designs.

Technical Context

The AP431SHBZTR-G1 implements a bandgap-referenced error amplifier driving an NPN output stage, delivering sharp turn-on characteristics and low dynamic impedance (0.1Ω typ.) for fast transient response in closed-loop feedback systems. Its reference voltage exhibits only 11mV deviation over –40°C to +125°C, ensuring consistent regulation across automotive and industrial ambient conditions.

It operates as a 2.495V adjustable shunt regulator with programmable output voltage range from V_REF to 36V via external resistor dividers, supporting sink currents from 100µA to 100mA. The device maintains stability with load capacitances up to 100µF without requiring series resistance compensation.

Key Specifications

Pinout & Package

AP431SHBZTR-G1 is supplied in TO-92 (Ammo Packing) package with 3 leads: Pin 1 = REF (reference input), Pin 2 = ANODE (ground connection), Pin 3 = CATHODE (regulated output node). This through-hole package provides 750mW power dissipation and 80°C/W junction-to-case thermal resistance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDR and AS431AZTR-E1, AP431SHBZTR-G1 uniquely combines TO-92 through-hole compatibility, 1% V_REF tolerance, and industry-lowest 50μA min cathode current-making it optimal for cost-sensitive, low-power, and thermally demanding applications where leaded packaging is specified.

Availability

AP431SHBZTR-G1 is available at Aetrix Electronics and suitable for USB-C power adapters, industrial 24V switching supplies, and automotive infotainment systems requiring stable component supply with full RoHS 3 and halogen-free compliance.

Supply support for AP431SHBZTR-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 semiconductor company specializing in discrete, analog, and mixed-signal ICs for power management, signal integrity, and connectivity applications.

AP431SHBZTR-G1 belongs to Diodes' precision shunt regulator product line, engineered specifically for energy-efficient AC/DC and DC/DC power conversion systems where low standby power and wide-temperature stability are critical design requirements.

FAQ

What is the maximum cathode voltage rating for AP431SHBZTR-G1?

The absolute maximum cathode voltage (V_KA) is 40V, but the recommended operating maximum is 36V per the datasheet's "Recommended Operating Conditions" table. Exceeding 36V may cause regulation instability or accelerated parametric drift, especially at high temperatures. Designers should maintain ≥4V margin below 40V for reliability in surge-prone applications like AC/DC front-ends.

Can AP431SHBZTR-G1 replace TL431 in existing designs without layout changes?

Yes-AP431SHBZTR-G1 uses the same TO-92 pinout (REF-ANODE-CATHODE) and matches TL431 electrical specifications except for lower minimum cathode current (50μA vs. 100μA). No PCB modification is needed, but designers should verify that reduced I_K(min) does not affect loop stability in high-ESR capacitor configurations; typical designs require no changes.

Does AP431SHBZTR-G1 require an external capacitor for stability?

No external capacitor is required for basic stability-the device remains stable with capacitive loads up to 100µF per the datasheet's "Stability Boundary Conditions" plot. Unlike many shunt regulators, it does not need a series resistor or bypass capacitor on the REF pin, simplifying feedback network design in space-constrained adapters and chargers.

What is the thermal resistance (θ_JC) of the TO-92 package used in AP431SHBZTR-G1?

The junction-to-case thermal resistance (θ_JC) for the TO-92 (Ammo Packing) package is 80°C/W, as specified in the "Absolute Maximum Ratings" table. This value assumes proper mounting on a copper pour; actual board-level θ_JA depends on PCB copper area and airflow, but θ_JC confirms suitability for 750mW continuous dissipation in ambient temperatures up to +125°C.