Diodes Incorporated ZTL432BFTA

Overview

ZTL432BFTA from Diodes Incorporated is a 0.5%-tolerance adjustable precision shunt regulator in SOT23 package, providing stable 2.5 V reference voltage with ±0.013 V initial accuracy at +25°C, 0.2 Ω typical dynamic output impedance, and 1–100 mA cathode sink current capability for linear regulator feedback and opto-coupler linearization circuits.

For engineers reviewing the ZTL432BFTA datasheet, ZTL432BFTA pinout, ZTL432BFTA application, or ZTL432BFTA equivalent, this device serves as a high-accuracy, temperature-stable (−40°C to +125°C) replacement for discrete zener diodes in voltage reference, overvoltage protection, and isolated feedback loop designs requiring tight regulation and low output impedance.

Technical Context

The ZTL432BFTA implements a bandgap-based 2.5 V reference with internal error amplifier and NPN output stage, configured as a three-terminal shunt regulator where the REF pin senses voltage via external resistor divider, and cathode sinks current to maintain regulation. Its architecture enables programmable output from 2.5 V to 20 V using two external resistors.

It features low reference input current (2–4 μA typ), minimal reference voltage drift over temperature (±34 mV max from −40°C to +125°C), and stable operation with ≥4.7 nF anode-to-cathode capacitance-critical for maintaining phase margin in opto-isolated SMPS feedback paths.

Key Specifications

Pinout & Package

SOT23-3 package (JEDEC TO-236AB), 2.9 mm × 1.3 mm × 1.0 mm body, gull-wing leads, RoHS-compliant matte tin lead finish. Thermal resistance θ_JA = 380°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL432BIDBVR and AS432BRTM, the ZTL432BFTA delivers superior thermal robustness (full +125°C ambient), tighter output impedance (0.2 Ω), and higher cathode voltage headroom (20 V), making it optimal for automotive and industrial power systems demanding long-term stability.

Availability

ZTL432BFTA is available at Aetrix Electronics and suitable for precision voltage reference, isolated feedback control, and overvoltage protection applications requiring stable component supply across automotive, industrial automation, and telecom infrastructure programs.

Supply support for ZTL432BFTA 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.

The ZTL43x series belongs to Diodes' precision reference product line, engineered specifically for high-accuracy shunt regulation in space-constrained, thermally demanding applications where zener diodes fall short in stability and current-handling capability.

FAQ

What is the minimum cathode current required for regulation in ZTL432BFTA?

The ZTL432BFTA requires a minimum cathode current of 0.4 mA to maintain regulation, as specified in the Electrical Characteristics table under IKA(MIN). This value ensures stable reference operation even at light loads, such as when driving high-impedance op-amp inputs or microcontroller ADC references.

Can ZTL432BFTA replace a standard 2.5 V zener diode directly?

Yes-ZTL432BFTA can directly replace a 2.5 V zener diode in most circuits, but requires two external resistors to set the reference point and must be used with ≥4.7 nF anode-to-cathode capacitance for stability. Unlike zeners, it provides 0.5% initial tolerance and superior temperature coefficient performance.

Is ZTL432BFTA pin-compatible with TL432 devices?

Yes, ZTL432BFTA uses the same SOT23-3 pinout as TL432 variants (Anode–Cathode–Reference), enabling drop-in replacement in existing layouts. However, its maximum cathode voltage rating is 20 V versus 18 V for most TL432 versions, offering additional headroom in high-voltage designs.

What is the recommended PCB layout practice for ZTL432BFTA stability?

Place a 4.7 nF ceramic capacitor directly between anode and cathode pins, with minimal trace length (<2 mm). Route the reference pin away from noisy nodes, and use a solid ground plane beneath the SOT23 footprint to minimize thermal gradients and parasitic inductance in the cathode return path.