Diodes Incorporated PT8A3235WEX

Overview

PT8A3235WEX from Pericom Semiconductor is a mixed-signal CMOS heating controller IC designed for automatic temperature regulation in 120V/240V hair curlers using external NTC sensing. It features dual-voltage auto-adaptation, NTC open-circuit protection, 1-hour auto-shutoff timer (at 60Hz), direct SCR gate drive, and single-key ON/OFF control with constant LED indication. Operates from 3.5–5.5V supply at -20°C to +85°C ambient.

For engineers reviewing the PT8A3235WEX datasheet, PT8A3235WEX pinout, PT8A3235WEX application, or PT8A3235WEX equivalent, key selection considerations include NTC-based thermal feedback accuracy, 50/60Hz line-synchronized timing, SCR trigger capability, LED driver integration on pins 5 and 7, and SOIC-8 lead-free/Green packaging compliance.

Technical Context

The PT8A3235WEX implements a 2-bit ADC for NTC voltage sampling (VNTC0–VNTC2 thresholds) synchronized to AC line frequency via CLK input, enabling precise temperature zone detection and adaptive SCR firing duty cycle. Its internal state machine transitions between Reset, Heating-On, and Heating-Off states based on button inputs and timer expiration.

It delivers active-high GATE output (2.5mA sink capability) for direct SCR triggering and dual LED drive (pins 5 and 7) with inverse polarity - one pin serves as both ON/OFF input and LED1 output, while pin 7 drives LED2 exclusively. NTC open detection uses dedicated I/O pair (NTC1/NTC2) with flash-2 fault signaling at 1/8 CLK frequency.

Key Specifications

Pinout & Package

PT8A3235WEX is packaged in a lead-free, RoHS-compliant SOIC-8 (JEDEC MS-012E/AA) with 1.27 mm pitch, 4.7–5.1 mm width, and 3.8–4.0 mm body height.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar heating controller applications.

Compared with PT8A3234WEX and PT8A3236WEX, the PT8A3235WEX uniquely combines constant LED indication with built-in 1-hour auto-shutoff - making it optimal for standalone, safety-certified curlers where user interface simplicity and regulatory compliance are primary design drivers.

Availability

PT8A3235WEX is available at Aetrix Electronics and suitable for handheld hair styling tools, electric curling irons, automatic heat-regulated appliances, and consumer thermal control modules requiring stable component supply and full RoHS/lead-free compliance.

Supply support for PT8A3235WEX 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

Pericom Semiconductor (now part of Diodes Incorporated) specialized in high-performance interface, timing, and power management ICs for consumer and industrial electronics before its 2016 acquisition.

The PT8A323x series was developed specifically for cost-sensitive, safety-critical thermal control in AC-powered personal care appliances - emphasizing integration, line-synchronized timing, and NTC-based closed-loop regulation without MCU dependency.

FAQ

What is the function of the NTC2 pin on PT8A3235WEX?

NTC2 is an output pin used exclusively for NTC open-circuit fault detection. When the NTC sensor becomes disconnected or fails open, NTC2 drives a signal that causes LED2 (pin 7) to flash at 1/8 the CLK frequency. This provides immediate visual fault indication without requiring external circuitry or software intervention.

Can PT8A3235WEX operate directly from rectified AC without a linear regulator?

No - PT8A3235WEX requires a regulated 3.5–5.5 V DC supply. It cannot be powered directly from rectified AC. A simple capacitive dropper + Zener or low-dropout linear regulator (e.g., AP2112) is necessary to generate VDD, as the IC's internal circuitry is not rated for high-voltage or unregulated input.

How does PT8A3235WEX adapt to 120V vs. 240V line voltages?

It uses the CLK input signal's zero-crossing timing to determine line frequency (50/60 Hz), then adjusts SCR gate pulse width and phase angle automatically. At 240V, it reduces conduction time proportionally to deliver equivalent thermal power as at 120V - preventing overheating or underheating without user adjustment or hardware changes.

Is PT8A3235WEX pin-compatible with other PT8A323x variants?

Yes - all PT8A323x devices (0–7) share identical SOIC-8 and DIP-8 pinouts and electrical interfaces. Function differences (e.g., LED mode, timer enable) are masked internally and do not affect PCB layout, allowing one board design to support multiple variants via firmware or configuration option.