Diodes Incorporated PT8A3237WE

Overview

PT8A3237WE from Pericom Semiconductor is a mixed-signal CMOS heating controller IC designed for single-key, constant-LED-indication hair curlers operating on 120V/240V AC mains. It integrates dual-voltage auto-adaptation, NTC-based temperature sensing with open-circuit protection, 1-hour auto-shutoff timer (at 60Hz), direct SCR gate drive, and LED indicator control in an 8-pin SOIC package.

For engineers reviewing the PT8A3237WE datasheet, PT8A3237WE pinout, PT8A3237WE application, or PT8A3237WE equivalent, key selection considerations include its fixed constant-LED mode (vs. flash), single-key ON/OFF logic, absence of auto power-off timer, and compatibility with external NTC thermistors and phase-controlled SCR heating stages.

Technical Context

The PT8A3237WE implements a 2-bit ADC for NTC voltage sampling (VNTC0–VNTC2 thresholds at 0.29–0.41×VDD), synchronized to 50/60Hz line-frequency clock input (CLK) for zero-crossing–referenced SCR triggering. Its internal state machine transitions between Reset, Heating-On, and Heating-Off states based on button input and timer expiry.

It delivers 2.5mA sink current on GATE (active-high SCR trigger) and supports dual-mode LED drive: Pin 5 (ON/OFF) sources current for LED1; Pin 7 (OFF) sinks current for LED2 with inverse polarity. NTC open detection uses dedicated NTC1/NTC2 pins with high-impedance monitoring and 1/8 CLK flashing fault indication.

Key Specifications

Pinout & Package

PT8A3237WE is housed in a lead-free, RoHS-compliant SOIC-8 package (JEDEC MS-012E/AA), measuring 4.7–5.1 mm × 3.8–4.0 mm × 1.35–1.75 mm (D × E × A).

Key Features

Applications

Equivalent & Alternatives

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

Compared with PT8A3235WE and PT8A3236WE, PT8A3237WE uniquely combines single-key operation, no auto-timer, and constant LED illumination - making it optimal for cost-sensitive, always-on-indication hair tools where manual shutdown suffices.

Availability

PT8A3237WE is available at Aetrix Electronics and suitable for hair curlers, flat irons, electric blankets, and beauty steamers requiring stable component supply and lead-free compliance.

Supply support for PT8A3237WE 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 applications before its 2016 acquisition.

The PT8A323x series was developed specifically for low-cost, single-chip thermal control in AC-powered personal care appliances - eliminating MCU dependency while delivering certified safety functions.

FAQ

What is the function of Pin 2 (NTC2) on the PT8A3237WE?

Pin 2 (NTC2) is an open-drain output used exclusively for NTC open-circuit detection. During normal operation, it is pulled low; when the NTC sensor disconnects, it floats high, triggering GATE disablement and LED2 flashing at 1/8 CLK frequency - a hardware-level safety response independent of software.

Does the PT8A3237WE support both 50Hz and 60Hz AC line frequencies?

Yes, the PT8A3237WE accepts 50Hz or 60Hz clock input on Pin 3 (CLK) and automatically adapts its internal timer and SCR firing logic. The 1-hour auto-shutoff (for variants that include it) scales accordingly: ~1.2 hours at 50Hz, ~1 hour at 60Hz - though PT8A3237WE itself omits this timer entirely.

Can the PT8A3237WE drive an SCR directly without external components?

Yes - its GATE output (Pin 6) delivers 2.5mA sink current at 5V VDD, sufficient to trigger common medium-power SCRs like MAC97A6 or BT134. No external transistor or optocoupler is needed, provided the SCR gate threshold and dV/dt requirements align with the PT8A3237WE's 10µs rise time and zero-crossing–locked pulse width.

How does the PT8A3237WE differ from PT8A3230 through PT8A3236?

PT8A3237WE is the only variant with single-key operation, constant LED indication (no flash), and no auto power-off timer. All other versions either use two keys (0–3), include the 1-hour timer (0,1,4,5), or implement flashing LED (0,2,4,6). This makes PT8A3237WE the minimal-feature, lowest-BOM option for basic ON/OFF thermal control.