Diodes Incorporated PT8A3237PE

Overview

PT8A3237PE from Pericom Semiconductor is a mixed-signal CMOS heating controller IC for automatic temperature regulation in 120V/240V hair curlers, featuring dual-voltage operation, NTC-based auto temperature control, NTC open-circuit protection, 1-hour auto-off timer (at 60Hz), and direct SCR gate drive. It uses an internal 2-bit ADC to interpret NTC voltage levels and adjusts heating power based on line voltage.

For engineers reviewing the PT8A3237PE datasheet, PT8A3237PE pinout, PT8A3237PE application, or PT8A3237PE equivalent, key selection considerations include its single-key ON/OFF control mode, constant LED indication during heating, absence of auto-off timer, 8-pin DIP-8 PE package, and compatibility with external NTC sensors and triac/SCR power stages.

Technical Context

The PT8A3237PE implements a state-machine-based thermal control architecture with three operational states: Reset, Heating-On, and Heating-Off. It samples NTC voltage at Pin 1 (NTC1) against three internal reference thresholds (VNTC0–VNTC2) and synchronizes timing to AC line frequency via CLK input (50/60 Hz).

Unlike variants with auto-off timers, PT8A3237PE disables the internal 216,000-clock-cycle power-off timer and supports only manual heating termination. Its ON/OFF pin (Pin 5) serves as both button input and LED1 driver output, while Pin 7 (OFF/LED) drives LED2 in inverse phase to LED1 - a fixed functional configuration per ordering code "7".

Key Specifications

Pinout & Package

PT8A3237PE is housed in a lead-free 8-pin DIP package (JEDEC MS-001D/BA compliant), 9.0–9.4 mm wide, 6.2–6.6 mm body width, 3.71–4.31 mm height, with 2.54 mm pin pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PT8A3235WE and PT8A3236PE, PT8A3237PE uniquely combines DIP-8 through-hole compatibility, constant LED indication, and zero auto-off functionality - ideal for cost-sensitive, manually operated styling tools where timerless operation is a design requirement.

Availability

PT8A3237PE is available at Aetrix Electronics and suitable for hair curlers, travel stylers, low-cost straighteners, and hotel-grade styling appliances requiring stable component supply and long-term manufacturability.

Supply support for PT8A3237PE 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 2017 acquisition.

The PT8A323x series was developed specifically for cost-optimized, single-chip thermal control in AC-powered personal care appliances - emphasizing integration of NTC sensing, SCR drive, and LED feedback without firmware.

FAQ

What is the function of Pin 2 (NTC2) on PT8A3237PE?

Pin 2 is an open-drain output that goes low when the NTC sensor is disconnected or open-circuited. This signal is used to disable the GATE output and activate LED2 flashing at 1/8 the CLK frequency, providing hardware-level fail-safe heater shutdown without software intervention.

Does PT8A3237PE support automatic power-off after a fixed heating duration?

No. Unlike PT8A3230/1/4/5, PT8A3237PE disables the internal 216,000-clock-cycle (≈1 hour at 60 Hz) auto-off timer. Heating continues until manually terminated via the ON/OFF key, making it suitable for applications requiring indefinite thermal hold.

Can PT8A3237PE drive a triac directly, or is an external driver required?

PT8A3237PE's GATE output provides 2.5 mA sink current at 5 V, sufficient to directly trigger small- to medium-current SCRs (e.g., 2N6071A) and sensitive-gate triacs (e.g., MAC97A6). For higher-current triacs, a discrete buffer transistor is recommended.

How does PT8A3237PE distinguish between 120 V and 240 V line operation?

It does not sense voltage directly. Instead, the external circuit applies the same CLK signal (50/60 Hz zero-crossing) regardless of line voltage, and internal logic adjusts SCR conduction angle proportionally - reducing duty cycle at 240 V to maintain consistent thermal output and prevent overheating.