Diodes Incorporated PT8A3307HWEX

Overview

PT8A3307HWEX from Pericom Semiconductor is a ceramic heating controller IC designed for direct SCR-triggered temperature-regulated heating systems. It integrates PTC-based temperature sensing, 50/60 Hz line-synchronized timing, internal 5 V zener regulation, and high-current gate pulse generation (200 µs, >15 mA) to drive 20 A SCRs without external drivers. It supports single-key toggle operation and auto power-off after 1.2 hours at 50 Hz - used in ceramic cooktops and industrial bench heaters.

For engineers reviewing the PT8A3307HWEX datasheet, PT8A3307HWEX pinout, PT8A3307HWEX application, or PT8A3307HWEX equivalent, key selection considerations include dual-voltage AC compatibility (120/240 VAC), VB-to-REF resistor tolerance (35–65 kΩ), GATE pulse width (120–300 µs over temperature), LED drive capability (5 mA sink), and internal POR threshold (2.0–3.0 V).

Technical Context

The PT8A3307HWEX implements a line-synchronized analog control loop: CLK input locks timing to AC mains (50/60 Hz), enabling precise 200 ms heating cycles; the PTC pin serves as both temperature sensor interface and push-button input via voltage threshold detection (VKON = 0.8–1.1 V). Internal comparator offset is ±3 mV, and reference bias (REF) sets thermal trip points relative to VB.

It features dual-mode operation: constant LED indication (non-flashing) and no-timer auto-off disabled (N), distinguishing it from timer-enabled variants like PT8A3300/1/4/5. The GATE output delivers active-high SCR trigger pulses with 120–300 µs width and ≥15 mA peak current, while VB provides a switched bias voltage (RON_VB ≤15 Ω) for PTC network excitation.

Key Specifications

Pinout & Package

PT8A3307HWEX is supplied in an 8-pin SOIC package (JEDEC MS-012E/AA), 4.7–5.1 mm wide, 3.8–4.0 mm body width, 1.27 mm pitch. Pin 1 (VDD) is marked by notch or dot; device orientation follows standard SOIC pin 1 indexing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PT8A3307HPE, the HWEX variant offers smaller footprint and reflow compatibility; versus PT8A3305LWE, it trades auto-off functionality for simplified thermal management in always-on applications.

Availability

PT8A3307HWEX is available at Aetrix Electronics and suitable for ceramic cooktops, industrial bench heaters, commercial food warmers, and medical warming trays requiring stable component supply and lead-free, green-compliant packaging.

Supply support for PT8A3307HWEX 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 analog and mixed-signal ICs for timing, interface, and power management before its 2016 acquisition.

The PT8A330x series was developed specifically for cost-sensitive, firmware-free ceramic heating control - targeting appliance manufacturers needing deterministic thermal response without MCU complexity or certification burden.

FAQ

What is the maximum SCR current rating supported by PT8A3307HWEX?

The PT8A3307HWEX delivers ≥15 mA peak gate current in 200 µs pulses, sufficient to trigger SCRs rated up to 20 A under typical gate sensitivity (IGT ≤50 mA). It does not drive higher-current SCRs directly; external amplification is required beyond this rating.

Can PT8A3307HWEX operate from a 12 V unregulated supply?

Yes - its internal 5 V zener regulator accepts 4.0–5.5 V at VDD, but the datasheet specifies use with an external 5 V rail derived from the zener. A 12 V input must be dropped via series resistor (e.g., 1.5 kΩ) to limit power dissipation and maintain VDD within 4.0–5.0 V.

How does the PTC pin distinguish between temperature sensing and button press?

The PTC pin reads voltage from a resistor divider formed by the PTC thermistor and a fixed resistor tied to VB. Button press pulls PTC low through a switch, crossing the VKON threshold (0.8–1.1 V); temperature change alters the divider ratio, shifting the DC level sensed by the internal comparator.

Is the CLK input compatible with both 50 Hz and 60 Hz AC lines?

Yes - the CLK input detects zero-crossings from full-wave rectified AC and automatically adapts timing: heating cycle period is 200 ms at 50 Hz and ~167 ms at 60 Hz. The internal counter scales accordingly, maintaining consistent thermal control resolution across global mains frequencies.