Diodes Incorporated PT8A3251WEX

Overview

PT8A3251WEX from Pericom Semiconductor is a mixed-signal CMOS ceramic heating controller IC with 6 programmable temperature setpoints (150°C to 230°C), SCR gate drive output, over-temperature protection at 280°C, and auto power-off timer (1.2 hr @ 50 Hz). It interfaces directly with PTC thermistors and drives high-watt-density alumina heaters in consumer cooking appliances.

For engineers reviewing the PT8A3251WEX datasheet, PT8A3251WEX pinout, PT8A3251WEX application, or PT8A3251WEX equivalent, key selection criteria include its dual-package support (SOIC-16), MHP algorithm for rapid heat-up/recovery, adjustable thermal coefficient compensation, and integrated 6-level LED interface for user feedback.

Technical Context

The PT8A3251WEX integrates an internal oscillator synchronized to AC line frequency via CLK input, enabling precise timing for its 216,000-cycle auto-shutdown timer. Its analog front-end includes dual reference inputs (REF1/REF2) and a PTC sensor interface with voltage threshold levels calibrated per temperature setpoint (e.g., VT150 = 0.482×(VB–REF2)).

Control logic implements a state machine managing button inputs (L1/L2/L3), LED scanning outputs (C1/C2/L4), and safety-critical functions: GATE drives SCR with double-pulse triggering, while OT asserts high at 280°C to trigger fuse-melting. The chip operates across –20°C to +85°C with VDD1/VDD2 = 4.0–5.5 V.

Key Specifications

Pinout & Package

PT8A3251WEX is supplied in lead-free SOIC-16 package (JEDEC MS-012E/AC), 10.0 mm × 4.0 mm body, 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PT8A3253WEX, PT8A3251WEX adds critical auto-shutoff for consumer safety compliance; STSPIN220 lacks all thermal control features and cannot substitute without full system architecture change.

Availability

PT8A3251WEX is available at Aetrix Electronics and suitable for induction cooktop control, ceramic hob temperature management, electric wok controllers, and commercial food warmers requiring stable component supply and RoHS-compliant packaging.

Supply support for PT8A3251WEX 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 PT8A3251WEX belongs to Pericom's ceramic heating controller product line, designed specifically for cost-sensitive, microcontroller-free thermal regulation in AC-powered cooking appliances with PTC sensors and SCR-based power control.

FAQ

What is the function of the CLK pin?

The CLK pin accepts AC line frequency (50 Hz or 60 Hz) as a timing reference for the internal 216,000-cycle auto power-off timer and synchronizes the MHP algorithm's sampling rate. It eliminates need for external crystal or RC oscillator, reducing BOM cost and board space while ensuring accurate time-based safety shutdown aligned to mains frequency.

How does the PT8A3251WEX compensate for ambient temperature drift?

It uses dual reference inputs (REF1 and REF2) and a VB-referenced PTC sensing architecture to generate temperature thresholds proportional to (VB–REF2). This ratio-metric design inherently rejects supply and ambient temperature variations, enabling ±1.5°C accuracy across –20°C to +85°C ambient without calibration.

Can the 6 temperature setpoints be reprogrammed?

No - the six default setpoints (150°C, 170°C, 185°C, 200°C, 215°C, 230°C) are factory-trimmed and fixed in silicon. However, the entire temperature scale can be shifted up or down by adjusting external series resistance on REF1, allowing matching to specific PTC curves or regional regulatory requirements.

What is the maximum load current supported by the GATE output?

The GATE output delivers ≥4.0 mA sink current and ≤3.0 mA source current at VDD = 5.0 V, sufficient to directly trigger standard 1–5 A SCRs such as BT136 or TYN1025. For higher-current SCRs (>8 A), an external transistor buffer is required per datasheet recommendation.