Diodes Incorporated PT8A3290WEX

Overview

PT8A3290WEX from Pericom Semiconductor is a mixed-signal CMOS heating controller IC designed for dual-voltage (120V/240V) hair styling appliances. It implements auto temperature control via external NTC, includes NTC open protection, proportional control algorithm, and delivers 160–240 µs TRIAC trigger pulses up to 15 mA. Used in curlers and straighteners, it integrates precise 5-bit ADC, internal Zener (4.5–5.5 V), and auto power-off timer (~1.2 hr at 50 Hz).

For engineers reviewing the PT8A3290WEX datasheet, PT8A3290WEX pinout, PT8A3290WEX application, or PT8A3290WEX equivalent, key selection criteria include NTC-based closed-loop thermal regulation, dual-line voltage adaptation, gate drive timing compliance with SCR/TRIAC phase-control topologies, and SOIC-8 package compatibility with compact consumer PCB layouts.

Technical Context

The PT8A3290WEX operates as a dedicated analog-digital hybrid controller: its 5-bit ADC digitizes NTC voltage for real-time temperature feedback, while internal logic synchronizes GATE output pulses to CLK input (50/60 Hz line frequency) for zero-crossing–aligned TRIAC triggering. The proportional control algorithm dynamically adjusts pulse width based on NTC voltage level relative to VADC_BIT1–VADC_BIT15 thresholds.

It features dual-mode LED indication (Flash1 = 1/32×CLK, Flash2 = 1/8×CLK), ON/OFF button interface with LED drive capability, and hardware-level NTC open detection via NTC1/NTC2 pin pair. Internal Zener (5.0 V typ.) enables self-biased operation without external regulator, and POR threshold (1.5–2.5 V) ensures reliable startup across supply transients.

Key Specifications

Pinout & Package

PT8A3290WEX is housed in a lead-free, RoHS-compliant 8-pin SOIC package (JEDEC MS-012E/AA), measuring 4.7–5.1 mm × 3.8–4.0 mm × 1.35–1.75 mm, suitable for reflow assembly and space-constrained consumer PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PT8A3294WEX, PT8A3290WEX supports independent ON/OFF buttons and dual LED control-critical for premium curlers requiring status differentiation. Versus PT8A3270PE, the WEX variant offers smaller SOIC-8 footprint and green/RoHS compliance, enabling higher-density consumer PCBs without sacrificing thermal control fidelity.

Availability

PT8A3290WEX is available at Aetrix Electronics and suitable for curlers, straighteners, and travel-sized hair styling appliances requiring stable component supply, dual-voltage adaptability, and integrated thermal safety features.

Supply support for PT8A3290WEX 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, computing, and communications markets.

The PT8A3290 series belongs to Pericom's dedicated analog-mixed-signal heating controller product line, engineered specifically for thermal safety and energy efficiency in AC-powered personal care appliances.

FAQ

What is the maximum TRIAC gate current drive capability of PT8A3290WEX?

The GATE pin delivers 5.0 mA sink current at 0.5 V output voltage under VDD = 4.5 V conditions, sufficient to trigger common medium-power TRIACs such as BT136 and TIC226. Pulse width is fixed at 160–240 µs, meeting minimum gate charge requirements without external amplification.

How does PT8A3290WEX detect NTC open-circuit failure?

When the NTC sensor opens, the internal circuit pulls NTC1 low and drives NTC2 low within one CLK cycle. This forces immediate exit from Heating-on state and disables GATE output. No external components are required-the detection is fully integrated and hardware-automated.

Can PT8A3290WEX operate from a 3.3 V supply?

No. The absolute minimum supply voltage is 3.5 V per datasheet specifications. At 3.3 V, the internal Zener (4.5–5.5 V) cannot regulate, POR may not assert correctly, and ADC accuracy degrades significantly. A 5 V supply-either from USB-derived regulator or Zener-biased rail-is mandatory.

Is the CLK input tolerant of noise on AC mains signals?

Yes. The CLK input has hysteresis and is designed to accept direct connection to a step-down transformer secondary or optocoupler output. It rejects glitches shorter than 1 ms and requires only clean zero-crossing edges-not sinusoidal fidelity-making it robust against typical mains noise and EMI in hair tool enclosures.