Diodes Incorporated PT8A3300BWEX

Overview

PT8A3300BWEX from Pericom Semiconductor is a ceramic heater controller IC with integrated SCR gate driver, temperature sensing interface (PTC input), and auto-shutdown timer. It operates at 4.0–5.0 V supply, delivers 15 mA high-current gate pulse (200 µs width), and supports dual AC line frequencies (50/60 Hz) for timing control. It drives alumina heaters directly in 120/240 VAC systems without external temperature sensors.

For engineers reviewing the PT8A3300BWEX datasheet, PT8A3300BWEX pinout, PT8A3300BWEX application, or PT8A3300BWEX equivalent, key selection factors include its internal 5 V zener regulation, VB bias voltage generation (80 kΩ internal switch), PTC-based thermal feedback loop, and fixed 1.2-hour auto-off at 50 Hz - critical for safety-compliant ceramic heating systems.

Technical Context

The PT8A3300BWEX implements a comparator-based thermal control loop using the PTC input referenced to an internally generated VB bias and REF voltage. Its clock synchronization circuit locks to AC line frequency via the CLK pin, enabling precise 50/60 Hz–based timing for both heating cycles and the 1.2-hour shutdown timer.

It integrates a high-current gate driver (IOH = –15 mA, Tal_GATE = 200 µs) optimized for triggering 20 A SCRs, with pulse timing designed to avoid false triggering due to SCR leakage at elevated temperatures. The internal zener-regulated VDD path supports operation across 4.0–5.5 V while maintaining functional stability over –20°C to +85°C.

Key Specifications

Pinout & Package

PT8A3300BWEX is available in lead-free, green-compliant SOIC-8 package (JEDEC MS-012E/AA), measuring 4.7–5.1 mm × 3.8–4.0 mm × 1.35–1.75 mm, with 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PT8A3301BWEX and PT8A3300BPE, the PT8A3300BWEX offers flash-mode LED feedback ideal for consumer appliances needing dynamic status indication, while retaining identical thermal accuracy, SCR drive capability, and safety timer - making it optimal for cost-sensitive, high-volume ceramic heating products requiring visual user feedback.

Availability

PT8A3300BWEX is available at Aetrix Electronics and suitable for ceramic hair straighteners, electric kettles, industrial heater modules, and medical warming pads requiring stable component supply, RoHS-compliant packaging, and long-term lifecycle support.

Supply support for PT8A3300BWEX 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 computing, communications, and consumer electronics before its 2016 acquisition.

The PT8A330x series was developed specifically for cost-sensitive, safety-critical ceramic heating applications - integrating SCR drive, PTC sensing, and line-synchronized timing into a single SOIC/DIP-8 IC to replace discrete MCU-based thermal controllers.

FAQ

What is the purpose of the VB pin and how is it used in the thermal control loop?

The VB pin provides a switched 80 kΩ resistor path from VDD to generate a stable bias voltage for the PTC thermistor bridge. It forms one leg of a differential sensing network with REF (0.7 V), enabling the internal comparator to detect temperature-dependent resistance changes without external components. This configuration directly determines VT and VTH thermal thresholds.

Can PT8A3300BWEX operate without an external crystal or oscillator?

Yes - PT8A3300BWEX derives all timing from the AC line frequency via the CLK pin, eliminating need for crystals, RC oscillators, or external clocks. Its internal counter uses 50/60 Hz zero-crossing signals to implement the 1.2-hour auto-off timer and heating cycle timing, making it inherently synchronized to mains power.

How does the GATE output interface with an SCR, and what external components are required?

The GATE pin delivers a 200 µs, –15 mA active-high pulse directly to the SCR gate. A series current-limiting resistor (typically 100 Ω) and snubber network (RC across SCR) are recommended per application circuit on page 6. No external transistor driver is needed, as the IC's output meets gate trigger requirements for 20 A SCRs at 120/240 VAC.

Is the internal 5 V zener regulator intended for powering external circuitry?

No - the internal zener regulates only the PT8A3300BWEX's internal circuitry. VDD is the sole power input pin; the zener allows operation from unregulated 5–12 V sources but does not source current to external loads. External components must be powered separately - the IC draws only 200–400 µA quiescent current.