Diodes Incorporated PT8A3303APEX

Overview

PT8A3303APEX 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 from 4.0–5.5 V, delivers 15 mA peak gate drive current, supports 50/60 Hz line-synchronized timing, and features internal 5 V zener regulation. It enables direct control of alumina ceramic heaters in dual-voltage (120/240 VAC) heating systems without external temperature sensors.

For engineers reviewing the PT8A3303APEX datasheet, PT8A3303APEX pinout, PT8A3303APEX application, or PT8A3303APEX equivalent, key selection considerations include its PTC-based closed-loop thermal control, 120 µs minimum GATE pulse width at -20°C to +85°C, built-in 1.2-hour auto-off timer for 50 Hz mains, and DIP-8 package compatibility with legacy ceramic heater PCB layouts.

Technical Context

The PT8A3303APEX implements a dedicated analog thermal control loop: the PTC pin accepts resistance-based temperature feedback, compared internally against dynamically scaled reference voltages (VT and VTH) to modulate SCR firing angle. Its CLK pin synchronizes sampling and gate triggering to AC line zero-crossing via internal comparator with ±300 mV hysteresis.

It integrates a POR circuit (2.0–3.0 V threshold), LED driver (5 mA sink capability), VB bias generator (15 Ω on-resistance, 5 MΩ off-resistance), and a digital counter-based power-off timer that counts 216,000 clock cycles-yielding 1.2 hours at 50 Hz and 1 hour at 60 Hz-before forcing GATE low.

Key Specifications

Pinout & Package

PT8A3303APEX is supplied in a lead-free 8-pin DIP package (JEDEC MS-001D/BA compliant), with 0.3 inch body width, 2.54 mm pitch, and 9.0–9.4 mm length.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PT8A3303BPE, the PT8A3303APEX offers higher preheat overshoot tolerance-beneficial in high-thermal-mass ceramic systems-while PT8A3302APE trades safety timer functionality for simpler control logic and lower cost in manually supervised environments.

Availability

PT8A3303APEX is available at Aetrix Electronics and suitable for ceramic hair straighteners, electric kettles, industrial drying modules, and medical warming pads requiring stable component supply, long-lifecycle support, and RoHS-compliant DIP packaging.

Supply support for PT8A3303APEX 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, industrial, and communications markets before its 2016 acquisition.

The PT8A330x series was designed specifically for cost-sensitive, safety-critical ceramic heating applications-replacing discrete transistor-based controllers with a single-chip solution integrating sensing, timing, drive, and protection functions.

FAQ

What is the function of the VB pin on PT8A3303APEX?

The VB pin is a switched 5 V bias output used to energize the PTC–REF resistor network. It exhibits ≤15 Ω on-resistance and ≥5 MΩ off-resistance, enabling precise voltage scaling for the internal comparator while minimizing power loss. Its switching is synchronized to the heater control cycle to reduce self-heating error in the PTC measurement path.

Can PT8A3303APEX drive a triac directly, or is an SCR mandatory?

PT8A3303APEX is optimized for SCR gate drive with active-high, 15 mA peak, 200 µs pulses. While it can trigger sensitive-gate triacs, standard triacs typically require longer or higher-current pulses; use of an external driver stage (e.g., MOC3021 optocoupler) is recommended for triac-based designs to ensure reliable turn-on across temperature and aging conditions.

How does the auto power-off timer behave if AC line power is interrupted and restored?

The internal timer resets on every power-on reset (POR). If AC power drops below the 2.0–3.0 V POR threshold and recovers, the counter restarts from zero-ensuring the full 1.2-hour (50 Hz) or 1-hour (60 Hz) window begins anew. No nonvolatile storage or external capacitor retention is used; safety compliance relies on deterministic reset behavior.

Is the LED output capable of driving multiple LEDs in series?

No-the LED pin is a 5 mA open-drain sink rated for 1.5 V forward drop. It supports only a single standard red/green LED (2.0–2.2 V VF) with appropriate current-limiting resistor. Driving multiple LEDs in series would exceed the 3.5 V compliance voltage limit and risk incomplete turn-off or excessive power dissipation in the IC's output stage.