Diodes Incorporated PT8A3305LPEX

Overview

PT8A3305LPEX from Pericom Semiconductor is a ceramic heating controller IC designed for direct SCR-triggered temperature regulation in alumina heater systems. It integrates PTC-based self-sensing temperature detection, dual-voltage AC line synchronization (50/60 Hz), internal 5V zener regulation, and auto power-off timing (1.2 hr @ 50 Hz). It operates across –20°C to +85°C, consumes ≤400 µA supply current, and drives SCR gates with 200 µs high-current pulses (≥15 mA) - deployed in compact countertop ceramic cooktops and industrial benchtop heaters.

For engineers reviewing the PT8A3305LPEX datasheet, PT8A3305LPEX pinout, PT8A3305LPEX application, or PT8A3305LPEX equivalent, key selection considerations include its one-key toggle interface, constant LED indication mode, low-overshoot thermal response (VTH–VT = +0.4% to +0.8% × (VB–VREF)), DIP-8 package compatibility, and integrated line-synchronized clock input for zero-crossing control.

Technical Context

The PT8A3305LPEX implements a dedicated analog thermal control loop: it samples heater resistance via the PTC pin using an internal comparator with ±3 mV offset, references VB bias (via 35–65 kΩ internal switch) against REF, and generates synchronized GATE pulses timed to AC line zero crossings detected on CLK. Its POR circuit ensures reliable startup at ≥2.0 V, and the built-in timer counts 216,000 CLK cycles before auto-shutdown.

It supports two functional variants: PT8A3305L denotes low-overshoot preheat behavior (VTH–VT = +0.4% to +0.8% × (VB–VREF)) and constant LED mode, distinguishing it from H-variant high-overshoot versions. The IC requires no external temperature sensor and tolerates ambient shifts due to insensitivity of its PTC threshold (VKON = 0.8–1.1 V) to temperature drift.

Key Specifications

Pinout & Package

PT8A3305LPEX is supplied in a lead-free 8-pin DIP package (JEDEC MS-001D/BA), with 2.54 mm pitch, body width 6.2–6.6 mm, and height 3.71–4.31 mm - compatible with through-hole wave soldering and manual prototyping.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PT8A3305HPEX and PT8A3304LPEX, PT8A3305LPEX uniquely combines constant LED indication, low-overshoot preheat, and one-key toggle - making it optimal for consumer-facing appliances where predictable thermal behavior and intuitive UI are prioritized over fastest ramp or visual feedback.

Availability

PT8A3305LPEX is available at Aetrix Electronics and suitable for ceramic cooktop control, industrial benchtop heaters, and compact space heaters requiring stable component supply, long-lifecycle availability, and RoHS-compliant packaging.

Supply support for PT8A3305LPEX 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) is a fabless provider of high-performance analog and mixed-signal ICs, specializing in timing, interface, and power management solutions for industrial and consumer electronics.

The PT8A330x series was developed specifically for cost-sensitive, sensorless ceramic heating systems - integrating line synchronization, thermal sensing, and SCR drive into a single 8-pin IC to replace multi-component discrete controllers.

FAQ

What is the maximum SCR current that PT8A3305LPEX can trigger directly?

The PT8A3305LPEX delivers ≥15 mA peak gate current in 200 µs pulses, sufficient to trigger SCRs rated up to 20 A RMS under standard gate sensitivity conditions (IGT ≤ 50 mA). It does not drive higher-current SCRs without an external gate driver stage, and its GATE output is not rated for continuous current.

Does PT8A3305LPEX require an external temperature sensor?

No. PT8A3305LPEX uses the ceramic heater's own PTC (positive temperature coefficient) characteristic as the temperature sensor - measuring resistance change directly at the PTC pin. No thermistor, RTD, or thermocouple is needed, reducing BOM count and calibration complexity.

How does the auto power-off timer behave if the heater is cycled ON/OFF manually?

The 1.2-hour (50 Hz) timer starts only after the ON button is pressed and runs continuously until either the OFF button is pressed or the full duration elapses. Manual OFF resets the timer; subsequent ON presses restart it from zero - no cumulative or paused timing logic is implemented.

Can PT8A3305LPEX operate from a 3.3 V supply?

No. PT8A3305LPEX requires a minimum VDD of 4.0 V and specifies operation only from 4.0–5.0 V. Its internal zener regulator and comparator thresholds are optimized for 4.5 V nominal; operation below 4.0 V may cause POR failure, inaccurate PTC detection, or GATE pulse truncation.