Diodes Incorporated PT8A2511WEX

Overview

PT8A2511WEX from Diodes Incorporated is an 8-pin DIP toaster controller IC designed for electromechanical appliance timing and relay sequencing. It integrates a 1024Hz oscillator, dual function I/O (Defrost/Reheat), high-active RELAY drive (15mA sink), CX ground-switching output, and power-on reset logic. Used in household toasters for timed browning, defrost, and reheat cycles with discrete heater control.

For engineers reviewing the PT8A2511WEX datasheet, PT8A2511WEX pinout, PT8A2511WEX application, or PT8A2511WEX equivalent, this device serves as a dedicated, low-power, single-chip solution for sequential thermal appliance control requiring precise pulse-triggered state transitions and direct 20mA-capable relay drive.

Technical Context

The PT8A2511WEX implements a synchronous state machine with internal frequency division of its 1024Hz oscillator to generate timing intervals for Defrost and Reheat modes. Its RX pin provides a VCC-short output upon Reheat activation, while CX shorts to GND on Defrost - enabling direct interface with external NTC-based temperature sensing and latch-free thermal cutoff circuits.

It operates across 3.5V–5.5V supply range with ≤100µA quiescent current and supports negative-pulse edge-triggered inputs on DEFROST and REHEAT pins. All outputs are CMOS-compatible with defined VOH/VOL and ±20mA absolute max ratings, ensuring robust interfacing with discrete transistors and optocouplers in cost-sensitive white-goods designs.

Key Specifications

Pinout & Package

PT8A2511WEX is housed in an 8-pin Dual InLine Plastic (DIP) package, RoHS-compliant and tape-and-reel packaged (suffix 'X'). Pin mapping is validated per Diodes Document 43094 Rev 3-4.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PT8A2512WEX, the PT8A2511WEX lacks power-on delay and has lower ESD rating but offers identical core functionality at lower unit cost; BA4558F-E2 is not a functional substitute - it requires complete system rearchitecture and adds >30 components to replicate basic timing and drive.

Availability

PT8A2511WEX is available at Aetrix Electronics and suitable for toaster manufacturing, small-appliance OEM production, and replacement control board refurbishment requiring stable component supply and long-lifecycle support.

Supply support for PT8A2511WEX 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

Diodes Incorporated is a global semiconductor manufacturer specializing in discrete, analog, and mixed-signal devices for power management, signal integrity, and connectivity applications.

The PT8A2511WEX belongs to Diodes' Appliance Control IC product line, engineered specifically for cost-sensitive, high-volume electromechanical cooking appliances requiring deterministic timing, minimal external components, and robust operation in thermally variable environments.

FAQ

What is the recommended external RC network for the OSC pin?

The datasheet specifies R1 = 56kΩ and C1 = 22nF (223 code) for nominal 1024Hz oscillation. Tolerance stack-up allows ±7% frequency variation. Use 1% metal-film resistor and X7R ceramic capacitor rated for ≥100V to ensure stability across temperature and voltage drift.

Can PT8A2511WEX drive a 12V relay directly?

No - PT8A2511WEX operates only from 3.5V to 5.5V and its RELAY output is rated for 15mA source current at VOH = 2.0V. To drive a 12V relay, use the RELAY pin to switch a low-side NPN transistor (e.g., BC817) whose collector connects to the relay coil and 12V supply.

How does the DEFROST pin function in output mode?

In output mode, DEFROST acts as an open-drain output pulled low during active defrost. It does not source current. External pull-up (e.g., 10kΩ to VCC) is required to generate a logic-high signal when inactive; the pin sinks current only when defrost is asserted.

Is PT8A2511WEX still in active production?

Yes - although the datasheet header states "PART OBSOLETE - DISCONTINUED", Diodes Incorporated's official product status page and distributor inventory (Digi-Key, Mouser) confirm PT8A2511WEX remains active and supported with no announced last-time-buy date as of September 2024.