Diodes Incorporated PT8A3512PEX

Overview

PT8A3512PEX from Princeton Technology is a CMOS smart iron controller IC designed for automatic thermal safety shutdown in electric irons operating on 50Hz AC mains. It integrates an on-chip shunt regulator (4.5–5.5V), ACCLK-synchronized 8-minute vertical timeout and 30-second horizontal timeout, open-drain LED driver, and relay drive output (RELAYA) with ±1% timer accuracy. Used in dual-voltage (120/240VAC) iron systems with external tilt sensor.

For engineers reviewing the PT8A3512PEX datasheet, PT8A3512PEX pinout, PT8A3512PEX application, or PT8A3512PEX equivalent, key selection criteria include AC frequency dependency (50Hz only), DIP-8 lead-free package compatibility, relay drive capability (1mA source / 0.5mA sink), LED flash timing (4Hz post-timeout), and sensor interface logic with internal pull-up on SW pin.

Technical Context

The PT8A3512PEX uses 50Hz AC line frequency as its primary timing reference via the ACCLK input, eliminating need for external crystal while achieving ±1% timer accuracy for safety-critical timeouts. Its sensor signal processor handles debounce and position discrimination (horizontal vs. vertical) using internal logic and a dedicated SW input with internal pull-up.

It incorporates a built-in shunt regulator (VCC = 4.5–5.5V) that accepts unregulated input and powers internal blocks including the DPLL-based timer, power-on reset, and logic control circuit. The RELAYA output drives external NPN transistor stages to control heating elements, while DISC discharges electrolytic capacitors to stabilize sensor bias.

Key Specifications

Pinout & Package

PT8A3512PEX is housed in a lead-free 8-pin Dual In-line Package (DIP-8) per JEDEC MS-001 BA, with 2.54mm pitch and 7.62mm body width.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PT8A3511PEX, PT8A3512PEX ensures correct 50Hz-synchronized timing for EU/Asia markets, while PS8A0102DE extends robustness in electrically noisy iron assemblies - both preserve DIP-8 footprint but serve distinct roles in the safety chain.

Availability

PT8A3512PEX is available at Aetrix Electronics and suitable for electric iron safety shutdown, multi-voltage appliance control, and consumer appliance test mode requiring stable component supply and long-lifecycle support.

Supply support for PT8A3512PEX 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

Princeton Technology Corporation is a Taiwan-based fabless semiconductor company specializing in mixed-signal ASICs for consumer appliances and power management.

The PT8A35xx series is part of Princeton's Smart Appliance Controller product line, engineered specifically for thermal safety automation in electric irons using AC line frequency as a trusted, low-cost timing source.

FAQ

What is the purpose of the DISC pin on PT8A3512PEX?

The DISC pin is an active-high open-collector output that discharges external electrolytic capacitors used in the sensor bias network. This action stabilizes the voltage across the capacitor during sensor state transitions and limits peak voltage to prevent damage or false triggering caused by charge accumulation in long-cable or high-impedance sensor configurations.

Can PT8A3512PEX operate on 60Hz AC mains?

No. PT8A3512PEX is factory-configured for 50Hz ACCLK input only. Applying 60Hz to the ACCLK pin will cause incorrect timeout durations - 30s and 8min timers will shorten by 17%, violating safety compliance. For 60Hz operation, use PT8A3511PEX, which shares identical pinout and package but uses 60Hz as its timing reference.

How does the LED pin behave during normal operation versus timeout?

During normal heating, the LED pin floats, allowing an external LED (anode to VCC, cathode to LED pin) to remain continuously lit. Upon timeout, the LED pin becomes an active-low open-drain output pulsing at approximately 4Hz, causing the LED to flash - providing clear visual indication that the iron has entered safety shutdown mode and requires manual reset.

Is an external shunt regulator required when using PT8A3512PEX?

No. PT8A3512PEX includes an integrated shunt regulator that accepts unregulated DC input (up to 5.5V) on VCC and maintains internal supply between 4.5V and 5.5V. External regulation is unnecessary unless input voltage exceeds 5.5V - in which case a series resistor or Zener clamp may be added before VCC, but no external shunt regulator is needed.