Diodes Incorporated PT8A3515BWE

Overview

PT8A3515BWE from Pericom Semiconductor is a dedicated smart electric iron controller IC with integrated shunt regulator, AC-line-synchronized timer (60Hz), 30s horizontal timeout and 8min vertical timeout, open-drain LED driver, active-high relay output, and buzzer tone generation at 4kHz. It enables automatic power cutoff in static positions for safety-critical household iron applications.

For engineers reviewing the PT8A3515BWE datasheet, PT8A3515BWE pinout, PT8A3515BWE application, or PT8A3515BWE equivalent, this device supports dual-voltage (120V/240V) systems, requires minimal external components, delivers <1W standby power, and provides configurable timeout behavior via part-number variant selection.

Technical Context

The PT8A3515BWE uses AC 60Hz line frequency as its primary timing reference, eliminating need for crystal or RC oscillator drift compensation. Its sensor interface processes SW input with Schmitt-triggered logic to distinguish horizontal (input high) vs vertical orientation, feeding position state into a deterministic finite-state machine that triggers 30s or 8min timeouts.

Internal blocks include a 4.5–5.5V shunt regulator for stable VCC, a sensor signal processor with vibration immunity, and logic-controlled outputs: RELAY (active-high, 5mA sink), DISC/BUZ (4kHz buzzer drive or capacitor discharge), and LED (open-drain, 10mA sink, 1Hz flash on timeout). Power-on reset ensures safe initialization.

Key Specifications

Pinout & Package

PT8A3515BWE is available in lead-free, RoHS-compliant SOIC-8 package (JEDEC MS-012E/AA), measuring 4.7–5.1mm × 3.8–4.0mm × 1.35–1.75mm, with 1.27mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PT8A3515BWE, PT8A3515AWE shifts timing reference to 50Hz for global 240V compatibility, while PT8A3517BWE retains 60Hz operation but modifies buzzer output to continual tone-both maintain identical safety logic, pinout, and power characteristics.

Availability

PT8A3515BWE is available at Aetrix Electronics and suitable for automatic shut-off irons, smart appliance safety modules, buzzer-alerted timeout systems, and dual-voltage iron platforms requiring stable component supply across global production cycles.

Supply support for PT8A3515BWE 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-reliability interface, timing, and power management ICs for consumer and industrial applications before acquisition in 2016.

The PT8A351x series was developed specifically for intelligent electric iron safety control, integrating sensor interface, AC-synchronized timing, and fail-safe output drivers into a single low-cost CMOS chip.

FAQ

What is the function of the TEST pin on PT8A3515BWE?

The TEST pin (Pin 5) is a low-active input that activates a diagnostic mode reducing all timeout durations by a factor of 10: 30s becomes 3s, and 8min becomes 9.6s. This allows rapid functional verification during production testing or field service without waiting full timeout periods. The pin must be pulled low externally; floating or high states disable test mode.

How does PT8A3515BWE achieve ±1% timer accuracy without a crystal?

PT8A3515BWE achieves ±1% timer accuracy by using the 60Hz AC mains frequency as its timing reference via the ACCLK pin. Internal circuitry conditions the 60Hz signal with Schmitt-trigger input and divides it precisely to generate 30s and 8min intervals. Since utility frequency is tightly regulated (±0.05% in most grids), this method eliminates crystal cost, footprint, and aging drift while meeting safety-critical timing requirements.

Can PT8A3515BWE drive a relay directly, or is external buffering required?

PT8A3515BWE's RELAY pin (Pin 2) provides active-high output capable of sinking up to 5mA at 0.5V drop, sufficient to drive small-signal NPN transistors like 2N5551 (as shown in official application circuits). It cannot directly drive typical 120VAC/240VAC relay coils; external transistor switching and flyback protection are required per reference designs. The IC controls the driver stage-not the coil itself.

What is the role of the DISC/BUZ pin beyond buzzer driving?

Beyond generating 4kHz tone for audible alerts, the DISC/BUZ pin (Pin 1) actively discharges external electrolytic capacitors in the power supply network to limit voltage rise during transient events or relay turn-off. This stabilizes rail voltage and prevents overvoltage stress on downstream components, enhancing system robustness in high-noise appliance environments.