Allegro MicroSystems A5364CA-T

Overview

A5364CA-T from Allegro MicroSystems is a low-current CMOS ionization smoke detector ASIC with interconnect capability, 16-pin DIP package, UL217 recognition (File #S2113), temporal horn pattern compliance (UL217/NFPA72/ISO8201), and integrated active guard amplifiers for chamber leakage suppression. It enables battery-operated residential smoke alarms with up to 125-unit networking.

For engineers reviewing the A5364CA-T datasheet, A5364CA-T pinout, A5364CA-T application, or A5364CA-T equivalent, key selection criteria include standby current (5.0 μA typ. at 9 V), sensitivity/low-battery threshold adjustability via external resistors, piezoelectric horn drive capability (±16 mA), and UL-recognized functional safety architecture for ionization chamber interfaces.

Technical Context

The A5364CA-T integrates a 1.67 s strobed oscillator that powers circuitry for only 10 ms per cycle to minimize average current draw, with built-in power-on reset and reverse battery protection. Its dual active guard outputs (GUARD1/GUARD2) maintain voltage within ±100 mV of DETECT IN to suppress surface leakage in ionization chambers.

Smoke detection uses comparator-based threshold comparison (V_DETECTIN < V_{SENSITIVITYSET}) with 130 mV typical hysteresis, while low-battery sensing occurs every 24 cycles (~40 s) using an internal reference and adjustable LOW-V SET pin. Horn outputs (HORN1/HORN2) deliver temporal patterns compliant with UL217: 500 ms on / 500 ms off ×3, then 1500 ms off.

Key Specifications

Pinout & Package

Package: 16-pin plastic dual in-line package (DIP), 0.300" body width, Pb-free matte tin leadframe plating (suffix –T).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ionization smoke detector ASIC applications.

Compared with ISL28134CAZ-T7A and SM550A-16, the A5364CA-T delivers certified temporal horn timing, dual active guards, and 5 μA standby in a drop-in UL-recognized package-reducing design validation effort and enabling faster time-to-certification for residential smoke alarms.

Availability

A5364CA-T is available at Aetrix Electronics and suitable for residential smoke alarms, interconnected safety systems, and low-power battery-operated safety sensors requiring stable component supply and UL217 compliance.

Supply support for A5364CA-T 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

Allegro MicroSystems is a U.S.-based semiconductor company specializing in magnetic sensing, power ICs, and safety-critical analog devices for automotive and industrial markets.

The A5364CA-T belongs to Allegro's smoke detector ASIC product line, designed specifically to integrate UL217-compliant timing, interconnect logic, and ultra-low-power analog front-ends into single-chip solutions for residential fire safety equipment.

FAQ

What is the minimum supply voltage required for reliable operation of the A5364CA-T?

The A5364CA-T operates reliably from 6.0 V to 12.0 V. At 6.0 V, all specifications-including 5.0 μA standby current, 130 mV hysteresis, and temporal horn pattern timing-remain valid per the datasheet. Operation below 6.0 V risks failure of the internal power-on reset and may cause erratic behavior during low-battery transitions. The A5364CA-T is engineered for 9 V alkaline batteries, which typically deliver 6.0–9.5 V over their service life.

How does the A5364CA-T implement active guarding on the DETECT IN pin?

The A5364CA-T implements active guarding using two dedicated amplifier outputs: GUARD1 (Pin 14) and GUARD2 (Pin 16). These outputs track the voltage at DETECT IN (Pin 15) within ±100 mV across the full operating temperature range. This eliminates surface leakage currents on PCB traces adjacent to the high-impedance ionization chamber input, a critical requirement for UL217 compliance. Unlike passive guarding, the A5364CA-T's active guards remain powered continuously-not strobed-ensuring constant protection during both standby and alarm states.

Can the A5364CA-T drive piezoelectric horns directly without external components?

Yes, the A5364CA-T drives piezoelectric horns directly via complementary HORN1 (Pin 10) and HORN2 (Pin 11) outputs, each capable of sourcing/sinking ±16 mA at 9.0 V. The device includes internal feedback (FEEDBACK, Pin 8) to stabilize drive waveforms across varying horn impedances. External components are only needed for tuning: a 0.1 μF low-leakage capacitor on OSC CAP (Pin 12) sets timing, and optional resistors on SENSITIVITY SET (Pin 13) and LOW-V SET (Pin 3) calibrate thresholds. No external transistors, drivers, or timing ICs are required for basic UL217-compliant operation.

What is the purpose of the 3-second delay on the I/O pin during alarm propagation?

The 3-second delay on the I/O pin (Pin 2) of the A5364CA-T prevents false interconnect alarms caused by electrical transients, EMI, or momentary chamber disturbances. After local smoke detection is confirmed across multiple sampling cycles, the I/O pin transitions high only after this fixed delay. This ensures that only sustained, validated alarm conditions trigger network-wide horn activation-meeting UL217's reliability requirements for interconnected systems. During the delay, local horn and LED remain fully active, providing immediate occupant warning while preventing spurious propagation.

Is the A5364CA-T RoHS-compliant and suitable for modern manufacturing processes?

Yes, the A5364CA-T is RoHS-compliant with 100% matte tin leadframe plating (Pb-free), as indicated by the "–T" suffix. It meets JEDEC MS-001 BB mechanical standards for 16-pin DIP packages and is qualified for reflow and wave soldering per IPC-J-STD-020. The matte tin finish ensures robust solderability, resistance to whisker growth, and long-term reliability in humid residential environments-critical for safety-critical smoke alarm applications where field failures are unacceptable. Aetrix Electronics guarantees full traceability and lifecycle support for the A5364CA-T in production programs.