Allegro MicroSystems A5364CA

Overview

A5364CA from Allegro MicroSystems is a low-current CMOS ionization smoke detector IC with interconnect capability, 16-pin DIP package, 9 V nominal supply, 5.0 μA typical standby current, and UL217 recognition for residential smoke alarms. It integrates oscillator, smoke comparator, dual active guard amplifiers, piezoelectric horn drivers (HORN1/HORN2), LED driver, and I/O networking for up to 125 units.

For engineers reviewing the A5364CA datasheet, A5364CA pinout, A5364CA application, or A5364CA equivalent, key selection considerations include its 1.67 s standby/10 ms sensing duty cycle, sensitivity and low-battery threshold adjustability via external resistors, temporal horn pattern compliance (UL217/NFPA72), and guard-amplifier–protected DETECT IN input for ultra-low leakage ion chamber interfacing.

Technical Context

The A5364CA employs a power-gated architecture: internal circuitry is strobed for only 10 ms every 1.67 s during standby, reducing average current to ≤9.0 μA at 9 V. Its smoke detection logic compares DETECT IN voltage against an adjustable SENSITIVITY SET reference, with built-in 130 mV hysteresis to suppress false triggers.

It features two independent active guard outputs (GUARD1/GUARD2) referenced within ±100 mV of DETECT IN to minimize surface leakage, plus a dedicated LOW-V SET pin enabling resistor-based adjustment of the 7.2–7.8 V low-battery threshold. The I/O pin supports wired-OR interconnection with 3 s alarm propagation delay and local alarm priority override.

Key Specifications

Pinout & Package

Package: 16-pin plastic dual in-line package (DIP), Pb-free version available as A5364CA-T. Rated for 0°C to 50°C ambient operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SL1300A and IS31FL3731, the A5364CA uniquely integrates interconnect capability, dual active guards, and sub-9 μA standby current in a single 16-pin DIP - making it the only option qualified for UL217-compliant multi-unit residential alarms requiring long battery life and chamber-level noise immunity.

Availability

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

Supply support for A5364CA 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 sensor interfaces, headquartered in Worcester, Massachusetts.

The A5364CA belongs to Allegro's ionization smoke detector IC product line, designed specifically to meet UL217 requirements while minimizing battery consumption and maximizing noise immunity in residential fire alarm systems.

FAQ

What is the maximum number of A5364CA units that can be interconnected?

The A5364CA supports interconnection of up to 125 units via its open-drain I/O pin. When any unit detects smoke, its I/O pin drives high after a nominal 3 s delay, pulling the shared bus high and triggering alarm sequences in all connected A5364CA devices. Local alarm conditions take precedence over remote signals, ensuring reliable prioritization in mixed-event scenarios.

How does the A5364CA achieve ultra-low standby current?

The A5364CA achieves ≤9.0 μA standby current through power-gated operation: internal circuitry is fully powered only for 10 ms every 1.67 s to perform smoke sampling and low-battery checks. This duty cycling, combined with CMOS design and optimized biasing (e.g., TIMING RES = 8.2 MΩ), ensures the A5364CA sustains >5 years of operation on a standard 9 V alkaline battery.

Can the A5364CA be used with photoelectric smoke chambers?

The A5364CA is specifically designed for ionization-type chambers and relies on ultra-low input bias current (±1.0 pA at DETECT IN) and dual active guard outputs (GUARD1/GUARD2) to interface with high-impedance ion chambers. While its comparator architecture could theoretically accept other sensor inputs, Allegro qualifies and specifies the A5364CA exclusively for ionization applications per UL217 file #S2113 - photoelectric use is not supported or tested.

What capacitor type is required on the OSC CAP pin of the A5364CA?

The OSC CAP pin of the A5364CA requires a low-leakage film capacitor - specifically PTFE, polystyrene, or polypropylene - rated at 0.1 μF. Electrolytic or ceramic capacitors are unsuitable due to higher leakage currents, which would disrupt the 1.67 s oscillator period and compromise standby current performance. The capacitor must also withstand 12 V DC rating to accommodate full supply range operation.

Does the A5364CA provide reverse battery protection?

Yes, the A5364CA includes internal reverse battery protection, allowing it to withstand reverse polarity connection of the 9 V supply for up to 20 seconds at 10.5 V without damage. This feature protects end-user installations where battery insertion errors may occur, and is specified in the Absolute Maximum Ratings table under "Reverse Battery Condition Duration" (tRBAT = 20 s).