A5364CA-T

Overview

The A5364CA-T is a low-current CMOS integrated circuit designed for ionization-type smoke detectors. It provides complete functionality including an internal oscillator, timing circuitry, and alarm logic compliant with UL217 standards. The device supports interconnecting up to 125 units via its I/O pin. Operating from a 6.0 V to 12 V supply, it features a standby current of typically 5.0 μA at 9.0 V. Key electrical parameters include a low-battery threshold of 7.2 V to 7.8 V, hysteresis of 90 mV to 170 mV, and horn output drive capability of ±16 mA. It operates within a temperature range of 0°C to 50°C and is housed in a 16-pin DIP package.

Feature Summary

• Interconnects up to 125 detectors for synchronized alarms
• Includes active guard outputs to minimize surface leakage currents
• Generates temporal horn patterns per UL217 and NFPA72 standards
• Features built-in hysteresis to reduce false triggering

Applications

• Ionization-type smoke detector systems
• Networked fire alarm systems requiring multiple unit synchronization
• Battery-operated safety and security applications using alternative sensors

Procurement Notes

Verify the specific ordering suffix to confirm lead-free status and packaging type. The CA-T designation indicates a lead-free version with matte tin leadframe plating supplied in tubes of 25 pieces. Confirm that the procurement channel sources directly from authorized distributors to ensure component authenticity and compliance with RoHS directives.

Selection Notes

Select this component for designs requiring UL217 recognition and low average standby current to maximize battery life. Ensure the application environment remains within the specified 0°C to 50°C operating temperature range. Verify that the external oscillator capacitor selected is a low-leakage type, such as PTFE or polypropylene, to maintain accurate timing cycles.

Part Context

This part belongs to the Allegro MicroSystems A5364 series of ionization smoke detector ICs. It is functionally similar to the A5366, which is designed for photoelectric smoke detection. Both devices share networking capabilities and low-power architectures but utilize different sensing technologies.

Replacement Considerations

The A5366CA-T serves as a functional replacement for photoelectric applications. Direct substitution requires verifying compatibility with the specific sensor chamber type, as the A5364 is optimized for ionization chambers while the A5366 is intended for photoelectric sensors.

FAQ

How is the detector sensitivity adjusted?

Sensitivity is adjusted by connecting an external resistor between the SENSITIVITY SET pin (Pin 13) and either VDD or VSS. This modifies the voltage divider network to set the smoke trip point relative to the specific ionization chamber characteristics.

What is the purpose of the GUARD1 and GUARD2 pins?

These pins provide active guarding for the detector input (DETECT IN). They maintain voltages within 100 mV of the input pin to minimize surface leakage currents and allow voltage measurement without loading the ionization chamber.

How does the device handle low-battery conditions?

Every 24 clock cycles (approximately 40 seconds), the device pulses the LED pin and compares VDD to an internal reference. If the voltage falls below the threshold (typically 7.5 V), it triggers a low-battery alarm pattern on the horn outputs.