MC145012P

Sensor And Detector Interfaces Overview

The MC145012P is a CMOS photoelectric smoke detector integrated circuit designed for battery-powered applications. It operates within a supply voltage range of 6.0 V to 12 V, with an average standby current of 8 µA. The device detects minute smoke particles by sensing scattered infrared light using an external photoelectric chamber and photodiode. It features a variable-gain photo amplifier where gain settings are determined by external capacitors C1 and C2. The IC includes on-chip push-pull drivers for an external piezoelectric transducer and supports temporal alarm patterns compliant with UL217, NFPA 72, ANSI S3.41, and ISO 8201 standards.

Sensor And Detector Interfaces Feature Summary

• Variable-gain photo amplifier allows direct interface to IR detectors (photodiodes) with gain settings determined by external capacitors.
• On-chip push-pull drivers activate an external piezoelectric transducer to sound a pulsating alarm upon detection.
• I/O pin enables interconnection of up to 40 units for common signaling and can activate auxiliary devices such as escape lights or auto-dialers.
• Low-supply detection circuitry conducts periodic checks during standby to indicate low battery or degraded chamber sensitivity.

Sensor And Detector Interfaces Applications

• Smoke detector systems complying with UL217 and UL268 specifications
• Battery-powered fire detection and alarm systems
• Multi-unit interconnected smoke detection networks

Sensor And Detector Interfaces Procurement Notes

Verify the specific ordering suffix to confirm package type and environmental compliance. The 'P' suffix indicates a 16-lead plastic DIP package. Ensure the selected variant meets the required operating temperature range and lead-free packaging standards if applicable to the target application.

Sensor And Detector Interfaces Selection Notes

Select this component for applications requiring a dedicated photoelectric smoke detection solution with low power consumption. Consider the operating temperature range of -55°C to +125°C for the P suffix variant. Ensure external components for gain setting and oscillator timing match the design requirements for the desired sensitivity and alarm pattern.

Sensor And Detector Interfaces Part Context

The MC145012 is part of a family of advanced smoke detector components containing sophisticated very-low-power analog and digital circuitry. It is specifically engineered to work in conjunction with an infrared photoelectric chamber to detect aerosols and smoke particles through light scattering principles.

Sensor And Detector Interfaces Replacement Considerations

MC145012ED: 16 PDIP (Pb-Free)

Sensor And Detector Interfaces FAQ

How does the MC145012 determine the gain of the photo amplifier?

The gain settings are determined by two external capacitors, C1 and C2. C1 is used for high gain during push-button tests and chamber sensitivity checks, while C2 sets the gain for normal operation.

What is the function of the I/O pin?

The I/O pin allows up to 40 units to be interconnected for common signaling. It can also be used to activate escape lights, enable auxiliary or remote alarms, and initiate auto-dialers.

How does the device indicate a low-supply condition?

A beep or chirp occurring virtually simultaneously with an LED flash indicates a low-supply condition. This check is performed periodically during standby using a pulsed load current from the LED pin.