The CT1721 is a compact, high-precision digital temperature sensor that uses a unique pulse count interface for data transmission. The sensor does not require an I²C or SMBus - just a single microcontroller GPIO pin and a pull-up resistor. With its low power consumption and ability to interface with multiple devices on a single pin, the CT1721 is perfect for applications in home appliances, HVAC and IoT systems.

Features:

• power supply (via DIO pin): 1.4 V - 5.5 V
• current consumption during measurement: 36 µA (typical)
• measurement accuracy:
  • ±0.5°C from -10°C to 80°C
  • ±1.0°C from -50°C to 150°C
• measurement resolution: 0.0625°C or 0.1°C (optional)
• temperature conversion time: 14 ms (typical)
• data transmission time: 38 ms (typical)
• single pulse time: 8.6 µs (typical)
• data output: number of pulses proportional to measured temperature
• operating modes: single-time and continuous
• addressing: up to 9 devices on one GPIO pin, selectable via pins AD0 and AD1
• operating temperature range: -50°C to +150°C
• enclosures: CSP-4, TO-92S-2, SOT-23, DFN1. 6x0.8-2, DFN1.6x1.6-6
• RoHS/REACH compliant (halogen-free)

Applications:

• household appliances (e.g. refrigerators, air conditioners)
• HVAC systems
• IoT and embedded devices
• applications requiring multiple measurement points with minimal MCU pin usage

Why choose CT1721:

• minimal hardware requirements: no need for a communication bus
• support for multiple sensors on a single GPIO pin
• reliability and simplicity of integration: data encoded by number of pulses
• surface mount and through-hole versions