DS1621 Digital Thermometer and Thermostat DIP-8 (DS1621 IC)
The DS1621 is a high-precision digital thermometer and thermostat that provides 9-bit temperature readings via a standard 2-wire serial (I2C) interface. Housed in an 8-pin DIP package, it measures temperatures ranging from -55 degrees Celsius to +125 degrees Celsius. Unlike its predecessor, the DS1620, the DS1621 uses the I2C protocol, allowing up to eight devices to reside on the same bus through its three address pins (A0, A1, A2). It features a programmable thermostat output (TOUT) that activates when the temperature exceeds a user-defined threshold (TH) and remains active until it drops below a lower threshold (TL).
This IC is a vital component for industrial systems, computer peripherals, and consumer products that require thermal monitoring without external analog-to-digital converters. In India, it is frequently used in Arduino and microcontroller projects for building networked temperature sensors, digital climate controllers, and smart data loggers that need nonvolatile storage for thermostat settings.
Key Features
- I2C Serial Interface: Simple 2-wire communication for reading data and configuring settings.
- Standalone Thermostat: Programmable TOUT output for direct hardware control of fans or heaters.
- Nonvolatile Settings: TH and TL trip points are stored internally and retained without power.
- 9-Bit Resolution: Temperature is read as a 2-byte value in 0.5 degree Celsius increments.
- Addressable: Three address pins allow up to 8 DS1621 chips on a single 2-wire bus.
- Wide Voltage Range: Operates efficiently on a supply of 2.7V to 5.5V.
- One-Shot Mode: Can be programmed to perform single conversions to conserve power.
Specifications
- IC Type: Digital Thermometer and Thermostat
- Temperature Range: -55 to +125 degrees Celsius
- Resolution: 9-bit (0.5 degree Celsius steps)
- Accuracy: +/- 0.5 degrees Celsius (from 0 to +70 degrees Celsius)
- Supply Voltage (VDD): 2.7V to 5.5V
- Conversion Time: Less than 1 second
- Communication: 2-wire Serial (I2C/SMBus)
- Package Type: PDIP-8
- Mounting Type: Through-Hole
- Operating Temperature: -55 to +125 degrees Celsius
Interfaces
- Pin 1 (SDA): Data Input/Output for 2-wire serial communication
- Pin 2 (SCL): Clock Input for 2-wire serial communication
- Pin 3 (TOUT): Thermostat Output (Active when T >= TH)
- Pin 4 (GND): Ground
- Pin 5 (A2): Address Input Pin (MSB)
- Pin 6 (A1): Address Input Pin
- Pin 7 (A0): Address Input Pin (LSB)
- Pin 8 (VDD): Supply Voltage Input (+5V typical)
