Overview
The DS18B20U+T&R, produced by Analog Devices Inc./Maxim Integrated, is a programmable resolution 1-Wire digital thermometer. This device is designed for high-precision temperature monitoring and is ideal for multisensor systems due to its minimal connection requirements. The DS18B20 communicates over a 1-Wire bus, which requires only one data line and ground for communication with a central microprocessor. It also features the ability to derive power directly from the data line, known as "parasite power," eliminating the need for an external power supply. Each DS18B20 has a unique 64-bit serial code, allowing multiple devices to function on the same 1-Wire bus, making it suitable for controlling many devices distributed over a large area.
Key Specifications
| Specification | Details |
|---|---|
| Resolution | 9-bit to 12-bit Celsius temperature measurements |
| Temperature Accuracy | ±0.5°C (9-bit), ±0.25°C (10-bit), ±0.125°C (11-bit), ±0.0625°C (12-bit) |
| Communication | 1-Wire bus |
| Power Supply | Parasite power from data line or external supply on VDD |
| Alarm Function | Nonvolatile user-programmable upper and lower trigger points |
| Memory | SRAM scratchpad with nonvolatile EEPROM storage for alarm trigger registers and configuration register |
| Package Options | TO92, Micro-MAX, Thin Shrink Small-Outline, Small-Outline IC |
| Unique Identifier | 64-bit serial code |
Key Features
- High-precision temperature measurements with configurable resolution (9-bit to 12-bit)
- 1-Wire bus communication requiring only one data line and ground
- Parasite power capability, eliminating the need for an external power supply
- Unique 64-bit serial code for each device, allowing multiple devices on the same bus
- Nonvolatile user-programmable upper and lower alarm trigger points
- SRAM scratchpad and nonvolatile EEPROM storage for configuration and alarm registers
Applications
- HVAC environmental controls
- Temperature monitoring systems inside buildings, equipment, or machinery
- Process monitoring and control systems
- Multisensor systems where minimal connections are beneficial
Q & A
- What is the resolution of the DS18B20 temperature measurements? The DS18B20 provides 9-bit to 12-bit Celsius temperature measurements.
- How does the DS18B20 communicate with a microprocessor? The DS18B20 communicates over a 1-Wire bus that requires only one data line and ground.
- Can the DS18B20 operate without an external power supply? Yes, the DS18B20 can derive power directly from the data line, known as "parasite power."
- What is the unique identifier for each DS18B20 device? Each DS18B20 has a unique 64-bit serial code.
- What is the purpose of the alarm function in the DS18B20? The alarm function allows for nonvolatile user-programmable upper and lower trigger points to monitor temperature thresholds.
- What types of memory does the DS18B20 have? The DS18B20 has an SRAM scratchpad and nonvolatile EEPROM storage for alarm trigger registers and configuration register.
- What are some common applications of the DS18B20? Common applications include HVAC environmental controls, temperature monitoring systems, and process monitoring and control systems.
- How many devices can be addressed on one 1-Wire bus? The number of devices that can be addressed on one bus is virtually unlimited due to the unique 64-bit serial code for each device.
- What is the default resolution of the DS18B20 at power-up? The default resolution at power-up is 12-bit.
- How does the DS18B20 perform temperature measurements? The DS18B20 performs temperature measurements by initiating a Convert T command from the master, which stores the resulting thermal data in the 2-byte temperature register.
