ZHHXDZ DS18B20Z+T&R-HX

DS18B20Z+T&R-HX is a high-precision digital temperature sensor that uses a 64-bit read-only memory to store a unique serial number for each device. The chip contains two bytes of temperature registers for storing temperature data, two bytes of temperature alarm threshold registers (TH and TL), and one byte of configuration register. The configuration register allows users to set the temperature resolution to 9, 10, 11, or 12 bits. The values in the TH, TL, and configuration registers are stored in non-volatile memory and are retained after power-off.

The sensor uses a 1-Wire protocol to communicate through a single port. When all devices are connected to the bus via tri-state or open-drain ports, a weak pull-up resistor must be connected to the control bus. The processor identifies devices on the bus and records their addresses using each device's unique 64-bit serial number, with theoretically unlimited devices connectable to the bus.

It can operate without an external power supply. When the bus is high, the DQ line charges the device's internal capacitor (Cpp) through a pull-up resistor; when the bus is low, the capacitor powers the device. This power supply method is called "parasite power." Alternatively, an external power supply can be connected via the VDD pin.

The programmable temperature resolution supports 9, 10, 11, or 12 bits, corresponding to resolutions of 0.5°C, 0.25°C, 0.125°C, and 0.0625°C respectively. The default resolution at power-up is 12 bits. After startup, the device remains in a low-power idle state. The host controller issues specific commands (e.g., [44H]) to initiate temperature measurement and A/D conversion. The converted temperature data is stored as two bytes in the temperature register, after which the device returns to the idle state.

When powered by an external supply, the host can initiate a "read time slot" after issuing the temperature conversion command — a '0' is read during conversion and a '1' is read upon completion. When powered by parasite power, the host cannot monitor the device status through this mechanism.

After temperature conversion is complete, the measured temperature is compared against the alarm thresholds in the TH and TL registers (applicable to 11-bit and 12-bit modes only). The comparison result uses a sign bit (S) to indicate the sign of the temperature: S = 0 for positive, S = 1 for negative. The TH and TL registers are non-volatile. When the measured temperature exceeds TH or falls below TL, an alarm condition is triggered and an internal alarm flag is set. This flag is updated with each temperature conversion and is cleared after the next conversion once the alarm condition clears. The host controller can send an alarm search command [ECH] to detect the alarm flags of all DS18B20Z+T&R-HX devices on the bus and locate devices meeting the alarm condition. After modifying TH or TL settings, the alarm condition is re-evaluated on the next temperature conversion.

The sensor can be powered externally via the VDD pin or operate in parasite power mode, which is useful for long-distance measurements and space-constrained applications. In parasite power mode, the 1-Wire bus and Cpp can supply sufficient current for most operations; however, a strong pull-up must be applied to the 1-Wire bus during temperature conversion or EEPROM write operations. Parasite power mode is not recommended above 100°C — external power via the VDD pin is recommended instead. The host can determine the sensor's power supply mode through specific commands.

• Single-wire interface design, effectively saving resources and simplifying circuit connections.
• Highly integrated, no external components required, reducing system complexity.
• Wide temperature measurement range from -55°C to +125°C, with ±0.5°C accuracy in the -10°C to +85°C range.
• Programmable digital temperature resolution output, 9 to 12 bits.
• Each DS18B20Z+T&R-HX has a unique 64-bit ROM code, facilitating use in distributed temperature measurement systems.
• Customizable alarm thresholds with alarm search command for quick identification of alarming devices.
• Compatible with 3V to 5.5V operating voltage, adaptable to various power supply environments.
• Available in SOP-8 package.

• Thermal systems
• Consumer electronics
• Industrial environments such as HVAC/building/large machinery
• Temperature measuring instruments such as thermometers
• Temperature monitors