Analog Devices Inc./Maxim Integrated DS18B20Z+

Overview

DS18B20Z+ from Maxim Integrated is a 1-Wire digital thermometer IC with ±0.5°C accuracy from −10°C to +85°C, programmable 9–12-bit resolution (0.0625°C min step), and parasitic power capability requiring only DQ and GND pins. It delivers calibrated Celsius temperature data over a single-wire bus and supports distributed sensing in HVAC control systems.

For engineers reviewing the DS18B20Z+ datasheet, DS18B20Z+ pinout, DS18B20Z+ application, or DS18B20Z+ equivalent, key selection considerations include 1-Wire multidrop support, nonvolatile alarm thresholds (TH/TL), EEPROM retention (10 years), −55°C to +125°C operating range, and SO-8 package compatibility with parasite or VDD-powered operation.

Technical Context

The DS18B20Z+ implements a 1-Wire interface using open-drain DQ signaling with weak pullup (4.7kΩ) and optional strong pullup for temperature conversion. Its internal architecture integrates a bandgap temperature sensor, 16-bit two's complement register, scratchpad SRAM, and EEPROM-stored TH/TL/alarm configuration registers.

It operates in either local VDD mode (3.0V–5.5V) or parasite power mode (DQ-derived), with conversion times ranging from 93.75 ms (9-bit) to 750 ms (12-bit). Each device features a unique 64-bit ROM code (family code 0x28), enabling bus-level addressing and alarm search via ECh command.

Key Specifications

Pinout & Package

DS18B20Z+ is supplied in an 8-pin SOIC (150 mils) package with exposed pad not electrically connected. Pin 1 is DQ (open-drain 1-Wire I/O), Pin 4 is GND, Pin 5 is VDD (grounded in parasite mode), and Pins 2,3,6,7,8 are no-connect terminals.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digital thermometer applications.

Compared with DS18B20Z+, DS18B20+T&R offers identical electrical performance in a different package form factor, while MAX31820M+ trades alarm autonomy and mid-range accuracy for lower unit cost - making DS18B20Z+ optimal for applications demanding guaranteed ±0.5°C fidelity and self-contained thermal event response.

Availability

DS18B20Z+ is available at Aetrix Electronics and suitable for HVAC environmental controls, industrial equipment monitoring, and consumer appliance sensing requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for DS18B20Z+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in precision analog, mixed-signal, and high-reliability interface solutions for industrial, communications, and computing markets.

The DS18B20Z+ belongs to Maxim's 1-Wire sensor family, designed specifically for distributed, low-pin-count temperature measurement in space-constrained or multi-node systems where wiring simplicity and device uniqueness are critical.

FAQ

What is the operating voltage range for DS18B20Z+ in local power mode?

The DS18B20Z+ operates from 3.0V to 5.5V when powered via the VDD pin. This range ensures compatibility with standard 3.3V and 5V microcontroller systems. In parasite power mode, the device derives power from the DQ line and does not require VDD - however, VDD must be grounded in that configuration. The DS18B20Z+ tolerates transient voltages up to +6.0V on any pin relative to ground, but sustained operation outside 3.0–5.5V may compromise accuracy or reliability.

How does DS18B20Z+ achieve ±0.5°C accuracy across its specified temperature range?

The DS18B20Z+ achieves ±0.5°C accuracy from −10°C to +85°C through factory calibration of its bandgap temperature sensor and digital conversion path, with error limits defined as 3-sigma statistical bounds. This specification is guaranteed under local power conditions (VDD = 3.0V–5.5V) and excludes parasitic power effects at temperature extremes. Accuracy degrades to ±1.0°C from −30°C to +100°C and ±2.0°C across the full −55°C to +125°C range, as confirmed in the DC Electrical Characteristics table of the official datasheet.

Can DS18B20Z+ operate reliably above +100°C in parasite power mode?

No - parasite power operation is not recommended above +100°C for DS18B20Z+. At elevated temperatures, increased leakage currents reduce the charge stored on the internal parasite capacitor (CPP), compromising bus communication stability during temperature conversions. For applications exceeding +100°C, DS18B20Z+ must be powered via the VDD pin with an external 3.0–5.5V supply. This ensures consistent timing compliance, sufficient active current (up to 1.5 mA), and reliable alarm flag assertion.

What is the function of the 64-bit ROM code in DS18B20Z+?

The 64-bit ROM code in DS18B20Z+ provides a globally unique identifier comprising an 8-bit family code (0x28), 48-bit serial number, and 8-bit CRC. It enables multidrop 1-Wire bus operation by allowing a single microcontroller to individually address, enumerate, and query hundreds of DS18B20Z+ units on one data line. The ROM code is laser-trimmed during manufacturing and cannot be altered - it is used in Search ROM, Match ROM, and Read ROM commands to manage device identity and prevent bus contention.

How does the DS18B20Z+ alarm system work without host polling?

The DS18B20Z+ alarm system uses nonvolatile EEPROM registers (TH and TL) to store user-defined temperature thresholds. After each conversion, the measured value is compared against these thresholds internally - setting an alarm flag if exceeded. The host can then issue an Alarm Search [ECh] command to discover which DS18B20Z+ units have active alarms, without needing continuous polling. This autonomous behavior persists across power cycles due to EEPROM retention (10 years at −55°C to +55°C), making DS18B20Z+ ideal for unattended thermal safety monitoring.