Analog Devices Inc./Maxim Integrated DS1822+

Overview

DS1822+ from Maxim Integrated (formerly Dallas Semiconductor) is a lead-free, 3-pin TO-92 packaged digital thermometer IC with 1-Wire interface, ±2.0°C accuracy from –10°C to +85°C, user-selectable 9–12-bit resolution, and parasite-power capability. It operates across –55°C to +125°C and requires no external components for basic temperature sensing in space-constrained thermal monitoring systems.

For engineers reviewing the DS1822+ datasheet, DS1822+ pinout, DS1822+ application, or DS1822+ equivalent, key selection considerations include its single-wire bus compatibility, EEPROM-stored alarm thresholds, parasitic vs. VDD power mode tradeoffs, and direct centigrade digital output format without signal conditioning.

Technical Context

The DS1822+ implements a 1-Wire bus protocol using open-drain DQ signaling with weak pullup, enabling multidrop topology via unique 64-bit ROM addressing. Its internal architecture integrates a calibrated temperature sensor, scratchpad SRAM, NV EEPROM for TH/TL/config registers, and CRC generator for data integrity.

Temperature conversion is initiated by Convert T [44h] command; result is stored as signed 16-bit two's complement in scratchpad bytes 0–1. Resolution is set via R0/R1 bits in configuration register (byte 4), directly determining conversion time (93.75ms–750ms) and LSB step size (0.5°C–0.0625°C).

Key Specifications

Pinout & Package

DS1822+ is supplied in lead-free 3-pin TO-92 package (ordering code DS1822+), with GND, DQ, and VDD pins arranged linearly; NC pins are absent in this variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS18B20+ and MAX31820, the DS1822+ offers the lowest bill-of-materials cost while retaining full 1-Wire software compatibility and proven reliability in harsh thermal environments-making it ideal for high-volume industrial deployments where ±2.0°C accuracy is sufficient.

Availability

DS1822+ is available at Aetrix Electronics and suitable for industrial equipment monitoring, building HVAC control, consumer appliance thermal safety, and medical device temperature logging requiring stable component supply and long-term lifecycle support.

Supply support for DS1822+ 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) designs precision analog, mixed-signal, and digital ICs for industrial, automotive, communications, and computing applications.

The DS1822+ belongs to Maxim's 1-Wire temperature sensor family, engineered for low-cost, low-pin-count distributed thermal sensing in resource-constrained embedded systems.

FAQ

What is the operating voltage range for DS1822+?

The DS1822+ operates from 3.0V to 5.5V when powered externally via VDD. In parasite-power mode, it derives all operating energy from the 1-Wire bus through the DQ pin, eliminating the need for a separate supply rail. This dual-power capability makes DS1822+ adaptable to both conventional and ultra-low-wiring sensor architectures.

How does DS1822+ achieve ±2.0°C accuracy without calibration?

The DS1822+ achieves ±2.0°C accuracy from –10°C to +85°C through factory laser-trimming of its on-chip temperature sensor and signal path. This calibration is permanently stored and applied internally during conversion-no user calibration or external compensation is required. The DS1822+ maintains this specification across its full –55°C to +125°C operating range, with reduced accuracy outside the –10°C to +85°C window.

Can DS1822+ be used in multidrop 1-Wire configurations?

Yes, DS1822+ supports true multidrop operation via its unique 64-bit ROM address. Multiple DS1822+ units can share a single 1-Wire bus, each identified individually using Match ROM [55h] or collectively using Skip ROM [CCh]. The bus master uses Alarm Search [ECh] to identify only those DS1822+ units exceeding programmed temperature thresholds-enabling scalable, fault-aware thermal networks.

What is the maximum conversion time for DS1822+ at 12-bit resolution?

The DS1822+ requires a maximum of 750ms to complete a temperature conversion at 12-bit resolution. This value is guaranteed across the full operating temperature range and supply voltage. Lower resolutions reduce conversion time proportionally: 375ms at 11-bit, 187.5ms at 10-bit, and 93.75ms at 9-bit-allowing designers to balance precision against system responsiveness in the DS1822+ implementation.

Does DS1822+ require external components for basic operation?

No, DS1822+ requires no external components for fundamental temperature measurement. A single 4.7kΩ pullup resistor on the DQ line suffices for 1-Wire communication. All sensing, digitization, memory, and alarm logic are integrated. Optional components-such as a MOSFET-based strong pullup for parasite-power conversions or external VDD decoupling-address specific power-mode or timing requirements but are not mandatory for DS1822+ functionality.