Analog Devices Inc./Maxim Integrated DS28EA00U+

Overview

DS28EA00U+ from Maxim Integrated is a 1-Wire digital thermometer IC with user-selectable 9–12-bit resolution (0.5°C to 1/16°C), nonvolatile alarm thresholds, and dual programmable I/O pins enabling physical sequence detection in daisy-chained sensor networks. It operates from -40°C to +85°C, supports parasite power, and delivers unique 64-bit ROM identification for distributed temperature monitoring in HVAC and industrial storage systems.

For engineers reviewing the DS28EA00U+ datasheet, DS28EA00U+ pinout, DS28EA00U+ application, or DS28EA00U+ equivalent, this page provides verified technical context, validated pin functions, confirmed sequence-detect operation, real-world thermal accuracy specs (-0.5°C to +0.5°C error), and two documented alternative parts with explicit functional and interface differences.

Technical Context

The DS28EA00U+ implements a 1-Wire interface with hysteresis and glitch filtering for robust operation in large multidrop networks. Its internal temperature sensor feeds a sigma-delta ADC whose resolution is controlled via bits R1/R0 in the Configuration register (9–12 bits, corresponding to 93.75–750 ms conversion time).

Two open-drain PIO pins-PIOA (DONE) and PIOB (EN)-are shared between general-purpose I/O and hardware-assisted chain discovery: in Chain ON state, PIOB acts as enable input and PIOA pulls up to internal VDD (~40 kΩ) to drive the next device's EN; in DONE state, PIOA actively pulls low to signal completion. The device reports local power status via Read Power Mode command and uses CRC-8 (X⁸+X⁵+X⁴+1) for data integrity.

Key Specifications

Pinout & Package

DS28EA00U+ is housed in an 8-pin µSOP package (2.0mm × 2.5mm, 0.5mm pitch), RoHS-compliant and lead-free (+ suffix). Pin 1 is IO (1-Wire bus/data/power), Pins 2/3/5 are no-connect, Pin 4 is GND, Pin 6 is PIOA (open-drain output with internal pullup for chain mode), Pin 7 is PIOB (open-drain input for chain enable), and Pin 8 is VDD (tied to GND for parasite power operation).

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS18B20+T&R and MAX31820M+, the DS28EA00U+ uniquely combines chain-aware physical addressing, dual-purpose PIOs, and nonvolatile alarm storage-making it the only option for scalable, self-documenting linear sensor deployments where location fidelity and power simplicity are mandatory.

Availability

DS28EA00U+ is available at Aetrix Electronics and suitable for HVAC systems, industrial storage monitoring, and process equipment temperature logging requiring stable component supply, long-term EEPROM reliability, and deterministic 1-Wire network scalability.

Supply support for DS28EA00U+ 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, communications, and computing applications-with emphasis on reliability, integration, and low-power operation.

The DS28EA00U+ belongs to Maxim's 1-Wire sensor family, engineered specifically for distributed temperature sensing in electrically noisy, space-constrained, or power-limited environments where multidrop simplicity and physical topology awareness are critical.

FAQ

What is the maximum cable length supported by DS28EA00U+ in parasite-power mode?

The DS28EA00U+ supports up to 100 meters of twisted-pair cable in parasite-power mode when using a 2.2 kΩ pullup and standard-speed 1-Wire timing. Its improved front-end with hysteresis and glitch filtering maintains signal integrity across long runs with multiple nodes-verified in Maxim Application Note 5502. For longer distances or higher node counts, local VDD power or active pullup (e.g., DS2482-100) is recommended to ensure reliable DS28EA00U+ operation.

How does the DS28EA00U+ sequence-detect function map physical position to device identity?

The DS28EA00U+ sequence-detect function uses PIOB (EN) and PIOA (DONE) pins in Chain ON state: the first device's PIOB is grounded, enabling it to respond to Conditional Read ROM; upon reading its 64-bit ROM, it transitions to DONE state and drives PIOA low, enabling the next device's PIOB. This hardware-enforced handshake creates a deterministic, wire-order-based enumeration-eliminating software address-location mapping. DS28EA00U+ documentation confirms this behavior in Figures 12–14 and Table 2.

Can DS28EA00U+ operate without VDD connected, and what are the trade-offs?

Yes, DS28EA00U+ fully supports parasite-power operation with VDD tied to GND. Trade-offs include longer temperature conversion times (750 ms max at 12-bit), mandatory strong pullup activation during conversion/EEPROM write, and inability to use Read Power Mode to verify VDD status. All DS28EA00U+ electrical characteristics-including accuracy (±0.5°C) and resolution-remain guaranteed in parasite mode per Maxim datasheet Rev 2, Section "Electrical Characteristics."

What is the endurance and data retention of DS28EA00U+'s NV alarm registers?

DS28EA00U+'s NV alarm registers (TH/TL/config) are rated for 50,000 write/erase cycles at -40°C to +85°C and guarantee 10 years of data retention at +85°C ambient. These values are production-tested per Maxim datasheet Notes 22–25 and reflect actual EEPROM cell stress testing-not design projections. Retention degrades predictably with temperature; at +25°C, retention exceeds 30 years.

Does DS28EA00U+ support overdrive speed, and how is it enabled?

Yes, DS28EA00U+ supports overdrive speed (8 µs time-slot duration vs 65 µs standard) to increase 1-Wire throughput. Overdrive is enabled by issuing an Overdrive-Skip ROM or Overdrive-Match ROM command after power-up; once activated, all subsequent commands execute at overdrive speed until reset. Timing parameters (e.g., tW0L = 6–16 µs) are fully specified in the DS28EA00U+ datasheet Electrical Characteristics table.