Analog Devices Inc./Maxim Integrated DS24B33S+

Overview

DS24B33S+ from Analog Devices is a 4096-bit, 1-Wire® EEPROM organized as 16 pages of 256 bits each, featuring a 32-byte scratchpad for write-verify operations, unique 64-bit factory-programmed registration number, and open-drain IO interface operating from +2.8V to +5.25V at -40°C to +85°C. It is used for calibration constant storage, PCB identification, and product revision tracking in embedded sensor nodes and industrial control modules.

For engineers reviewing the DS24B33S+ datasheet, DS24B33S+ pinout, DS24B33S+ application, or DS24B33S+ equivalent, key selection considerations include 1-Wire bus timing compliance (standard/overdrive modes), parasitic power capability, EEPROM endurance (50k cycles at +85°C), data retention (40 years at +85°C), and SO-8 package compatibility with legacy DS2433-based designs.

Technical Context

The DS24B33S+ implements a fully compliant 1-Wire slave interface with ROM function command support (Read ROM, Match ROM, Skip ROM) and memory function commands (Write Scratchpad, Read Scratchpad, Copy Scratchpad, Read Memory). Its parasitic power architecture derives all operating energy from the IO line during high states, eliminating need for VCC.

Memory access follows a strict two-step protocol: data is first written to the volatile 32-byte scratchpad, verified via readback and CRC-16, then copied to nonvolatile EEPROM using a self-timed 5ms programming cycle. The device uses internal address registers TA1/TA2 and E/S status register to manage byte offsets, partial writes, and authorization validation.

Key Specifications

Pinout & Package

DS24B33S+ is housed in an 8-pin SOIC package (208 mils width), RoHS-compliant and lead-free. Pin 1 is NC, Pin 2 is NC, Pin 3 is IO (1-Wire bus interface, open-drain), Pin 4 is GND, Pins 5–8 are NC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 1-Wire EEPROM applications.

Compared with DS24B33S+, DS2433+T&R offers lower cost but reduced high-temperature reliability and ESD robustness, while DS24B33AS+ improves startup timing and HBM immunity at the expense of archival data retention - making DS24B33S+ the balanced choice for industrial-grade 1-Wire identity and calibration storage.

Availability

DS24B33S+ is available at Aetrix Electronics and suitable for calibration data storage, board identification, and product revision tracking requiring stable component supply across industrial, automotive, and IoT production programs.

Supply support for DS24B33S+ 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

Analog Devices is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and connectivity applications.

The DS24B33S+ belongs to Analog Devices' 1-Wire EEPROM product line, designed specifically for reliable, low-pin-count, parasitic-powered identity and configuration storage in space-constrained and thermally demanding embedded systems.

FAQ

What is the primary function of the DS24B33S+ in a 1-Wire system?

The DS24B33S+ serves as a parasitic-powered, 4096-bit nonvolatile EEPROM slave device on a 1-Wire bus. Its primary function is to store calibration constants, board identification data, and product revision information using a unique 64-bit registration number for absolute device addressing. The DS24B33S+ performs all operations-including write-verify via scratchpad and self-timed EEPROM programming-using only the IO line for both communication and power, eliminating the need for a separate VCC supply.

Does the DS24B33S+ require an external power supply?

No, the DS24B33S+ operates in parasitic power mode and does not require an external VCC supply. It derives all operating energy from the 1-Wire bus through the IO pin during high-voltage periods, enabled by internal charge-pump circuitry. This design simplifies PCB layout and reduces system component count. However, a properly sized external pullup resistor (0.3–2.2kΩ) is mandatory on the IO line to ensure correct voltage levels and timing compliance per the 1-Wire specification.

How does the DS24B33S+ ensure data integrity during EEPROM writes?

The DS24B33S+ enforces data integrity through a mandatory two-step write process: first writing to a 32-byte volatile scratchpad and verifying contents via Read Scratchpad command, then copying validated data to EEPROM using the Copy Scratchpad command. The DS24B33S+ calculates and returns a CRC-16 of the Write Scratchpad command stream, allowing the host to confirm transmission accuracy before committing to nonvolatile memory. This prevents corruption from bus noise, timing violations, or transient power loss.

Is the DS24B33S+ pin-compatible with the DS2433?

Yes, the DS24B33S+ is pin-compatible and software-compatible with the DS2433 in the same SO-8 package. Both share identical pinout (IO on Pin 3, GND on Pin 4, NC on Pins 1, 2, 5–8), 1-Wire command set, family code (0x23), and memory organization. This allows direct replacement in existing DS2433 designs without PCB or firmware modifications, while delivering improved high-temperature endurance (50k cycles at +85°C vs. DS2433's 100k at +25°C) and enhanced ESD protection.

What is the maximum data retention period for the DS24B33S+ at industrial temperature?

The DS24B33S+ guarantees 40 years of data retention at +85°C - its maximum rated operating temperature. This specification is production-tested and applies to data stored in EEPROM after successful Copy Scratchpad execution. Retention degrades with increasing temperature; at +125°C (beyond operational range), retention drops to approximately 10 years. For long-term archival use, operation within the -40°C to +85°C range ensures full compliance with the 40-year retention claim stated in the official Analog Devices datasheet for DS24B33S+.