1-Wire® to I2C/SPI Bridge with Command Sequencer

1-Wire Slave to I2C or SPI Master Bridge Device Which Is Parasitically Powered from a Host Microcontroller.

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The DS28E18 is a simple communications bridge that resides at a remote SPI or I2C sensor and allows the sensor to be controlled by just two wires coming from the host system. It reduces the wire count from six (for SPI) or four (for I2C). These two wires use Maxim's 1-Wire protocol that combines power and signal on a single wire, and which is driven by the programmable I/O pins on the host's microcontroller. The 1-Wire network supports connection lengths up to 100m and 10 sensor nodes or more.

The IC provides a 512-byte command sequencer in SRAM that can be loaded with multiple I2C or SPI commands. Once loaded, the host controller sends a command to execute the sequence, power, and collect data from attached I2C or SPI peripherals. A subsequent 1-Wire command reads collected data. Power for attached sensors or peripherals is sourced from the 1-Wire line making the DS28E18 a very efficient solution to remotely power and control complex I2C or SPI devices such as sensors, ADCs, DACs, and display controllers.

When used as a bridge for I2C slave devices, the DS28E18 communicates at standard mode (100kHz), fast mode (400kHz) or fast-mode plus (Fm+, 1MHz). In SPI mode, multiple clock rates are supported up to 2.3MHz. Configuring for I2C or SPI operation is performed with a 1-Wire command; I2C is the power-on default. When operating in I2C mode, two programmable GPIO pins are available for additional peripheral control.

Each DS28E18 provides a unique and secure 64-bit ROM identification number (ROM ID) that serves as the device's address on the 1-Wire bus. Multiple DS28E18 devices can coexist with other devices in a 1-Wire network and be accessed individually without affecting other devices.​

DS28E18: Simplified Application Block Diagram DS28E18: Simplified Application Block Diagram Enlarge+

Key Features

  • Operate Remote I2C or SPI Devices Using Single-Contact 1-Wire Interface
    • Extending I2C/SPI Communication Distance
    • Reduce Six Wires (for SPI) or Four Wires (for I2C) to Two Wires
    • 512-Byte Sequencer for Autonomous Operation of Attached Devices
    • Two Configurable GPIO Pins for Additional Peripheral Control
  • No External Power Required
    • DS28E18 Parasitically Powered from 1-Wire
    • I2C/SPI Peripheral Power Derived from the 1-Wire Line
  • Flexible 1-Wire and I2C/SPI Master Operational Modes
    • Supports Standard (11kbps) and Overdrive (90kbps) 1-Wire Communication
    • 100kHz, 400kHz, and 1MHz for I2C Slaves
    • Up to 2.3MHz for SPI Slaves
  • Easy to Integrate
    • Small, 2mm x 3mm x 0.75mm, 8-Pin TDFN Package
    • -40°C to +85°C Operation
    • 2.97V to 3.63V Operating Voltage Range


  • Accessory Identification and Control
  • Equipment Configuration and Monitoring
  • Examining Environmental Conditions
  • Grain Elevator Monitoring

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

DS28E18EVKIT: Evaluation Kit for the DS28E18

Technical Documents

Tutorial 214 Using a UART to Implement a 1-Wire Bus Master
Request Reliability Report for: DS28E18 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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