2-Wire-Interfaced, 16-Bit, I/O Port Expander with Interrupt and Hot-Insertion Protection


The MAX7318 2-wire-interfaced expander provides 16-bit parallel input/output (I/O) port expansion for SMBus™ and I²C applications. The MAX7318 consists of input port registers, output port registers, polarity inversion registers, configuration registers, and an I²C-compatible serial interface logic compatible with SMBus. The system master can invert the MAX7318 input data by writing to the active-high polarity inversion register.

Any of the 16 I/O ports can be configured as an input or output. A power-on reset (POR) initializes the 16 I/Os as inputs. Three address select pins configure one of 64 slave ID addresses.

The MAX7318 supports hot insertion. All port pins, the active-low INT output, SDA, SCL, and the slave address inputs AD0–2 remain high impedance in power-down (V+ = 0V) with up to 6V asserted upon them.

The MAX7318 is available in 24-pin SO, SSOP, TSSOP, and thin QFN packages and is specified over the -40°C to +125°C automotive temperature range.

For applications requiring an SMBus timeout function, refer to the MAX7311 data sheet.
MAX7318: Block Diagram MAX7318: Block Diagram Enlarge+

Key Features

  • 400kbps I²C-Compatible Serial Interface
  • 2V to 5.5V Operation
  • 5.5V Overvoltage-Tolerant I/Os
  • Supports Hot Insertion
  • 16 I/O Pins that Default to Inputs on Power-Up
  • 100kΩ Pullup on Each I/O
  • Open-Drain Interrupt Output (Active-Low INT)
  • Noise Filter on SCL/SDA Inputs
  • 64 Slave ID Addresses Available
  • Low Standby Current (5.4µA typ)
  • Polarity Inversion
  • 4mm x 4mm, 0.8mm Thin QFN Package
  • -40°C to +125°C Operation


  • Industrial Control
  • Instrumentation and Test Measurement
  • Medical Equipment
  • PLCs
  • RAID Systems
  • Servers
Part Number Interface I/O Interr.Out Over Voltage Protection
Drive Current
Package/Pins Budgetary
min max See Notes
MAX7318  Serial 2-Wire 400kbit 16 Yes 5.5 40 2 5.5
$2.31 @1k
See All I/O Port Expanders (31)
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.

MAX7318EVKIT: Evaluation Kit for the MAX7318

Technical Documents

App Note 2199 Driving LEDs with Push-Pull Port Expander Outputs

Quality and Environmental Data

Product Reliability Reports: MAX7318.pdf 
Lead-Free Package Tin (Sn) Whisker Reports

Related Resources