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

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The MAX7312 2-wire-interfaced expander provides 16-bit parallel input/output (I/O) port expansion in SMBus™ and I²C applications. The MAX7312 consists of input port registers, output port registers, polarity inversion registers, configuration registers, a bus timeout register, and an I²C-compatible serial interface logic, compatible with SMBus. The system master can invert the MAX7312 input data by writing to the active-high polarity inversion register. The system master can enable or disable bus timeout by writing to the bus timeout register.

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

The MAX7312 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 (Vt = 0V) up to 6V.

The MAX7312 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 I/Os with integrated 100kΩ pullup resistors, refer to the MAX7311 data sheet.
MAX7312: Block Diagram MAX7312: Block Diagram Enlarge+

Key Features

  • 400kbps I²C-Compatible Serial Interface
  • 2V to 5.5V Operation
  • 5V Overvoltage Tolerant I/Os
  • Supports Hot Insertion
  • 16 I/O Pins that Default to Inputs on Power-Up
  • Open-Drain Interrupt Output (Active-Low INT)
  • Bus Timeout for Lock-Up-Free Operation
  • Noise Filter on SCL/SDA Inputs
  • 64 User-Selectable Slave ID Addresses
  • Low Standby Current (2.9µA typ)
  • Polarity Inversion
  • 4mm x 4mm, 0.8mm Thin QFN Package
  • -40°C to +125°C Operation


  • Instrumentation and Test Measurement Networking
  • Medical Equipment
  • RAID Systems
  • Servers/Blades

See parametric specs for I/O Port Expanders (31)

Part NumberInterfaceI/OInterrupt OutputOver Voltage Protection
Drive Current
minmaxSee Notes
MAX7312 Serial 2-Wire 400kbit16Yes5.54025.5
SOIC (W)/24
$2.48 @1k

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.

MAX7312EVKIT: Evaluation Kit for the MAX7312
Product Reliability Reports: MAX7312.pdf 
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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