MIC74

The MIC74 is a fully programmable serial-to-parallel I/O expander compatible with the SMBus(TM) (system manage-ment bus) protocol. It acts as a "slave" on the bus, providing eight independent I/O lines.


Each I/O MIC74 bit can be individually programmed as an input or output. If programmed of MIC74 as an output, each I/O bit can be programmed as an open-drain or complementary push-pull output. If desired, the four most significant I/O bits can be programmed to implement fan speed control. An internal clock generator and state machine eliminate the overhead generally associated with "bit-banging" fan speed control.


Programming MIC74 and reading/writing the I/O bits is accomplished using seven internal registers. All registers can be read by the host. Output bits are capable of directly driving high-current loads such as LEDs. A separate interrupt output can notify the host of state changes on the input bits without requiring the MIC74 to perform a transaction on the serial bus or be polled by the host. Three address selection inputs of MIC74 are provided, allowing up to eight devices to share the same bus and provide a total of 64 bits of I/O.


The MIC74 is available in an ultra-small-footprint 16-lead QSOP. Low quiescent current, small footprint, and low package height make it ideal for portable and desktop applications.