Toshiba has introduced a family of flexible I/O expander ICs for use in mobile phone handsets and industrial and medical applications. The TC35892/3/4 devices provide a low power solution to help overcome CPU limitations, adding connectivity and programmable functionality, including signal generation, keyboard support and PAL logic functions.
The TC35892/3/4 combines up to 24 general purpose and configurable input/output pins for signal control, with additional built-in functionality for managing a keyboard, PWM signal generation, a rotator wheel interface and offer a logic quasi PAL function. Connection to a host CPU is via a two-wire I2C serial interface, simplifying integration and minimising the possibility of EMI issues. Designers can effectively expand the I/O capabilities of an application processor while limiting the connections to just the serial interface and the clock signal. An additional interrupt signal may be used for real-time signal processing. Once triggered, the device can use its own internal or an external oscillator to work independently. This means the system is able to reduce power consumption by allowing the CPU to enter sleep mode while keeping all IO functions alive.
Operating from a low frequency 32kHz (optional up to 20MHz) clock source running on a supply voltage from 1.62V to 3.6V (and drawing less than 140μA), TC35892/3/4 family is optimised for low power operation. Three different power modes ensure power consumption is kept low across a wide variety of operating conditions. It can be powered down completely without affecting the connected system. The devices can be supplied in a miniature 36-pin BGA package with a footprint of 3.5 x 3.5 or 25-pin BGA. QFN package variants are planned.



