Toshiba introduces flexible I/O expander family for mobile telecom, industrial and medical applications

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.

Toshiba’s new IC family offers the flexibility to handle keyboard configurations with as many as 96 keys in a keyboard matrix. The device monitors for key presses and releases, can detect up to four simultaneous key depressions, and incorporates integral de-bouncing algorithms in hardware. PWM functionality is based on three versatile, cascadable timers that can be programmed to generate modulated PWM signals or well-defined one shot signals, without the need for interaction of an external processor. The rotator wheel state machine counts up or down the rotations of an external rotator wheel and can handle rotator devices with up to three dedicated click positions. The PAL function allows the programmable free logic combination of up to four input signals, generating another signal according to the programmed logic.

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 just 3.5mm x 3.5mm or 25-pin BGA (3.0 x 3.0mm). QFN package variants are planned to be introduced to satisfy the needs of industrial applications.

Effective project quantities from 20,000pcs upwards can be supported by Toshiba.