Semtech SX1508 and SX1509 are complete ultra low voltage 1.2V to 3.6V general-purpose parallel input/output (GPIO) expanders that are ideal for low power handheld battery-powered equipment. This family of GPIOs comes in 4-, 8-, and16-channel configurations and allows easy serial expansion of I/O through a standard 400kHz I2C interface. GPIO devices can provide additional control and monitoring when the microcontrollers or chipsets have insufficient I/O ports or in systems where serial communication and control from a remote location is advantageous.
These devices can also act as level shifters to connect microcontrollers running at one voltage level to components running at a different voltage levels, thus eliminating the need for extra level translating circuits. The core is operating as low as 1.425V while the dual I/O banks can operate between 1.2V and 3.6V independent of the core voltage and each other (5.5V tolerant).
The SX1508 and SX1509 feature fully programmable LED drivers with internal oscillators for enhanced lighting control such as intensity (via 256- step PWM), blinking and breathing (fade in/out), making them highly versatile for a wide range of LED applications.
In addition, keypad applications are also supported with the on-chip scanning engine which enables continuous keypad monitoring up to 64 keys without any additional host interaction and further reduce the bus activity.
The SX1508 and SX1509 have the ability to generate mask-programmable interrupts based on falling/rising edge of any of its GPIO lines. A dedicated pin indicates to a host controller that a state change occurred in one or more of the lines. Each GPIO is programmable via 8-bit configuration registers such as data registers, direction registers, pull-up/pull-down registers, interrupt mask registers, and interrupt registers. These I/O expanders come in small footprint packages and are rated from -40°C to +85°C temperature range.
