Semtech SX1507/SX1508/SX1509 Low Voltage GPIO Expanders with LED Driver and Keypad Engine

Overview

This design document specifies the SX1507, SX1508, and SX1509 family of ultra-low voltage GPIO expanders, offering 4, 8, and 16 channels respectively. These devices operate between 1.2V and 3.6V, making them suitable for low-power battery-operated equipment. They interface via a 400kHz I2C bus and include dual independent I/O rails to provide direct level shifting between components at different voltage levels. Integrated features include a fully programmable LED driver with 256-step PWM intensity control, blinking, and breathing effects. The SX1508 and SX1509 variants further include an on-chip keypad scanning engine capable of monitoring up to 64 keys in an 8x8 matrix without host interaction. All devices support mask-programmable interrupts and offer 5.5V tolerant I/Os with up to 15mA sink current.

Referenced Parts