MAX6969

The MAX6969 serial-interfaced LED driver provides 16 open-drain, constant-current-sinking LED driver outputs r ted at 5.5V. The MAX6969 operates from a 3V to 5.5V supply. The MAX6969 supply and the LEDs' supply or supplies can power up in any order. The constant-current outputs are programmed together to up to 55mA using a single external resistor. The MAX6969 operates with a 25Mb, industry-standard, 4-wire serial interface.

The MAX6969 uses the industry-standard, shift-registerplus- latch-type serial interface. The driver accepts data shifted into a 16-bit shift register using data input DIN and clock input CLK. Input data appears at the DOUT output 16 clock cycles later to allow cascading of multiple MAX6969s. The latch-enable input, LE, loads the 16 bits of shift register data into a 16-bit output latch to set which LEDs are on and which are off. The outputenable, OE, gates all 16 outputs on and off, and is fast enough to be used as a PWM input for LED intensity control.

For applications requiring LED fault detection, refer to the MAX6984*, which automatically detects open-circuit LEDs.

For safety-related applications requiring a watchdog timer, refer to the MAX6979, which includes a fail-safe feature that blanks the display if the serial interface becomes inactive for more than 1s.

The MAX6969 is one of a family of 12 shift-register-pluslatch- type LED drivers. The family includes 8-port and 16-port types, with 5.5V- or 36V-rated LED outputs, with and without open-circuit LED detection and watchdog. All versions operate from a 3V to 5.5V supply, and are specified over the -40°C to +125°C temperature range.