I'm planning to use a STP16CP05MTR LED sink driver to drive some LEDs in a matrix. The STP16CP05MTR supports constant current by the use of an external resistor marked R-EXT in the datasheet.
The idea is to provide a ~20 mA current to each LED by using one 1 K resistor on R-EXT.
What i cannot figure out from the datasheet is if this resistor should be connected to GND or VDD. Page 17 in the datasheet might suggest GND, but with my limited knowledge I'm unsure.
Best Answer
The R-EXT resistor in figures 17-18 of the datasheet is shown connected to the R-EXT pin at one end, and a not-very-commonly-used symbol for Ground, at the other end. Thus, the resistor does need to be connected to ground.
Notice also that the GND pin connects to the same symbol, such as in Figure 17.