STP08DP05 resistor R-EXT current

[Central SUPPORT]

Background:

In our application STP08DP05XTTR is supposed to drive six LEDs with 20mA constant current each using an external, 1 k-Ohm output current programming resistor connected to the R-EXT pin (pin 15). The LED supply voltage is 5Vdc.

Question: 

Does the return current for the LEDs to GND go through this external resistor? The datasheet and AP3981 do not say anything about the power rating requirement of this external resistor. Please advise.

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[Central SUPPORT · Accepted solution]

Max power for R-EXT is: 100mA/16*1,25V=~8mW. Even 1/4 or 1/8W rating can be used.

Please ensure not to increase resistor value by temperature. Thanks.