Currently R1 is 2.7k (derived from the typical application schematic for the TLV320). However, this only allows 1mA of current to the microphone; the Android specs indicate 1.8-2.9 mA according to this post. A 1k resistor instead would result in 2.5mA of current @ 2.5V, which would be within spec.
Currently R1 is 2.7k (derived from the typical application schematic for the TLV320). However, this only allows 1mA of current to the microphone; the Android specs indicate 1.8-2.9 mA according to this post. A 1k resistor instead would result in 2.5mA of current @ 2.5V, which would be within spec.