Number of Required External Components:
Maxim: 10
G1421: 15
*GMT eliminates the DC blocking capacitors by biasing the headphone return (sleeve) to the DC bias voltage of the headphone amplifier. This approach raises a few issues:
During an ESD strike, the driver's ESD structures are the only path to system ground. Thus, the driver must be able to withstand the full ESD strike.
When combining a microphone and headphone on a single connector, the microphone bias scheme typically requires a 0V reference.
The sleeve is typically grounded to the chassis. Using this biasing approach, the sleeve must be isolated form system ground, complicating product design.
Load: