© 2009 Fairchild Semiconductor Corporation

www.fairchildsemi.com

FSA2000

• Rev. 1.0.0

5

Detailed Description

USB Compliance

Figure 5. High-Speed USB 2.0 Eye Compliance (5.5V)

Transient Suppression

A common issue with headphone amplifiers is audible noises

through the headset when the amplifier is powering up or

down. Sharp transients often occur on the audio outputs

during this transition that cause audible “click and pop.” The

FSA2000 prevents these transients during power-up by

muting the outputs until the internal charge pumps are

stable. This ensures that any transients caused by the

charge pump are not propagated to the outputs. In cases

where the application needs a longer startup time for mute,

the FSA2000 has a MUTE pin that allows application control

over the behavior of the amplifier during startup and power

down. The MUTE pin forces the audio outputs into a known

and controlled state so that any transients of the amplifier

are not propagated to the headphones as clicks and pops.

Figure 6 shows the correct timing of the MUTE pin in relation

to the /SHDN pin for optimal click and pop performance.

Figure 6. Power-Up and Power-Down Timing

Table 1.

Recommended MUTE Timing

Parameter

Description

Suggested

Timing

MUTE setup time to /SHDN

rising edge

>500ns

MUTE hold time to /SHDN

rising edge

~500ns

MUTE setup time to /SHDN

falling edge

>500ns

MUTE hold time to /SHDN

falling edge

~500ns