Microsemi

Linfinity Microelectronics Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 13

Copyright

© 2000

Rev. 1.1, 2000-12-01

The LC filter design section discusses filter options

and the calculation of component values.

However,

the specification of capacitor type depends on the

application

in

the

circuit.

The

table

provides

descriptions and guidelines for capacitors in the

AudioMAX amplifier board.

Reference

Designator

Capacitor

Comments

C10, C11

FET gate drive

These

   ! "#!  $!  $ "! % #! &'!

C3 C14

Audio input path

These decoupling capacitors are used for the audio input +/- signals.

C18, C19,

C20, C21

Output filter

The output filter metal film capacitors (low ESR, 5% tolerance) work well to set an accurate

corner frequency at a low cost.

C8, C12

FET bypass

These metal film capacitors are used for the power supply bypass for the FETs.

Place

adjacent to the FETs or consider lower value ESR solutions depending on the PCB

component placement.

C22

LX1710 bypass

The metal film capacitor is a high frequency bypass for the LX1710 IC.

C9, C13

VDD,

PVDD bypass

These tantalum capacitors provide the bypass for the IC supply voltage and output driver

supply voltage utilizing a minimal footprint area.

C17

Output power stage

The electrolytic filter capacitor smoothes out ripple current and should be placed close to the

output FETs.

C16

Oscillator frequency

The timing capacitor (5% tolerance) sets the oscillator frequency.

C6, C7

Feedback filter

These (5%) capacitors are used in the RC filter to provide feedback for the control loop.

C4, C5

Error amplifier

These (5%) capacitors create the compensation network.

Make sure the appropriate

“temperature grade” is used to ensure stability.

C1, C2

Voltage references

The filter capacitors provide the bypass for the 5V and 2.5V references.

C26

Audio input filter

The RC filter minimizes high frequency noise to the amplifier.

  Capacitor Description