Cirrus-logic CDB5560 User Manual download pdf (Page 9)

CDB5560

DS713DB4 9

APPENDIX A. MAXIMIZING THE PERFORMANCE OF THE CS5560

A.1 PCB Layout Considerations

• Keep the signal path short between the CS5560 ADC input capacitors C20, C28, C37, C44 and

the ADC input pins to minimize trace inductance.

• The analog input buffer amplifiers and ADC input buffer capacitors are placed before the multi-

plexer. Placing the buffer amplifiers before the multiplexer allows the amplifiers driving the ADC

buffer capacitors to be fully settled when sampled by the ADC. Therefore, the multiplexer must

be of a low on-resistance type to prevent distortion or latency issues.

• Power supply noise is a major design consideration and the power supplies need adequate

bypassing and bulk capacitance.

• When operating the ADC from +2.5 V and -2.5 V split supplies, place the power supply & buffer

amplifier bypass capacitor ground connections close together.

• Keep all ground connections on each differential buffer amplifier as close to the device as pos-

sible to avoid introducing differential noise through high-impedance connections.

• Keep trace lengths short between the ADC and the voltage reference IC negative supply pins.

• Route the oscillator output away from analog circuitry.

• Use a solid ground plane in the PCB layout.

• Provide adequate separation between analog and digital signals.

• To minimize distortion within the analog signal path, consider using components with smaller

voltage dependencies.

• Minimize ADC digital output edge transition current loading.

A.2 Hardware Considerations

At a system level, use shielded cable for interconnects. Keep interconnect cable lengths as short as pos-

sible. Route analog and digital signals connecting to the PCB away from each other.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 ... 25 26

No comments

Cirrus-logic CDB5560 User Manual Page 9