CS5372 datasheet(16/22 Pages) CIRRUS

16 / 22 page

CS5371/CS5372

DS255PP2

When using dual power supplies, it is recommend-

ed to connect the VA- analog supply pin to system

ground using a reversed biased Schottky diode.

This configuration clamps the VA- pin a maximum

of 0.3 V above ground to ensure SCR latch-up does

not occur during power up. If the VA+ supply

ramps before the VA- supply, the VA- pin can be

pulled above ground through the CS5371/CS5372.

If the VA- supply pin is unintentionally pulled

0.7 V above the DGND pin, SCR latch-up can oc-

cur.

9.4.

DC-DC Converter Considerations

Many measurement systems are battery powered

and utilize DC-DC converters to generate the nec-

essary supply voltages for the system. To mini-

mize the effects of interference, it is desirable to

operate the DC-DC converter at a frequency which

is rejected by the digital filter, or else synchronous-

ly to the modulator sample clock rate. A synchro-

nous DC-DC converter whose operating frequency

is derived from MCLK minimizes the potential for

‘beat frequencies’ appearing in the measurement

band.

9.5.

Power Supply Rejection

Power supply rejection of the CS5371/CS5372

modulators is frequency dependent. The CS5376

digital filter rejects power supply noise for frequen-

cies above the filter corner frequency. For frequen-

cies between DC and the digital filter corner

frequency, power supply rejection is nearly con-

stant at 90 dB.

CS5372 Datasheet(PDF) 16 Page - Cirrus Logic