CS5376A datasheet(24/107 Pages) CIRRUS

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CS5376A

6. CLOCK GENERATION

The CS5376A requires a 32.768 MHz master clock

input, which is used to generate internal digital fil-

ter clocks and external modulator clocks.

6.1 Pin Description

CLK - Pin 58

Clock input, nominal frequency 32.768 MHz.

6.2 Synchronous Clocking

To guarantee synchronous measurements through-

out a sensor network, the CS5376A master clock

should be distributed to arrive at all nodes in phase.

The 32.768 MHz master clock can either be direct-

ly distributed through the system telemetry, or re-

constructed locally using a VCXO based PLL. To

ensure recovered clocks have identical phase, sys-

tem PLL designs should use a phase/frequency de-

tector architecture.

6.3 Master Clock Jitter and Skew

Care must be taken to minimize jitter and skew in

the received master clock as both parameters affect

measurement performance.

Jitter in the master clock causes jitter in the gener-

ated modulator clocks, resulting in sample timing

errors and increased noise.

Skew in the master clock from node to node creates

a sample timing offset, resulting in systematic mea-

surement errors in the reconstructed signal.

Clock Divider

CLK

DSPCFG Register

MCLK

Internal

Clocks

Figure 12. Clock Generation Block Diagram

and

Generator

MCLK

Output

CS5376A Datasheet(PDF) 24 Page - Cirrus Logic