20

DS626F4

CS5366

4.3

Master Clock Source

The CS5366 requires a Master Clock that can come from one of two sources: an on-chip crystal oscillator

driver or an externally generated clock.

4.3.1

On-Chip Crystal Oscillator Driver

When using the on-board crystal oscillator driver, the XTI pin (pin 21) is the input for the Master Clock

(MCLK) to the device. The XTO pin (pin 22) must not be used to drive anything other than the oscillator

tank circuitry. When using the on-board crystal driver, the topology shown in Figure 7 must be used. The

crystal oscillator manufacturer supplies recommended capacitor values. A buffered copy of the XTI input is

available as an output on the MCLK pin (pin 23), which is level-controlled by VLS and may be used to syn-

chronize other parts to the device.

Figure 7. Crystal Oscillator Topology

4.3.2

Externally Generated Master Clock

If an external clock is used, the XTI and XTO pins must be grounded, and the MCLK pin becomes an input

for the system master clock. The incoming MCLK should be at the logic level set by the user on the VLS

supply pin.

XTI

XTO

22

21