RC32012A datasheet(59/66 Pages) RENESAS

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R31DS0078EU0103 Rev.1.03

Page 59

Sep 15, 2022

RC32012A Datasheet

Figure 21. LVCMOS Driver to XTAL Input Interface

Figure 22 shows an example of the interface diagram for an LVPECL driver. This is a standard LVPECL

termination with one side of the driver feeding the XTAL_IN input. It is recommended that all components in the

schematics be placed in the layout. Though some components may not be used, they can be used for debugging

purposes. The datasheet specifications are characterized and guaranteed using a quartz crystal as the input.

Figure 22. LVPECL Driver to XTAL Input Interface

5.4

Wiring the Differential Input to Accept Single-Ended Levels

For information, see Differential Input to Accept Single-ended Levels Application Note (AN-836).

5.5

Differential Output Termination

For all types of differential protocols, the same termination schemes are recommended (see Figure 23 and

Figure 24). These schemes are the same as normally used for an LVDS output type.

The recommended value for the termination impedance (ZT) is between 90Ω and 132Ω. The actual value should

be selected to match the differential impedance (ZDiff) of your transmission line. A typical point-to-point LVDS

design uses a 100Ω parallel resistor at the receiver and a 100Ω differential transmission-line environment. To

avoid any transmission-line reflection issues, the components should be surface-mounted and must be placed as

close to the receiver as possible.

LVCMOS_Driver

Zo = 50

Zo = Ro + Rs

100

VCC

OSCO

OSCI

0.1

μF

LVPECL_Driver

Zo = 50

0.1

μF

OSCO

OSCI

Zo = 50

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