

2021 - 2023 Microchip Technology Inc. and its subsidiaries

DS20006363D-page 21

SY75608/612

FIGURE 4-3:

Input Driven from a Single-Ended CMOS Output.

4.2

Clock Outputs

Differential outputs have embedded termination resistors as shown in Figure 4-4. This provides significant saving

relative to traditional current-based HCSL outputs that require four resistors per differential output.

FIGURE 4-4:

Terminating Differential Outputs.

Embedded termination resistors in SY75608/612 are matched for 85Ω or 100Ω differential transmission lines.

4.3

Crystal Oscillator Circuit

The crystal oscillator circuit can work with crystal resonators from 8 MHz to 160 MHz. As can be seen in Figure 4-5, only

a crystal resonator is required and all the other components are built into the device. To be able support crystal

resonators with different characteristics all internal components are programmable in I2C Controlled mode.

FIGURE 4-5:

Crystal Oscillator Circuit in SPI Controlled Mode.

R1

R2

Z0 = 50

MCHP

Device

VDD

Rs

VDD

0.1 μF

Ro

Ro + Rs = Z0

VDD

R3

R4

R1/R2 = R3/R4

VDD

0.1 μF

R1

R2

442

332

237

56

59

62

VDD

3.3V

2.5V

1.8V

R3

R4

10 k

10 k

10 k

1.27 k

1.78 k

2.61 k

100

di eren al

MCHP Device

Rs

Rs

VDD

HCSL Inp ut

0.1875pF

0.375pF

12pF

XOU T

0.1875pF

0.375pF

12pF

500

XIN

Gain and series

resistor adjustment

MCHP Device