Rev 2.6, August 1, 2010

Page 6 of 8

SL16010DC

External Components and Design Considerations

Typical Application Circuit

SL16010DC

XIN(1)

VDD2(8)

XOUT(10)

SSCLK(5)

SSEL1(3)

SSEL0(7)

100MHz

27MHz

CL1

CL2

0.1

μF

VSS2(2)

REFCLK(9)

27MHz

VSS1(6)

VDD1(4)

10

μF

External crystal load

capacitors are required if

crystal is used.

If external clock (XO) is

used leave Pin-10 XOUT

unconnected (N/C) and

drive Pin-1 XIN with clock.

VDD

VDD

0.1

μF

5K

5K

This example is

configured for -0.5%

Spread

SSEL0=M (VDD/2) and

SSEL1=LOW (VSS)

5K

Figure 4. Typical Application Schematic

Comments and Recommendations

Crystal and Crystal Load: Only use a parallel resonant fundamental AT cut crystal. DO NOT USE higher overtone

crystals. To meet the crystal initial accuracy specification (in ppm) make sure that external crystal load capacitor is

matched to crystal load specification. To determine the value of CL1 and CL2, use the following formula;

C1 = C2 = 2CL – (Cpin + Cp)

Where: CL is load capacitance stated by crystal manufacturer

Cpin is the SL16010 pin capacitance (4pF)

Cp is the parasitic capacitance of the PCB traces.

EXAMPLE; if a crystal with CL=12pF specification is used and Cp=1pF (parasitic PCB capacitance on PCB), 19 or

20pF external capacitors from pins XIN (pin-1) and XOUT (Pin-10) to VSS are required since CXIN=CXOUT=4pF for

the SL1610DC product. Users must verify Cp value.

Decoupling Capacitor: A decoupling ca

pacitor of 0.1μF must be used between VDD1/2 pins and VSS1/2 pin. Place

the capacitor on the component side of the PCB as close to the VDD1/2 pins as possible. The PCB trace to the

VDD1/2 pins and to the VSS via should be kept as short as possible Do not use vias between the decoupling

capacitor and the VDD1/2 pins. In addition, a 10uf capacitor should be placed between VDD and VSS.

Series Termination Resistor: A series termination resistor is recommended if the distance between the outputs

(REFCLK and SSCLK) and the load if PCB trace is over 1 ½ inch. The nominal impedance of the outputs is about 24

Ω. Use 22 Ω resistors in series with the outputs to terminate 50Ω trace impedance and place 22 Ω resistors as close

to the clock outputs as possible.