ICS650-27

NETWORKING CLOCK SOURCE

CLOCK SYNTHESIZER

IDT™ / ICS™ NETWORKING CLOCK SOURCE

4

ICS650-27

REV F 051310

External Components

The ICS650-27 requires a minimum number of external

components for proper operation.

Decoupling Capacitor

Decoupling capacitors of 0.01µF must be connected

between each VDD and GND (pins 4 and 6, pins 16 and 14),

as close to the device as possible. For optimum device

performance, the decoupling capacitor should be mounted

on the component side of the PCB. Avoid the use of vias in

the decoupling circuit.

Series Termination Resistor

When the PCB trace between the clock outputs and the

loads are over 1 inch, series termination should be used. To

series terminate a 50

Ω trace (a commonly used trace

impedance), place a 33

Ωresistor in series with the clock line

as close to the clock output pin as possible. The nominal

impedance of the clock output is 20

Ω.

Crystal Information

The crystal used should be a fundamental mode (do not use

third overtone), parallel resonant. Crystal capacitors should

be connected from pins X1 to ground and X2 to ground to

optimize the initial accuracy. The value of these capacitors

is given by the following equation:

Crystal caps (pF) = (CL - 6) x 2

In the equation, CL is the crystal load capacitance. So, for a

crystal with a 16pF load capacitance, two 20 pF [(16-6) x 2]

capacitors should be used.

Absolute Maximum Ratings

Stresses above the ratings listed below can cause permanent damage to the ICS650-27. These ratings, which are

standard values for IDT commercially rated parts, are stress ratings only. Functional operation of the device at these

or any other conditions above those indicated in the operational sections of the specifications is not implied.

Exposure to absolute maximum rating conditions for extended periods can affect product reliability. Electrical

parameters are guaranteed only over the recommended operating temperature range.

Recommended Operation Conditions

Item

Rating

Supply Voltage, VDD

7 V

All Inputs and Outputs

-0.5 V to VDD+0.5 V

Ambient Operating Temperature

-40 to +85

° C

Storage Temperature

-65 to +150

° C

Junction Temperature

175

° C

Soldering Temperature

260

° C

Parameter

Min.

Typ.

Max.

Units

Ambient Operating Temperature

-40

+85

° C

Power Supply Voltage (measured in respect to GND)

+3.0

+3.3

+3.6

V