ICS525R-04T IDT, Integrated Device Technology Inc, ICS525R-04T Datasheet - Page 4

• Manufacturer Part Number: ICS525R-04T
• Description: IC PECL CLK USER CONFIG 28-SSOP
• Manufacturer: IDT, Integrated Device Technology Inc
• Series: OSCaR™r
• Type: Clock Generator, Fanout Distributionr

Specifications of ICS525R-04T

• Pll: Yes
• Input: CMOS, Crystal
• Output: PECL
• Number Of Circuits: 1
• Ratio - Input:output: 2:2
• Differential - Input:output: No/No
• Frequency - Max: 200MHz
• Divider/multiplier: Yes/Yes
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 28-SSOP
• Frequency-max: 200MHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 525R-04T

IDT™ / ICS™ OSCAR™ USER CONFIGURABLE PECL CLOCK
External Components
Decoupling Capacitors
As with any high performance mixed-signal IC, the
ICS525-04 must be isolated from system power supply
noise to perform optimally.
Decoupling capacitors of 0.01µF must be connected
between each VDD and the GND, one on each side of the
chip.The capacitor must be connected close to the device to
minimize lead inductance. No external power supply filtering
is required for this device.
External Resistors
A 560 resistor must be connected between RES (pin 19)
and VDD. A total of four resistors are needed for the PECL
outputs as shown on the block diagram on page 1. The
value of these resistors are shown, but can be varied to
change the differential pair output swing and the common
mode voltage. Consult application note MAN09 for more
information.
Crystal Load Capacitors
The total on-chip capacitance for a crystal is approximately
16 pF, so a parallel resonant, fundamental mode crystal with
this value of load (correlation) capacitance should be used.
For crystals with a specified load capacitance greater than
16 pF, crystal capacitors may be connected from each of the
pins X1 and X2 to Ground as shown in the block diagram.
The value (in pF) of these crystal caps should be (CL -
16)*2, where CL is the crystal load capacitance. These
external capacitors are only required for applications where
the exact frequency is critical. For a clock input, connect to
X1 and leave X2 unconnected (no capacitors on either).
Determining the Output Frequency
Users have full control in setting the desired output
frequency over the range shown in the table on page 2. To
replace a standard oscillator, users should connect the
divider select input pins directly to ground (or VDD, although
this is not required because of internal pull-ups) during
Printed Circuit Board layout. The ICS525-04 will
automatically produce the correct clock when all
components are soldered. It is also possible to connect the
inputs to parallel I/O ports to switch frequencies. By
choosing divides carefully, the number of inputs which need
to be changed can be minimized. Observe the restrictions
on allowed values of VDW and RDW.
ICS525-04
OSCAR™ USER CONFIGURABLE PECL CLOCK
4
The output of the ICS525-04 can be determined by the
following simple equation:
Where:
Also, the following operating ranges should be observed:
The dividers are expressed as integers. For example, if a
66.66 MHz output on CLK1 is desired from a 14.31818 MHz
input, the VCO divider word (VDW) should be 276, with an
output divide (OD) of 2. In this example, R6:R0 is 0111011,
V8:V0 is 100010100 and S2:S0 is 001. Since all of these
inputs have pull-up resistors, it is only necessary to ground
the zero pins, namely V7, V6, V5, V3, V1, V0, R6, R2, S2,
and S1.
To determine the best combination of VCO, reference, and
output divide, use the ICS525 Calculator on our web site:
www.idt.com. The online form is easy to use and quickly
shows you up to three options for these settings.
See table on page 2 for full details of maximum output.
10M
200kHz
PECL Frequency
<
Input Frequency
Reference Divider Word (RDW) = 0 to 127
VCO Divider Word (VDW) = 0 to 511
Output Divider (OD) = values on page 2
<
InputFrequency
---------------------------------------------- -
RDW
+
=
2
x
Input Frequency
-----------------------------
RDW
VDW
+
+
8
2
<
200M 5V or162M 3.3v
-------------------------------------------- -
ICS525-04
RDW
VDW
PECL MULTIPLIER
+
2
+
8
OD
REV E 051310