ICS291_10 Datasheet, PDF (4/10 Pages) Integrated Device Technology – TRIPLE PLL FIELD PROG. SPREAD SPECTRUM CLOCK SYNTHESIZER

ICS291
TRIPLE PLL FIELD PROG. SPREAD SPECTRUM CLOCK SYNTHESIZER
EPROM CLOCK SYNTHESIZER
Spread Spectrum Modulation can be applied as either
“center spread” or “down spread”. During center spread
modulation, the deviation from the target frequency is equal
in the positive and negative directions. The effective
average frequency is equal to the target frequency. In
applications where the clock is driving a component with a
maximum frequency rating, down spread should be applied.
In this case, the maximum frequency, including modulation,
is the target frequency. The effective average frequency is
less than the target frequency.
The ICS291 operates in both center spread and down
spread modes. For center spread, the frequency can be
modulated between ±0.125% to ±2.0%. For down spread,
the frequency can be modulated between -0.25% to -4.0%.
Both output frequency banks will utilize identical spread
spectrum percentage deviations and modulation rates, if a
common VCO frequency can be identified.
Spread Spectrum Modulation Rate
The spread spectrum modulation frequency applied to the
output clock frequency may occur at a variety of rates. For
applications requiring the driving of “down-circuit” PLLs,
Zero Delay Buffers, or those adhering to PCI standards, the
spread spectrum modulation rate should be set to 30-33
kHz. For other applications, a 120 kHz modulation option is
available.
Absolute Maximum Ratings
Stresses above the ratings listed below can cause permanent damage to the ICS291. 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.
Parameter
Supply Voltage, VDD
Inputs
Clock Outputs
Storage Temperature
Soldering Temperature
Junction Temperature
Condition
Referenced to GND
Referenced to GND
Referenced to GND
Max 10 seconds
Recommended Operation Conditions
Min.
-0.5
-0.5
-65
Typ.
Max.
7
VDD+0.5
VDD+0.5
150
260
125
Units
V
V
V
°C
°C
°C
Parameter
Ambient Operating Temperature (ICS291GP)
Ambient Operating Temperature (ICS291GIP)
Power Supply Voltage (measured in respect to GND)
Power Supply Ramp Time
Min.
0
-40
+3.135
Typ.
+3.3
Max.
+70
+85
+3.465
4
Units
°C
°C
V
ms
IDT™ / ICS™ TRIPLE PLL FIELD PROG. SPREAD SPECTRUM CLOCK SYNTHESIZER 4
ICS291
REV F 051310