SI5368B-B-GQ Silicon Laboratories Inc, SI5368B-B-GQ Datasheet - Page 6
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SI5368B-B-GQ
Manufacturer Part Number
SI5368B-B-GQ
Description
IC ANY-RATE MULTI/ATTEN 100TQFP
Manufacturer
Silicon Laboratories Inc
Type
Clock Multiplierr
Specifications of SI5368B-B-GQ
Number Of Circuits
1
Package / Case
100-TQFP, 100-VQFP
Pll
Yes with Bypass
Input
Clock
Output
CML, CMOS, LVDS, LVPECL
Ratio - Input:output
4:5
Differential - Input:output
Yes/Yes
Frequency - Max
808MHz
Divider/multiplier
No/Yes
Voltage - Supply
1.62 V ~ 2.75 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Frequency-max
808MHz
Maximum Input Frequency
710 MHz
Minimum Input Frequency
0.002 MHz
Output Frequency Range
0.002 MHz to 1417 MHz
Supply Voltage (max)
2.75 V
Supply Voltage (min)
1.62 V
Maximum Operating Temperature
+ 85 C
Minimum Operating Temperature
- 40 C
Mounting Style
SMD/SMT
Operating Supply Voltage
1.8 V, 2.5 V
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
SI5368B-B-GQ
Manufacturer:
Silicon Laboratories Inc
Quantity:
10 000
Si5368
1. Functional Description
The Si5368 is a jitter-attenuating precision clock
multiplier for applications requiring sub 1 ps rms jitter
performance. The Si5368 accepts four clock inputs
ranging from 2 kHz to 710 MHz and generates five
independent, synchronous clock outputs ranging from
2 kHz to 945 MHz and select frequencies to 1.4 GHz.
The device provides virtually any frequency translation
combination across this operating range. Independent
dividers are available for every input clock and output
clock, so the Si5368 can accept input clocks at different
frequencies and it can generate output clocks at
different frequencies. The Si5368 input clock frequency
and clock multiplication ratio are programmable through
an I
output can be configured as a 2 to 512 kHz
SONET/SDH frame synchronization output that is
phase aligned with one of the high-speed output clocks.
Silicon Laboratories offers a PC-based software utility,
DSPLLsim, that can be used to determine the optimum
PLL divider settings for a given input frequency/clock
multiplication ratio combination that minimizes phase
noise and power consumption. This utility can be
downloaded from www.silabs.com/timing.
The Si5368 is based on Silicon Laboratories' 3rd-
generation DSPLL
rate frequency synthesis and jitter attenuation in a
highly integrated PLL solution that eliminates the need
for external VCXO and loop filter components. The
Si5368 PLL loop bandwidth is digitally programmable
and supports a range from 60 Hz to 8.4 kHz. The
DSPLLsim software utility can be used to calculate valid
loop bandwidth settings for a given input clock
frequency/clock multiplication ratio.
The Si5368 supports hitless switching between input
clocks in compliance with GR-253-CORE and GR-1244-
CORE that greatly minimizes the propagation of phase
transients to the clock outputs during an input clock
transition (<200 ps typ). Manual, automatic revertive
and non-revertive input clock switching options are
available. The Si5368 monitors the four input clocks for
loss-of-signal and provides a LOS alarm when it detects
missing pulses on any of the four input clocks. The
device monitors the lock status of the PLL. The lock
detect algorithm works by continuously monitoring the
phase of the input clock in relation to the phase of the
feedback clock. The Si5368 monitors the frequency of
CKIN1, CKIN3, and CKIN4 with respect to a reference
frequency applied to CKIN2, and generates a frequency
offset alarm (FOS) if the threshold is exceeded. This
FOS feature is available for SONET applications in
which both the monitored frequency on CKIN1, CKIN3,
and CKIN4 and the reference frequency are integer
multiples of 19.44 MHz. Both Stratum 3/3E and SONET
Minimum Clock (SMC) FOS thresholds are supported.
The Si5368 provides a digital hold capability that allows
6
2
C or SPI interface.
®
technology, which provides any-
Optionally, the fifth clock
Preliminary Rev. 0.3
the device to continue generation of a stable output
clock when the selected input reference is lost. During
digital hold, the DSPLL generates an output frequency
based on a historical average that existed a fixed
amount of time before the error event occurred,
eliminating the effects of phase and frequency transients
that may occur immediately preceding digital hold.
Fine phase adjustment is available and is set using the
FLAT register bits. The nominal range and resolution of
the FLAT[14:0] latency adjustment word are: ±110 ps
and 3.05 ps, respectively.
The Si5368 has five differential clock outputs. The
electrical format of the clock outputs is programmable to
support LVPECL, LVDS, CML, or CMOS loads. If not
required, unused clock outputs can be powered down to
minimize power consumption. The phase difference
between the selected input clock and the output clocks
is adjustable in 200 ps increments for system skew
control. In addition, the phase of one output clock may
be adjusted in relation to the phase of the other output
clock. The resolution varies from 800 ps to 2.2 ns
depending on the PLL divider settings. Consult the
DSPLLsim configuration software to determine the
phase offset resolution for a given input clock/clock
multiplication
debugging, a bypass mode is available which drives the
output clock directly from the input clock, bypassing the
internal DSPLL. The device is powered by a single 1.8
or 2.5 V supply.
1.1. External Reference
An
114.285 MHz 3rd overtone crystal is used as part of a
fixed-frequency oscillator within the DSPLL. This
external reference is required for the device to perform
jitter attenuation. Silicon Laboratories recommends
using a high-quality crystal from TXC (www.txc.com.tw),
part number 7MA1400014. An external 38.88 MHz
clock from a high quality OCXO or TCXO can also be
used as a reference for the device.
In digital hold, the DSPLL remains locked to this
external reference. Any changes in the frequency of this
reference when the DSPLL is in digital hold, will be
tracked by the output of the device. Note that crystals
can have temperature sensitivities.
1.2. Further Documentation
Consult the Silicon Laboratories Any-Rate Precision
Clock Family Reference Manual (FRM) for more
detailed information about the Si5368. The FRM can be
downloaded from www.silabs.com/timing.
Silicon Laboratories has developed a PC-based
software utility called DSPLLsim to simplify device
configuration, including frequency planning and loop
bandwidth selection. This utility can be downloaded
from www.silabs.com/timing.
external,
ratio
38.88 MHz
combination.
clock
For
or
system-level
a
low-cost