™
Ultra Series Crystal Oscillator
Si541 Data Sheet
Ultra Low Jitter Dual Any-Frequency XO (125 fs), 0.2 to 1500 MHz
The Si541 Ultra Series™ oscillator utilizes Silicon Laboratories’ advanced 4th gen-
eration DSPLL® technology to provide an ultra-low jitter, low phase noise clock at
two selectable frequencies. The device is factory-programmed to provide any two
selectable frequencies from 0.2 to 1500 MHz with <1 ppb resolution and maintains
exceptionally low jitter for both integer and fractional frequencies across its operat-
ing range. The Si541 offers excellent reliability and frequency stability as well as
guaranteed aging performance. On-chip power supply filtering provides industry-
leading power supply noise rejection, simplifying the task of generating low jitter
clocks in noisy systems that use switched-mode power supplies. Offered in indus-
try-standard 3.2x5 mm and 5x7 mm footprints, the Si541 has a dramatically simpli-
fied supply chain that enables Silicon Labs to ship custom frequency samples 1-2
weeks after receipt of order. Unlike a traditional XO, where a different crystal is re-
quired for each output frequency, the Si541 uses one simple crystal and a DSPLL
IC-based approach to provide the desired output frequencies. This process also
guarantees 100% electrical testing of every device. The Si541 is factory-configura-
ble for a wide variety of user specifications, including frequency, output format,
and OE pin location/polarity. Specific configurations are factory-programmed at
time of shipment, eliminating the long lead times associated with custom oscilla-
tors.
KEY FEATURES
• Available with any two selectable frequencies
from 0.2 MHz to 1500 MHz
• Very low jitter: 125 fs Typ RMS
(12 kHz – 20 MHz)
• Excellent PSRR and supply noise immunity:
–80 dBc Typ
• 7 ppm stability option (-40 to 85 C)
• 3.3 V, 2.5 V and 1.8 V V supply operation
DD
from the same part number
• LVPECL, LVDS, CML, HCSL, CMOS, and
Dual CMOS output options
• 3.2×5, 5x7 mm package footprints
• Any custom frequency available with 1-2
week lead times
APPLICATIONS
Pin Assignments
• 100G/200G/400G OTN, coherent optics
• 10G/40G/100G optical ethernet
1
2
3
6
5
4
VDD
CLK-
CLK+
OE/FS
FS/OE
GND
• 3G-SDI/12G-SDI/24G-SDI broadcast video
• Servers, switches, storage, NICs, search
acceleration
• Test and measurement
• Clock and data recovery
• FPGA/ASIC clocking
(Top View)
Fixed
Frequency
Crystal
Frequency
Flexible
DSPLL
Pin #
Descriptions
Low
Noise
Driver
1, 2
Selectable via ordering option
OE = Output enable; FS = Frequency Select
DCO
Digital
Phase
Detector
Digital
Phase Error
Loop
OSC
Cancellation
Filter
3
4
5
GND = Ground
Flexible
Formats,
1.8V – 3.3V
Phase Error
CLK+ = Clock output
Fractional
Operation
Divider
CLK- = Complementary clock output. Not used
for CMOS.
NVM
Control
Power Supply Regulation
6
VDD = Power supply
OE, Frequency Select
(Pin Control)
Built-in Power Supply
Noise Rejection
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