SI5345 Datasheet, PDF (43/62 Pages) Silicon Laboratories – 10-CHANNEL, ANY-FREQUENCY, ANY-OUTPUT JITTER ATTENUATOR/CLOCK MULTIPLIER

Si5345/44/42
5.9. Power Management
Unused inputs and output drivers can be powered down when unused. Consult the Si5345/44/42 Family
Reference Manual and ClockBuilder Pro configuration utility for details.
5.10. In-Circuit Programming
The Si5345/44/42 is fully configurable using the serial interface (I²C or SPI). At power-up the device downloads its
default register values from internal non-volatile memory (NVM). Application specific default configurations can be
written into NVM allowing the device to generate specific clock frequencies at power-up. Writing default values to
NVM is in-circuit programmable with normal operating power supply voltages applied to its V_DD and V_DDA pins.
The NVM is two time writable. Once a new configuration has been written to NVM, the old configuration is no
longer accessible. Refer to the Si5345/44/42 Family Reference Manual for a detailed procedure for writing
registers to NVM.
5.11. Serial Interface
Configuration and operation of the Si5345/44/42 is controlled by reading and writing registers using the I²C or SPI
interface. The I2C_SEL pin selects I²C or SPI operation. Communication with both 3.3 V and 1.8 V host is
supported. The SPI mode operates in either 4-wire or 3-wire. See the Si5345/44/42 Family Reference Manual for
details.
5.12. Custom Factory Preprogrammed Parts
For applications where a serial interface is not available for programming the device, custom pre-programmed
parts can be ordered with a specific configuration written into NVM. A factory pre-programmed part will generate
clocks at power-up. Custom, factory-preprogrammed devices are available. Use the ClockBuilder Pro custom part
number wizard (www.silabs.com/clockbuilderpro) to quickly and easily request and generate a custom part number
for your configuration.
In less than three minutes, you will be able to generate a custom part number with a detailed data sheet addendum
matching your design’s configuration. Once you receive the confirmation email with the data sheet addendum,
simply place an order with your local Silicon Labs sales representative. Samples of your preprogrammed device
will typically ship in about two weeks.
5.13. Enabling Features and/or Configuration Settings Unavailable in ClockBuilder Pro
for Factory Preprogrammed Devices
As with essentially all modern software utilities, ClockBuilder Pro is continuously updated and enhanced. By
registering at www.silabs.com, you will be notified whenever changes are made and what the impact of those
changes are. This update process will ultimately enable ClockBuilder Pro users to access all features and register
setting values documented in this data sheet and the Si5345/44/42 Family Reference Manual.
However, if you must enable or access a feature or register setting value so that the device starts up with this
feature or a register setting, but the feature or register setting is not yet available in CBPro, you must contact a
Silicon Labs applications engineer for assistance. One example of this type of feature or custom setting is the
customizable output amplitude and common voltages for the clock outputs. After careful review of your project file
and requirements, the Silicon Labs applications engineer will email back your CBPro project file with your specific
features and register settings enabled using what's referred to as the manual "settings override" feature of CBPro.
"Override" settings to match your request(s) will be listed in your design report file. Examples of setting "overrides"
in a CBPro design report are shown in Table 17.
Rev. 1.0
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