SI5348 Datasheet, PDF (21/54 Pages) Silicon Laboratories – Network Synchronizer for SyncE/ 1588 PTP Telecom Boundary (T-BC) and Slave (T-SC) Clocks

3.9.13 Output Driver State When Disabled
The disabled state of an output driver is register configurable as disable low or high.
Si5348 Rev D Data Sheet
Functional Description
3.9.14 Synchronous/Asynchronous Output Disable
Outputs can be configured to disable synchronously or asynchronously. In synchronous disable mode the output will wait until a clock
period has completed before the driver is disabled. This prevents unwanted runt pulses from occurring when disabling an output. In
asynchronous disable mode, the output clock will disable immediately without waiting for the period to complete.
3.9.15 Output Divider (R) Synchronization
All the output R dividers are reset to a known state during the power-up initialization period. This ensures consistent and repeatable
phase alignment across all output drivers. Resetting the device using the RSTb pin or asserting the hard reset bit will have the same
result.
3.10 Power Management
Unused inputs, output drivers, and DSPLLs can be powered down when unused. Contact your local representative to access the
Si5348 Reference Manual and ClockBuilder Pro configuration utility for details.
3.11 In-Circuit Programming
The Si5348 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. Contact your local representative to access the Si5348 Reference Manual for a detailed proce-
dure for writing registers to NVM.
3.12 Serial Interface
Configuration and operation of the Si5348 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 mode. Contact your local representative to access the Si5348 Reference Manual for details.
3.13 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-pre-
programmed 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 pre-programmed device will typically ship in about two weeks.
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