SI5356-EVB Datasheet, PDF (3/16 Pages) Silicon Laboratories – Fully powered from a single USB port

Si5356-EVB
2.1. Status LEDS
There are three status LEDs on the EVB:
 RDY (Green) indicates that the EVB is operating as normal. This LED should always be on.
 BUSY (Green) lights when there is active communication between the PC, the MCU, and the Si5356.
 INTR (Red) indicates the MCU has detected that the interrupt pin of the Si5356 device is enabled. The most
probable cause for an interrupt is because the Si5356 has lost its input signal or the PLL has lost lock. The
“Status” tab of the GUI will identify the event that caused the interrupt to happen.
2.2. Inputs
The Si5356 EVB provides two reference options - using the on-board XTAL or an external reference.
Note: Si5356-EVB Rev 1.0 does not support synchronous operation using the CLKIN input. This feature will be supported in
future revisions.
2.2.1. External Input reference
An SMA connector (CLKIN) is provided to receive an external single-ended CMOS signal. This input is dc-coupled
to the device. The signal should have a minimum amount of dc bias to ensure that it never swings below ground
level.
2.2.2. On-board XTAL
The on-board 25 MHz allows the Si5356 EVB to generate asynchronous clocks. To use this option, select the XTAL
input from the Si5356 “ClockBuilder Desktop” software.
2.3. Outputs (CLK0-CLK7)
Each of the eight output clocks can be accessed using SMA connectors. The outputs are dc-coupled (no in-line dc
blocking capacitors between the output pin and the SMA connector).
2.4. Control Pins
Header J7 located on the backside of the Si5356 EVB allows setting three Si5356 control pins: SSC_DIS,
I2C_LSB, and OEB.
2.4.1. SSC_DIS
This pin allows disabling of the spread spectrum feature on the output clocks. Spread spectrum is disabled when
the jumper is installed.
2.4.2. I2C_LSB
This pin is the least significant bit of the Si5356 I²C address allowing up to two Si5356 devices to occupy the same
I²C bus. I²C address of the Si5356 = 0x70 when the jumper is installed. I²C address of the Si5356 = 0x71 when the
jumper is not installed.
2.4.3. OEB
This pin allows disabling all output clocks. All outputs are enabled when the jumper is installed.
2.5. Voltage Regulators
The Si5356 EVB has five built-in programmable voltage regulators to allow setting of the VDD supply (to 3.3 V,
2.5 V, and 1.8 V) and the four VDDO supplies (to 3.3 V, 2.5 V, and 1.8 V). The voltage level on each of these
supplies can be set independently.
2.6. Reset Switch
A reset switch is provided to reset communication between the PC and Si5356 EVB.
Rev. 0.2
3