Si5355-EVB Silicon Laboratories Inc, Si5355-EVB Datasheet - Page 12

• Manufacturer Part Number: Si5355-EVB
• Description: Clock & Timer Development Tools Si5355 custom clk eval board
• Manufacturer: Silicon Laboratories Inc

Specifications of Si5355-EVB

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Si5355
3.5. Output Enable
Each of the device’s four banks of CMOS clock outputs can be individually disabled using OEB_01, OEB_23,
OEB_45 and OEB_67, respectively. Alternatively, all clock outputs can be disabled using the master output enable
OEB_all. When a Si5355 clock output bank is disabled, both outputs are driven to an active low state. When one or
more banks of clock outputs are enabled or disabled, clock start and stop transitions are handled glitchlessly.
3.6. Frequency Select/Device Reset
The device frequency plan is customized using the ClockBuilder web utility. The Si5355 optionally supports up to
three unique, pin-selectable configurations per device, enabling one device to replace up to three separate clock
ICs. To select a particular frequency plan, set the FS pins as outlined below:
For custom Si5355 devices configured to support 2 frequency plans, the FS pin should be set as follows:
For custom Si5355 devices configured to support 3 frequency plans, the FS[1:0] pins should be set as follows:
I
pulse width specified in Table 4 on page 6 to change the device configuration. The output clocks will be
momentarily squelched until the device begins operation with the new frequency plan.
The corresponding input/output frequency configuration (profiles) for a custom Si5355 device can be looked up
using the ClockBuilder web-based utility.
3.7. Loss-of-Signal Alarm
The Si5355 supports a loss of signal (LOS) output indicator for monitoring the condition of the crystal/clock
reference input. The LOS condition occurs when there is no input clock to the device. When an input clock is
removed, the LOS pin will assert and the output clocks may drift up to 5%. When the input clock with an
appropriate frequency is reapplied, the LOS pin will de-assert.
12
f a change is made to the FS[1:0] pin settings, the device reset pin (Reset) must be held high for the minimum
LOS Output
State
0
1
FS[1:0]
FS
00
01
10
11
0
1
Rev. 0.3
Loss of signal present
No loss of signal
Reserved
Description
Profile
Profile
1
2
1
2
3