SI57X-EVB Datasheet, PDF (8/34 Pages) Silicon Laboratories – Si57X/598/599 ANY FREQUENCY I2C PROGRAMMABLE XO/VCXO EVALUATION BOARD

Si57x-EVB
1.6. Si57x/598/599 I²C Communication Configuration
The Si57x/598/599 supports I²C serial communication through the SDA and SCL pins. All Si570 and Si598 XOs
are pin and register compatible, and all Si571 and Si599 VCXOs are pin and register compatible. The device can
be operated as an I²C slave only. The MCU supports I²C communication to the DUT. The Si57x-EVB must be
configured by jumpers as described below to select the intended I²C communications path depending on the
DUT's nominal supply voltage.
For I²C communication with the Si57x/598/599 DUT = 2.5 or 3.3 V nominal, there must be jumpers installed at J1,
J2, and J11 pin 2. This defeats and bypasses the installed bidirectional voltage level translator at U3.
(For I²C communication with the Si57x/598/599 DUT at 1.8 V nominal supply, please consult the factory.)
1.7. Si57x/598/599 Digital Control Signals
There is one normally static digital input control signal that routes to the Si57x/598/599: Output Enable or OE. By
default, the OE signal is pulled HIGH on the Si57x-EVB and may be pulled low by installing a jumper at J9.
To support OE active LOW control, make the following changes to the Si57x motherboard:
 Install R9.
 Remove R14.
You can then selectively disable the OE active LOW by installing a jumper at J3. See Figure 4 for the location of
these components.
1.8. Si57x/598/599 Voltage Control Signal
An external voltage control signal may be applied to the control voltage modulation input at SMA connector J17,
silkscreen designation VC_MOD). This voltage supplies the control voltage or voltage modulation input to an Si571
when installed on the DB. No jumper changes are required to support the Si570/598 versus the Si571/599. Pin 1
on the Si571 is the V_C pin and is a N/C for the Si570.
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