SI477X-EVB Datasheet, PDF (28/62 Pages) Silicon Laboratories – Complete antenna-to-audio evaluation system

Si477x-EVB
6.2. Daughtercard
Each evaluation kit will be provided with an Si477x daughtercard.
Each daughtercard contains the minimal application circuit, including the following:
Si477x Tuner IC
RF Input circuitry
Crystal
EEPROM for serial number, calibration constants, and crystal information
Each daughtercard features a number of test points with direct access to the tuner signal pins. These signals may
be disconnected from the baseboard connector by removing either a 0  jumper or by removing a solder dot on a
printed chevron pattern. Small vias allow for connection via wire-wrap wire.
The reference frequency is generated by the on-chip crystal oscillator by default. If desired, the reference clock
may be sourced by the baseboard oscillator or an external generator by removing the crystal and inserting a 0.1uF
capacitor to bridge the connection.
Refer to "7. Hardware Schematics and PCB Layout" on page 32 for daughtercard schematics and PCB layouts.
6.3. Baseboard
The Quark baseboard contains all support circuitry, including the following:
Power supplies: all four Si477x supplies derived from USB 5 V or wall pack 9 V supplies
USB HID-based communications interface via C8051F340 microcontroller
Test points for all tuner interface I/O lines
Direct and buffered L/R/MPX analog outputs
6.3.1. Power Supplies
On-board LDOs generate VA, VD, VIO1, and VIO2 supplies for the tuner. Three of these, VD, VIO1, and VIO2, are
adjustable via trimpot. Level translation to other blocks, such as the microcontroller, is via discrete translators.
Switch SW1 selects the LDO configuration as sourced from the 9 V coaxial connector or the USB 5 V supply from
the PC. When in the USB position, the 5 V analog supply to the tuner is derived directly from the PC USB supply.
Notes:
The USB power supply option is provided for convenience but may result in decreased RF performance
due to PC power supply noise and lack of regulation between PC and the tuner's analog power supply.
Regulation inaccuracy and cable loss may result in a VA supply voltage below specification.
Ensure any wall power supply has a maximum output voltage of less than 11 V. Higher voltages will
engage a clamping diode and may damage the LDOs.
Jumpers, shown highlighted in Figure 32. “Power Supply Jumpers”, select each tuner supply's source as either the
on-board LDO (shown) or external (via J1/J2).
Tuner supply currents may be measured by opening jumpers J9-J12 and inserting an ammeter in positions JP8-
JP11.
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Rev. 0.4