Evaluation Kit for CMX724x/CMX734x
PE0403
2014 CML Microsystems Plc
18
um0403/1
6.1.3. Control Interface
The C-BUS and CMX7240/CMX7340 boot control signals are brought out on connector J7. This is a right
angle male header designed to plug directly into the PE0002 interface card that has a matching female
header.
Alternatively, if not using the PE0002, the CMX7240/CMX7340 boot control signals can be manually set
with jumpers on header J2.
6.1.4. Baseband Interfacing
The availability and usage of these signals are Function Image
TM
dependent.
PE0403-724x only:
The CMX7240 single ended inputs are fed through a RC network. Specific requirements for this network
are FI dependent. Single-ended signals can be input to the RC networks at header, J9, but must be biased
around AVDD/2.
PE0403-734x only:
The CMX7340 differential inputs are fed through a RC network. Specific requirements for this network are
FI dependent
. Differential signals can be input to the RC networks at header, J9. The ‘P’ and ‘N’ signals
should each be biased, nominally, around AVDD/2 for maximum use of the available dynamic range. CML
evaluation kits for RF receiver products have matching headers, but the signal polarity must be observed.
Alternatively, check Function Image
™ documentation for the possibility of a programmable signal
inversion.
The MIC input and Audio output connections can be made via 3.5mm jack sockets, see section 6.1.6.
The MOD1 and MOD2 outputs can be accessed by using J14 and J17 respectively. Both MOD outputs
have the option of using 50 Ohm drivers; this can be configured with J13 and J16 for MOD1 and MOD2
respectively. To configure the outputs, short pin 2 and pin 1 to use the 50 Ohm driver, or short pin 2 and
pin 3 to bypass the driver. Use of this section of the PE0403 requires an additional negative supply rail,
nominally
–5 volts.
For example: to use the 50 Ohm driver with the MOD1 output connect J13 pin 1 to pin 2.
Connector J8 provides access to Auxiliary ADCs 1 to 4 and Auxiliary DACs 1 to 4 of the
CMX7240/CMX7340 reference device.
6.1.5. Instrumentation Interface
An instrumentation interface has been provided to enable connection of the signal inputs to laboratory
equipment that has only single-ended connections. Use of this section of the PE0403 requires an
additional negative supply rail, nominally
–5 volts.
PE0403-724x only:
The input path has a gain of 0dB.
The input path is configured to give a signal biased around AVDD/2 at the input to the CMX7240,
assuming that the input signal is biased around GNDA. This can be made adjustable by removing resistors
R34 and R31 then replacing them with 50k Ohm potentiometers in positions VR2 and VR1 for the DISC
and ALT input paths respectively. Bourns type 3386P or similar will fit the footprints provided.
PE0403-734x only:
The input path has an effective gain of 6dB.
The input path is configured for, nominally, 0 volts offset in the differential signal input to the CMX7340,
assuming that the input signal is biased around GNDA. This can be made adjustable by removing resistors
