Evaluation Board Hardware; Power Supplies; Vocm Input; Smb Input/Output Connectors - Analog Devices AD8476 User Manual

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EVALUATION BOARD HARDWARE

POWER SUPPLIES

Power is applied to the board through test pins +V
(see Figure 3). The board accommodates single or dual supplies.
For single-supply operation, connect the negative supply to the
ground plane.
It is very important that the power supply pins of the device
under test (DUT) have a broadband decoupling circuitry. The
board layout facilitates this with footprints for a 0603 ceramic
capacitor (C1 and C2) on each supply. Bulk decoupling is
provided by C3 and C4; 10 µF tantalum capacitors are
recommended.

VOCM INPUT

To set the output common-mode voltage of the AD8476, an
and −V
S S
external voltage can be applied to VOCM via J3 (referenced
to the ground plane of the board) or the VOCM test point. In
ADC driving applications, it is convenient to apply the ADC
dc reference voltage output directly to J3. A 0.1 μF capacitor
(C5) is used in normal applications to provide bypassing for
the dc voltage applied to the VOCM pin.
VOCM can also be left unconnected. The
sets the output common-mode to mid-supply.

SMB INPUT/OUTPUT CONNECTORS

The inputs and outputs have through-hole SMB connector
footprints (which are compatible with most SMA connector
footprints) for convenient connection to coaxial cables. The
recommended connector type is Johnson Components™,
Part Number 131-0701-371 (jack) and 131-1801-371 (plug),
or equivalent.
Rev. 0 | Page 4 of 8
Evaluation Board User Guide
AD8476 internally