EVAL-AD7475 Datasheet, PDF (2/13 Pages) Analog Devices – Evaluation Board for 1MSPS, 12-Bit ADC

EVAL-AD7475/AD7495CB
LINK AND SWITCH OPTIONS
There are 12 link options which must be set for the required operating setup before using the evaluation board. The
functions of these options are outlined below.
Link No.
LK1
LK2
LK3
LK4
LK5
LK6
LK7
LK8
LK9
LK10
LK11, LK12
Function.
This link is used to connect the input of the AD711 op-amp to ground if the user needs to do this.
When this link is in position "A" a signal applied to the AIN socket is routed to the input of the AD711 op-
amp. This is the normal application for this link.
When this link is in position "B", the input of the AD711 op-amp is tied to GND.
This link option controls the program pin of the AD780 voltage reference.
When this link is "inserted" the AD780 output is set to +3.0 V.
When this link is "removed" the AD780 output is set to +2.5 V
This link is used to select the source of the reference voltage applied to the AD7475 REFIN pin.
When this link is in position "A", the AD780 provides the 2.5V reference to the AD7475.
When this link is in position "B" an external reference must be supplied to the AD7475 via J5.
For the AD7495 this pin must be removed
This link selects the source of the V_DD +5V supply.
When this link is in position "A" the +5V is supplied from an exteranl source via J6.
When this link is in position "B" the +5V must be supplied from the EVALUATION-BOARD
CONTROLLER
This link option selects the source of the VDRIVE input.
When this link is in position "A" the VDRIVE supply voltage is provided from VDD.
When this link is in position "B" the VDRIVE supply voltage is provided from the EVALUATION-BOARD
CONTROLLER.
When this link is in position "C" an external VDRIVE supply voltage must be supplied via J7.
This link option is used to select the source of the +12V supply
In position A, the +12V is supplied from the EVALUATION-BOARD CONTROLLER through the 96 way
connector.
In position B, the +12V is supplied from an external source through the power connector, J8.
This link option is used to select the source of the -12V supply.
In position A, the -12V is supplied from the EVALUATION-BOARD CONTROLLER through the 96 way
connector.
In position B, the -12V is supplied from an external source through the power connector, J8.
This link option sets the dc bias voltage applied to the optional bais-up/filter circuit.
When the link is in position "A", the bias voltage is set to the same level as the voltage that is applied to the
REF IN on the AD7475 and the REF OUT pin on the AD7495. In this configuration a bipolar anlag input
applied to the Vin SMB socket as a unipolar signal biased around Vref/2. When in position "B", the bias
voltage is set to A_GND. In this configuration the bias up circuit is not used.
This link option adds a 50 Ohm termination to AGND at the Ain socket. In most applications this link will
be left unconnected. If a 50 Ohm termination is required, this link should be inserted.
This link option adds a 50 Ohm termination to AGND at the Vin socket. In most applications this link will
be left unconnected. If a 50 Ohm termination is required, this link should be inserted.
When both these links are in position "A", for slower SCLK frequencies, giving valid data on the rising edge.
When both these links are in position "B", for fast SCLK frequencies, giving valid data on the falling edge,
the SCLK signal is connected directly to the AD7898 SCLK pin. This is the normal position for these 2 link
options.
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