EVAL-AD7898CB Datasheet, PDF (2/13 Pages) Analog Devices – Evaluation Board for 5V, 12-Bit, Serial 220kSPS ADC in 8-Pin Package

EVAL-AD7898CB
LINK AND SWITCH OPTIONS
There are 11 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
Function.
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.
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 VIN 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 is used to select the source of the reference voltage applied to the AD7898 REFIN pin.
When this link is in position "A", the AD780 provides the 2.5V reference to the AD7898.
When this link is in position "B" an external reference must be supplied via J5.
This link selects the source of the V_DD +5V supply.
When this link is in position "A" the +5V is supplied from the EVALUATION-BOARD CONTROLLER.
When this link is in position "B" the +5V must be supplied from an external source via J2.
This link option selects the source of the CS/CONVST input.
When this link is in position "A" the CS/CONVST input is provided by the EVALUATION-BOARD
CONTROLLER.
When this link is in position "B" the CS/CONVST input is provided via the external socket, J6.
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" an external VDRIVE supply voltage must be supplied via J7.
This link link option selects the source of the SCLK input.
When this link is in position "A" the SCLK input is provided by the EVALUATION-BOARD CONTROL-
LER.
When this link is in position "B" the SCLK input is provided via the external socket, J9.
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, J3.
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, J3.
These two link options are used to add an invertor to the SCLK path.
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. "B" is the normal position for these 2 link
options.
–2–
REV. 0