Evaluation Board Hardware; Power Supplies; Link Options - Analog Devices EVAL-ADG2108EBZ User Manual

EVAL-ADG2108EBZ User Guide

EVALUATION BOARD HARDWARE

POWER SUPPLIES

The EVAL-ADG2108EBZ can be operated with both single and
dual supplies. The device is specified to operate in single-supply
mode at 12 V ± 10% and at 8 V ± 10% operation. It is also
specified to operate at ±5 V dual supply. To apply these supplies
to the evaluation board, the following guidelines apply:

V provides the digital supply for the
L
digital circuitry on the board. This supply can be applied
externally, or the USB port can be used to power the digital
circuitry (Link 5 inserted). Note that in this case, the logic
supply power is 3.3 V.

The positive supply voltage (for example, 8 V/12 V) is
applied between the AVDD and AGND inputs of the
ADG2108 evaluation board. Note that the maximum
single supply the chip can handle is 15 V. In this case,
AVSS must equal 0 V.

The negative supply (for example, −5 V) is applied between
AVSS and AGND inputs for the negative supply (V
the ADG2108. Note that the maximum voltage between
AVDD and AVSS is 15 V.
Table 1. Link Functions
Link No. Function
LK1 This link chooses the LSB bit of the chip address on the USB I
evaluation board software is launched.
When inserted, the address bit is set to 0.
When removed, the address bit is set to 1.
LK2 This link chooses the second LSB bit of the chip address on the USB I
the evaluation board software is launched.
When inserted, the address bit is set to 0.
When removed, the address bit is set to 1.
LK3 This link chooses the third LSB bit of the chip address on the USB I
evaluation board software is launched.
When inserted, the address bit is set to 0.
When removed, the address bit is set to 1.
LK4 This link selects whether the supply at V
supply system.
Position A: V sourced from AVSS.
SS
Position B: V is connected to ground. This implies single-supply operation of the ADG2108.
SS
LK5 This link selects whether the logic supply power comes from the USB power (if connected to a PC) or from the user supplied V
(if used as a standalone unit).
When inserted, logic power supply comes from USB power, that is, 3.3 V.
When removed, logic power supply comes from user supplied V
ADG2108 and all
) of
SS
is sourced from ground or from the input AVSS. If sourced from ground, it is a single-
SS
Rev. B | Page 3 of 12
Both analog GND and digital GND inputs are provided on the
board. The AGND and DGND planes are connected at one
location close to the ADG2108. It is recommended not to
connect AGND and DGND elsewhere in the system to avoid
ground loop problems.
Each supply is decoupled to the relevant ground plane with
10 μF and 0.1 μF capacitors. Each device supply pin is also
decoupled with a 10 μF and 0.1 μF capacitor pair to the relevant
ground plane.

LINK OPTIONS

There are a number of links and switch options on the evaluation
board that must be set for the required operating setup before
using the board. The functions of these link options are described
in Table 1.
2 2
C interface. Note that the I C address must be set before the
2
C interface. Note that the I
2
C interface. Note that the I
.
L
UG-465
2
C address must be set before
2
C address must be set before the
L