EVAL-ADG772_15 Datasheet, PDF (3/8 Pages) Analog Devices – Evaluation Board for CMOS Low Power Dual 2:1

HARDWARE DESCRIPTION
USB DEVICE 1
ADG772 EVALUATION BOARD
TO USB DEVICE 1
USB DEVICE 2
TO USB HOST
ADG772
TO USB DEVICE 2
USB HOST
EVAL-ADG772
L3
L2
CONTROL SECTION:
SWITCHES CAN BE CONTROLLED MANUALLY BY
CHANGING JUMPER POSITIONS OR FROM AN EXTERNAL
SIGNAL SOURCE TO THE SMB CONNECTORS.
SMB CONNECTORS
Figure 2. Evaluation Board Application
The ADG772 evaluation kit contains a fully fitted PCB and a CD
that contains the ADG772 and the EVAL-ADG772 data sheets.
Ensure L1 is set to Position A to use the USB voltage supply and
set to Position B to use an external supply.
The evaluation board allows the user to connect the host to the
ADG772. The ADG772 then allows the host to switch between
two USB devices connected to the evaluation board by using the
on-board jumpers or by applying the correct control signals to
the appropriate connectors.
The following sections describe in detail the function of the
connectors and links.
POWER SUPPLY
For convenience, a regulator supplies the ADG772 with a 3.3 V
supply. If an external power supply is used, a supply range of
3.3 V to 12 V can be connected to J6.
The EVAL-ADG772 can also be powered from the USB port
from the PC. No additional power supply is required in this case.
SWITCH CONTROL CONNECTORS
The ADG772 device offers a standard CMOS/LVTTL parallel
interface consisting of two IN inputs. The input pins of the
ADG772, IN1 and IN2, control the switch state and operation
modes. The evaluation board allows users to control the signals
required to set the logic levels applied to these pins by using
links L2 and L3 as described in Table 1 or by applying external
signals to the SMB connectors, IN1 and IN2, respectively, as
described in Table 2.
To control the ADG772 using the SMB connectors, L2 and L3
must be set to Position B. Note that there are 51 Ω termination
resistors to GND at the IN1 and IN2 SMB connectors.
Table 1. Control via Link L2/Link L3
L2 and L3 Position
A
B
USB Device 1 Status
Inactive
Active
Switch Status
USB Device 2 Status
Active
Inactive
Table 2. Control via SMB Connector Settings
L2 and L3 Position
B
Switch Status—USB Device Status
SMB High = USB Device 2 Active
SMB Low = USB Device 1 Active
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