Evaluates: MAX4885E
MAX4885E Evaluation Kit
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Quick Start
Required Equipment
• MAX4885E EV kit
• 5V, 100mA DC power supply (optional)
• One user-supplied PC
• One 15-pin, VGA HD sub-D cable (all pins present)
• Two VGA monitors
Procedure
The MAX4885E EV kit is fully assembled and tested.
Follow the steps below to verify board operation.
Caution: Do not turn on the power supply until all
connections are completed.
1) Verify that a shunt is installed on pins 1-2 of jumper
JU1 (EV kit enabled).
2) Verify that a shunt is installed on pins 2-3 of jumper
JU2 (VGA0 connected to VGA1).
3) Connect the PC VGA output to the VGA0 connector.
4) Connect the first monitor to the VGA1 connector on
the EV kit.
5) Connect the second monitor to the VGA2 connector
on the EV kit.
6) Turn on the power to the PC and both monitors.
7) Verify that both green LEDs D3 and D4 are on (if
not, verify that the VGA cable from the PC has all 15
pins present. If pin 9 on the VGA cable is missing,
use an external power supply. Connect the 5V
external power supply across the VIN and GND
PCB pads.)
8) Verify that the first monitor is in operation, while the
second monitor is off.
9) Move the shunt on jumper JU2 to pins 1-2 (VGA0
connected to VGA2).
10) Verify that both green LEDs D3 and D5 are on.
11) Verify that the second monitor is in operation, while
the first monitor is off.
12) Move the shunt on jumper JU1 to pins 2-3 (EV kit
disabled).
13) Verify that both monitors are off. The LEDs remain in
their last position.
Detailed Description of Hardware
The MAX4885E evaluation kit (EV kit) is an assembled
and tested circuit board that contains all the compo-
nents necessary to evaluate the MAX4885E IC. The
MAX4885E is a 1:2 switch for VGA signals. The EV kit
can be powered from the 5V DC (typically up to 10mA)
that is delivered through the VGA cable or an external
regulated 5V DC power supply. The MAX4885E EV kit
also provides test points to monitor the individual video
signals on the EV kit.
Power Source Mismatch Protection
The EV kit circuit features two wired-OR Schottky
diodes (D1 and D2) to prevent damage due to mis-
matching power-supply voltages.
VGA Signal-Path Indicators
The MAX4885E EV kit features three LEDs (D3, D4, and
D5) to indicate the VGA signal paths on the EV kit.
LEDs D3 and D4 light when VGA0 is connected to
VGA1. Similarly, LEDs D3 and D5 light when VGA0 is
connected to VGA2.
Printed-Circuit Board (PCB)
The MAX4885E EV kit is built on a four-layer, 1oz cop-
per FR4 PCB. All the video signal trace impedances are
controlled to 75Ω and a matched length to 25 mils.
Jumper Selection
Enable, EN (JU1)
The MAX4885E EV kit provides jumper JU1 to enable or
disable the MAX4885E IC, thus reducing the supply
current to the EV kit. Table 1 lists JU1 options to enable
or disable the MAX4885E EV kit.
VGA Channel Select, SEL (JU2)
The MAX4885E EV kit provides jumper JU2 to select
the connection between the video source connector
(VGA0) to one of the two destination connectors (VGA1
or VGA2). Table 2 lists jumper JU2 options.
Table 1. JU1 Jumper Functions (EN)
