Power Measurements - Analog Devices EZ-Board ADSP-21489 Manual

For more information about daughter boards, visit the Analog Devices
Web site at:
http://www.analog.com/en/embedded-processing-dsp/sharc/con-
tent/sharc_development_tools/fca.html
Limits to current and interface speed must be taken into consideration
when using the expansion interface II. Current for the expansion
interface II is sourced from the EZ-Board; therefore, the current should be
limited to 1A for 5V and 500 mA for the 3.3V planes. If more current is
required, then a separate power connector and a regulator must be
designed on a daughter card. Additional circuitry can add extra loading to
signals, decreasing their maximum effective speed.
Analog Devices does not support and is not responsible for the
effects of additional circuitry.

Power Measurements

Several locations are provided for measuring the current draw from vari-
ous power planes. Precision 0.05 ohm shunt resistors are available on the
VDDINT and VDDEXT voltage domains. For current draw measure-
ments, the associated jumper on connectors
Once the jumper is removed, voltage across the resistor can be measured
using an oscilloscope. Once voltage is measured, current can be calculated
by dividing voltage by 0.05. For the highest accuracy, a differential probe
should be used for measuring voltage across the resistor.
For more information, see
page 2-28 and
ADSP-21489 EZ-Board Evaluation System Manual
"VDDINT Power Connector (P14)" on
"VDDEXT Power Connector (P15)" on page
Using ADSP-21489 EZ-Board
.
must be removed.
P14—15
2-29.
1-21