Intrinsyc Open-Q 2500, User Manual

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Open-Q™ 2500 Development Kit User Guide Version 1.1
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Copyright Intrinsyc Technologies Corporation
Figure 4 - SOM Current Sense Header
The table below summarizes the pin outs of header J400
Table 3 - Power Header J400 Pin-out
Description Signal pin
SOM power positive current sense line SOM_PWR_SENSE_P J400[1]
SOM power negative current sense line SOM_PWR_SENSE_N J400[2]
GND GND J400[3]
To obtain power consumption measurements, the header is connected to a data acquisition unit (e.g.
Keithley 2701) and the voltages on the SOM_PWR_SENSE_P/N pins are captured every few
seconds over the test period (typically 30 minutes). The SOM power consumption is then calculated
as (where R
sense
= 5 milliohms):
𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃 = 𝑉𝑉𝑃𝑃𝑃𝑃𝑃𝑃
𝑝𝑝𝑝𝑝𝑟𝑟
𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑁𝑁
∗
( 𝑉𝑉𝑃𝑃𝑃𝑃𝑃𝑃
𝑝𝑝𝑝𝑝𝑟𝑟
𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑃𝑃
− 𝑉𝑉𝑃𝑃𝑃𝑃𝑃𝑃
𝑝𝑝𝑝𝑝𝑟𝑟
𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑁𝑁
)
𝑅𝑅𝑃𝑃𝑠𝑠𝑠𝑠𝑃𝑃𝑠𝑠
3.7.5 Coin Cell Battery Holder B400
The coin cell holder allows the user to use a coin cell for supplying power to the SOM VCOIN
power input. It is recommended that a Panasonics ML621 series rechargeable coin cell be used (not
supplied with the development kit).