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AFE4490: AFE4490

Part Number: AFE4490
Other Parts Discussed in Thread: MSP430F2416

Hi,

My customer need assistance.

We designed a PCB with AFE4490 and MSP430F2416 controller.

When the board is connected to the SpO2 simulator we get correct SpO2 readings. But, when it is placed on a patient with low SpO2 the readings are always higher than 90%

The notable issue with our board is the INN, INP, TXN and TXP are not connected to same DB9 pins as shown in the AFE4490 development guide

INN  to Pin 9

INP   to Pin 5

TXN to Pin 2

TXP  to Pin 3

Please help. Thanks.

  • Hello Chong,

    With the TXN and TXP reversed, the red and IR leds are reversed. Then the SpO2 measurement will not be accurate since the ratios would be inverted.

    Also with the photodiode inputs reversed, the signal swing will be negative.