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PN7150 - Standby Mode

Question asked by Adrian Pakosiński on May 17, 2017
Latest reply on Jun 2, 2017 by Adrian Pakosiński

Hello,

 

I have a question about standby mode in the   PN7150 chip. I have a running example NXP-NCI LPCXpresso example (SW3241) - NXP-NCI_LPC11xx_example on my uC. I would like very low current consumption on my device so I want to use standby mode. Theoretically, it is enabled. Below a snippet of code and send command and response from PN7150.

 

NxpNci_CORE_STANDBY[]={0x2F, 0x00, 0x01, 0x01};    /* last byte indicates enable/disable */

...

NCI >>  0x2f  0x00  0x01  0x01
NCI <<  0x4f  0x00  0x01  0x00

...

I measured current on the oscilloscope. These  waveforms show voltage drop on 1 Ohm resistor.

 

The first graph shows current on listening  mode and the second when  the  card is reading.

 

As you can see Imax = 223mA. This is a value that is not consistent with the catalog note. I will add that when I  disable standby mode (NCI >>  0x2f  0x00  0x01  0x00). The waveforms looked the same, the current has the same value.  Why the current is so large? What could be the reason?

 

Best Regards,

Adrian Pakosinski

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