STR25R100 Different system diagrams

[IGOR_DD]

HI,

i will have to use the STR25R100 in a project, and in the datasheet 3 different system diagram are proposed to control the antenna; Differential antenna; singled-ended antenna and two singled-ended antenna.

Is somebody can explain to me what the fundamental difference between these 3 system diagram.

Is there one more powerful one with higher consumption?

I don't know which one must I choose?

thanks 

Igor

[Travis Palmer]

Hi Igor,

Lets start with the last one.

The two antenna single ended is, if you want to operate two antennas, single ended. The antennas can be operated after each other by switching certain registers.

The single ended antenna (only one) has less components as the differential one, but only one driver is used to drive the antenna. Compared to differential, less output power can be delivered to the matching network. 

In differential configuration. the antenna is connected in the middle of the H-Bridge. while one driver puts the one antenna side to VDD_DR, the other one puts it to GND_DR. in the next half wave it is vice versa. It means that the Antenna sees twice the voltage compared to single ended antenna and more power could be transmitted if required.

I recommend you to look through the antenna design application note, which also describes the adjustment of the output power as well as AN5592 - ST25R single ended antenna matching (also applicable for R200 and R100).

BR Travis