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What is the output power of the ST25R3916-DSICO board?

SSita
Associate

The X-Nucleo-NFC06A1 mentions 1.7W output power with differential antenna.

I understand that the ST25R3916 chip is capable of 1.7W max output. I've been unsuccessful in finding out what the output power of the DISCO board is.

1 ACCEPTED SOLUTION

Accepted Solutions
Travis Palmer
ST Employee

Hello SSita,

The maximum output power is mentioned in the ST25R3916 Datasheet. It depends on many factors like supply voltage and proper selection of the matching circuit.

The easiest was to estimate the output power is to measure the Power consumed by the ST25R3916 and then calculate the output power by P_out = P_in - P_d.

P_d ... dissipated power in the IC.

This is an example which does not relate to any demoboard.

Since the P_In depends on your power supply , please measure and calculate those values accordingly.

VDD = 5V ... supply voltage of the ST25R3916

I_VDD = 200mA ... Current consumption during Tx

I_rdy 20mA ... Current consumption during ready mode

R_dson 1.6Ohm ... typcial driver resistance

VDD_RF 4.7V ... regulated driver supply

P_rdy ... power dissipated by the analog and digital circuit

P_reg ... power dissipated by the internal regulator

P_drv ... power dissipated by the driver during Tx

P_in = VDD * I_VDD = 5 * 0.2 = 1W

P_d = P_rdy + P_reg + P_drv

P_rdy = VDD * I_rdy = 5*0.02 = 0.1W

P_reg = (VDD - VDD_RF)*(I_VDD-I_rdy) = 0.3*0.18 = 0.054W

P_drv = (I_VDD-I_rdy)*(I_VDD-I_rdy)*R_dson*2 = 0.18*0.18*1.6*2=0.10368W

P_out = 1 - (0.1+0.054+1.0368) = 1 - 0.25768 = 0.74232W

By lowering the target matching impedance and increasing the VDD the I_VDD can be increased. Also the dissipated power inside the IC will increase.

br Travis

View solution in original post

1 REPLY 1
Travis Palmer
ST Employee

Hello SSita,

The maximum output power is mentioned in the ST25R3916 Datasheet. It depends on many factors like supply voltage and proper selection of the matching circuit.

The easiest was to estimate the output power is to measure the Power consumed by the ST25R3916 and then calculate the output power by P_out = P_in - P_d.

P_d ... dissipated power in the IC.

This is an example which does not relate to any demoboard.

Since the P_In depends on your power supply , please measure and calculate those values accordingly.

VDD = 5V ... supply voltage of the ST25R3916

I_VDD = 200mA ... Current consumption during Tx

I_rdy 20mA ... Current consumption during ready mode

R_dson 1.6Ohm ... typcial driver resistance

VDD_RF 4.7V ... regulated driver supply

P_rdy ... power dissipated by the analog and digital circuit

P_reg ... power dissipated by the internal regulator

P_drv ... power dissipated by the driver during Tx

P_in = VDD * I_VDD = 5 * 0.2 = 1W

P_d = P_rdy + P_reg + P_drv

P_rdy = VDD * I_rdy = 5*0.02 = 0.1W

P_reg = (VDD - VDD_RF)*(I_VDD-I_rdy) = 0.3*0.18 = 0.054W

P_drv = (I_VDD-I_rdy)*(I_VDD-I_rdy)*R_dson*2 = 0.18*0.18*1.6*2=0.10368W

P_out = 1 - (0.1+0.054+1.0368) = 1 - 0.25768 = 0.74232W

By lowering the target matching impedance and increasing the VDD the I_VDD can be increased. Also the dissipated power inside the IC will increase.

br Travis