topic Re: Single-ended CLRC663 RF design in NFC

Single-ended CLRC663 RF design

hengma — Fri, 06 Dec 2024 12:30:53 GMT

Hi,

I have a question related to the single-ended CLRC663 RF circuit design. The datasheet mentions that the receiver can be configured in single-end mode by connecting RxN and RxP and setting the quasi differential mode in the rcv_rx_single register.

May I know how to configure the single-ended mode for TxN and TxP? Can I connect TxN and TxP? If so, is there any register setting for the TxN and TxP?

Thanks,

Heng

Re: Single-ended CLRC663 RF design

Tomas_Parizek — Fri, 06 Dec 2024 14:14:21 GMT

Hello hengma,

You should be able to change the phase of the TX signal using the following register. If both signal are in phase (TX1 and TX2). You should be able to connect them and get proper signal and waveform.

Tomas

Re: Single-ended CLRC663 RF design

hengma — Mon, 09 Dec 2024 12:08:58 GMT

Hi Tomas,

Thanks for your prompt reply.

In order to use a single-ended transmitter solution, shall I configure both Tx1Inv and Tx2Inv to 1 or 0? In this case, both TxN and TxP will deliver a non-inverted or inverted 13.56 MHz carrier, which is in phase.

Also, may I know the setting of TxEn? Can we define the source of the transmitter using the setting of TxEn?

Thanks,

Heng

Re: Single-ended CLRC663 RF design

Tomas_Parizek — Tue, 17 Dec 2024 12:40:13 GMT

Hello @hengma ,

Correct, Once both Tx paths are anabled and they are in phase. The maximum power of the TX driver can be used.

If only one TX side is enabled (TxEn), the power is reduced by 50%.

Tomas

Re: Single-ended CLRC663 RF design

hengma — Tue, 25 Feb 2025 10:14:26 GMT

Hi Tomas,

One more question, what is the desired impedance for the single-end solution? For the differential solution, the desired impedance is between 18 and 20 ohms for maximum field strength and power transfer. For the single-end solution, will the desired impedance become 10 ohms when measuring the TX and GND?

Thanks,

Heng

Re: Single-ended CLRC663 RF design

Tomas_Parizek — Wed, 26 Feb 2025 07:56:35 GMT

Hello hengma,

Yes, for single ended, the target impedance would be around 10 Ohms.

Once you tune your system to 10 Ohm, please also check the trasmitter current. You should not exceed the maximum TVDD current.

Tomas

Re: Single-ended CLRC663 RF design

hengma — Thu, 06 Mar 2025 13:26:09 GMT

Hi Tomas,

Thanks for the confirming.

Heng