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Original question:

CC1020: RF sensitivity issue

CC1020: Sensitivity issue in CC1020 Transceiver

Surya Ganesh
Prodigy 40 points
Part Number: CC1020

Tool/software:

Hi everyone,

I'm facing the same sensitivity issue that has been discussed in the community, but unfortunately, I haven't seen any responses or solutions yet.

Issue: Sensitivity issue

Details: even I got similar sensitivity with same settings, I'm sharing the register values in text format below.

Rx

Reset:

00h – 1E/9E
00h – 1F/9F

Init:

01h – 70
04h – 39
05h – F0
06h – 0F
07h – 3A
08h – 39
09h – FA
0Ah – B9
0Bh – 3A
0Ch – 44
0Dh – 54
0Eh – 9B
0Fh – C6
10h – 2F
11h – FB
12h – 57
13h – 2F
14h – 38
15h – 20
16h – 78
17h – 47
18h – 14
19h – 22
1Ah – AE
1Bh – 34
1Ch – (00-FF)

Wakeup Rx:

00h – 1B (Turn on crystal oscillator)
00h – 19 (Turn on Bias generator)
00h – 11 (Turn on frequency synthesizer)

Setup Rx:

00h – 01
01h – 40

CC1020_calibrate:
1Ch – 00
1Bh – B4

1Ch – 0F

Setup PD:
00h – 1F
1Ch - 00

RESET:

02h – FF

INTERFACE:

03h - 8F

Tx

Reset:

00h – 1E/9E
00h – 1F/9F

            Init:

01h – 20
04h – 39
05h – F0
06h – 0F
07h – 3A
08h – 39
09h – FA
0Ah – B9
0Bh – 3A
0Ch – 44
0Dh – 54
0Eh – 9B
0Fh – C6
10h – 2F
11h – 61
12h – 55
13h – 2F
14h – 08
15h – 20
16h – 78
17h – 47
18h – 14
19h – 22
1Ah – AE
1Bh – 34
1Ch – (00-FF)

Wakeup Tx:

00h – DB (Turn on crystal oscillator)
00h – D9 (Turn on Bias generator)
00h – D1 (Turn on frequency synthesizer)

              Setup Tx:

00h – C1
1Ch – 01

    CC1020_calibrate:
              1Ch – 00
              1Bh – B4

1Ch – 0F

Setup PD:
00h – DF
1Ch - 00

RESET:

02h – FF

        INTERFACE:

03h - 8F

Can anyone provide guidance or solutions to resolve this issue?

  • 0
    TI__Genius 17915 points

    Hi,

    Are you measuring the RX Sensitivity according to the recommended test procedure in SWRA370 (Basic RF Testing of CCxxxx Devices): https://www.ti.com/lit/swra370 ?

    Please can you outline your test setup?

    Regards,

    Zack

  • 0 in reply to ZC
    Prodigy 40 points

    Hello, 

    Thanks for response. I have attached test setup for your reference and unmodulated carrier power is -28dBm. So, if 65 dB attenuation is given between Tx & Rx path, the received power level at RF in of transceiver to be considered is -91 dBm but in datasheet it was mentioned -112dBm. I have configured both synchronous NRZ mode with 4.8kbps data rate and tried to change VGA settings, deviation and loop filter values to 12.5KHz & 25KHz channel spacing.   

  • 0 in reply to Surya Ganesh
    TI__Genius 17915 points

    Hi,

    If you select a default PHY (completely unchanged), do you still observe the higher RX Sensitivity? Are you using a calibrated signal generator or a known "golden unit" to transmit the packets?

    Regards,

    Zack

  • 0 in reply to ZC
    Prodigy 40 points

    Hello,

    I did not observe higher RX sensitivity with the default PHY settings. Additionally, the signal generator we are using is properly calibrated. 

  • 0 in reply to Surya Ganesh
    TI__Genius 17915 points

    Thank you for clarifying.

    If the default settings also do not replicate the datasheet numbers then that suggests it is not a settings issue.

    The next step would be to double-check the LNA input matching network, described in Section 5.11 of the CC1020 datasheet:

    What is your frequency of operation? We would be interested in checking the values of L1 and C1:

    Regards,

    Zack