SWRZ073C May   2017  – May 2021 IWR1642

 

  1. 1Introduction
  2. 2Device Nomenclature
  3. 3Device Markings
  4. 4Usage Notes
    1. 4.1 MSS: SPI Speed in 3-Wire Mode Usage Note
  5. 5Advisory to Silicon Variant / Revision Map
  6. 6Known Design Exceptions to Functional Specifications
    1.     MSS#10
    2.     MSS#11
    3.     MSS#12
    4.     MSS#14
    5.     MSS#16
    6.     MSS#17
    7.     MSS#18
    8.     MSS#19
    9.     MSS#20
    10.     MSS#22
    11.     MSS#37B
    12.     MSS#38A
    13.     MSS#39
    14.     MSS#42
    15.     MSS#43A
    16.     MSS#44
    17.     MSS#45
    18.     ANA#06
    19.     ANA#08A
    20.     ANA#09A
    21.     ANA#10A
    22.     ANA#11A
    23.     ANA#12A
    24.     ANA#15
    25.     ANA#16
    26.     ANA#17A
    27.     ANA#18B
    28.     ANA#20
    29.     ANA#21A
    30.     ANA#22A
    31.     ANA#24A
    32.     ANA#27
    33.     DSS#01
    34.     DSS#02
    35.     DSS#03
    36.     DSS#04
    37.     DSS#05
    38.     DSS#06
    39.     DSS#07
  7. 7Trademarks
  8. 8Revision History

ANA#12A

Second Harmonic (HD2) Present in the Receiver

Revision(s) Affected:

IWR1642 ES1.0 and ES2.0

Description:

There is a finite isolation between the RF pins/package and the FMCW synthesizer. This can create spurious tones at the synthesizer output and lead to appearance of 2nd order harmonics and inter-modulations of expected IF frequencies at RX ADC output. The amplitude of the 2nd harmonic could be as high as -55 dBc , referenced to the power level of the intended tone at the LNA input.

Workaround(s):

No workaround available at this time. However, in many typical radar use-cases the HD2 does not affect the system performance due to two reasons:

  1. Since the HD2 comes from a coupling to the LO signal, there is an inherent suppression of the HD2 level due to the self-mixing effect (that is, phase noise and phase spur suppression effect at the mixer).
  2. In real-life scenarios there is often a double-bounce effect of the radar signal reflected from the target, which leads to a ghost object at twice the distance of the actual object. This effect is often indistinguishable from the effect of HD2 itself.