Proprietary Knowledge Base

    Publish
     
      • Replacement for the uPG2214 SPDT RF-switch

        zovida | 03/76/2014 | 07:48 AM

        Question

        What kind of RF-switch is recommended for the replacement of the uPG2214 SPDT RF-switch used in most of reference designs?

        Answer

        The RF-switches listed below can be good alternatives to replace the uPG2214 SPDT RF-switch. These switches have approximately the same specifications/characteristics/ratings and footprint as the uPG2214.

         

        Example list of RF switches for the replacement:

        - CG2179M2: http://www.cel.com/pdf/datasheets/CG2179M2.pdf

        - AS179: http://www.skyworksinc.com/Product/44/AS179-92LF

        AS213-92: http://www.skyworksinc.com/Product/57/AS213-92LF

        - SKY13323: http://www.skyworksinc.com/Product/615/SKY13323-378LF

        - CKRF2179: http://www.en.cdk.co.jp/products/highfrequency/rf/

        - UPG2179: http://www.cel.com/pdf/datasheets/upg2179tb.pdf

         

        The RF switch used in the designs needs to have:
        - low insertion loss
        - high enough frequency capability
        - high isolation

        - high enough power capability

        - low harmonic re-generation, i.e. low distortion

        - small size
        etc. 

         

        Good references for RF switch IC selection guide:

        http://www.cel.com/pdf/brochures/rf_switch_ic_web.pdf

        http://www.cel.com/pdf/press/phase-out_timeline.pdf

        http://www.en.cdk.co.jp/info/siryou/20160909.pdf

         

      • Supported TX power level settings for EM3xx chips

        zigmaster | 03/60/2014 | 05:51 AM

        Question

        What are the available TX power level settings for EM3xx chips?

        Answer

        The EM3xx chips (such as EM357 or EM3588) include a 2.4GHz DSSS radio, which is capable of output power levels ranging from -43 dBm to +8 dBm (prior to any external amplification by a PA or FEM).  This TX power level is set in software through an 8-bit, signed integer value in commands like NodeTest's "setTxPower" CLI command, or the EmberZNet Manufacturing Library's "mfglibSetPower()" API, or the radioTxPower member of the EmberNetworkParameters struct passed to the Ember Application Framework's emberAfJoinNetwork() or emberAfFormNetwork() functions.  However, because there is a limited number of registers available to select individual power levels, not every integer value in this range is selectable.  The granularity is focused on the top end of the range, where most users utilize the radio.

         

        The following list specifies the selectable power levels of the 2.4GHz PHY in the EM3xx chipset:

         

        -43,
        -26,
        -20,
        -17,
        -14,
        -12,
        -11,
        -9,
        -8,

        -7,

        -6,

        -5,

        -4,

        -3,

        -2,

        -1,

        0,

        +1,

        +2,

        +3,

        +4,

        +5,

        +6,

        +7,
        +8

         

        Note that any power levels above +3 dBm are considered "boost mode" for the transmitter and will consume significantly more current than other power levels.  Please consult the data sheet or reference manual for your EM3xx IC for electrical specifications.

         

        Also note that any power level chosen in software that is within the -43 to +8 range but doesn't correspond to an integer in this set will result in the next-lowest setting from the list.  For example, selecting TX power of -10 in software causes the PHY to choose the -11 dBm setting.