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CC115L: Looking for LowCost transmitter-chip, low current in coin cell application

GGA
Genius 3985 points
Part Number: CC115L
Other Parts Discussed in Thread: CC1120, , CC1311R3, CC1310

Hello,

working with CC112x since many years, now we do have the need of a low cost TX chip, which works with CR2032 coin cells in a keyfob (large volume).

The main application will work with FSK and appr. 20ms packet length  (as we need to provide an MCU anyway, we can do packeting by bit-bang, if the chip doesn't provide a packet engine), receiver is a CC1120 in packet mode. (Another -legacy- mode will be ASK with >100ms packet length, legacy receiver. We expect much less current consumption in ASK, so if it fits for FSK 20ms it should also fit for this ASK mode).

Operation is under ETSI EN regulations, so it needs to meet all the OOB and harmonics limitations.

CC115L would fit, but (as usual with all CC's < CC13xx) we do have a current issue: minimum current of all CC11x is ~25mA for a few dBm PA plus the MCU.
The coin cell can't deliver more than 15mA (short term only)- with a simple cap one can't mitigate. And a buck isn't possible due to budget.

Thanks in advance for advice!

  • 0
    TI__Expert 4940 points

    Hi,

    What output power would you like to achieve? For the ASK legacy receiver, is OOK support ok?

  • 0 in reply to Diego P
    Genius 3985 points

    PA of 5-7 dBm is ok, and yes, OOK is fine

  • 0 in reply to GGA
    TI__Expert 4940 points

    Unfortunately, as you have noted, from our transceiver portfolio we don't have a device that has a Tx current consumption under 15 mA  with 5-7 dBm output power. since your application requires an MCU have you considered using one of our wireless MCUs? For example the CC1310 or CC1311R3 might work for your application. Radio Tx current consumption at 10 dBm is 13.4 mA typical for the CC1310 and 13.9 mA for the CC1311R3.

  • 0 in reply to Diego P
    Genius 3985 points

    Diego, thx.

    It's an old game meanwhile: we use CC112x since almost 10 years now and are fine with all the functions and reliability. But current is always a mess. I keep asking for it....

    Talked that subject to a TI product manager about 8 years ago and got promised "there will be something with CC's RF ability and TI's low power knowledge from former mobile projects". Happy about it.
    Then TI launched CC13xx - great technology and current consumption.

    But: no real narrow band and it's a SoC. And everything what followed has been a SoC.
    This is by far too expensive (and oversized) for some of our projects: they need a low power RF plus a < 1$ MCU.

    I still don't understand why TI doesn't strip CC13xx from all Cortex M3/4 and IO stuff and issues just the RF core as single chip...

    But this is off topic....

    best regards