LLCC68 datasheet(72/111 Pages) SEMTECH

72 / 111 page

LLCC68

Data Sheet

Rev. 1.1

DS.LLCC68.W.APP

Dec 2024

72 of 111

Semtech

LLCC68

www.semtech.com

Figure 13-2: RX Duty Cycle Energy Profile

Upon preamble detection, the radio is set to look for a Sync Word (in GFSK) or a header (in LoRa) and the timer is restarted with a new value

which is computed as

2 * rxPeriod + sleepPeriod. This is to ensure that the radio does not spend an indefinite amount of time waiting in Rx

for a packet which may never arrive (false preamble detection).

This implies a strong relationship between the time-on-air of the packet to be received, and the amount of time the radio spends in RX and

in SLEEP mode. If a long preamble is used on the TX side, care must be taken that the formula below is respected:

Tpreamble + Theader ≤ 2 * rxPeriod + sleepPeriod

Figure 13-3: RX Duty Cycle when Receiving

Note: When using a TCXO controlled by the LLCC68 itself, the startup delay defined in delay(23:0) is added between the Sleep and

Rx periods.

time

Radio Current

rxPeriod

sleepPeriod

500 us

Radio in SLEEP mode

Radio in RX mode

Radio in STDBY_RC

500 us

Radio in RX mode

time

Radio Current

Preamble Detected

2 x rxPeriod + sleepPeriod

Radio in RX mode

Radio in STDBY_RC

500 us

Radio in SLEEP mode

LLCC68 Datasheet(PDF) 72 Page - Semtech Corporation