sx1231h Semtech Corporation, sx1231h Datasheet - Page 18

• Manufacturer Part Number: sx1231h
• Description: Low Power Integrated Uhf Transceiver With On-chip +20dbm Pa
• Manufacturer: Semtech Corporation

3.2.4. Lock Time
PLL lock time TS_FS is a function of a number of technical factors, such as synthesized frequency, frequency step, etc.
When using the built-in sequencer, the SX1231H optimizes the startup time and automatically starts the receiver or the
transmitter when the PLL has locked. To manually control the startup time, the user should either wait for TS_FS max given
in the specification, or monitor the signal PLL lock detect indicator, which is set when the PLL has is within its locking
range.
When performing an AFC, which usually corrects very small frequency errors, the PLL response time is approximately:
In a frequency hopping scheme, the timings TS_HOP given in the table of specifications give an order of magnitude for the
expected lock times.
3.2.5. Lock Detect Indicator
A lock indication signal can be made available on some of the DIO pins, and is toggled high when the PLL reaches its
locking range. Please refer to Table 21 and Table 22 to map this interrupt to the desired pins.
Note
Rev 1 - Oct 2011
ADVANCED COMMUNICATIONS & SENSING
The lock detect block may indicate an unlock condition (signal toggling low) when the transmitter is FSK modulated
with large frequency deviation settings.
T
PLLAFC
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PLLBW
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SX1231H
DATASHEET
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