AS3930-BQFT austriamicrosystems, AS3930-BQFT Datasheet - Page 26

• Manufacturer Part Number: AS3930-BQFT
• Description: IC RF PROGRAM RECEIVER 16-QFN
• Manufacturer: austriamicrosystems

Specifications of AS3930-BQFT

• Rf Type: Read / Write
• Frequency: 110kHz ~ 150kHz
• Features: RSSI Equipped
• Package / Case: 16-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: AS3930-BQFTTR

AS3930
Data Sheet - D e t a i l e d D e s c r i p t i o n
Most wakeup receivers have to deal with environments that can rapidly change. By periodically monitoring the number of false wakeup events it
is possible to adapt the system setup to the actual characteristics of the environment and enables a better use of the full flexibility of AS3930.
Note: If the Manchester decoder is enabled, the false wakeup register is not able to store the false wakeup events.
Figure 20. Concept of False Wakeup Register together with System
8.9 Real Time Clock (RTC)
The RTC can be based on a crystal oscillator (R1<0>=1), the internal RC-oscillator (R1<0>=0) or an external clock source (R1<0>=1). The
crystal has higher precision of the frequency but a higher current consumption and needs three external components (crystal plus two
capacitors). The RC-oscillator is completely integrated and can be calibrated if a reference signal is available for a very short time to improve the
frequency accuracy. The calibration gets started with the trim_osc direct command. Since no non-volatile memory is available on the chip, the
calibration must be done every time after battery replacement. Since the RTC defines the time base of the frequency detection, the selected
frequency (frequency of the crystal oscillator or the reference frequency used for calibration of the RC oscillator) should be about one forth of the
carrier frequency:
Where: F
Note: The third option for the RTC is the use of an external clock source, which must be applied directly to the XIN pin (XOUT floating).
www.austriamicrosystems.com/AS3930
CAR
is the carrier frequency and F
Frequency Detector
Register Setup
Microcontroller
RTC
is the RTC frequency
Wakeup
Level1
F
RTC
READ FALSE WAKEUP REGISTER
~ F
CAR
Revision 1.0
* 0.25
Pattern Correlator
False wakeup
register
Unsuccessful
correlation
pattern
Wakeup
Level2
WAKE
(EQ 1)
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