AS3932-BQFT austriamicrosystems, AS3932-BQFT Datasheet - Page 28

• Manufacturer Part Number: AS3932-BQFT
• Description: IC RF PROGRAM 16-QFN
• Manufacturer: austriamicrosystems

Specifications of AS3932-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: AS3932-BQFTTR

AS3932
Datasheet - D e t a i l e d D e s c r i p t i o n
Figure 22. Concept of the False Wakeup Register together with the system
8.8 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 oscillator has higher precision of the frequency with 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
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/LF-Receiver/AS3932
CAR
is the carrier frequency and F
Frequency Detector
RTC
Register Setup
Microcontroller
is the RTC frequency
F
Wakeup
Level 1
RTC
~ F
READ FALSE WAKEUP REGISTER
CAR
Revision 1.4
* 0.25
Pattern Correlator
False wakeup
register
Unsuccessful
correlation
pattern
Wakeup
Level 2
WAKE
(EQ 1)
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