AS3932-BTST austriamicrosystems, AS3932-BTST Datasheet - Page 12

• Manufacturer Part Number: AS3932-BTST
• Description: IC RF PROGRAM 16-TSSOP
• Manufacturer: austriamicrosystems

Specifications of AS3932-BTST

• Rf Type: Read / Write
• Frequency: 110kHz ~ 150kHz
• Features: RSSI Equipped
• Package / Case: 16-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: AS3932-BTSTTR

AS3932
Datasheet - D e t a i l e d D e s c r i p t i o n
AS3932 needs the following external components:
In case the internal RC-oscillator is used (no crystal oscillator is mounted), the pin XIN has to be connected to the supply, while pin XOUT should
stay floating. Application diagrams with and without crystal are shown in
8.1 Operating Modes
8.1.1 Power Down Mode
In Power Down Mode AS3932 is completely switched off. The typical current consumption is 400 nA.
8.1.2 Listening Mode
In listening mode only the active channel amplifiers and the RTC are running. In this mode the system detects the presence of a carrier. In case
the carrier is detected the RSSI can be displayed.
If the three dimensional detection is not required it is possible to deactivate one or more channels. In case only two channels are required the
deactivated channel must be the number three, while if only one channel detection is needed the active channel must be the number one.
Inside this mode it is possible to distinguish the following three sub modes:
Standard Listening mode.
Scanning mode (Low Power mode 1).
for example all three channels are used in the first millisecond the only active channel is the number one, after the first millisecond the channel
three will be active for the same period of time and at the end the channel two will be working for one millisecond, handing over to the channel
one again. This channel rotation goes on until the presence of the carrier is detected by any of the channels; then immediately all three channels
will become active at the same time. Now AS3932 can perform a simultaneous multidirectional evaluation (on all three channels) of the field and
evaluate which channel has the strongest RSSI. The channel with the highest RSSI will be put through to the demodulator. In this way it is
possible to perform multidirectional monitoring of the field with a current consumption of a single channel, keeping the sensitivity as good as if all
channels are active at the same time.
Figure 11. Scanning Mode
www.austriamicrosystems.com/LF-Receiver/AS3932
Channel 2
Channel 3
of carrier
Channel 1
Presence
Power supply capacitor - CBAT – 100 nF
32.768 kHz crystal with its two pulling capacitors – XTAL and CL – (it is possible to omit these components if the internal RC oscillator is
used instead of the crystal oscillator).
One, two, or three LC resonators according to the number of used channels.
t 0
All channels are active at the same time
t 0 + T
All used channels are active, but only one per time slot, where the time slot T is defined as 1ms. If,
t 0 + 2 T
t 0 + 3 T
Revision 1.4
Figure 1
t 0 + 4 T
and
Figure 2
t 0 + 5 T
t 1
time
time
time
time
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