AS3935-BQFT ams, AS3935-BQFT Datasheet - Page 19

• Manufacturer Part Number: AS3935-BQFT
• Description: Interface - Specialized
• Manufacturer: ams

Specifications of AS3935-BQFT

• Rohs: yes
• Operating Supply Voltage: 2.4 V to 5.5 V
• Supply Current: 100 mA
• Maximum Power Dissipation: 0.1 W
• Mounting Style: SMD/SMT
• Package / Case: MLPQ-16
• Supply Voltage - Max: 5.5 V

AS3935
Datasheet - D e t a i l e d D e s c r i p t i o n
8.7 Analog Front-end (AFE) and Watchdog
The AFE amplifies and demodulates the AC-signal picked up by the antenna. Since the AS3935 is a lightning sensor based on narrowband
receiving technique (center frequency of 500kHz and a bandwidth of about 33kHz), the AFE bandwidth is meant to be greater than the antenna
bandwidth. In this way, it is possible to consider that the gain within the antenna bandwidth as constant.
The gain of the AFE by default is optimized to operate indoor (e.g. inside a building). If the AS3935 operates outdoor, then the AFE gain setting
has to be set to a lower value, as shown in the
Table 15. AFE Setting, Outdoor vs. Indoor
The output signal of the AFE is monitored by the watchdog, which enables the signal validation
input signal crosses a certain threshold. The AS3935 is automatically set back to Listening Mode once the Signal Validation block has made an
assessment on the nature of the received signal (lighting or disturber). With register REG0x01[3:0] it is possible to change the level of this
threshold to increase the robustness to disturbers. If higher thresholds are used, the AS3935 would loose sensitivity for very far lightning events,
with an improvement of the man-made disturber rejection as benefit.
Figure 20
Figure 20. Detection Efficiencies vs. Distance for Different Settings for WDTH, if SREJ=0000
www.austriamicrosystems.com
shows the degradation of the detection efficiency (sensitivity of lightning detection) over the distance for different threshold settings.
AFE Setting
60%
40%
20%
0.0
Outdoor
Indoor
0
WDTH
0000
0001
0010
0011
0100
0101
0110
1000
1001
1010
0111
Table
10
15. Indoor and Outdoor setting must be selected according to the type of the application.
Radius [km]
Revision 1.2
20
30
(see Signal Verification on page 11)
REG0x00[5:1]
10010
01110
40
in case the
19 - 27