Sierra Wireless AIRPRIME WISMO218 - Manual (Page 61)

WA_DEV_W218_PTS_002 Rev 006 April 29, 2010 61
Product Technical Specification &
Customer Design Guidelines Interfaces
BUZZER
C1 D1
VBATT
R1
WISMO218
34
R2
R3
T1
GND GND
Figure 28. Example of Buzzer Implementation
Where:
 R1 must be chosen in order to limit the current at I
PEAK
max of 100mA and must be adjusted in
function of the frequency and the duty cycle used.
 D1 = BAV70T-7 or BAS16 (for example)
 T1 = FDN335N (for example)
 R2 = 0
 R3 = 1M
 A low filter is recommended at low frequencies.