WMO2 G900 / G1800 / G1900
WCOM/GSM/WMO2/WMO2ATDOC
Friday 21 May 1999
WAVECOM confidential ©
9
2.6.2
Electrical environment
The following table sums up electrical constraints in an automotive
environment:
Length of transient
Cause
Energy
capability
Voltage
Amplitude
Possible
frequency of
application
Steady state
Failed Voltage Regulator
oo
+ 18 V
Infrequent
3 - 5 minutes
Jump start with 24 V
battery
oo
+/- 24 V
Infrequent
200ms to 400ms
Load dump - i.e.,
disconnection of battery
while at high charging
rates
≥
10 J
≤
125V
Infrequent
< 0.32 s
Inductive Load
Switching Transient
<1 J
-300V to +80V
Often
< 0.20 s
Alternator Field Decay
<1 J
-100V to -40V
Each Turn-Off
90ms
Ignition Pulse, Battery
Disconnected
<0.5 J
≤
75V
<500Hz Several
Times in vehicle
Life
1ms
Mutual Coupling in
Harness (Note)
<1 J
<200V
Often
15µs
Ignition Pulse, Normal
<0.001 J
<3V
<500Hz
Continuous
Accessory Noise
<1.5V
50 Hz to 10 kHz
Transceiver Feedback
20mV
R.F.
Note: These transients may be present on any wire in the vehicle.
