Specifications

AirPrime Embedded Module Hardware Integration Guide
24 Proprietary and Confidential 2130114
Inrush currents
The following power events can cause large inrush currents from the host supply
to the module on the power pins:
• Application of the host’s power supply
• Host leaves W_Disable# floating (high impedance) to power up the module
(as shown in Figure 2-1 on page 17).
Figure 2-4 and Figure 2-5 show the inrush models for the MC57xx and MC8xxx.
Application of the host’s power supply typically occurs when the switch is open;
W_Disable# is left floating (high impedance) when the switch is closed.
Figure 2-4: Inrush model - MC57xx
Figure 2-5: Inrush model - MC8xxx
REG
PWR (1,2,3,4,5)
ON/OFF
(18)
Current
+3.3VDC
Power source
250m
LDO pass
element
1 ohm typ
ESR
80m
8.5m 2.8m
1.7m
2.2m
1uF
ESR
20m
ESR
20m
38m
Cin
2x 1uF
10m
32m
Current Probe
MC57xx
Regulator input capacitor
Regulator
output
capacitor
ESR +
trace Z
60m
RF Cap
4.7uF
EM board decoupling cap
Recommended host power rail
capacitance = 470 µF - 1000 µF
Cin
2x 1uF
ESR +
trace Z
40m
EM board decoupling cap
15m
ON/OFF
50m
2 ohm
30m
0.1m
10uF
ESR
50m
4.5m
47uF
MC8xxx