Power Interface; Overview Of Operation; Power Signals - Sierra Wireless MC5725 Hardware Integration Manual

2: Power Interface

Rev 1.9.1 Feb.09
In the event of a discrepancy in values between this guide and the Product Specification Document (PSD), the PSD takes precedence.

Overview of operation

Note: This chapter contains information for CDMA (MC57xx) and
GSM (MC87xx) modules.
Information that is unique to specific module types is clearly
identified.
The module is designed to use a 3.3V (nominal) power supply,
provided by the host. It is the host's responsibility to provide
safe and continuous power to the module at all times; the
module does NOT have an independent power supply, or
protection circuits to guard against electrical issues.
The host controls the module's power state using the
signal as shown in Figure 2‐1. The signal is driven
W_Disable#
low by the host to power off the modem, or left floating (high
impedance) to power on the modem. The module also
monitors its supply voltage and requests shutdown if the
supply is insufficient (see
page 20).
Figure 2-1: Recommended W_Disable# connection (open
drain circuit)
Control

Power signals

The module must be connected to a 3.3V power supply (as
described in PCI Express Mini Card Electromechanical Specifi‐
cation Revision 1.1).
The MC87xx has more power pins than the MC57xx due to
higher peak current requirements for GSM devices.
For detailed pinout and voltage / current requirements of these
modules, see the Product Specification Document for your
Mini Card.
Proprietary and Confidential
Voltage monitoring state machine
3
1
Q
R
2
2
,
W_Disable#
17