[SI-LIST] Isolation between +3.3V & +3.3V AUX supplies (section 3.2.5 of ExpressCard Standard)

Dear SI membsers,
 
                We are designing a USB based module for the 
ExpressCard interface.
1. Our device require about 400 mA for full functionality. Hence +3.3V AUX 
supply alone is not sufficient for our device functionality.
2. We need to support remote wake up so we need the +3.3V AUX supply. 
 
                    Can we tap both the +3.3V and +3.3V AUX 
supply for our device. We will provide a diode (Make : On Semiconductor, Part 
number : MBR0520LT1G) in the +3.3V supply to isolate the 2 power rails. 
 
1.Anode of this diode will be connected to the +3.3V (PIN numbers 14 & 15) and 
the cathode of this diode will be connected to the +3.3V AUX supply (pin number 
12). 
2. The device can draw power from both +3.3V and +3.3V AUX rails. 
3. With this arrangement, required power will be available and remote wake up 
is also possible.
4. During suspend state, the +3.3V AUX power supply cannot flow into the +3.3V 
supply as this will be blocked by the reverse biased diode. 
 
                    I hope this is an acceptable design and will 
comply with ExpressCard specification. The diode will provide necessary 
isolation, is this correct?



Bharath


      Add more friends to your messenger and enjoy! Go to 
http://messenger.yahoo.com/invite/
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field


List technical documents are available at:
                http://www.si-list.net

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: