Edward, In my opinion the prTBR 21 committee members should also rewrite the laws of physics to insure a PCMCIA modem can dissipate 2 Watts and survive while the holding circuit is limiting the current to 60 mA.
All the modem chips I know of for general consumer usage are spec'd for 0 to 70 degrees C ambient operating temperature. The metal covers of PC cards tested for 60 mA limiting had the temperature stablize at 64 degrees while plugged into a card extender. I don't have any way of knowing the temp delta from holding circuit to metal case, but I do know the the darlington and load resistor do not have intimate contact with case. The rise case temperature is only caused by radiated heat. If the card was inside a laptop temperature would be much higher. There is nothing I would like better than to design to prTBR 21, but a realistic PCMCIA design would require MIL parts or an external DAA. If anyone can has a solution to this problem I hope they will share it. Regards, Duane On Tue, 27 Aug 1996 [email protected] wrote: > Hello Duane, Joe et al. > > If you can I would be working to prTBR21 as this will be > good for the UK shortly and others if they will accept the > June 1996 draft version. > > Best regards, > > Edward Fitzgerald > > GSM : +44-4685-33-100 > Internet : [email protected] > X.400 : G=Edward; S=Fitzgerald; A=400net; P=itu; C=ch >
