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GSM modules - To supercap or not to supercap.... - RF Cafe Forums

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RF Head
Post subject: GSM modules - To supercap or not to supercap.... Posted: Tue May 05, 2009 3:47 am

Captain

Joined: Mon Feb 09, 2009 12:26 pm
Posts: 11
I haven't had to play with GSM stuff for a while so please bear with me. The last time I did delve into this area I went with manufacturers recommendations and added a supercap to the design to keep the supply voltage stable. This was probably using something like siemens MC55.

I recently checked out Telit GE864. There was no mention of any need for very large supercaps, only a 100uF low esr cap.

Just wondered if anyone had any practical experience with the latest GSM modules, most specicically, if they really are ok with a simple 100uF low esr capacitor OR maybe they do need a bit more help?

Of course, battery internal resistance must be considered!

Steve

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IR
Post subject: Re: GSM modules - To supercap or not to supercap....Posted: Tue May 05, 2009 4:29 pm

Site Admin

Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373
Location: Germany
Hello Steve,

I used a GSM/GPRS module in one of my designs.
A low-noise linear regulator will do the work, I checked the datasheet of the Telit GE864, and what they mentioned is OK.

The purpose of Supercapcitor is quite different, it is used in applications with low quiescent currents and where it can be charged for multiple use, instead of using batteries.

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- IR

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