Interfacing with GSM module

There is a question about interfacing arduino with GSM module (datasheet: http://grandelectronic.com/images/stories/pdf/wireless/GSM/Quectel/M10/M10_HD_V103.pdf).

Module has UART port with voltage level 2.8v The datasheet says, that if consumer device's voltage level doesn't match with the module, then level shifter circuit should be inserted. The question is what transistors they are mean?

Alternative circuit talks that I could use BSS138 with 10k resistors. (http://www.sparkfun.com/datasheets/BreakoutBoards/Level-Converter-v10.pdf) But I'm not sure about referenced resistors on Figure 4 above - are they suitable to BSS138? And more - I need transistors in TO92 package (may be 2N7000 suitable?).

Open drain buffers and logic level shifters are not suitable. It's almost impossible to get them.

The second question is about powering GSM module. It remains 3.4~4.5v with peak current 2A. How to deliver power both arduino and GSM-module with minimal circuit (maybe voltage devider?).

Thnx in advance.

P.S. Sorry, I'm electronic newbee and need simple explanations.

I don't know what that means? Are you saying that you can not get BSS138? Then why not 2N2222?

If you need TO92, why not just use 2N2222 and the reference design in Fig. 4?

2N2222 is not available too....

Only store that has something on stock is http://translate.google.com/translate?hl=ru&sl=ru&tl=en&u=http://www.promelec.ru/search/

No, voltage divider is not suitable for a high-current load like 2A. Don't even consider it. Since you did not say what is your power source (volts?), we cannot answer your question.

Maybe this is the question too. What kind of power supply? Linear? Pulse? Arduino need 5v, so power source will be 5v too.

Complete the user profile so that we know where you are?

Done :) (Russia, Yekaterinburg)

Only store that has something on stock is …

Put in transistor and choose option 8. Any of those will do.

What kind of power supply? Linear? Pulse?

Pulse is not the right name it is called a “switch mode” supply and is the best for regulating current. But as you are having trouble getting a simple transistor you might struggle to get one. Look for DC to DC converters. Here is an example:-
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=152-524&x=0&y=0

Look for DC to DC converters

Ok. Thanks!

Put in transistor and choose option 8. Any of those will do.

Sorry, I didn't understend what does mean "option 8"...

Look for DC to DC converters

I’ve just found one: http://www.promelec.ru/pdf/lm2576.pdf
Adjustable 3A Step-Down Voltage Regulator.

Question about powering is answered. Thanks!

<…>any common NPN transistor. In the US, the most common is something like 2N2222

And about 2N2222 - I just found russian analog of this transistor - [ch1050][ch1058]3117[ch1040] (http://www.datasheetarchive.com/KT3117A-datasheet.html)

Another piece of advice is to pay close attention to the bypass capacitor that is used on the input. The datasheet recommends a 100uF low ESR cap but from what I’ve seen it helps to choose a higher value.

Are you planning on having this battery powered also?

Are you planning on having this battery powered also?

Yes, I'll... Pin-to-pin compatible SIM300CZ has in-circuit charger for Li-ion batteries. And it's reasonable to make some sort of UPS, using this feature and battery, if I'll use SIM300CZ.