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All things pertaining to wireless and RF links
By alanAK
I am using the Xbee Regulated Explorer board with the Xbee XSC high-power long-distance module. However, the XSC draws 265 mA of current when transmitting. From the marking on the regulator on the Explorer board, I'm guessing it is a Micrel MIC5205 regulator, which can only supply 150 mA. Is this correct? Also, the RSSI LED on the board connects to Pin 6, which is not RSSI on the XSC module; it is a pin that can put the XSC module into command mode at boot-up. Has anybody had success with the Explorer board and the XSC module? Thanks.
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By mitchind
I have both in my possession now - but haven't tested the combination. Been using the XSC Development boards

Will see what I can find. Hadn't found any others using the XSC up until now.
By alanAK
I went as far as removing the regulator (I left the caps) and the RSSI LED from the Explorer board and powering the Xbee directly from 3.3 V. For some strange reason it still won't work on the Explorer board. Yet, when I wire the Xbee up on a breadboard, it works fine. I'll be anxious to hear about your experience.
Last edited by alanAK on Mon Nov 02, 2009 4:16 pm, edited 1 time in total.
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By mitchind
alanAK wrote:.. From the marking on the regulator on the Explorer board, I'm guessing it is a Micrel MIC5205 regulator, which can only supply 150 mA. Is this correct?
You are correct - just checked the Sparkfun product site and a tech posted a link to the datasheet:

First line in datasheet describes it as "150mA Low-Noise LDO Regulator"
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By mitchind
alanAK wrote:Also, the RSSI LED on the board connects to Pin 6, which is not RSSI on the XSC module; it is a pin that can put the XSC module into command mode at boot-up.
Thanks for finding this Alan. I looked closer in the manuals after you mentioned this. The pins have more than a few variations - so I guess my breakout boards will be limited to the Pro 2.4 versions I have.

Glad I picked up the dev kit with the two boards specifically for the XSC!

Here's the two screenshots - note pins 17-20 on the XSC aren't even supposed to be connected.

Xbee and XBee Pro

By alanAK
I did see later in the XSC manual on page 32 that the Pin 6, the Config pin, can be used to output RSSI if you use the RP command properly; that wasn't described in the Pin Spec table.

I also was looking at the Xbee ZB (Zigbee) manual. There it states that the Pro module can draw 295 mA of supply current. So, I would be worried about using the Regulated Explorer module with that Xbee module as well, if they really are using the MIC5205 regulator.

It would be helpful to have someone from SparkFun weigh in on this issue.
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By mitchind
Good point - Even the Series 1 XBee Pro is listed at 215 mA @ 3.3VDC
By stevech
Xbee Series 1 PRO, at 63mW (US)
Both PRO and non-PRO use about 40mA in receive. You can sleep the receiver, wakeup for rendevous or poll coordinator, to get a 90% or more sleep time.

The transmit duty cycle is quite low - like 2% or some such. So the average power dissipation in the linear regulator is low.

I use 6VDC into the regulators on XBees rather than 9 or 12V to keep them cooler.
By alanAK
I worried that some current limiting might kick in with the regulator, causing the output voltage to sag. However, I did put a scope on the voltage and did not see any sag during the transmission period. I agree that average current would be well within the 150 mA limit for most applications.

I think there is some other compatibility issue between the XSC module and Xbee Explorer board. I went as far as removing the regulator and powering the module directly; I also disconnected the RSSI LED. The Xbee module still did not operate correctly. I tried two Explorer modules with the same result. I am using the Droids breakout board now and all is fine.
By sylvie369
Just a relevant warning: out of sheer ignorance, I recently smoked the 150 mA regulator on an Arduino Pro Mini board by trying to power an XBee Pro that was transmitting several times per second from the Arduino board's 3.3V output.

Lots of smoke. Very educational. I now know a lot more about current requirements of various devices than I did a week ago.

I'll bet you can also guess how I learned about reverse voltage protection diodes.
By stevech
A packet is just a couple of mSec of Transmitter-on time. Seems like your app would have to go berzerk to use a lot of DC power.
By sylvie369
mitchind wrote:alan:

If you're still looking for a higher power Xbee board, I saw this one at adafruit recommended - apparently 250mA ... cts_id=126
A little warning on that Adafruit board: the voltage regulator and the capacitor sit right where the bottom end of an XBee Pro needs to go, so the Pro versions of the XBee do not fit properly on the board. Look at the photo on the product page, and imagine another 1/4" or so of XBee coming off the bottom. You could, I suppose, put it together with those parts bent over far enough to make it work. I haven't tried that. The regular XBee (not Pro) fits fine on these boards (as you can see in the photo). I'm using the same voltage regulator from that board, but mounted externally, to power an XBee Pro (215 mA transmit) with no problems.

An alternative is the Selmaware boards, at The SIP board takes 5-12V input, and uses a larger 500 mA regulator. The XBee Pro fits well on that board, partly because the board is larger overall.

@stevech - my app was transmitting about as quickly as it could, over and over again, and blinking that LED quickly as well. I'm starting to understand why people here are always asking about removing LEDs from boards.
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