Hi,
While I am waiting for my MOD54415 and accompanying DEV-70 board to arrive (hopefully today) I am trying to work out what I would need to power the board and how much margin I have got on the 3.3V power supply for some additional stuff I need to add.
From the datasheet of the MAX5082 chip on the DEV-70 board and the fact that the board can be powered by USB I guess a 5V supply is probably fine. I also know the MOD54415 uses about 450 mA (maximum) but I wonder how much extra current I could use (50 mA would do just fine).
Any info much appreciated.
Power on DEV-70 board
Re: Power on DEV-70 board
First off, I'm a software guy, so I'm not giving the final word, just my experience using the board. Looking at the scope, without external loads, the supply rail has peak to peak ripple ~25-30mV fed from an external wall wart. I know from experience that it can feed an external IC and modules fairly well; I would presume they use a fair bit more than 50 mA.
If you're using the usb cable for serial and power, keep in mind that you're limited to 500mA@5V going into the supply, which means you'll have ~600-700mA@3.3V depending on the switcher's efficiency.
-Dan
If you're using the usb cable for serial and power, keep in mind that you're limited to 500mA@5V going into the supply, which means you'll have ~600-700mA@3.3V depending on the switcher's efficiency.
-Dan
Dan Ciliske
Project Engineer
Netburner, Inc
Project Engineer
Netburner, Inc
Re: Power on DEV-70 board
Thanks Dan,
That confirms what I was thinking.
In the mean time I have been doing some more checking so for anyone who is interested here is what I found:
- The MAX5802 chip will operate (provide 3.3V) with an input voltage between 4.5 and 40V. That is why you can supply the board perfectly well with 5V DC (e.g.: through the USB port). The specified 7...24V input is a bit conservative, 5...24V volt is OK.
- The chip is rated at 1.5 A but that is the absolute limit. I would guess it can probably safely do +/- 1A.
- the MOD51145 board takes a max of 450 mA so that leaves quite a bit of surplus power, I would guess a 100mA is plenty safe.
In my application I need +5V as well and have 24V DC available so I will be feeding it with a neat switching DC/DC converter to convert the 24V DC to 5V DC. There are plenty of those around from all sorts of manufacturers.
All for now
That confirms what I was thinking.
In the mean time I have been doing some more checking so for anyone who is interested here is what I found:
- The MAX5802 chip will operate (provide 3.3V) with an input voltage between 4.5 and 40V. That is why you can supply the board perfectly well with 5V DC (e.g.: through the USB port). The specified 7...24V input is a bit conservative, 5...24V volt is OK.
- The chip is rated at 1.5 A but that is the absolute limit. I would guess it can probably safely do +/- 1A.
- the MOD51145 board takes a max of 450 mA so that leaves quite a bit of surplus power, I would guess a 100mA is plenty safe.
In my application I need +5V as well and have 24V DC available so I will be feeding it with a neat switching DC/DC converter to convert the 24V DC to 5V DC. There are plenty of those around from all sorts of manufacturers.
All for now
Re: Power on DEV-70 board
Be careful with 5V around the MOD54415, it is a 3.3V module and not very tolerant of 5V directly on any of the pins.
If you are talking about powering the MOD-DEV-70CR board, then a USB wall wart gives you lots of extra power from the board.
If you are looking to design hardware incorporating the MOD-DEV-70CR board, be careful, some of the MOD54415 pins are connected to things on the board and can't be easily used as GPIO.
If you are talking about powering the MOD-DEV-70CR board, then a USB wall wart gives you lots of extra power from the board.
If you are looking to design hardware incorporating the MOD-DEV-70CR board, be careful, some of the MOD54415 pins are connected to things on the board and can't be easily used as GPIO.
Re: Power on DEV-70 board
Just to extend ecasey's warning a bit and add a bit of commentary on your analysis: the MAX5802 chip can take 4.5-40V, but I don't think all the components in the switching supply can. Be careful that if you're using a 24V supply that it doesn't have nasty transients (specifically, at turn on or turn off time). As for the 7-24V silkscreen, that may be left over from the earlier supply design, prior to adding the usb port, when it was using a different switching regulator.
Also, if your designing a prototype, or a one-off research (or hobby) type project, its OK to design in the devboard, but if this is for a finished product, do not include the devboard; the schematics for it are available in the documents folder of the NNDK to provide you with a starting point for you own device. If it is a hobby or research project feel free to keep us posted on it's development
-Dan
Also, if your designing a prototype, or a one-off research (or hobby) type project, its OK to design in the devboard, but if this is for a finished product, do not include the devboard; the schematics for it are available in the documents folder of the NNDK to provide you with a starting point for you own device. If it is a hobby or research project feel free to keep us posted on it's development
-Dan
Dan Ciliske
Project Engineer
Netburner, Inc
Project Engineer
Netburner, Inc
Re: Power on DEV-70 board
Things are progressing nicely, I feed the whole assembly with +24V DC.
From that I produce +5VDC to feed the dev-70 board and, of course, the MOD54415 module.
Other than that I use the 5V to feed some high speed AD converters and a few level shifters which translate the 5V digital levels to 3.3V levels which are okay for the MOD54415 module and I use the module's 3.3V to feed my sensor + the other supply side of the level shifters. All in all I use about 50 mA of that 3.3V supply so that is no problem at all.
For now it is just a prototype but ultimately it is supposed to become a finished product so we won't be using any more development boards. Instead we will design our own board which will have some elements of the development board, and our own stuff, on it.
All for now.
From that I produce +5VDC to feed the dev-70 board and, of course, the MOD54415 module.
Other than that I use the 5V to feed some high speed AD converters and a few level shifters which translate the 5V digital levels to 3.3V levels which are okay for the MOD54415 module and I use the module's 3.3V to feed my sensor + the other supply side of the level shifters. All in all I use about 50 mA of that 3.3V supply so that is no problem at all.
For now it is just a prototype but ultimately it is supposed to become a finished product so we won't be using any more development boards. Instead we will design our own board which will have some elements of the development board, and our own stuff, on it.
All for now.