Arduino Forum

Development => Other Hardware Development => Topic started by: ktellefsen on Feb 26, 2016, 05:45 pm

Title: LTC2495 ADC breakout board
Post by: ktellefsen on Feb 26, 2016, 05:45 pm
I've recently discovered Arduino controllers, and I like them.  I used an Uno, a 256kbit memory chip and some sensors to make a datalogger.  It was fun and it worked!

I collect a lot of electrical data, slowly, but a lot.  I need lots of channels and and at least 16 bit resolution.  Linear makes the LTC2495 16 bit, 16 single ended/8 differential channel I2C MUX ADC chip.  I designed a breakout board for this chip to be controlled by an UNO, and I'd like to have someone else look at my gerber files.  The circuit was copied from the chip's datasheet.

I also designed a temperature humidity sensor and a real time clock breakout, again the circuit was copied from the chips datasheet.

Is this the right place to post this?
Title: Re: LTC2495 ADC breakout board
Post by: CrossRoads on Feb 26, 2016, 05:51 pm
Sure. Please post the schematic and the board.
Are you using Eagle, something else?
Title: Re: LTC2495 ADC breakout board
Post by: ktellefsen on Feb 26, 2016, 06:13 pm
I use ViewMate Deluxe; I started by designing test coupons with little or no electrical functionality.  Until now, any functional circuits have been built on vector board.  QFN packages can't be used on vector board.  I get pad and paste footprints from the datasheets, just as when I design coupons for dummies (packages with no chip).

Where do I post my circuits and gerber files?
Title: Re: LTC2495 ADC breakout board
Post by: CrossRoads on Feb 26, 2016, 06:46 pm
Reply, and Attach jpgs of the schematic and board design. Not gerbers. 
Title: Re: LTC2495 ADC breakout board
Post by: ktellefsen on Feb 26, 2016, 07:26 pm
Here are gif files
Title: Re: LTC2495 ADC breakout board
Post by: CrossRoads on Feb 26, 2016, 07:47 pm
The individual files are hard to make out with the component values overlaid on the traces.
Things I could see:
1. Add more 0.1uF decoupling caps (Vcc to Gnd). 1 on the VCC pin of each device, locate close to the pin.  If a device has multiple VCC pins, use multiple caps. 0.1uFs react fast to supply current for fast switching transistors in a device. 10uF are good for smoothing out incoming DC and  big current surges.
2. Add pin 1 indicator to the board symbols, helps prevent parts being installed backwards.
3. Add cathode indicator to the board diode symbols.
4. Add + (or -) indicator to any polarized caps if used.
Title: Re: LTC2495 ADC breakout board
Post by: ktellefsen on Feb 26, 2016, 08:07 pm
Thanks for the advice.  I was unaware of point 1; that's why a 0.1µf AND a 10µf capacitor was shown on the datasheet schematic.  2 - 4 are good practice, thanks.

If you like I can post better pictures.
Title: Re: LTC2495 ADC breakout board
Post by: CrossRoads on Feb 26, 2016, 08:11 pm
Its up to you. I don't think I'll have any more to offer tho.
Title: Re: LTC2495 ADC breakout board
Post by: Billhigdon on Apr 09, 2017, 12:43 am
I used Ultralibrarian to do conversion of the Linear technologies LTC2495 cad package  . bxl file for use in Eagle. I'm not sure how to post the results to the forum.