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Getting two LM3916 chips to act as one? Answered

I've tried to connect two LM3916 chips together in a VU meter to increase the number of LEDs to make the range broader with no luck. Each chips acts independently as if it were stand alone. Does anyone have a suggestion or possibly a diagram showing how to connect the chips to make them act as a single chip increasing the number of lights to increase the range? I followed the cascading connection in the manufacturer's data sheet, but I'm not sure how to power and deliver the signal to the second chip so I connected it like you would a single chip, tested it in dot mode with a potentiometer and than connected pin #9 from the first chip to pin #1 on the second chip. The power connection where the same as they were for the 1st chip. Any advise and/or assitance would be greatly appreciated. Thanks,

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steveastrouk (author)2009-09-21

I think I commented on this offline to you. Basically, you have to connect the dividers in each device together, as per the datasheet. Sean makes a valid point (didn't I say it too ? ) that you'd be better with a 3915 and a 3916. Steve

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seandogue (author)2009-09-21

See pg 12> Cascading the LM3916. I suspect that you need to use am LM3915 and LM3916, rather than a pair of LM3016s to accomplish the task (note the dynamic range offered using the pair of 16s vs 15 & 16) Also, see pgs 13-18 for more discussion on extended range operation. To use the dual LM3916s, you'll need to change the resolution on the second LM3916

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Re-design (author)seandogue2009-09-21

Huh? page 12 in my book is an add for perfume. Pages 13-18 are an expose on the tax system. I must be lookin in the wrong book!

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seandogue (author)Re-design2009-09-21

The LM3916 PDF re-design...the pdf.

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