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Design >> Mixed-Signal Design >> regarding DAC output impedance calculation
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Message started by venki_vlsi on May 13^th, 2007, 9:32pm

Title: regarding DAC output impedance calculation
Post by venki_vlsi on May 13^th, 2007, 9:32pm

hi,i am designing 10 bit DAC with sinlge ended output.
I want to know how much output impedance is required for single current source to acheive sfdr of 60db and inl of 1 lsb.
I searched many papers ,they r giving for differenctial output impedance. Is there any relation to find outimpedance for single ended ouput i from differenal output having same sfdr and inl. I am not sure if this valids ( 2*differentaloutput impedance=single ended outout imopedance).
Thanks in advance.

Title: Re: regarding DAC output impedance calculation
Post by ywguo on May 15^th, 2007, 1:24am

venki,

Just calculate the output impedance regardless your DAC is differential output or single-ended output. If your DAC is single-ended output, the result is impedance for single-ended output. If your DAC is differential, the result is impedance for differential output. I think so.

Yawei

Title: Re: regarding DAC output impedance calculation
Post by venki_vlsi on May 16^th, 2007, 2:12am

Thanks for ur reply.

Title: Re: regarding DAC output impedance calculation
Post by neoflash on Mar 22^nd, 2011, 10:47pm

venki_vlsi wrote on May 13^th, 2007, 9:32pm:

Single ended and differential current steering DAC suffer distortion from different mechanism.

Differential DAC can cancel HD2 and suffer only HD3 which is a lot lower.

Single ended DAC suffer HD2 which is approximated by

(RL/Ru)*2^N/4