Hi,
I have two questions about the output voltage calculation of DAC3484:
1. Page 57, 58 in the datasheet, the one driving a doubly terminated 50-Ω using a 4:1 impedance ratio transformer. The Vp-p of DAC output calculated for this configuration is:
VOUTP= 20mAx 100Ω= 2 V
VOUTN= 0mAx 100Ω= 0 V
VDIFF= VOUTP– VOUTN= 2 Vp-p
After transformer (impedance ratio 4:1 -> voltage 2:1), the voltage will be 1 Vp-p.
My question is that it seems the 2 Vp-p has exceed the DAC output compliance range from –0.5 to 0.6V. Is it acceptable ?
2. Also for page 57, 58, if I normalize the calculation of DAC out put voltage, it will be VDIFF=IFS x RL.
I found another calculation in a DAC datasheet of Analog Device:
(AD9122, page 47, 48) -> The calculation here is VDIFF=IFS x RL x 2.
This confuse me a lot, I am not sure which method I should choose.
Another source here talks about the same thing (same configuration with transformer of DAC3484), with 1:1 tranformer they calculate 1 Vp-p instead of 0.5 Vp-p declared in the datasheet of DAC3484:
(DAC Interface Fundamentals - MT-019, page 4)
Could you help me ?
Thanks in advance,
BR
XIN
