Other Parts Discussed in Thread: DAC37J84, DAC38J84,
I have a questions regard a couple of calculations in the data sheet.
The DAC37J84 uses this definition:
The default full-scale output current equals 64 times this bias current and can thus be expressed as:
IOUTFS = 16 x IBIAS = 64 x VEXTIO / RBIAS
The DAC37J84/DAC38J84 has a 4-bit coarse gain control coarse_dac(3:0) in the configtbd register. Using gain
control, the IOUTFS can be expressed as:
IOUTFS = (coarse_dac + 1) /16 x IBIAS x 64 = (coarse_dac + 1) /16 x VEXTIO / RBIAS x 64
The DAC3482 states the following:
The default full-scale output current equals 64 times this bias current and can thus be expressed as:
IOUTFS = 64 x IBIAS = 64 x (VEXTIO / RBIAS ) / 2 (14)
The DAC3482 has a 4-bit coarse gain control coarse_dac(3:0) in the config3 register. Using gain control, the
IOUTFS can be expressed as:
IOUTFS = (coarse_dac + 1)/16 x IBIAS x 64 = (coarse_dac + 1)/16 x (VEXTIO / RBIAS) / 2 x 64
The calculations appear to be different. Can you tell me which calculation is correct? Or am I missing something in looking at the calculations shown above?
Thanks for your help with this!
Richard Elmquist
