这个帖子时隔两年又被我挖出来了。
因为确实遇到了问题，想要问下AD694英文DATASHEET里面的，偏置电流调节、输入电压范围设定这些所用的电阻是怎么计算的。
RP = 180 W (1/X – 4.5)
RF = 500 W [(VREF / 1.22 V) – 0.18 – 0.82X][1/X – 4.5]
These formulae take into account the ±10% internal resistor
tolerance and ensure a minimum adjustment range for the 4 mA
offset. For example, assume the 2 V reference option has been
selected. Choosing X = 0.05; gives an adjustment range of ±5%
of the 4 mA offset.
RP = 180 W (1/0.05 – 4.5) = 2.79 kW
RF = 500 W [(2 V / 1.22) – 0.18 – 0.82 ´ 0.05][1/0.05 – 4.5]
= 10.99 kW
RT = 1.8 kW ((1 – X)/X)
RS = 9 kW [1 – 0.2 (1 + X)( 1 – X )] / 2X
These formulae take into account the ±10% absolute resistor
tolerance of the internal span resistors and ensures a minimum
adjustment range of the span. For example, choosing the adjustment
range to be ±2%, or 0.02 gives:
RT = 1.8 kW ((1 – 0.02) / 0.02) = 88.2 kW.
RS = 9 kW [1 – 0.2 (1 + 0.02)( 1 – 0.02 )] / (2 ´ 0.02) =
175.5 kW
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