Mantracourt Electronics Limited
– ICA User Manual
12
If the gain is to be decreased for a higher mV/V input then the two surface mount resistors must be removed. It is then
possible to use just the top pair of formulas as with the other models.
Example 1
: ICA1H, no offset, 0.5 mV/V required sensitivity.
𝐺𝑎𝑖𝑛 = (
Gain constant
𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑚𝑉/𝑉
) = (
372
0.5
) = 744
𝑅
𝑔𝑎𝑖𝑛
= (
Resistor constant
(𝐺𝑎𝑖𝑛 − 1)
) = (
40000
744 − 1
) = 53.8 Ω
(Use preferred value 53.6R – E96 series)
Example 2
: ICA2H, no offset, 5 mV/V required sensitivity.
𝐺𝑎𝑖𝑛 = (
Gain constant
𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑚𝑉/𝑉
) = (
186
5
) = 37.2
𝑅
𝑔𝑎𝑖𝑛
= (
Resistor constant
(𝐺𝑎𝑖𝑛 − 1)
) = (
40000
37.2 − 1
) = 1105 Ω
(Use preferred value 1k1)
Example 3
: ICA3H, no offset, ±2.5 mV/V required sensitivity at ±5 V output.
𝐺𝑎𝑖𝑛 = (
Gain constant
𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑚𝑉/𝑉
) × (
Required output
Maximum output
) = (
372
2.5
) (
5
10
) = 74.5
𝑅
𝑔𝑎𝑖𝑛
= (
Resistor constant
(𝐺𝑎𝑖𝑛 − 1)
) = (
40000
74.5 − 1
) = 545 Ω
(Use preferred value 549R – E96 series)
Example 4
, ICA2H, 2.5 V offset, ±2.5 mV/V required sensitivity at 0.1 V and 5.1 V output.
𝑅
𝑜𝑓𝑓𝑠
=
148
(𝑉
𝑜𝑓𝑓𝑠
− 0.1)
=
148
2.5 − 0.1
=
148
2.4
= 61.7 kΩ
(Use preferred value 61.9k – E96 series)
𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 mV/V =
5V
𝑏𝑖𝑝𝑜𝑙𝑎𝑟 𝑜𝑢𝑡𝑝𝑢𝑡 𝑐ℎ𝑎𝑛𝑔𝑒
× 𝑙𝑜𝑎𝑑 𝑐𝑒𝑙𝑙 mV/V =
5
2.5
× 2.5
= 5 mV/V
𝐺𝑎𝑖𝑛 = (
Gain constant
𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑚𝑉/𝑉
) = (
186
5
) = 37.2
𝑅
𝑔𝑎𝑖𝑛
= (
Resistor constant
(𝐺𝑎𝑖𝑛 − 1)
) = (
40000
37.2 − 1
) = 1105 Ω
(Use preferred value 1k1)
Example 5
, ICA4H, 2.0 mV/V required sensitivity
𝐺𝑎𝑖𝑛 = (
Gain constant
𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑚𝑉/𝑉
) = (
160
2
) = 80
𝑅
𝑔𝑎𝑖𝑛
= (
Resistor constant
(𝐺𝑎𝑖𝑛 − 1)
) = (
63200
80 − 1
) = 800 Ω
𝑅 = (
1
(1/𝑅
𝑔𝑎𝑖𝑛
) − 0.001
) = (
1
(1/800) − 0.001
) = 4000 Ω
(Use preferred value 3k9 or 4k01 (E96))
