Datasheet

ADA4941-1
Rev. C | Page 18 of 24
Table 10. Output Voltage Noise, G = 2.4 Differential Amplifier Shown in Figure 48
Noise Source
Typical Value
VOP Contribution (nV√Hz)
VON Contribution (nV√Hz)
V
O
, dm Contribution (nV√Hz)
vn_A1
2.1 nV/√Hz 2.5 2.5 5
ip_A1
1 pA/√Hz 1 1 2
in_A1
1 pA/√Hz 1 1 2
√
4 kTR
F
4 nV/√Hz 4 4 8
√
4 kTR
G
9 nV/√Hz
1.8
1.8
3.6
√
4 kTR
S
3.6 nV/√Hz 4.4 4.4 8.8
vn_inverter
9.2 nV/√Hz 0 9.2 9.2
√R
S
_REF
0 0 0 0
ip_A2 × R
S
_REF
0 0 0 0
Totals 6.8 11.4 16.5
R
F
= 1.0 kΩ, R
G
= 4.99 kΩ, R
S
= 825 Ω, R
S
_REF = 0 Ω.
vn_inverter
= noise contributions from A2 and its associated internal 1 kΩ feedback resistors and 500 Ω offset current balancing resistor.
Table 11. Output Voltage Noise, G = 2 Differential Amplifier Shown in Figure 49
Noise Source Typical Value VOP Contribution (nV√Hz) VON Contribution (nV√Hz) V
O
, dm Contribution (nV√Hz)
vn_A1
2.1 nV/√Hz 2.1 2.1 4.2
ip_A1
0 0 0 0
in_A1
0 0 0 0
√
4 kTR
F
0 0 0 0
√
4 kTR
G
0 0 0 0
√
4 kTR
S
0 0 0 0
vn_inverter
9.2 nV/√Hz 0 9.2 9.2
√R
S
_REF
0 0 0 0
ip_A2 × R
S
_REF
0 0 0 0
Totals 2.1 9.4 10
R
F
= 0 Ω, R
G
= ∞, R
S
= 0 Ω, R
S
_REF = 0 Ω.
Table 12. Output Voltage Noise, G = 5 Differential Amplifier Shown in Figure 50
Noise Source Typical Value VOP Contribution (nV√Hz) VON Contribution (nV√Hz) V
O
, dm Contribution (nV√Hz)
vn_A1
2.1 nV/√Hz 5.25 5.25 10.5
ip_A1
1 pA/√Hz 1 1 2
in_A1
1 pA/√Hz 1 1 2
√
4 kTR
F
4 nV/√Hz 4 4 8
√
4 kTR
G
3.26 nV/√Hz 4.9 4.9 9.8
√
4 kTR
S
2.54 nV/√Hz 6.54 6.54 13.1
vn_inverter
9.2 nV/√Hz 0 9.2 9.2
√R
S
_REF
0 0 0 0
ip_A2 × R
S
_REF
0 0 0 0
Totals 10.7 14.1 23.1
R
F
= 1.02 kΩ, R
G
= 665 Ω, R
S
= 402 Ω, R
S
_REF = 0 Ω.