Datasheet

ADA4938-1/ADA4938-2
Rev. A | Page 22 of 28
Table 10 and Table 11 list several common gain settings, associated
resistor values, input impedances, and output noise densities for
both balanced and unbalanced input configurations. Also shown
are the input common-mode voltages under the given conditions
for different V
OCM
settings for both a 10 V single supply and
±5 V dual supplies.
Table 10. Differential Ground-Referenced Input, DC-Coupled; See Figure 59
Nominal
Gain (V/V) R
F
(Ω) R
G
(Ω) R
IN, dm
(Ω)
Differential
Output
Noise Density
(nV/√Hz)
Common-Mode Level at +IN, −IN (V)
+V
S
= 10 V, −V
S
= 0 V
V
OUT, dm
= 2.0 V p-p
+V
S
= 5 V, −V
S
= −5 V
V
OUT, dm
= 2.0 V p-p
V
OCM
= 2.5 V V
OCM
= 3.5 V V
OCM
= 1.0 V V
OCM
= 3.2 V
1 200 200 400 6.5 1.25 1.75 0.50 1.60
2 402 200 400 10.4 0.83 1.16 0.33 1.06
3.16 402 127 254 13.4 0.60 0.84 0.24 0.77
5 402 80.6 161 18.2 0.42 0.58 0.17 0.53
Table 11. Single-Ended Ground-Referenced Input, DC-Coupled, R
S
= 50 Ω; See Figure 60
Nominal
Gain (V/V)
R
F
(Ω) R
G1
(Ω) R
T
(Ω) R
IN,se
(Ω) R
G2
(Ω)
1
Overall
Gain (V/V)
2
Differential
Output
Noise
Density
(nV/√Hz)
Common-Mode Swing at +IN, −IN (V)
+V
S
= 10 V, −V
S
= 0 V
V
OUT, dm
= 2.0 V p-p
+V
S
= 5 V, −V
S
= −5 V
V
OUT, dm
= 2.0 V p-p
V
OCM
= 2.5 V V
OCM
= 3.5 V V
OCM
= 0 V V
OCM
= 2.0 V
1 200 200 60.4 267 226 0.9 6.2 1.00 to 1.50 1.50 to 2.00 −0.25 to +0.25 0.75 to 1.25
2 402 200 60.4 300 226 1.8 9.8 0.66 to 1.00 1.00 to 1.33 −0.17 to +0.17 0.50 to 0.83
3.16 402 127 66.5 205 158 2.5 11.8 0.48 to 0.72 0.72 to 0.96 −0.12 to +0.12 0.36 to 0.60
5 402 80.6 76.8 138 110 3.6 14.7 0.33 to 0.50 0.50 to 0.67 −0.08 to +0.08 0.25 to 0.42
1
R
G2
= R
G1
+ R
TS.
2
Includes effects of termination match.