LM2902
TYPICAL SINGLE - SUPPLY APPLICATIONS
NON-INVERTING DC GAIN
DC SUMMING AMPLIFIER
Ω
e 1
100k
R2
AV= 1 +
R1
Ω
10k
A
(As shown V = 101)
e O
1/4
LM2902
Ω
eO
100k
+5V
1/4
LM2902
Ω
Ω
e 2
e 3
100k
100k
R2
Ω
1M
R1
Ω
10k
Ω
100k
0
e I
(mV)
Ω
e 4
100k
eo = e1 + e2 - e3 - e4
where (e1 + e2) ≥ (e3 + e4)
to keep eo ≥ 0V
HIGH INPUT Z ADJUSTABLE GAIN DC
INSTRUMENTATION AMPLIFIER
LOW DRIFT PEAK DETECTOR
R1
100k
Ω
I
B
1/4
R3
100k
R4
eo
LM2902
I
B
Ω
Ω
100k
1/4
LM2902
1/4
Zo
LM2902
C
*
2I
e 1
e I
B
µ
F
1
eO
1/4
LM2902
ZI
2N 929
µ
0.001
F
Gain adjust
R2
Ω
2k
I
R5
100k
2I
B
B
Ω
R
1/4
LM2902
3R
Ω
1M
Ω
3M
R6
R7
Input current
compensation
Ω
Ω
100k
100k
I
B
1/4
LM2902
* Polycarbonate or polyethylene
e
2
if R1 = R5 and R3 = R4 = R6 = R7
2R1
eo = [ 1+
] (e2 − e1)
R2
As shown eo = 101 (e2 - e1).
8/14
STMICROELECTRONICS [ ST ]
