ICL7650S Intersil Corporation, ICL7650S Datasheet - Page 7

• Manufacturer Part Number: ICL7650S
• Description: Super Chopper-Stabilized Operational Amplifier
• Manufacturer: Intersil Corporation

NOTE: R
NOTE: For further Applications Assistance, see AN053.
Normal logarithmic amplifiers are limited in dynamic range in
the voltage-input mode by their input-offset voltage. The
built-in temperature compensation and convenience
features of the ICL8048 can be extended to a voltage-input
dynamic range of close to 6 decades by using the ICL7650S
to offset-null the ICL8048, as shown in Figure 6. The same
concept can also be used with such devices as the HA2500
or HA2600 families of op amps to add very low offset voltage
FIGURE 3. INVERTING AMPLIFIER WITH (OPTIONAL) CLAMP
(R
For Full Clamp Effect
1
1
||R
||R
2
2
) ≥ 100kΩ
indicates the parallel combination of R
INPUT
V
IN
R
0.1µF
1
7
I
R
IN
7650S
+
-
IN
C
CLAMP
R
R
C
2
ICL7650S
0.1µF
GROUND
FIGURE 6. ICL8048 OFFSET NULLED BY ICL7650S
+
-
FIGURE 5. LOW OFFSET COMPARATOR
OUTPUT
1
and R
2
1
150pF
V
IN
33kΩ
2
0.1µF
.
CLAMP
10kΩ
+
R
-
A
ICL8048
0
ICL7650S
5
1
C
1
7650S
+
200kΩ - 2MΩ
-
4
C
33kΩ
R
Q
(+15V)
R
V
1
C
REF
0.1µF
7
capability to their very high slew rates and bandwidths. Note
that these circuits will also have their DC gains, CMRR, and
PSRR enhanced.
FIGURE 4. USING 741 TO BOOST OUTPUT DRIVE CAPACITY
R
V
3
TH
R
V
Q
GAIN
REF
OUT
IN
2
15
16
I
(LOW T.C.)
REF
13
0.1µF
15.9kΩ
+
680Ω
-
-7.5V
A
R
2
1
2kΩ
V+
R
7650S
-
+
CLAMP
5
1kΩ
R
12
2
10
+7.5V
0.1µF
V
OUT
-
+
741
10kΩ
+15V
-15V
10kΩ
OUT