ICL7650-SCPD Datasheet, PDF (7/13 Pages) Intersil Corporation – 2MHz, Super Chopper-Stabilized Operational Amplifier

R₂
INPUT
R₁
CLAMP
-
7650S
+C
CR
0.1μF
0.1μF
OUTPUT
(R₁||R₂) ≥ 100kΩ
For Full Clamp Effect
NOTE: R₁||R₂ indicates the parallel combination of R₁ and R₂.
FIGURE 3. INVERTING AMPLIFIER WITH (OPTIONAL) CLAMP
CLAMP
+
+7.5V
+15V
IN
7650S
+
-
741
OUT
-
-7.5V
-15V
0.1μF
0.1μF
10kΩ
10kΩ
FIGURE 4. USING 741 TO BOOST OUTPUT DRIVE CAPACITY
0.1μF
0.1μF
V_IN
C
+
R
C
7650S
-
V_OUT
CLAMP ^R
V_TH
200kΩ - 2MΩ
FIGURE 5. LOW OFFSET COMPARATOR
V_REF
R_REF
V+
(+15V)
-
33kΩ
33kΩ
I_REF
R₅
ICL7650S
54
16 13 ^2kΩ 12
+
I_IN
Q₁
Q₂
V_IN
R_IN
2
-
A₁
+
1
R₃
+
-^A2
V_OUT
10
R₁
ICL8048
GROUND
GAIN
15.9kΩ
150pF C₁
7
15
R₂
680Ω 1kΩ
R₀
10kΩ
(LOW T.C.)
NOTE: For further Applications Assistance, see AN053.
FIGURE 6. ICL8048 OFFSET NULLED BY ICL7650S
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
capability to their very high slew rates and bandwidths. Note
that these circuits will also have their DC gains, CMRR, and
PSRR enhanced.
7
FN2920.10
April 12, 2007