ICL7621 Maxim, ICL7621 Datasheet - Page 22

• Manufacturer Part Number: ICL7621
• Description: The ICL761X–ICL764X family of monolithic CMOS op amps combine ultra-low input current with low-power operation over a wide supply voltage range
• Manufacturer: Maxim

Single/Dual/Triple/Quad
Operational Amplifiers
The ICL7611 family will operate from a single 2V to 16V
power supply. The common-mode voltage range of the
standard amplifier types when operated from a single
supply is 1.0V to (V+ - 0.6V) at 10µA I
the CMVR is 1.0V to (V+ - 0.8V), and at 1mA I
CMVR is 1.3V to (V+ - 1.3V). If this CMVR range is
insufficient, use the ICL7612, whose CMVR includes
both ground and V+, or the ICL7616, whose CMVR
includes ground.
A convenient way to generate a psuedo-ground at V+/2
is to use one op amp of a quad to buffer a V+/2 voltage
from a high-impedance resistive divider.
Figure 1. Instrumentation Amplifier—Adjust R3 to improve
CMRR. The offset of all three amplifiers is nulled by the offset
adjustment of A2.
22
______________________________________________________________________________________
V
IN
R1
+
-
+18V
GAIN =
+
-
A2
+
-
R3
R
A1
R2
R2
25kΩ
(
2R2
R1
Single-Supply Operation
+1
)
R
R
R3
R3
+
-
Q
A3
. At 100µA I
Q
, the
V
OUT
Q
,
Operation at V
10µA. Output swings to within a few millivolts of the
supply rails are achievable for R
Guaranteed input CMVR is ±0.6V minimum and typical-
ly +0.9V to -0.7V at V
where greater common-mode range is desirable, see
the description of ICL7612 and ICL7616 above.
Note that in no case is IQ shown. The value of IQ must
be chosen by the designer with regard to frequency
response and power dissipation.
Figure 2. Simple Follower—By using the ICL7612 in these
applications, the circuits will follow rail-to-rail inputs
V
IN
SUPP
Applications Information
ICL7612
+
-
= ±1.0V is only guaranteed at I
SUPP
Low-Voltage Operation
= ±1.0V. For applications
L
(> or =) 1MΩ.
R
L
≥ 10kΩ
V
Q
OUT
=