For more info, you can refer to the original Datasheet of the IC LM321
The LM321 IC is extremely versatile, it can be easily replaced with our very own, the ubiquitous IC 741.
Although IC 741 is also a good opamp IC, LM321 outmatches it due to its wider operating voltage range which extends right from 3V to 32V with a single supply, that implies for dual supplies this IC can work with voltages up to 64V.
Other in-built features of this IC include:
Gain Band-Width Product - 1MHz
Minimal Supply Consumption = 430uA
Small Input Bias Current = 45nA
Stability even with high capacitive loads and currents
IC LM321 pinout Details can be witnessed in the following diagram:
Pin Functions of the IC LM 321 may be learned from the following Table:
The Absolute maximum Tolerable or Breakdown Limits of the IC can be studied from the following Table:
The LM 321 provides efficiency and cost effectiveness to low
power devices. With a superior unity-gain-frequency along with a designated
0.4-V/ps slew rate, the quiescent current is barely 430-pA/amplifier (5 V).
input common mode range consists of ground as well as the unit has the ability
to perform in single supply purposes not to mention in dual supply applications
too. Additionally it is competent at conveniently handling significant
The LM 321 comes in the SOT-23 packet. In general the
Ll/l321 is a low power, broad supply range efficient operational amplifier
which can be engineered into a variety of products at a relatively inexpensive
cost without affecting precious floor area.
The LM 321
operational ampllfer may work with a single or dual power supply voltage,
carries true-differential inputs, and continues to be in the linear format with
an input c0mmon-mode voltage of zero VDC.
This amplifier performs over a wide
selection of power supply voltages, with minor difference in overall performance
aspects. At 25°C amplifier functionality is achievable right down to the very
least supply voltage of three volts.
Substantial differential input voltages could
very well be lodged and, as input differential voltage protection diodes are not
being used, simply no large input currents originate from big differential input
The differential input voltage could be bigger than V+ without causing
damage to the device.
Safety ought to be offered to reduce the input voltages
from heading negative in excess of -0.3 VDC (at 25°C). An input clamp diode with
a resistor to the IC input pinouts should be considered.
To decrease the power depletion, the amplifier bears
a class A output stage for smaller signal levels which transforms to class-B in
bigger signal formats.
This permits the opamp to both supply and sink
significant output currents. For that reason both NPN and PNP outer current
boost transistors may be used to stretch the power potential of the fundamental
The output voltage ought to increase up to 1 diode decrease above the negative rail to bias the on IC vertical PNP transistor for output current sink
For AC usages, wherein the load is capacitively connected to the
output of the amplifier, a resistor needs to be put into use, from the output of
the amplifier to the negative to maximize the class-A bias current also to cut
Capacitive loads which are usually employed right to the output
of the amplifier help reduce the loop balance margin. Magnitudes of 50 pF might
be adjusted making use of the worst-case non-inverting unity gain connectivity.
Massive closed loop gains or resistive isolation ought to be employed in case
massive load capacitance needs to be powered by the amplifier.
configuration of the LM321 creates a supply current that could be independent of
the strength of the power supply voltage over the range of from 3 VDC to 30 VDC.
Output short circuits possibly to ground or to the positive power source needs
to be of brief time period.
Devices could be damaged, not as a consequence of
the short circuit current leading to metal fusing, but instead on account of the
massive rise in IC chip dissipation that should result in inevitable malfunction
on account of extreme junction temperatures.
The more substantial value of
output supply current that could be within 25°C presents an increased output
current functionality at increased heat compared to a typical IC operational
Device Functional Modes
Common-Mode Voltage Range
input common-mode voltage range of the LM321 series extends from 300 mV below
ground to 32 V for normal operation. The typical performance in this range is
summarized in Table 1:
I have discussed many IC 741 opamp based circuits, typically these include the battery chargers where the opamp can be seen effectively implementing the essential automatic high and low charging level cut offs.
The above discussed IC can be also used in place of the IC 741 for getting identical results.
A typical automatic battery circuit using the IC LM 321 application can be learned from the following diagram: