SM73302_15 Datasheet, PDF (13/31 Pages) Texas Instruments – SM73302 88 MHz, Precision, Low Noise, 1.8V CMOS Input, Decompensated Operational Amplifier

SM73302
www.ti.com
SNOSB93A – AUGUST 2011 – REVISED APRIL 2013
APPLICATION INFORMATION
ADVANTAGES OF THE SM73302
Wide Bandwidth at Low Supply Current
The SM73302 is a high performance op amp that provides a GBW of 88 MHz with a gain of 10 while drawing a
low supply current of 1.15 mA. This makes it ideal for providing wideband amplification in data acquisition
applications.
With the proper external compensation, the SM73302 can be operated at gains of ±1 and still maintain much
faster slew rates than comparable unity gain stable amplifiers. The increase in bandwidth and slew rate is
obtained without any additional power consumption over the LMP7715.
Low Input Referred Noise and Low Input Bias Current
The SM73302 has a very low input referred voltage noise density (5.8 nV/√Hz at 1 kHz). A CMOS input stage
ensures a small input bias current (100 fA) and low input referred current noise (0.01 pA/√Hz). This is very
helpful in maintaining signal integrity, and makes the SM73302 ideal for audio and sensor based applications.
Low Supply Voltage
The SM73302 operates with a 2.5V and 5V supply. This device operates at all supply voltages between 2.0V and
5.5V, for ambient temperatures ranging from −40°C to 125°C, thus utilizing the entire battery lifetime. The
SM73302 is also operational at 1.8V supply voltage, for temperatures between 0°C and 125°C optimizing their
usage in low-voltage applications.
RRO and Ground Sensing
Rail-to-Rail output (RRO) swing provides the maximum possible dynamic range. This is particularly important
when operating at low supply voltages. An innovative positive feedback scheme is used to boost the current drive
capability of the output stage. This allows the SM73302 to source more than 40 mA of current at 1.8V supply.
This also limits the performance of this part as a comparator, and hence the usage of the SM73302 in an open-
loop configuration is not recommended. The input common-mode range includes the negative supply rail which
allows direct sensing at ground in single supply operation.
Small Size
The small footprint of the SM73302 package saves space on printed circuit boards, and enables the design of
smaller electronic products, such as cellular phones, pagers, or other portable systems. Long traces between the
signal source and the op amp make the signal path more susceptible to noise pick up.
The physically smaller SM73302 allows the op amp to be placed closer to the signal source, thus reducing noise
pickup and maintaining signal integrity.
USING THE DECOMPENSATED SM73302
Advantages of Decompensated Op Amp
A unity gain stable op amp, which is fully compensated, is designed to operate with good stability down to gains
of ±1. The large amount of compensation does provide an op amp that is relatively easy to use; however, a
decompensated op amp is designed to maximize the bandwidth and slew rate without any additional power
consumption. This can be very advantageous.
The SM73302 requires a gain of ±10 to be stable. However, with an external compensation network (a simple
RC network) these parts can be stable with gains of ±1 and still maintain the higher slew rate. Looking at the
Bode plots for the SM73302 and its closest equivalent unity gain stable op amp, the LMP7715, one can clearly
see the increased bandwidth of the SM73302. Both plots are taken with a parallel combination of 20 pF and 10
kΩ for the output load.
Copyright © 2011–2013, Texas Instruments Incorporated
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