LMV793, LMV794

SNOSAX6D – MARCH 2007 – REVISED MARCH 2013

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APPLICATION INFORMATION

ADVANTAGES OF THE LMV793/LMV794

Wide Bandwidth at Low Supply Current

The LMV793/LMV794 are high performance op amps that provide a GBW of 88 MHz with a gain of 10 while

drawing a low supply current of 1.15 mA. This makes them ideal for providing wideband amplification in data

acquisition applications.

With the proper external compensation the LMV793/LMV794 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 LMV796.

Low Input Referred Noise and Low Input Bias Current

The LMV793/LMV794 have 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 LMV793/LMV794 ideal for audio and sensor based

applications.

Low Supply Voltage

The LMV793 and LMV794 have performance specified at 2.5V and 5V supply. These parts are specified to be

operational 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 LMV793/LMV794 are also specified to be 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 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 LMV793/LMV794 to source more than 40 mA of current at 1.8V

supply. This also limits the performance of these parts as comparators, and hence the usage of the LMV793 and

the LMV794 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 LMV793 and the LMV794 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 LMV793/LMV794 packages, allow the op amp to be placed closer to the signal source,

thus reducing noise pickup and maintaining signal integrity.

USING THE DECOMPENSATED LMV793

Advantages of Decompensated Op Amps

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 LMV793/LMV794 require 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 LMV793 and its closest equivalent unity gain stable op amp, the LMV796, one can clearly

see the increased bandwidth of the LMV793. Both plots are taken with a parallel combination of 20 pF and 10 k

Ω

for the output load.

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Product Folder Links: LMV793 LMV794