Typical Performance
Characteristics (Continued)
Application Information
The LM6152/6154 is ideally suited for operation with about
10kΩ(Feedback Resistor, R
F
) between the output and the
negative input terminal.
With R
F
set to this value, for most applications requiring a
close loop gain of 10 or less, an additional small compensa-
tion capacitor (C
F
) (see
Figure 1
) is recommended across R
F
in order to achieve a reasonable overshoot (10%) at the out-
put by compensating for stray capacitance across the inputs.
The optimum value for C
F
can best be established experi-
mentally with a trimmer cap in place since its value is depen-
dant on the supply voltage, output driving load, and the oper-
ating gain. Below, some typical values used in an inverting
configuration and driving a 10kΩload have been tabulated
for reference:
TABLE 1. Typical BW (−3 dB) at Various
Supply Voltage and Gains
V
S
Volts Gain C
F
pF BW (−3 dB)
MHz
3−1 5.6 4
−10 6.8 1.97
−100 None 0.797
24 −1 2.2 6.6
−10 4.7 2.2
−100 None 0.962
In the non-inverting configuration, the LM6152/6154 can be
used for closed loop gains of +2 and above. In this case,
also, the compensation capacitor (C
F
) is recommended
across R
F
(= 10 kΩ) for gains of 10 or less.
Because of the unique structure of this amplifier, when used
at low closed loop gains, the realizable BW will be much less
than the GBW product would suggest.
The LM6152/6154 brings a new level of ease of use to op
amp system design.
The greater than rail-to-rail input voltage range eliminates
concern over exceeding the common-mode voltage range.
The rail-to-rail output swing provides the maximum possible
dynamic range at the output. This is particularly important
when operating on low supply voltages.
The high gain-bandwidth with low supply current opens new
battery powered applications where higher power consump-
tion previously reduced battery life to unacceptable levels.
The ability to drive large capacitive loads without oscillating
functional removes this common problem.
To take advantage of these features, some ideas should be
kept in mind.
The LM6152/6154, capacitive loads do not lead to oscilla-
tions, in all but the most extreme conditions, but they will re-
sult in reduced bandwidth. They also cause increased set-
tling time.
Unlike most bipolar op amps, the unique phase reversal
prevention/speed-up circuit in the input stage, caused the
slew rate to be very much a function of the input pulse ampli-
tude. This results in a 10 to 1 increase in slew rate when the
differential input signal increases. Large fast pulses will raise
the slew-rate to more than 30V/µs.
Total Harmonic Distortion
vs. Frequency
DS012350-31
DS012350-30
FIGURE 1. Typical Inverting Gain Circuit A
V
=−1
DS012350-21
FIGURE 2. Slew Rate vs. V
diff
LM6152/LM6154
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