Datasheet

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SBOS305D − JUNE 2004 − REVISED AUGUST 2008
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18
OPA2614 vs OPA2613 PERFORMANCE
The OPA2614 is a de-compensated version of the unity
gain stable OPA2613. This decompensation gives a flat
response at a gain of +4, higher gain bandwidth product,
and twice the slew rate of the OPA2613. The OPA2614
should not be used for integrator-based active filters as
unity gain stability is required for the correct operation of
that filter type. It can be used for Sallen-Key type filters
where the filter is implemented using a simple gain
stage—as long as that gain is ≥ 2 when using the
OPA2614.
The higher slew rate of the OPA2614 (145V/µs vs 70V/µs
for the OPA2613) will give a higher full-power bandwidth
and lower distortion to higher output swings. For example,
comparing the ±6V differential plots for the OPA2613 to
those of the OPA2614, we see about twice the large signal
bandwidth for the OPA2614. This is also operating at twice
the signal gain, but since the gain bandwidth for the
OPA2614 is approximately twice that of the OPA2613, this
is as expected.
DIFFERENTIAL LARGE−SIGNAL
FREQUENCY RESPONSE
Frequency (MHz)
1 10 100
15
12
9
6
3
0
Gain (dB)
V
O
=5V
PP
V
O
=2V
PP
V
O
=0.2V
PP
R
L
=70
Ω
G
D
=+4
V
O
=1V
PP
Figure 6. OPA2613 Differential Gain of +4
Large-Signal Bandwidth
DIFFERENTIAL LARGE−SIGNAL
FREQUENCY RESPONSE
Frequency (MHz)
1 10 100
21
18
15
12
9
6
3
Gain (dB)
V
O
=5V
PP
V
O
=2V
PP
V
O
=0.5V
PP
R
L
=70
Ω
G
D
=+8
Figure 7. OPA2614 Differential Gain of +8
Large-Signal Bandwidth
The increased slew rate of the OPA2614 over the
OPA2613 will also give lower distortion at higher output
swings and/or frequency. Figure 8 and Figure 9 show the
differential test data for the OPA2613 and OPA2614,
respectively.
DIFFERENTIAL DISTORTION
vs OUTPUT VOLTAGE
Output Voltage Swing (V
PP
)
0.1
−
70
−
75
−
80
−
85
−
90
−
95
−
100
−
105
20101
Harmonic Distortion (dBc)
G
D
=4
R
L
=70
Ω
f=1MHz
2nd−Harmonic
3rd−Harmonic
Figure 8. OPA2613 Differential Gain of +4
Distortion vs Output at 1MHz
DIFFERENTIAL DISTORTION
vs OUTPUT VOLTAGE
Output Voltage Swing (V
PP
)
0.1
−
80
−
85
−
90
−
95
−
100
20101
Harmonic Distortion (dBc)
G
D
=+8V/V
R
L
=70
Ω
f=1MHz
2nd−Harmonic
3rd−Harmonic
Figure 9. OPA2614 Differential Gain of +8
Distortion vs Output at 1MHz
Notice how much lower the 3rd-harmonic is above 10V
PP
for the OPA2614 vs the OPA2613. These test conditions
were set up to have the same loop gain so the difference
in high output 3rd-harmonics can be attributed principally
to the high slew rate for the OPA2614.
These differences show that the OPA2614 would be
preferred for higher gains, higher frequency applications
over the OPA2613 while the OPA2613 would be preferred
where unity gain stability is required in the application.