OP162 Datasheet, PDF (12/16 Pages) Analog Devices – 15 MHz Rail-to-Rail Operational Amplifiers

OP162/OP262/OP462
0.010
V_S = ؎2.5V
A_V = 1
V_IN = 1.0V rms
R_L = 10k⍀
BANDWIDTH:
<10Hz TO 22kHz
0.001
0.0001
20
100
1k
FREQUENCY – Hz
10k 20k
Figure 38. THD+N vs. Frequency Graph
–40
A_V = 1
–50 _{VIN = 1.0V rms}
(0dBV)
–60
R_L = 10k⍀
–70 V_S = ؎2.5V
–80
–90
–100
–110
–120
–130
–140
20
100
1k
FREQUENCY – Hz
10k 20k
Figure 39. Crosstalk vs. Frequency Graph
PCB Layout Considerations
Because the OP162/OP262/OP462 can provide gain at high
frequency, careful attention to board layout and component
selection is recommended. As with any high speed application,
a good ground plane is essential to achieve the optimum perfor-
mance. This can significantly reduce the undesirable effects of
ground loops and IÂ¥R losses by providing a low impedance refer-
ence point. Best results are obtained with a multilayer board
design with one layer assigned to ground plane.
Chip capacitors should be used for supply bypassing, with one
end of the capacitor connected to the ground plane and the
other end connected within 1/8 inch of each power pin. An
additional large tantalum electrolytic capacitor (4.7 mF–10 mF)
should be connected in parallel. This capacitor does not need to
be placed as close to the supply pins, as it is to provide current
for fast large-signal changes at the device’s output.
APPLICATION CIRCUITS
Single Supply Stereo Headphone Driver
Figure 40 shows a stereo headphone output amplifier that can
be run from a single +5 V supply. The reference voltage is
derived by dividing the supply voltage down with two 100 kW
resistors. A 10 mF capacitor prevents power supply noise from
contaminating the audio signal and establishes an ac ground for
the volume control potentiometers.
The audio signal is ac coupled to each noninverting input
through a 10 mF capacitor. The gain of the amplifier is con-
trolled by the feedback resistors and is: (R2/R1) + 1. For this
example, the gain is 6. By removing R1 altogether, the amplifier
would have unity gain. A 169 W resistor is placed at the output
in the feedback network to short-circuit protect the output of
the device. This would prevent any damage to the device from
occurring if the headphone output became shorted. A 270 mF
capacitor is used at the output to couple the amplifier to the
headphone. This value is much larger than that used for the
input because of the low impedance of headphones, which can
range from 32 W to 600 W or more.
R1 = 10k⍀
R2 = 50k⍀
10␮F
LEFT IN
10␮F
L VOLUME
CONTROL
10k⍀
5V
5V
OP262-A
169⍀
270␮F
47k⍀
100k⍀
100k⍀
10␮F
5V
RIGHT IN
10k⍀
10␮F
R VOLUME
CONTROL
OP262-B
169⍀
270␮F
47k⍀
R2 = 50k⍀
R1 = 10k⍀
10␮F
HEADPHONE
LEFT
HEADPHONE
RIGHT
Figure 40. Headphone Output Amplifier
Instrumentation Amplifier
Because of its high speed, low offset voltages and low noise
characteristics, the OP162/OP262/OP462 can be used in a wide
variety of high speed applications, including a precision instru-
mentation amplifier. Figure 41 shows an example of such an
application.
–V_IN
OP462-A
2k⍀
OP462-D
+V_IN
1k⍀
2k⍀
R_{G 1k⍀}
10k⍀
OP462-C
2k⍀
10k⍀
OP462-B
1.9k⍀
200⍀
10 TURN
(OPTIONAL)
OUTPUT
Figure 41. A High Speed Instrumentation Amplifier
–12–
REV. D