OP113_15 Datasheet, PDF (17/24 Pages) Analog Devices – Low Noise, Low Drift Single-Supply Operational Amplifiers

LOW VOLTAGE HEADPHONE AMPLIFIERS
Figure 49 shows a stereo headphone output amplifier for the
AD1849 16-bit SOUNDPORT® stereo codec device.¹ The
pseudo-reference voltage is derived from the common-mode
voltage generated internally by the AD1849, thus providing a
convenient bias for the headphone output amplifiers.
OPTIONAL
GAIN
1kΩ
V_REF
10µF
LOUT1L 31
10kΩ
L VOLUME
CONTROL
5kΩ
5V
–
1/2
OP213
+
16Ω
220µF
+
47kΩ
HEADPHONE
LEFT
AD1849
V_REF
5V
–
1/2
OP213
+
CMOUT 19
10kΩ
LOUT1R 29
10µF
R VOLUME
CONTROL
–
1/2
OP213
+
5kΩ
1kΩ _OPTIONAL
GAIN
V_REF
16Ω
220µF
+
47kΩ
HEADPHONE
RIGHT
Figure 49. Headphone Output Amplifier for Multimedia Sound Codec
LOW NOISE MICROPHONE AMPLIFIER FOR
MULTIMEDIA
The OPx13 family is ideally suited as a low noise microphone
preamp for low voltage audio applications. Figure 50 shows a
gain of 100 stereo preamp for the AD1849 16-bit SOUNDPORT
stereo codec chip. The common-mode output buffer serves as a
phantom power driver for the microphones.
OP113/OP213/OP413
10kΩ
LEFT
ELECTRET
CONDENSER
MIC
INPUT
10µF
+
50Ω
20Ω
10kΩ
5V
–
1/2
OP213
+
100Ω
17 MINL
AD1849
5V
–
1/2
OP213
+
100Ω
19 CMOUT
RIGHT
ELECTRET
CONDENSER
MIC
INPUT
20Ω
10µF
+
10kΩ
50Ω
+ _1/2
OP213
–
10kΩ
15 MINR
Figure 50. Low Noise Stereo Microphone Amplifier for Multimedia Sound
Codec
PRECISION VOLTAGE COMPARATOR
With its PNP inputs and 0 V common-mode capability, the
OPx13 family can make useful voltage comparators. There is
only a slight penalty in speed in comparison to IC comparators.
However, the significant advantage is its voltage accuracy. For
example, VOS can be a few hundred microvolts or less, combined
with CMRR and PSRR exceeding 100 dB, while operating from
a 5 V supply. Standard comparators like the 111/311 family
operate on 5 V, but not with common mode at ground, nor with
offset below 3 mV. Indeed, no commercially available single-
supply comparator has a VOS less than 200 μV.
1 _{SOUNDPORT is a registered trademark of Analog Devices, Inc.}
Rev. F | Page 17 of 24