OP113 datasheet(8/16 Pages) AD

8 / 16 page

OP113/OP213/OP413

–8–

REV. C

Precision Voltage Comparator

With its PNP inputs and zero volt common-mode capability, the

OP113 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 on

5 V supply. Standard comparators like the 111/311 family oper-

ate on 5 volts, 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.

Figure 11 shows the OP113 family response to a 10 mV over-

drive signal when operating in open loop. The top trace shows

the output rising edge has a 15

µs propagation delay, while the

bottom trace shows a 7

µs delay on the output falling edge. This

ac response is quite acceptable in many applications.

+5V

100

25k

–2.5V

+2.5V

tr = tf = 5ms

10mV OVERDRIVE

1/2

OP113

100

5 s

Figure 11. Precision Comparator

The low noise and 250

µV (maximum) offset voltage enhance

the overall dc accuracy of this type of comparator. Note that

zero crossing detectors and similar ground referred comparisons

can be implemented even if the input swings to –0.3 volts below

ground.

Low Voltage Headphone Amplifiers

Figure 9 shows a stereo headphone output amplifier for the

AD1849 16-bit SoundPort

® Stereo Codec device. The pseudo-

reference voltage is derived from the common-mode voltage

generated internally by the AD1849, thus providing a conve-

nient bias for the headphone output amplifiers.

1/2

OP213

+5V

1/2

OP213

OPTIONAL

GAIN

VREF

1/2

OP213

+5V

VREF

OPTIONAL

GAIN

10k

LOUT1L

LOUT1R

CMOUT

AD1849

VREF

10 F

10k

L VOLUME

CONTROL

R VOLUME

CONTROL

220 F

47k

HEADPHONE

LEFT

HEADPHONE

RIGHT

10 F

220 F

47k

Figure 9. Headphone Output Amplifier for Multimedia

Sound Codec

Low Noise Microphone Amplifier for Multimedia

The OP113 family is ideally suited as a low noise microphone

preamp for low voltage audio applications. Figure 10 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.

+5V

1/2

OP213

10k

10 F

100

10k

+5V

1/2

OP213

10 F

10k

1/2

OP213

10k

100

MINL

MINR

CMOUT

AD1849

RIGHT

ELECTRET

CONDENSER

MIC

INPUT

LEFT

ELECTRET

CONDENSER

MIC

INPUT

Figure 10. Low Noise Stereo Microphone Amplifier for

Multimedia Sound Codec

SoundPort is a registered trademark of Analog Device, Inc.

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