OP113 Datasheet, PDF (7/16 Pages) Analog Devices – Low Noise, Low Drift Single-Supply Operational Amplifiers

OP113/OP213/OP413
Supply Splitter Circuit
The OP113 family has excellent frequency response characteris-
tic that makes it an ideal pseudo-ground reference generator as
shown in Figure 6. The OP113 family serves as a voltage fol-
lower buffer. In addition, it drives a large capacitor that serves
as a charge reservoir to minimize transient load changes, as well
as a low impedance output device at high frequencies. The
circuit easily supplies 25 mA load current with good settling
characteristics.
R1
5k⍀
R2
5k⍀
V_S⁺ = +5V +12V
R3
2.5k⍀
C1
0.1␮F
8
2
1/2 OP113 1
3
4
R4
100⍀
+
C2
1␮F
V_S⁺ _OUTPUT
2
Figure 6. False Ground Generator
Low Noise Voltage Reference
Few reference devices combine low noise and high output drive
capabilities. Figure 7 shows the OP113 family used as a two-
pole active filter that band limits the noise of the 2.500 V refer-
ence. Total noise measures 3 µV p-p.
+5V
2
IN
OUT 6
REF43
GND
4
–
10␮F
+
10k⍀
10k⍀
+5V
8
2
1/2 OP113 1
OUTPUT
+2.500V
3
+
C2
10␮F
4
3␮V p-p NOISE
Figure 7. Low Noise Voltage Reference
+5 V Only Stereo DAC for Multimedia
The OP113 family’s low noise and single supply capability are
ideally suited for stereo DAC audio reproduction or sound
synthesis applications such as multimedia systems. Figure 8
shows an 18-bit stereo DAC output setup that is powered from a
single +5 volt supply. The low noise preserves the 18-bit dynamic
range of the AD1868. For DACs that operate on dual supplies,
the OP113 family can also be powered from the same supplies.
+5V SUPPLY
AD1868
1 V_{L 18-BIT}
LL ^DAC
2
VBL
16
15
3
18-BIT
DL SERIAL
REG.
4 _CK
DR
5
18-BIT
LR SERIAL
6
REG.
7 ^DGND
18-BIT
DAC
8
VBR
14
VOL
V_REF
13
AGND 12
V_REF
11
VOR
10
V_S 9
7.68k⍀ 9.76k⍀
330pF
7.68k⍀ 9.76k⍀
330pF
8
220␮F
LEFT
1/2 OP213 ¹
+–
CHANNEL
OUTPUT
47k⍀
100pF
7.68k⍀
7.68k⍀
100pF
6
220␮F _RIGHT
1/2 OP213 7 _{+ –}
CHANNEL
OUTPUT
5
47k⍀
Figure 8. +5 V Only 18-Bit Stereo DAC
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REV. C
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