OP213EP AD [Analog Devices], OP213EP Datasheet - Page 7

• Manufacturer Part Number: OP213EP
• Description: Low Noise, Low Drift Single-Supply Operational Amplifiers
• Manufacturer: AD [Analog Devices]

REV. C
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.
SoundPort is a registered trademark of Analog Devices, Inc.
5k
5k
R1
R2
Figure 6. False Ground Generator
V
2
3
S
+ = +5V
1/2 OP113
4
8
+12V
0.1 F
C1
3
4
1
2
5
6
7
8
1
2.5k
R3
DR
DGND
VBR
V
LL
CK
LR
DL
L
18-BIT
SERIAL
SERIAL
18-BIT
18-BIT
18-BIT
DAC
DAC
REG.
REG.
100
R4
AD1868
V
V
+
REF
REF
C2
1 F
Figure 8. +5 V Only 18-Bit Stereo DAC
AGND
VOR
VBL
VOL
V
V
S
2
S
+
+5V SUPPLY
OUTPUT
15
14
12
16
13
11
10
9
330pF
330pF
7.68k
7.68k
–7–
9.76k
9.76k
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 V p-p.
+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.
REF43
GND
+5V
OUT
4
IN
2
6
5
7.68k
7.68k
1/2 OP213
1/2 OP213
6
Figure 7. Low Noise Voltage Reference
10k
8
10 F
100pF
100pF
–
+
1
7
10k
220 F
+ –
+ –
220 F
OP113/OP213/OP413
+
C2
10 F
47k
47k
2
3
LEFT
CHANNEL
OUTPUT
RIGHT
CHANNEL
OUTPUT
1/2 OP113
+5V
8
4
3 V p-p NOISE
1
OUTPUT
+2.500V