Datasheet

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ANALOG OUTPUTS
28
27
26
25
24
23
22
21
20
19
18
17
16
15
PCM1738E
+
+
+
+5V
10 Fm
10 Fm
0.1 Fm
+
10 Fm
10 Fm
V 3
CC
AGND2
I
OUT
L–
I
OUT
L+
V
CC
2
V
CC
1
V
COM
3
I
REF
V
COM
2
V
COM
1
AGND1
I
OUT
R+
I
OUT
R–
MUTE
R
1
16kW
C
11
C
12
C
21
C
13
C
17
C
27
C
23
C
15
C
16
C
14
C
24
R
11
R
21
R
15
R
25
R
12
R
22
R
13
R
23
R
14
R
24
R
16
R
26
R
17
R
27
R
18
C
22
V
L-Channel
OUT
V
R-Channel
OUT
C
25
C
26
R
28
NOTE:ExampleR/CValuesforf 45kHz.
C
R –R ,R –R :620
C ,C ,C ,C :NotPopulated
C ,C ,C ,C :5600pF
C ,C :8200pF
C ,C ,C ,C :1800pF
11 18 21 28
11 12 21 22
13 14 23 24
15 25
16 17 26 27
W
OPA627BP,BM
orOPA5534Op Amp
OPA134,OPA2134,or
OPA604,OPA2604Op Amp
S0242-01
ANALOG OUTPUT LEVEL AND I/V CONVERTER
Operational Amplifiers for I/V Converter Circuit
PCM1738
SBAS174C – FEBRUARY 2002 – REVISED FEBRUARY 2007
Figure 40. Typical Application for Analog Output Stage
The signal level of the DAC current output pins (I
OUT
L+, I
OUT
L–, I
OUT
R+, and I
OUT
R–) is ± 2.48 mAp-p at 0 dB (full
scale). The voltage output of the I/V converter is given by the following equation:
V
OUT
= ± 2.48 mAp-p × R
F
Here, R
F
is the feedback resistor in the I/V (current-to-voltage) conversion circuit, R
11
, R
12
, R
21
, and R
22
in the
typical application circuit, Figure 40 . The common level of the I/V conversion circuit must be the same as the
common level of DAC I
OUT
that is given by the V
COM
2 reference voltage, 2.5 V dc. The non-inverting inputs of
the operational amplifiers shown in the I/V circuits are connected to V
COM
2 to provide the common bias voltage.
The OPA627BP/BM, or 5534 type operational amplifier, is recommended for the I/V conversion circuit to obtain
the specified audio performance. Dynamic performance, such as gain bandwidth, settling time, and slew rate of
the operational amplifiers creates the audio dynamic performance of the I/V section. The input noise
specification of the operational amplifiers should be considered to obtain 120-dB S/N ratio.
31
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