5171N32-U THAT Corporation, 5171N32-U Datasheet - Page 10

• Manufacturer Part Number: 5171N32-U
• Description: Microphone Preamplifiers High-Perform Digital Pre-Amp Controller
• Manufacturer: THAT Corporation

Specifications of 5171N32-U

• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 3 V to 17 V
• Operating Temperature Range: - 40 C to + 85 C
• Supply Current: 8.3 mA
• Supply Voltage (max): 17 V
• Supply Voltage (min): 3 V
• Thd Plus Noise: 0.0003 %
• Available Set Gain: 13.6 dB to 68.6 dB
• Input Offset Voltage: +/- 1.5 mV
• Maximum Operating Temperature: + 85 C
• Package / Case: QFN-32
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Document 600133 Rev 04
its differential gain, as does the passive attenuator
shown in Figure 5. This circuit 5 relies entirely upon
the A/D converter’s common-mode rejection.
quality A/D converters, and to improve common-
mode rejection, consider circuits like the one in
Figure 6. The active (buffered) attenuator provides
differential drive to the ADC, which improves per-
formance. Note, however, that noise in the 2114
opamps shown will compromise the performance of
the 5171/1570 combination by ~3dB at minimum
gains, so choose the active devices for low noise as
well as good audio performance.
RFI Protection (and Common-Mode
Rejection)
tection in two sections. Small capacitors (C
are used from the positive and negative signal inputs
to chassis ground, along with a larger capacitor (C
across the two inputs. These components should be
located as close as possible to the input signal con-
nector, and are intended to prevent RF from entering
the chassis of the device.
to the 1570, and is intended to prevent any RF
picked up inside the unit from reaching the 1570’s
input, where it might be rectified and cause audio-
band interference. This network consists of a pair of
larger capacitors (C
capacitor (C
vented from entering the unit, and none is generated
For better distortion performance with high-
The circuits of Fig 3 through 6 include RFI pro-
A second RF protection network is located close
8
) across the two input lines. If RF is pre-
6
THAT
5171
and C
U1
Figure 6. 5171/1570 high-performance application for output to an A/D convertor.
Tel: [phone]; Fax: [phone]; Web: www.thatcorp.com
THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA
19 18 17 16
To: Host
MCU
7
) to ground and one more
Copyright © 2010, THAT Corporation; All rights reserved.
15
26 25 24 23
Control
14
Logic
22
32
13
31
Servo
21
-
+
Vee
Vcc
1
+
-
and C
29
20
30
12
10
Switches
Page 10 of 20
with FET
Resistor
Network
2
3
)
)
6
5
3
4
11
THAT
1570
U2
9
10
7
6
15
inside the unit, then these capacitors may be omitted
or reduced in value.
some consideration for common-mode rejection.
Unbalanced capacitance from either input line (IN+
or IN-) to ground can unbalance common-mode sig-
nals, converting them to differential signals, which
will be amplified along with the desired (differential)
signal. The 1570 differential amplifier in the above
circuits offers gain only to differential signals:
common-mode signal gain is always 0dB. Therefore,
its common-mode rejection is equal to the differen-
tial gain.
verted to differential ones, this common-mode rejec-
tion will prevail. Because they are relatively small,
differences in the values of C
to cause imbalance than the larger capacitors at C
and C
tors C
to ensure matching between their values. Note that C
and C
not affect common-mode rejection.
Power Supply Decoupling
of the 1570, the servo in the 5171, and to minimize
digital switching noise from propagating on the
power supplies. The V
nected to the same analog supply which powers the
analog gain stage, while the V
be powered in common with other logic circuitry
(microprocessors, etc.) in the unit.
Vcc
The design of these networks was arrived at after
So long as common-mode signals are not con-
Power supply decoupling is required for stability
13
12
7
6
8
. For this reason, we recommend that capaci-
and C
affect only differential signals, and thus do
3
2
7
should be at least 5% types, in order
Digital Preamplifier Controller IC
CC
and V
THAT5171 High-Performance
DD
1
EE
pins (13 and 21) may
and C
pins should be con-
2
are less likely
OUT+
OUT-
6
3