5173N24-U THAT, 5173N24-U Datasheet - Page 6

• Manufacturer Part Number: 5173N24-U
• Description: Microphone Preamplifiers 36V, 100mA
• Manufacturer: THAT

Specifications of 5173N24-U

• Rohs: yes
• Common Mode Rejection Ratio (min): - 9 dB
• Input Offset Voltage: - 1.75 mV to + 1.75 mV
• Maximum Operating Temperature: + 85 C
• Package / Case: QFN-24
• Input Voltage Range (max): 3.6 V, 17 V
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 3 V to 3.6 V, 4.75 V to 17 V
• Operating Temperature Range: - 40 C to + 85 C
• Supply Current: 2 uA, 7.6 mA
• Supply Voltage - Max: 3.6 V, 17 V
• Supply Voltage - Min: 3 V, 4.75 V
• Thd Plus Noise: 0.001 %
• Voltage Gain Db: 60 dB

Document 600166 Rev 01
tors, switched by a set of CMOS FET switches, con-
figured to create a variable, switched, differential
attenuation network. The network’s impedances are
ideal
current-feed- back instrumentation amplifiers, and
are
applications.
Using the 5173
the feedback loop of differential current-feedback
gain stages, such as the THAT 1570. Designed spe-
cifically for use in high-performance microphone pre-
amplifiers, THAT’s engineers paid careful attention
to precision, stability, and control over the resistors
and their switches, in order to maintain excellent
audio performance over a wide range of gains and
signal levels.
connected to a 1570. Resistors R
differential attenuator (“U-pad”). The amplifier’s dif-
ferential output is applied to R
of the attenuator, appearing across R
to the inverting differential input of the dual current-
feedback amplifiers (the R
age divider ratio thus controls the differential gain of
the circuit.
on the gain command provided via the SPI control
interface. At 0dB gain R
R
while R
three resistors are varied by CMOS switches in order
to produce 3dB gain steps from 0 to +60dB. At all
gains, the impedance levels are chosen to minimize
noise and distortion within the circuit as a whole.
A
= R
The THAT 5173 contains a set of precision resis-
The attenuator is intended primarily for use in
Figure 3 shows the analog portion of the 5173
The 5173 changes the attenuator settings based
optimized
Figure 3. 5173 analog connections to a 1570.
for
A
B
= R
=2.5kΩ. At +3dB gain, R
controlling
B
= ~2.5kΩ. To achieve other gains, all
for
U1
THAT5173
Tel: [phone]; Fax: [phone]; Web: www.thatcorp.com
gain
THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA
low
G
G1
is an open circuit and
and R
U2
THAT1570
Copyright © 2012, THAT Corporation; All rights reserved.
in
A
source
A
and R
, R
G2
low-voltage-noise,
B
G
, and R
pins). The volt-
G
, is connected
is ~12.12kΩ,
B
. The output
impedance
Theory of Operation
G
form a
Page 6 of 20
tor values for each gain setting.
Accommodating High Signal Levels
accommodate full professional-audio signal levels.
Accordingly, it is fabricated in a high-voltage CMOS
process which allows operation from up to ±17V
analog power supplies. Along with proprietary (and
patent-pending) drive circuitry to the switching FETs,
this permits low-distortion operation at signal levels
up to over +27dBu in, and +27dBu out. See also
DN140 for more discussion and ideas.
Switching Noise
mize switching noise during gain changes. Special
(patent pending) circuitry slows down the FET gate
drive to minimize charge injection. This helps sup-
press clicks when changing gain. As well, the FET
switches are implemented in a balanced fashion so
as to maintain equal perturbation to the positive and
negative sides of the balanced signal path.
restrict gain changes to times when the analog signal
is very close to zero. The detector monitors the dif-
ferential signal present between the IN
Table 2 lists the typical internal attenuator resis-
One key objective of the 5173 design was to
The 5173 includes several features which mini-
A built-in zero-crossing detector can be used to
Setting
Gain
12
15
18
21
24
27
30
33
36
39
42
45
48
51
54
57
60
0
3
6
9
Table 2. Internal attenuator resistor values.
12,120.2
Audio Preamplifier Digital Controller IC
8,580.5
3,044.5
3,044.5
3,044.5
1,080.2
1,080.2
1,080.2
(Ohms)
383.3
383.3
383.3
48.3
48.3
48.3
17.1
17.1
17.1
136
136
136
Rg
Inf
(Ohms)
4,269.9
4,537.9
7,037.9
3,750.1
4,098.6
5,868.5
8,368.5
4,222.2
5,992.1
8,492.1
4,266.1
4,281.7
6,051.6
8,551.6
Ra, Rb
2,500
2,500
2,768
5,520
8,020
6,036
8,536
1
and IN
THAT5173
Register
“Gain”
10
11
12
13
14
15
16
17
18
19
20
0
1
2
3
4
5
6
7
8
9
2
pins