DATA SHEET
www.onsemi.com
Low Voltage Compandor
20
SA575
The SA575 is a precision dual gain control circuit designed for low
voltage applications. The SA575’s channel 1 is an expandor, while
channel 2 can be configured either for expandor, compressor, or
automatic level controller (ALC) application.
Features
• Operating Voltage Range from 3.0 V to 7.0 V
• Reference Voltage of 100 mVRMS = 0 dB
• One Dedicated Summing Op Amp Per Channel and Two Extra
•
•
•
•
Uncommitted Op Amps
600 Drive Capability
Single or Split Supply Operation
Wide Input/Output Swing Capability
These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
Compliant
Applications
•
•
•
•
•
•
•
•
•
Portable Communications
Cellular Radio
Cordless Telephone
Consumer Audio
Portable Broadcast Mixers
Wireless Microphones
Modems
Electric Organs
Hearing Aids
1
TSSOP−20
DTB SUFFIX
CASE 948E
MARKING DIAGRAM
SA
575
ALYWG
G
A
WL, L
YY, Y
WW, W
G
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
(Note: Microdot may be in either location)
PIN CONNECTIONS
+VIN1
1
20 VCC
-VIN1
2
19 +VIN2
VOUT1
3
18 -VIN2
RECT. IN1
4
17 VOUT2
CRECT1 5
16 RECT.IN2
SUM OUT 1
6
15 CRECT2
COMP. IN1
7
14 SUM OUT2
VREF
8
13 COMP.IN2
GAIN CELL IN1
9
12 SUM NODE 2
GND 10
11 GAIN CELL IN2
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 12 of this data sheet.
© Semiconductor Components Industries, LLC, 2006
October, 2021 − Rev. 5
1
Publication Order Number:
SA575/D
SA575
0.1F
VCC +5V
C15
1
+
2
−
575
3
+
OP AMP
10F
4
+
CRECT
2.2F
19
−
18
GND
10F
R13
VIN
+
C14
VREF
10k
17
3.8k
C11
5
3.8k
6
20
+
OP AMP
C3
VOUT
VCC
16
15
+
4.7F
C10
CRECT
+
+
2.2F
GND
C6
VIN
10F
7
+
+
10F
9
VREF
10k
10k
GND
GND
11
PIN FUNCTION DESCRIPTION
Symbol
1
+VIN1
Non−Inverted Input 1
2
−VIN1
Inverted Input 1
3
VOUT
Output
4
RECT. IN1
5
CRECT1
6
SUM OUT1
Summation Output 1
7
COMP. IN1
Compensator Pin
8
VREF
Voltage Reference
9
GAIN CELL IN1
10
GND
Description
Rectifier 1 Input
External Capacitor Pinout for Rectifier 1
Variable Gain Cell Input 1
Ground
11
GAIN CELL IN2
12
SUM NODE 2
13
COMP. IN2
Compensator Pin
14
SUM OUT2
Summation Output 2
15
CRECT2
16
RECT. IN2
17
VOUT2
Output 2
18
−VIN2
Inverted Input 2
19
+VIN2
Non−Inverted Input 2
20
VCC
+
C8
1F
GND
Figure 1. Block Diagram and Test Circuit
Pin
R7
30k
G
R8
30k
13
12
G
10k
10
GND
14
10k
8
VREF
10F
Variable Gain Cell Input 2
Summation Node 2
External Capacitor Pinout for Rectifier 2
Rectifier 2 Input
Positive Power Supply
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2
VOUT
SA575
MAXIMUM RATINGS
Symbol
Value
Unit
Single Supply Voltage
Rating
VCC
−0.3 to 8.0
V
Voltage Applied to Any Other Pin
VIN
−0.3 to (VCC + 0.3)
V
Operating Ambient Temperature Range
TA
-40 to +85
°C
Operating Junction Temperature
TJ
150
°C
TSTG
150
°C
Storage Temperature Range
Thermal Impedance
JA
124
°C/W
Maximum Power Dissipation
PD
1068
mW
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality
should not be assumed, damage may occur and reliability may be affected.
DC ELECTRICAL CHARACTERISTICS Typical values are at TA = 25°C. Minimum and Maximum values are for the full operating
temperature range: -40 to +85°C for SA575, except SSOP package is tested at +25°C only. VCC = 5.0 V, unless otherwise stated. Both
channels are tested in the Expandor mode (see Test Circuit).
Characteristic
Symbol
Test Conditions
Min
Typ
Max
Unit
FOR COMPANDOR, INCLUDING SUMMING AMPLIFIER
Supply Voltage (Note 1)
VCC
−
3.0
5.0
7.0
V
Supply Current
ICC
No Signal
3.0
4.2
5.5
mA
Reference Voltage (Note 2)
VREF
VCC = 5.0 V
2.4
2.5
2.6
V
Summing Amp Output Load
RL
−
10
−
−
k
Total Harmonic Distortion
THD
1.0 kHz, 0 dB, BW = 3.5 kHz
−
0.12
1.5
%
Output Voltage Noise
ENO
BW = 20 kHz, RS = 0
−
6.0
30
V
Unity Gain Level
0dB
1.0 kHz
-1.5
−
1.5
dB
Output Voltage Offset
VOS
No Signal
-150
−
150
mV
Output DC Shift
Tracking Error Relative to 0 dB
Crosstalk
No Signal to 0 dB
-100
−
100
mV
Gain Cell Input = 0 dB, 1.0 kHz
Rectifier Input = 6.0 dB, 1.0 kHz
-1.0
−
1.0
dB
Gain Cell Input = 0 dB, 1.0 kHz
Rectifier Input = -30 dB, 1.0 kHz
-1.0
−
1.0
dB
1.0 kHz, 0 dB, CREF = 220 F
−
-80
-65
dB
FOR OPERATIONAL AMPLIFIER
Output Swing
VO
RL = 10 k
VCC-0.4
VCC
−
V
Output Load
RL
1.0 kHz
600
−
−
Input Common-Mode Range
Common-Mode Rejection Ratio
Input Bias Current
CMR
−
0
−
VCC
V
CMRR
−
60
80
−
dB
IB
VIN = 0.5 V to 4.5 V
-1.0
−
1.0
A
Input Offset Voltage
VOS
−
−
3.0
−
mV
Open-Loop Gain
AVOL
RL = 10 k
−
80
−
dB
Slew Rate
SR
Unity Gain
−
1.0
−
V/s
Bandwidth
GBW
Unity Gain
−
3.0
−
MHz
ENI
BW = 20 kHz
−
2.5
−
V
PSRR
1.0 kHz, 250 mV
−
60
−
dB
Input Voltage Noise
Power Supply Rejection Ratio
1. Operation down to VCC = 2.0 V is possible, but performance is reduced. See curves in Figures 6 and 7.
2. Reference voltage, VREF, is typically at 1/2 VCC.
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3
SA575
Functional Description
C6 is for decoupling and stabilizing the voltage reference
circuit. The value of C6 should be such that it will offer a
very low impedance to the lowest frequencies of interest.
Too small a capacitor will allow supply ripple to modulate
the audio path. The better filtered the power supply, the
smaller this capacitor can be. R12 provides DC reference
voltage to the amplifier of channel B. R6 and R7 provide a
DC feedback path for the summing amp of channel B,
while C7 is a short-circuit to ground for signals. C14 and C15
are for power supply decoupling. C14 can also be
eliminated if the power supply is well regulated with very
low noise and ripple.
This section describes the basic subsystems and
applications of the SA575 Compandor. More theory of
operation on compandors can be found in AND8159 and
AND8160. The typical applications of the SA575 low
voltage compandor in an Expandor (1:2), Compressor (2:1)
and Automatic Level Control (ALC) function are
explained. These three circuit configurations are shown in
Figures 2, 3, and 4 respectively.
The SA575 has two channels for a complete companding
system. The left channel, A, can be configured as a 1:2
Expandor while the right channel, B, can be configured as
either a 2:1 Compressor, a 1:2 Expandor or an ALC. Each
channel consists of the basic companding building blocks
of rectifier cell, variable gain cell, summing amplifier
and VREF cell. In addition, the SA575 has two additional
high performance uncommitted op amps which can be
utilized for application such as filtering, pre-emphasis/
de-emphasis or buffering.
Figure 5 shows the complete schematic for the
applications demo board. Channel A is configured as an
expandor while channel B is configured so that it can be
used either as a compressor or as an ALC circuit. The
switch, S1, toggles the circuit between compressor and
ALC mode. Jumpers J1 and J2 can be used to either include
the additional op amps for signal conditioning or exclude
them from the signal path. Bread boarding space is
provided for R1, R2, C1, C2, R10, R11, C10 and C11 so that
the response can be tailored for each individual need. The
components as specified are suitable for the complete
audio spectrum from 20 Hz to 20 kHz.
The most common configuration is as a unity gain
non-inverting buffer where R1, C1, C2, R10, C10 and C11 are
eliminated and R2 and R11 are shorted. Capacitors C3, C5,
C8, and C12 are for DC blocking. In systems where the
inputs and outputs are AC coupled, these capacitors and
resistors can be eliminated. Capacitors C4 and C9 are for
setting the attack and release time constant.
Demonstrated Performance
The applications demo board was built and tested for a
frequency range of 20 Hz to 20 kHz with the component
values as shown in Figure 5 and VCC = 5.0 V. In the
expandor mode, the typical input dynamic range was from
-34 dB to +12 dB where 0 dB is equal to 100 mVRMS. The
typical unity gain level measured at 0 dB @ 1.0 kHz input
was "0.5 dB and the typical tracking error was "0.1 dB
for input range of -30 to +10 dB.
In the compressor mode, the typical input dynamic range
was from -42 dB to "18 dB with a tracking error +0.1 dB
and the typical unity gain level was "0.5 dB.
In the ALC mode, the typical input dynamic range was
from -42 dB to +8.0 dB with typical output deviation of
"0.2 dB about the nominal output of 0 dB. For input
greater than +9.0 dB in ALC configuration, the summing
amplifier sometimes exhibits high frequency oscillations.
There are several solutions to this problem. The first is to
lower the values of R6 and R7 to 20 k each. The second
is to add a current limiting resistor in series with C12 at
Pin 13. The third is to add a compensating capacitor of
about 22 to 30 pF between the input and output of summing
amplifier (Pins 12 and 14). With any one of the above
recommendations, the typical ALC mode input range
increased to +18 dB yielding a dynamic range of over
60 dB.
www.onsemi.com
4
SA575
Expandor
accuracy of the gain cell. This can be improved by using an
extra capacitor from the input to Pin 4 and eliminating the
DC connection between Pins 4 and 9.
The expandor gain expression and the attack and release
time constant is given by Equation 1 and Equation 2,
respectively.
The typical expandor configuration is shown in Figure 2.
The variable gain cell and the rectifier cell are in the signal
input path. The VREF is always 1/2 VCC to provide the
maximum headroom without clipping. The 0 dB ref is
100 mVRMS. The input is AC coupled through C5, and the
output is AC coupled through C3. If in a system the inputs
and outputs are AC coupled, then C3 and C5 can be
eliminated, thus requiring only one external component,
C4. The variable gain cell and rectifier cell are DC coupled
so any offset voltage between Pins 4 and 9 will cause small
offset error current in the rectifier cell. This will affect the
Expandor gain =
4VIN(avg)
3.8 k x 100 A
2
where VIN(avg) = 0.95VIN(RMS)
R = A = 10 k x CRECT = 10 k x C4
7, 13
C5
EXP IN
10k
9, 11
G
10k
10F
6, 14
C3
EXP OUT
10F
4, 16
3.8k
5, 15
C4
(eq. 1)
8
2.2F
VREF
Figure 2. Typical Expandor Configuration
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5
(eq. 2)
SA575
Compressor
the output to input. In the presence of an AC signal this
phenomenon is not observed and the circuit will appear to
function properly.
The compressor gain expression and the attack and
release time constant is given by Equation 3 and
Equation 4, respectively.
The typical compressor configuration is shown in
Figure 3. In this mode, the rectifier cell and variable gain
cell are in the feedback path. R6 and R7 provide the DC
feedback to the summing amplifier. The input is AC
coupled through C12 and output is AC coupled through C8.
In a system with inputs and outputs AC coupled, C8 and C12
could be eliminated and only R6, R7, C7, and C13 would be
required. If the external components R6, R7 and C7 are
eliminated, then the output of the summing amplifier will
motor-boat in absence of signals or at extremely low
signals. This is because there is no DC feedback path from
Compressor gain =
3.8 k x 100 A
1/2
4VIN(avg)
where VIN(avg) = 0.95VIN(RMS)
R = A = 10 k x CRECT = 10 k x C4
R6
R7
30k
30k
1F
C7
VREF
8
C12
COMP IN
10F
12
C8
14
COMP OUT
13
10F
10k
11
G
10k
16
3.8k
C13
4.7F
15
C9
(eq. 3)
2.2F
Figure 3. Typical Compressor Configuration
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6
(eq. 4)
SA575
Automatic Level Control
absence of signals. CCOMP is necessary to stabilize the
summing amplifier at higher input levels. This circuit
provides an input dynamic range greater than 60 dB with
the output within "0.5 dB typical. The necessary design
expressions are given by Equation 5 and Equation 6,
respectively.
The typical Automatic Level Control circuit
configuration is shown in Figure 4. It can be seen that it is
quite similar to the compressor schematic except that the
input to the rectifier cell is from the input path and not from
the feedback path. The input is AC coupled through C12
and C13 and the output is AC coupled through C8. Once
again, as in the previous cases, if the system input and
output signals are already AC coupled, then C12, C13 and
C8 could be eliminated. Concerning the compressor,
removing R6, R7 and C7 will cause motor-boating in
ALC gain =
3.8 k x 100 A
(eq. 5)
4VIN(avg)
R = A = 10 k x CRECT = 10 k x C9
R6
R7
30k
1F
C7
30k
C COMP
VREF
22pF
8
C12
ALC IN
12
14
13
11
G
10k
C13
4.7F
ALC OUT
10F
10k
10F
C8
16
3.8k
15
C9
2.2F
Figure 4. Typical ALC Configuration
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7
(eq. 6)
SA575
VCC -5V
C15
VREF
0.1F
1
R1
2
C1
C2
−
R2
575
J1
4
10F
VCC
OP AMP
EXP
IN
10F
8
VREF
C6
10F
9
18
C12
10F
R10
COMP/
ALC
IN
C10
C11
17
J2
C13
16
ALC
4.7F
S1
C9
COMP
15
2.2F
14
10k
VREF
10k
R12
10k
47F
R11
6
7
−
3.8k
C4
C5
19
3.8k
5
2.2F
20
+
OP AMP
3
C3
EXP
OUT
C14
+
10k
13
12
G
G
10
GND
10k
C8
R6
R7
30k
30k
11
Figure 5. SA575 Low Voltage Expandor/Compressor/ALC Demo Board
www.onsemi.com
8
10F
C7
1F
COMP/
ALC
OUT
SA575
1.0
0.9
0.8
0.7
0.6
UNITY GAIN ERROR (dB)
0.5
0.4
0.3
0.2
VCC 7V
0.1
0.0
VCC 5V
−0.1
−0.2
−0.3
VCC 3V
−0.4
−0.5
VCC 2V
−0.6
−0.7
−0.8
−0.9
−1.0
−50
−25
0
25
50
75
100
TEMPERATURE (°C)
Figure 6. Unity Gain Error vs. Temperature and VCC
4.4
4.2
4.0
(mA)
I
CC
VCC 7V
3.8
3.6
VCC 5V
3.4
VCC 3V
VCC 2V
3.2
3.0
−50
−25
0
25
50
TEMPERATURE (°C)
Figure 7. ICC vs. Temperature and VCC
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9
75
100
SA575
TYPICAL PERFORMANCE CHARACTERISTICS
8
GENERAL DIAGRAM
4.7F
10F
6
10dB IN
INPUT
(20−20kHz)
4
G
REC
SUM
OUTPUT
2
0dB IN
VCC = 5V
0
OUTPUT LEVEL (dB)
−2
−4
−6
−8
−10
−12
−14
−16
−18
-40dB IN
−20
−22
10
100
1000
10000
30000
FREQUENCY (Hz)
Figure 8. Compressor Output Frequency Response
www.onsemi.com
10
SA575
TYPICAL PERFORMANCE CHARACTERISTICS
8
INPUT
(20−20kHz)
6
2.5dB IN
GENERAL DIAGRAM
4.7F
REC
4
OUTPUT
SUM
2
G
0dB IN
10F
VCC = 5V
0
OUTPUT LEVEL (dB)
−2
−4
−6
−8
−10
−12
−14
−16
−18
-10dB IN
−20
−22
10
100
1000
10000
FREQUENCY (Hz)
Figure 9. Expandor Output Frequency Response
www.onsemi.com
11
30000
SA575
COMPRESSOR IN
EXPANDOR OUT
+10dB
+10dB
+5dB
0dB
100mV
100mV
0dB
0dB
−5dB
−10dB
−10dB
−10dB
−15dB
−20dB
−20dB
−20dB
−25dB
−30dB
−30dB
−40dB
−40dB
−50dB
−50dB
}
}
COMPRESSION
EXPANSION
Figure 10. The Companding Function
ORDERING INFORMATION
Device
Package
Temperature Range
Shipping†
SA575DTBR2G
TSSOP−20
(Pb−Free)
−40 to +85°C
2500 / Tape & Reel
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specification
Brochure, BRD8011/D.
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12
MECHANICAL CASE OUTLINE
PACKAGE DIMENSIONS
TSSOP−20 WB
CASE 948E
ISSUE D
DATE 17 FEB 2016
SCALE 2:1
20X
0.15 (0.006) T U
2X
L
K REF
0.10 (0.004)
S
L/2
20
M
T U
S
V
ÍÍÍÍ
ÍÍÍÍ
ÍÍÍÍ
K
K1
S
J J1
11
B
SECTION N−N
−U−
PIN 1
IDENT
0.25 (0.010)
N
1
10
M
0.15 (0.006) T U
S
A
−V−
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ANSI Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. DIMENSION A DOES NOT INCLUDE MOLD
FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH OR GATE BURRS SHALL NOT
EXCEED 0.15 (0.006) PER SIDE.
4. DIMENSION B DOES NOT INCLUDE
INTERLEAD FLASH OR PROTRUSION.
INTERLEAD FLASH OR PROTRUSION
SHALL NOT EXCEED 0.25 (0.010) PER SIDE.
5. DIMENSION K DOES NOT INCLUDE
DAMBAR PROTRUSION. ALLOWABLE
DAMBAR PROTRUSION SHALL BE 0.08
(0.003) TOTAL IN EXCESS OF THE K
DIMENSION AT MAXIMUM MATERIAL
CONDITION.
6. TERMINAL NUMBERS ARE SHOWN FOR
REFERENCE ONLY.
7. DIMENSION A AND B ARE TO BE
DETERMINED AT DATUM PLANE −W−.
N
F
DETAIL E
−W−
C
G
D
H
DETAIL E
0.100 (0.004)
−T− SEATING
PLANE
DIM
A
B
C
D
F
G
H
J
J1
K
K1
L
M
MILLIMETERS
MIN
MAX
6.40
6.60
4.30
4.50
--1.20
0.05
0.15
0.50
0.75
0.65 BSC
0.27
0.37
0.09
0.20
0.09
0.16
0.19
0.30
0.19
0.25
6.40 BSC
0_
8_
INCHES
MIN
MAX
0.252
0.260
0.169
0.177
--0.047
0.002
0.006
0.020
0.030
0.026 BSC
0.011
0.015
0.004
0.008
0.004
0.006
0.007
0.012
0.007
0.010
0.252 BSC
0_
8_
GENERIC
MARKING DIAGRAM*
SOLDERING FOOTPRINT
7.06
XXXX
XXXX
ALYWG
G
1
0.65
PITCH
16X
0.36
16X
1.26
DOCUMENT NUMBER:
98ASH70169A
DESCRIPTION:
TSSOP−20 WB
A
L
Y
W
G
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
(Note: Microdot may be in either location)
*This information is generic. Please refer to
device data sheet for actual part marking.
Pb−Free indicator, “G” or microdot “ G”,
may or may not be present.
DIMENSIONS: MILLIMETERS
Electronic versions are uncontrolled except when accessed directly from the Document Repository.
Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red.
PAGE 1 OF 1
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TECHNICAL SUPPORT
North American Technical Support:
Voice Mail: 1 800−282−9855 Toll Free USA/Canada
Phone: 011 421 33 790 2910
Europe, Middle East and Africa Technical Support:
Phone: 00421 33 790 2910
For additional information, please contact your local Sales Representative
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