MOTOROLA MC33111D Low voltage compander Datasheet

Order this data sheet by MC33111/D
MOTOROLA
SEMICONDUCTOR
TECHNICAL DATA
MC33111
Advance Information
Low Voltage Compander
The MC33111 contains two variable gain circuits configured for
compressing and expanding the dynamic range of an audio signal. One
circuit is configured as an expander, and the other is configured as a
compressor. Each circuit has a full wave rectifier to provide average value
information to a variable gain cell located in either the input stage or the
feedback path. An internal temperature stable bandgap reference provides
the necessary precision voltages.
LOW VOLTAGE
COMPANDER
SILICON MONOLITHIC
INTEGRATED CIRCUIT
Included in the MC33111 are controls for muting each section
independently, and for passthrough of both. Two uncommitted op amps
are available for peripheral functions.
The MC33111 will operate from a supply voltage of 3.0 V to 7.0 V, and
over a temperature range of – 40° to + 85°C. It is designed to
accommodate a 60 dB dynamic range; from – 40 dB to + 20 dB referenced
to 100 mVrms.
Applications include cordless telephone, CBs, walkie-talkies, and most
voice RF links, and any application where an improvement in the signal to
noise ratio is desired. Other applications include speakerphones and voice
activated intercoms, dictating machines, etc.
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16
1
P SUFFIX
PLASTIC PACKAGE
CASE 648
Operating Supply Voltage: 3.0 V to 7.0 V
Output Voltage Swing = 2.8 Vp-p with VCC = 3.0 V
No Precision External Components Required
60 dB Dynamic Range Compressed to 30 dB, Re-expandable to 60 dB
Unity Gain Level set at 100 mVrms
Attack and Decay Times Adjustable
Mute and Passthrough Controls
16
Two Uncommitted Op Amps
1
Temperature Compensated Reference
Available in Standard DIP and Surface Mount Packages
D SUFFIX
PLASTIC PACKAGE
CASE 751B
(SO-16)
Simplified Block Diagram
Expander
Input
20 k
0.5 14 MC33111
11
1.0 µF
Compressor
3
Input
∆ Gain
40 k
Rectifier
Compressor
2 Output
Vb
7.5 k
∆ Gain
5
Bias &
Reference
Generator
40 k
Rectifier
V+
9
16
VCC
TRUTH TABLE
CM
EM
PT
Function
0
1
X
0
0
X
1
0
0
X
X
1
Normal
Comp. Mute
Expander Mute
Passthrough
1
ORDERING INFORMATION
10
Microphone
Expander
15 Output
Vb
10 k
0.5
1.0 µF
15 k
Vb
Mute/
Passthrough
Logic
Vb
7
4
12
8
CM
EM
PT
6
This document contains information on a new product. Specifications and information herein are subject to change
without notice. This device contains 329 active transistors.
Device
MC33111D
MC33111P
Temperature
Range
– 40° to + 85°C
Package
SO-16
Plastic DIP
 Motorola, Inc. 1994
PIN FUNCTION DESCRIPTION
Name
Pin
Description
Ground
1
Connect to a clean power supply ground.
Compressor Output
2
Output of the compressor section.
Compressor Input
3
Compressor input. The input impedance is nominally 10 kΩ. Nominal signal range is
1.0 mVrms to 1.0 Vrms in normal mode, and up to 0.8 Vrms in passthrough mode.
Must be capacitor coupled to the signal source.
Compressor Mute
4
A logic high mutes the compressor. A logic low permits normal operation and passthrough.
Compressor Filter
5
Connect an external capacitor to filter the full wave rectifier’s output.
This capacitor affects attack and decay times, and low frequency accuracy.
Amplifier #1
6, 7
Inverting input (7) and output (6) of an op amp internally referenced to Vb.
Passthrough
8
Amplifier #2
9, 10
Inverting input (9) and output (10) of an op amp internally referenced to Vb.
Expander Filter
11
Connect an external capacitor to filter the full wave rectifier’s output.
This capacitor affects attack and decay times, and low frequency accuracy.
Expander Mute
12
A logic high mutes the expander. A logic low permits normal operation and passthrough.
No Connect
13
This pin is not internally connected to anything.
Expander Input
14
Expander input. The input impedance is nominally 10.9 kΩ. Nominal signal range is
10 mVrms to 316 mVrms in normal mode, and up to 1.0 Vrms in passthrough mode.
Must be capacitor coupled to the signal source.
Expander Output
15
Output of the expander section.
VCC
16
Power supply. Connect to a power supply voltage in the range of 3.0 V to 7.0 V.
Bypass capacitor should be provided at this pin.
A logic high sets the gain of both expander and compressor to ≈ 0 dB, independent of
input level.
TRANSFER FUNCTIONS
Compressor
Compression
Rectifier
20 dB
10 k
V out
1.0 V
0 dB
Vout
Vb
+ 0.3162 x ǸVin
Expander
Vin
316 mV
10 dB
∆ Gain
Vin
Expansion
15 k
100 mV
31.6 mV
10 mV
–10 dB
– 20 dB 10 mV
40 k
Vb
Vout
∆ Gain
Rectifier
– 30 dB
– 40 dB
1.0 mV
Vout = 10 x Vin2
(Voltages are rms)
MAXIMUM RATINGS
Rating
Symbol
Value
Unit
VCC Supply Voltage (Pin 16 – Pin 1)
VCC
– 0.5, +12
Vdc
High Input Voltage (Pins 3, 4, 8, 12, 14)
VIH
VCC + 0.5
Vdc
Low Input Voltage (Pins 3, 4, 8, 12, 14)
VIL
– 0.5
Vdc
Output Source Current (Pins 2, 6, 10, 15)
IO+
Self-limiting
mA
Output Sink Current (Pins 2, 6, 10, 15)
IO–
Self-limiting
mA
Storage Temperature
Tstg
– 65, +150
°C
NOTE: Devices should not be operated at these limits. The “Recommended Operating Conditions”
provides for actual device operation.
MOTOROLA
2
MC33111
RECOMMENDED OPERATING CONDITIONS
Characteristic
VCC Supply Voltage
Symbol
Min
Typ
Max
Unit
VCC
3.0
—
7.0
Vdc
0
0
0
0
0
—
—
—
—
—
1.3
0.8
0.32
1.3
1.0
Vrms
Input Signal Voltage Range (3.0 V < VCC < 7.0 V)
Compressor — Normal and Mute Mode
— Passthrough Mode
Expander
— Normal Mode
— Mute Mode
— Passthrough Mode
Vin
Frequency Range (± 1.0 dB accuracy)
Fin
0.300
—
10
kHz
Logic Input Voltage Range (Pins 4, 8, 12)
Vin
0
—
VCC
Vdc
Operating Ambient Temperature
TA
– 40
—
+ 85
°C
NOTE: All limits are not necessarily functional concurrently.
ELECTRICAL CHARACTERISTICS (VCC = 3.6 V, f = 1.0 kHz, TA = + 25°C, unless noted.)
Characteristic
Symbol
Min
Typ
Max
Unit
0 dB Gain (Vin = 100 mVrms)
GOC
–1.5
0
1.5
dB
Gain tracking relative to GOC
Vin = 1.0 Vrms
Vin = 1.0 mVrms
GTC
9.0
– 21
10
– 20
11
–19
COMPRESSOR (Pin 4 = Low unless noted)
dB
Passthrough Gain (Pin 8 = High, Pin 4 = Low, Vin = 1.0 Vrms)
GPTC
– 2.0
0
1.0
dB
Muting (∆ Gain) with Pin 4 = High (Vin = 1.0 Vrms)
GMTC
55
67
—
dB
Max. Output Swing @ Pin 2 (3.0 V < VCC < 7.0 V)
Normal Mode
Passthrough Mode
Vout
—
—
1.1
2.3
—
—
Peak Output Current (3.0 ≤ VCC ≤ 7.0 V, Normal or Passthrough Modes,
Vin = Max)
IPK
—
± 4.0
—
mA
Total Harmonic Distoration (Vin = 100 mVrms)
THD
—
0.2
1.0
%
—
—
—
37
64
72
—
—
—
3.0
14
—
—
Vp-p
Power Supply Rejection @ 1.0 KHz
Vin (Pin 3) = 0
Vin (Pin 3) = 10 mVrms
Vin (Pin 3) = 1.0 Vrms
PSRR
Attack Time (Capacitor @ Pin 5 = 1.0 µF, per EIA-553)
Decay Time (Capacitor @ Pin 5 = 1.0 µF, per EIA-553)
tAT(C)
tD(C)
—
—
Input Impedance at Pin 3
dB
ms
Rin
8.0
10
14
kΩ
VbIAS
1.4
– 20
Vb
1.6
1.6
2.0
Vdc
mVdc
0 dB Gain (Vin = 100 mVrms)
GOE
–1.5
0
1.5
dB
Gain Tracking Relative to GOE
Vin = 316 mVrms
Vin = 10 mVrms
GTE
19
– 41
20
– 40
21
– 39
DC Bias Level (Pin 2)
Output DC Shift (Vin Changed from 0 to 100 mVrms)
EXPANDER (Pin 12 = Low, unless noted)
dB
Passthrough Gain (Pin 8 = High, Pin 12 = Low, Vin = 1.0 Vrms)
GPTE
–1.0
0
2.0
dB
Muting (∆ Gain) with Pin 12 = High (Vin = 0.316 Vrms)
GMTE
60
76
—
dB
—
—
2.8
2.8
—
—
—
—
—
± 3.5
±1.0
± 4.0
—
—
—
—
0.2
1.0
Max. Output Swing @ Pin 15 (3.0 V < VCC , 7.0 V)
Normal Mode
Passthrough Mode
Vout
Peak Output Current
VCC = 3.0 V, Vout ≤ 2.4 Vp-p
VCC = 3.0 V, Vout = 2.7 Vp-p
VCC ≥ 3.6 V, Vout ≤ 2.8 Vp-p
IPK
Total Harmonic Distoration (Vin = 100 mVrms)
THD
MC33111
Vp-p
mA
%
MOTOROLA
3
ELECTRICAL CHARACTERISTICS (VCC = 3.6 V, f = 1.0 kHz, TA = + 25°C, unless noted.)
Characteristic
Symbol
Min
Typ
Max
—
—
—
74
76
62
—
—
—
—
—
Unit
EXPANDER (Pin 12 = Low, unless noted)
Power Supply Rejection @ 1.0 kHz
Vin (Pin 14) = 0
Vin (Pin 14) = 10 mVrms
Vin (Pin 14) = 316 mVrms
PSRR
Attack Time (Capacitor @ Pin 11 = 1.0 µF, per EIA-553)
Decay Time (Capacitor @ Pin 11 = 1.0 µF, per EIA-553)
tAT(E)
tD(E)
—
—
3.0
14
Input Impedance at Pin 14
dB
ms
Rin
8.0
10.9
14
kΩ
VbIAS
1.4
– 20
Vb
1.0
1.6
20
Vdc
mVdc
Switching Threshold (3.0 < VCC < 7.0 V)
VST
—
1.3
—
Vdc
Input Current
@ Vin = 0 V
@ Vin = 3.6 V
Rin
—
—
0
55
—
—
tCMLH
tCMHL
tEMLH
tEMHL
tPCLH
tPCHL
tPELH
tPEHL
—
—
—
—
—
—
—
—
2.0
3.0
2.0
3.0
2.0
5.0
6.0
7.0
—
—
—
—
—
—
—
—
Open Loop Gain
AVOL
—
100
—
dB
Gain Bandwidth
BW
—
300
—
kHz
DC Bias Level (Pin 15)
Output DC Shift (Vin changed from 0 to 100 mVrms)
LOGIC INPUTS (Pins 4, 8, 12)
Timing (Vin @ Pins 3 and 14 = 300 mVrms, See Figures 1, 2)
Comp. Mute (Pin 4) to Comp. Output
Low-to-High
High-to-Low
Exp. Mute (Pin 12) to Exp. Output
Low-to-High
High-to-Low
Passthrough (Pin 8) to Comp. Output
Low-to-High
High-to-Low
Passthrough (Pin 8) to Exp. Output
Low-to-High
High-to-Low
µA
µs
OP AMPS (Pins 6, 7, 9, 10)
Input Bias Current @ Pins 7, 9
IIB
—
8.0
—
nA
Max Output Swing @ Pins 6, 10 (3.0 V < VCC < 7.0 V)
Vout
—
2.8
—
Vp-p
Peak Output Current
VCC = 3.0 V, Vout ≤ 2.4 Vp-p
VCC = 3.0 V, Vout = 2.6 Vp-p
VCC ≥ 3.6 V, Vout ≤ 2.8 Vp-p
IPK
—
—
—
± 3.0
± 2.0
± 3.7
—
—
—
Total Harmonic Distoration (Vout = 1.0 Vrms, Unity Gain)
THD
—
0.02
0.2
—
—
1.5
1.7
2.0
—
—
1.5
—
mA
%
MISCELLANEOUS
Power Supply Current
@ VCC = 3.6 V
@ VCC = 7.0 V
ICC
Reference Voltage
Vb
Channel Separation
Expander to Compressor
(Pin 14 = 316 mVrms @ 1.0 kHz and Pin 3 = 0 mVrms)
(Pin 14 = 100 mVrms (300 Hz < f < 20 kHz),
Pin 3 = 100 mVrms @ 1.2 kHz)
Compressor to Expander
(Pin 3 = 1.0 Vrms @ 1.0 kHz and Pin 14 = 0 mVrms)
(Pin 3 = 100 mVrms (300 Hz < f < 20 kHz),
Pin 14 = 100 mVrms @ 1.2 kHz)
CS
MOTOROLA
4
mA
Vdc
dB
40
70
—
—
96
—
60
100
—
—
97
—
MC33111
TEMPERATURE PERFORMANCE (Typical performance based on device characterization, not guaranteed.)
– 40°C
+25°C
+ 85°C
Power Supply Current
@ VCC = 3.6 V
@ VCC = 7.0 V
1.2 mA
1.4 mA
1.5 mA
1.7 mA
1.6 mA
1.9 mA
Reference Voltage (Vb)
1.495 V
1.5 V
1.505 V
0 dB Gain (Vin = 100 mVrms) — Compressor
0.08 dB
0 dB
– 0.04 dB
0 dB Gain (Vin = 100 mVrms) — Expander
0.04 dB
0 dB
– 0.03 dB
Total Harmonic Distortion (Vin = 100 mVrms) — Compressor
0.3%
0.2%
0.2%
Total Harmonic Distortion (Vin = 100 mVrms) — Expander
0.3%
0.2%
0.16%
Gain Tracking Relative to 0 dB Gain — Compressor
Vin = 1.0 Vrms
Vin = 1.0 mVrms
10.8 dB
–19.95 dB
10 dB
– 20 dB
10 dB
– 20.1 dB
Gain Tracking Relative to 0 dB Gain — Expander
Vin = 316 mVrms
Vin = 10 mVrms
18.6 dB
– 40.2 dB
20 dB
– 40 dB
19.95 dB
– 39.9 dB
Muting (∆ Gain) with Pin 4 = High (Vin = 1.0 Vrms) — Compressor
68 dB
67 dB
66 dB
Muting (∆ Gain) with Pin 12 = High (Vin = 0.316 Vrms) — Expander
76 dB
76 dB
75 dB
Characteristic
Figure 1. Mute Timing
Compressor
or Expander
Mute Input
ÇÇÇÇ
ÇÇÇÇ
ÇÇÇÇ
tEMLH
tCMLH
Compressor
or Expander
Output
ÇÇÇÇÇ
ÇÇÇÇÇ
ÇÇÇÇÇ
tCMHL
tEMHL
Figure 2. Passthrough Timing
Passthrough
Input
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇÇ
tPCLH
tPCHL
Compressor
Output
tPELH
tPEHL
Expander
Output
MC33111
MOTOROLA
5
Figure 4. Transfer Characteristics
Figure 3. Transfer Characteristics
20
Vout , OUTPUT VOLTAGE (dB)
Vout , OUTPUT VOLTAGE (mVrms)
1000
100
Compressor
10
Expander
0
Compressor
– 20
Expander
0 dB = 100 mVrms
1.0
1.0
10
100
– 40
– 40
1000
Vin, INPUT VOLTAGE (mVrms)
Figure 5. Frequency Response (Compressor)
10
Vin = 1.0 mVrms
Vin = 10 mVrms
5.0
0
Vin = 100 mVrms
– 5.0
–10
–15
100
Vin = 1.0 Vrms
1000
20
Figure 6. Frequency Response (Expander)
15
OUTPUT RELATIVE TO INPUT (dB)
OUTPUT RELATIVE TO INPUT (dB)
15
0
Vin, INPUT VOLTAGE (dB)
25
20
– 20
10k
100k
5.0
0
– 5.0
–15
Vin = 316 mVrms
Vin = 100 mVrms
Vin = 31.6 mVrms
Vin = 10 mVrms
– 25
– 35
100
1000
10k
100k
f, FREQUENCY (Hz)
f, FREQUENCY (Hz)
Figure 7. Attack and Decay Times (Compressor)
Figure 8. Attack and Decay Times (Expander)
V1
V2
Output
(Pin 15)
Output
(Pin 2)
V2
90 mV
Input
(Pin 3)
100 mV
360 mV
200 mV
Input
(Pin 14)
Attack Time = Time to 1.5 x V1 from input increase.
Decay Time = Time to 0.75 x V2 from input decrease.
Test per EIA-553.
MOTOROLA
6
V1
Attack Time = Time to 0.57 x V1 from input increase.
Decay Time = Time to 1.5 x V2 from input decrease.
Test per EIA-553.
MC33111
Figure 10. Attack and Decay Times (Expander)
100
80
80
Decay Time
60
t, TIME (ms)
t, TIME (ms)
Figure 9. Attack and Decay Times (Compressor)
100
40
20
Attack Time
1.0
2.0
3.0
4.0
0
0
5.0
1.0
2.0
3.0
4.0
5.0
C, CAPACITANCE AT PIN 11 (µF)
Figure 11. Compressor Gain Tracking
versus Temperature
Figure 12. Expander Gain Tracking
versus Temperature
2.0
GAIN DRIFT VS +25° C (dB)
GAIN DRIFT VS +25° C (dB)
Attack Time
C, CAPACITANCE AT PIN 5 (µF)
1.0
0
Shaded area depicts typical drift range
1.0 mVrms ≤ Vin ≤ 1.0 Vrms
– 20
0
20
40
60
1.0
0
–1.0
Shaded area depicts typical drift range
10 mVrms ≤ Vin ≤ 316 mVrms
– 2.0
– 40
85
TA, AMBIENT TEMPERATURE (°C)
– 20
0
20
40
60
85
TA, AMBIENT TEMPERATURE (°C)
Figure 13. THD versus Temperature
Figure 14. Logic Inputs’ Current
120
1.0
100
I in , INPUT CURRENT ( µA)
TOTAL HARMONIC DISTORTION (%)
Decay Time
40
20
0
0
–1.0
– 40
60
0.5
Compressor
Expander
0
– 40
– 20
0
20
40
TA, AMBIENT TEMPERATURE (°C)
MC33111
60
85
80
60
40
Pins 4, 8, 12
Vin ≤ VCC
20
0
0
2.0
4.0
6.0
7.0
Vin, INPUT VOLTAGE (V)
MOTOROLA
7
FUNCTIONAL DESCRIPTION
Introduction
The MC33111 compander (COMpressor and exPANDER)
is composed of two variable gain circuits which provide
compression and expansion of a signal’s dynamic range. The
compressor will take a signal with a 60 dB dynamic range (1.0
mV to 1.0 Vrms), and reduce that to a 30 dB dynamic range
(10 mV to 316 mV) by attenuating strong signals, while
amplifying low level signals. The expander does the opposite
in that the 30 dB signal range is increased to a dynamic range
of 60 dB by amplifying strong signals and attenuating low level
signals. The 0 dB level is internally set at 100 mVrms — that is
the signal level which is neither amplified nor attenuated. Both
circuits contain the necessary precision full wave rectifier,
variable gain cell, and temperature compensated references
required for accurate and stable performance.
Both the compressor and expander can be muted
independently by the use of Pins 4 and 12, respectively. A
minimum of 55 dB of muting is guaranteed for the
compressor, and 60 dB for the expander. A passthrough
function (Pin 8) is provided which sets both sections to unity
gain, regardless of input level.
Two uncommitted op amps are provided which can be
used for perpherial functions. Each is internally biased at Vb
(≈ +1.5 V), and has a bandwidth of ≈ 300 kHz.
NOTE: All dB values mentioned in this data sheet, unless
otherwise noted, are referenced to 100 mVrms.
Figure 15. Compressor
5
1.0 µF
40 k
Rectifier
ICONTROL
Iref
∆ Gain
VCC
7.5 k
Input
3
2
10 k
Vb
Compressor
The compressor is a noninverting amplifier with a fixed
input resistor and a variable gain cell in its feedback path as
shown in Figure 15.
The amplifier output is sampled by the precision rectifier
which, in turn, supplies a DC signal (ICONTROL), representative of the rectifier’s AC signal, to the variable gain cell. The
reference current (IREF) is an internally generated precision
current. The effective impedance of the variable gain cell
varies with the ratio of the two currents, and decreases as
ICONTROL increases, thereby providing compression. The
output is related to the input by the following equation
(Vin and Vout are rms volts):
+
Ǹ
(1)
V out
0.3162 x V
in
In terms of dB levels, the relationship is:
Vo(dB) = 0.5 x Vi(dB)
(2)
where 0 dB = 100 mVrms (See Figures 3 and 4).
The input and output are internally biased at Vb (≈ +1.5 V),
and must therefore be capacitor coupled to external circuitry.
Pin 3 input impedance is nominally 10 kΩ (± 20%), and the
maximum functional input signal is listed in the Recommended
MOTOROLA
8
Output
Operating Conditions table. Bias currents required by the op
amp and the variable gain cell are internally supplied. Due to
clamp diodes at the input (to VCC and ground), the input signal
must be maintained between the supply rails. If the input signal
goes more than 0.5 V above VCC or below ground, excessive
currents will flow, and distortion will show up at the output and
possibly in other parts of the circuit.
When AC signals are not present at the input, the variable
gain cell will attempt to set a very high gain to comply with
Equation 2. An internal clamp limits the maximum gain to
≈ 26 dB to prevent instabilities.
The output of the rectifier is filtered by the capacitor at
Pin 5, which, in conjunction with an internal 20 k resistor,
provides the time constant for the attack and decay times.
The attack and decay times listed in the Electrical
Characteristics were determined using the test procedure
defined in EIA-553. Figure 9 indicates how the times vary
with the capacitor value. If the attack and decay times are
decreased using a smaller capacitor, performance at low
frequencies will degrade.
MC33111
Figure 16. Expander
11
40 k
1.0 µF
Rectifier
VCC
Input
14
15 k
20 k
ICONTROL
15
∆ Gain
Output
Vb
Iref
Expander
The expander is an noninverting amplifier with a fixed
feedback resistor and a variable gain cell in its input path as
shown in Figure 16.
The input signal is sampled by the precision rectifier which, in
turn, supplies a DC signal (ICONTROL), representative of the AC
input signal, to the variable gain cell. The reference current
(IREF) is an internally generated precision current. The effective
impedance of the variable gain cell varies with the ratio of the
two currents, and decreases as ICONTROL increases, thereby
providing expansion. The output is related to the input by the
following equation (Vin and Vout are rms volts):
Vout = 10 x (Vin)2
(3)
In terms of dB levels, the relationship is:
Vo(dB) = 2.0 x Vi(dB)
(4)
where 0 dB = 100 mVrms (See Figures 3 and 4).
The input and output are internally biased at Vb (≈ +1.5 V),
and must therefore be capacitor coupled to external circuitry.
The input impedance at Pin 14 is nominally 10.9 kΩ (± 20%),
and the maximum functional input signal is listed in the
Recommended Operating Conditions table. Bias currents
required by the op amp and the variable gain cell are
internally supplied. Due to clamp diodes at the input (to VCC
and ground), the input signal must be maintained between
the supply rails. If the input signal goes more than 0.5 V
above VCC or below ground, excessive currents will flow, and
distortion will show up at the output, and possibly in other
parts of the circuit.
The output of the rectifier is filtered by the capacitor at
Pin 11, which, in conjunction with an internal 20 k resistor,
provides the time constant for the attack and decay times.
The attack and decay times listed in the Electrical
Characteristics were determined using the test procedure
defined in EIA-553. Figure 10 indicates how the times vary
with the capacitor value. If the attack and decay times are
decreased by using a smaller capacitor, performance at low
frequencies will degrade.
Op Amps
The two op amps (at Pins 6, 7, 9, and 10) are identical and
can be used for peripheral functions, such as a microphone
amplifier, buffer, filter, etc. They have an open loop gain of
≈100 dB, and a bandwidth of ≈ 300 kHz. The noninverting
inputs are internally biased at Vb (≈ +1.5 V). The inverting
inputs (Pins 7, 9) require a bias current of ≈ 8.0 nA, which flows
into the pin. The outputs can typically supply a maximum of 3.7
mA load current (see Electrical Characteristics).
MC33111
NOTE: If an op amp is unused, its output MUST be tied to
its input (Pin 6 to 7 and/or 9 to 10). Leaving an input open can
affect other portions of the IC.
Logic Inputs
The three inputs (Pins 4, 8, 12) provide for muting and
passthrough functions for the compressor and expander
according to the following truth table:
CM
(Pin 4)
EM
(Pin 12)
PT
(Pin 8)
0
0
0
Normal Operation
1
X
X
Compressor Mute
X
1
X
Expander Mute
0
0
1
Passthrough
Function
The logic section permits the compressor and expander to
be muted independently. The Passthrough control affects both
sections simultaneously, but only if the Mute inputs are at a logic
level 0. If both the Passthrough and a Mute input are asserted,
the Mute will override the Passthrough. The logic controls do
not affect the two uncommitted op amps in any way.
Figure 17 depicts a typical logic input stage configuration,
and Figure 14 indicates the typical input current. The inputs’
threshold is ≈ +1.3 V, independent of VCC. An open input is
equivalent to a logic low, but good design practices dictate
that inputs should never be left open. The inputs must be kept
within the range of VCC and GND. If an input is taken more
than 0.5 V above VCC or below GND excessive currents will
flow, and the device’s operation will be distorted.
Figure 17. Logic Input Stage
VCC
Pins
4, 8, 12
50 k
50 k
MOTOROLA
9
Power Supply
The MC33111 requires a supply voltage between 3.0 V
and 7.0 V, and a nominal current of ≈ 1.6 mA. The supply
voltage should be well filtered and free of ripple. A minimum
of 4.7 µF in parallel with a 0.01 µF capacitor is recommended
for filtering and RF bypass.
Vb is an internally generated reference set at ≈ +1.5 V, and
is used internally as an AC ground. It is not available directly
at any pins, but can be obtained as a buffered reference from
either op amp by connecting the op amp as a follower.
APPLICATION INFORMATION
Typical Application Circuit
Figure 18 indicates a typical implementation of the
MC33111 compander. The following points apply:
a) The values shown adjacent to some components are
based on the expected use of the IC:
— The input capacitors (Pins 3 and 14) provide a 3.0 dB
rolloff of ≈ 30 Hz, a decade below the nominal
voiceband.
— The rectifier capacitors provide attack and decay times
as indicated in the Electrical Tables.
b) The values for the unlabeled components are application
dependent:
— The components around the op amps depend on their
use.
— The value of the capacitors at the compressor and
expander outputs depend on the circuit to which they
are connected.
c) If either the compressor or expander is not used, its input
must not be left open. It can be connected to ground
either through a capacitor, or directly to ground.
d) The two op amps can be used for any purpose which suits
the application. The indicated use of the one op amp as a
microphone amplifier is only an example.
e) If an op amp is not used, its output and input must be
connected together. Do not leave Pin 7 or Pin 9 open.
f) The logic inputs (Pins 4, 8, 12) are TTL/CMOS compatible.
The logic high voltage must not exceed the VCC voltage on
the MC33111. Any unused input should be connected to
ground and not left open.
Figure 18. Typical Application
Expander
Input
0.47
1.0 µF
20 k
MC33111
14
15 k
11
∆ Gain
40 k
15
Expander
Output
2
Compressor
Output
Vb
Rectifier
Compressor
Input
10 k
3
Vb
0.47
1.0 µF
7.5 k
∆ Gain
5
16
Bias &
Reference
Generator
40 k
Rectifier
4.7/
0.01
1
VCC
V+
10
Microphone
9
4
Vb
Vb
7
Signal-To-Noise Improvement
Among the basic reasons for the original development of
compander type circuits was to improve the signal-to-noise
ratio of long distance communications circuits, and of voice
circuits which are transmitted over RF links (CBs,
walkie-talkies, cordless phones, etc.). Since much of the
interfering noise heard at the receiving end of a transmission
is due to noise picked up, for example, in the airway portion of
the RF link, the compressor was developed to increase the
low-level signals at the transmitting end. Then any noise
picked up in the RF link would be a smaller percentage of the
transmitted signal level. At the receiving end, the signal is
MOTOROLA
10
Mute/
Passthrough
Logic
6
CM
12 EM
8
PT
µP or
Other Control Circuit
(See Text For Component Values)
then expanded back to is original level, retaining the same
high signal-to-noise ratio. While the above explanation
indicates it is not necessary to attenuate strong signals (at
the transmitting end), a benefit of doing this is the reduced
dynamic range which must be handled by the system
transmitter and receiver. The MC33111 was designed for a
two-to-one compression and expansion, i.e. a 60 dB dynamic
signal is compressed to a 30 dB dynamic range, transmitted
to the receiving end, and then expanded back to a 60 dB
dynamic range.
MC33111
The MC33111 compander is not limited to RF or long
distance telephony applications. It can be used in any system
requiring either an improved signal-to-noise ratio, or a reduced
dynamic range. Such applications include telephones,
speakerphones, tape recorders, wireless microphones, digital
recording, and many others.
Power Supplies, Grounding
The PC board layout, and the quality of the power supplies
and the ground system at the IC are very important in order
to obtain proper operation. Noise, from any source, coming
into the device on VCC or ground, can cause a distorted
output, or incorrect gain levels.
VCC must be decoupled to the appropriate ground at the IC
(within 1″ max.) with a 4.7 µF capacitor and a 0.01 µF ceramic.
A tantalum capacitor is recommended for the larger value if
very high frequency noise is present, since electrolytic
capacitors simply have too much inductance at those
frequencies. The quality of the power supply voltage should be
checked at the IC with a high frequency scope. Noise spikes
(always present if digital circuits are near this IC) can easily
exceed 400 mV, and if they get into the IC, the output can have
noise or distortion. Noise can be reduced by inserting resistors
and/or inductors between the supply and the IC.
If switching power supplies are used, there will be spikes
of 0.5 V or greater at frequencies of 50 kHz – 1.0 MHz. These
spikes are generally more difficult to reduce because of their
greater energy content. In extreme cases, a 3-terminal
regulator (e.g., MC78L05ACP), with appropriate high
frequency filtering, should be used and dedicated to the
analog portion of the circuit.
The ripple content of the supply should not allow its
magnitude to exceed the values in the Recommended
Operating Conditions table.
The PC board tracks supplying VCC and ground to the
MC33111 should preferably not be at the tail end of the bus
distribution, after passing through a maze of digital circuitry.
The analog circuitry containing the MC33111 should be close
to the power supply, or the connector where the supply
voltages enter the board. If VCC is supplying considerable
current to other parts of the board, then it is preferable to
have dedicated lines directly to the MC33111 and associated
circuitry.
PC Board Layout
Although this device is intended for use in the audio
frequency range, the various amplifiers have a bandwidth of
≈ 300 kHz, and can therefore oscillate at frequencies outside
the voiceband should there be excessive stray capacitance
or other unintended feedback loops. A solid ground plane is
strongly recommended to minimize coupling of any digital
noise into the analog section. Use of wire wrapped boards
should definitely be avoided.
Since many applications of the MC33111 compander
involve voice transmission over RF links, care must be taken
in the design of the product to keep RF signals out of the
MC33111 and associated circuitry. This involves proper
layout of the PC boards and the physical arrangement of the
boards, shielding, proper RF ground, etc.
DEFINITIONS
Attack Time — The settling time for a circuit after its input
signal has been increased.
Attenuation — A decrease in magnitude of a
communication signal, usually expressed in dB.
Bandwidth — The range of information carrying
frequencies of a communication system.
Channel Separation — The ability of one circuit to reject
outputting signals which are being processed by another
circuit. Also referred to as crosstalk rejection, it is usually
expressed in dB.
Compander — A contraction of the words compressor
and expander. A compander is composed of two circuits, one
of each kind.
Compressor — A circuit which compresses, or reduces,
the dynamic range of a signal by attenuating strong signals
and amplifying low level signals.
dB — A power or voltage measurement unit, referred to
another power or voltage. It is generally computed as:
10 x log (P1/P2) for power signals, and
20 x log (V1/V2) for voltage signals.
dBm — An indication of signal power. 1.0 mW across 600 Ω,
or 0.775 Vrms, is typically defined as 0 dBm for telecom
applications. Any voltage level is converted to dBm by:
dBm = 20 x log (Vrms/0.775), or
dBm = [20 x log (Vrms)] + 2.22.
dBrn — Indicates a dBm measurement relative to 1.0 pW
power level into 600 Ω. Generally used for noise measurements, 0 dBm = – 90 dBm.
MC33111
dBrnC — Indicates a dBrn measurement using a
C-message weighting filter.
Decay Time — The settling time for a circuit after its input
signal has been decreased.
Expander — A circuit which expands, or increases the
dynamic range of a signal by amplifying strong signals and
attenuating low level signals.
Gain — The change in signal amplitude (increase or
decrease) after passing through an amplifier, or other circuit
stage. Usually expressed in dB, an increase is a positive
number, and a decrease is a negative number.
Mute — Reducing the level of an audio signal, generally
so that it is inaudible. Partial muting is used in some
applications.
Passthrough — Bypassing the compression and/or
expansion function by setting the gain to a fixed value
(usually unity). This is usually employed when data, rather
than voice, is to be transmitted without attenuation.
Power Supply Rejection Ratio — The ability of a circuit
to reject outputting noise, or ripple, which is present on the
power supply lines. PSRR is usually expressed in dB.
Signal to Noise Ratio — The ratio of the desired signal to
unwanted signals (noise) within a defined frequency range.
The larger the number, the better.
Voiceband — That portion of the audio frequency range
used for transmission in the telephone system. Typically it is
300-3400 Hz.
Zero dB Point — The signal level which has its amplitude
unchanged by a compressor or expander.
MOTOROLA
11
OUTLINE DIMENSIONS
P SUFFIX
PLASTIC PACKAGE
CASE 648-08
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. DIMENSION L TO CENTER OF LEADS WHEN
FORMED PARALLEL.
4. DIMENSION B DOES NOT INCLUDE MOLD FLASH.
5. ROUNDED CORNERS OPTIONAL.
-A16
9
1
8
B
F
C
DIM
A
B
C
D
F
G
H
J
K
L
M
S
L
S
-T-
SEATING
PLANE
K
H
D 16 PL
0.25 (0.010)
M
M
J
G
T
A
M
INCHES
MIN
MAX
0.740 0.770
0.250 0.270
0.145 0.175
0.015 0.021
0.040 0.070
0.100 BSC
0.050 BSC
0.008 0.015
0.110 0.130
0.295 0.305
0°
10°
0.020 0.040
MILLIMETERS
MIN
MAX
18.80 19.55
6.35
6.85
3.69
4.44
0.39
0.53
1.02
1.77
2.54 BSC
1.27 BSC
0.21
0.38
2.80
3.30
7.50
7.74
0°
10°
0.51
1.01
D SUFFIX
PLASTIC PACKAGE
CASE 751B-05
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. DIMENSIONS A AND B DO NOT INCLUDE
MOLD PROTRUSION.
4. MAXIMUM MOLD PROTRUSION 0.15 (0.006)
PER SIDE.
5. DIMENSION D DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE DAMBAR
PROTRUSION SHALL BE 0.127 (0.005) TOTAL
IN EXCESS OF THE D DIMENSION AT
MAXIMUM MATERIAL CONDITION.
-A-
16
9
-B1
P 8 PL
0.25 (0.010)
8
M
B
M
G
K
F
R X 45°
C
-TSEATING
PLANE
M
D 16 PL
0.25 (0.010)
M
T B
S
A
J
DIM
A
B
C
D
F
G
J
K
M
P
R
MILLIMETERS
MIN
MAX
9.80 10.00
4.00
3.80
1.75
1.35
0.49
0.35
1.25
0.40
1.27 BSC
0.25
0.19
0.25
0.10
7°
0°
6.20
5.80
0.50
0.25
INCHES
MIN
MAX
0.386 0.393
0.150 0.157
0.054 0.068
0.014 0.019
0.016 0.049
0.050 BSC
0.008 0.009
0.004 0.009
7°
0°
0.229 0.244
0.010 0.019
S
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the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit,
and specifically disclaims any and all liability, including without limitation consequential or incidental damages. “Typical” parameters can and do vary in different
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◊MOTOROLA
12
*MC33111/D*
MC33111/D
MC33111
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