LANSDALE ML33111 Low voltage compander silicon monolithic integrated circuit Datasheet

ML33111
Low Voltage Compander
Silicon Monolithic Integrated Circuit
Legacy Device: Motorola MC33111
The ML33111 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.
Included in the ML33111 are controls for muting each section independently, and for pass through of both. Two uncommitted op amps are available
for peripheral functions.
The ML33111 will operate from a supply voltage of 3.0 V to 7.0 V, and
over a temperature range of TA –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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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
Two Uncommitted Op Amps
Temperature Compensated Reference
Available in Standard DIP and Surface Mount Packages
16
1
P DIP 16 = EP
PLASTIC PACKAGE
CASE 648
16
1
SO 16 = -5P
PLASTIC PACKAGE
CASE 751B
(SO-16)
CROSS REFERENCE/ORDERING INFORMATION
PACKAGE
MOTOROLA
LANSDALE
P DIP 16
MC33111P
ML33111EP
SO 16
MC33111D
ML33111-5P
Note: Lansdale lead free (Pb) product, as it
becomes available, will be identified by a part
number prefix change from ML to MLE.
TRUTH TABLE
Simplified Block Diagram
Expander
Input
11
1.0 µF
Compressor
3
Input
1.0 µF
Page 1 of 12
∆ Gain
Rectifier
7.5 k
∆ Gain
5
10
Vb
Mute/
Passthrough
Logic
Vb
7
EM
PT
Function
0
1
X
0
0
X
1
0
0
X
X
1
Normal
Comp. Mute
Expander Mute
Passthrough
Compressor
2 Output
Bias &
Reference
Generator
40 k
Rectifier
Expander
15 Output
Vb
10 k
Vb
9
Microphone
15 k
40 k
0.5
V+
20 k
0.5 14 ML33111
CM
16
VCC
1
4
12
8
CM
EM
PT
6
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Issue A
ML33111
LANSDALE Semiconductor, Inc.
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 dB
∆ Gain
Vin
10 k
Vout
Vb
0 dB
1.0 V
15 k
100 mV
31.6 mV
10 mV
– 20 dB 10 mV
0.3162 x V
in
– 40 dB
Expander
Vin
316 mV
–10 dB
– 30 dB
V out
Expansion
40 k
Vb
Vout
∆ Gain
Rectifier
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.
Page 2 of 12
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Issue A
ML33111
LANSDALE Semiconductor, Inc.
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 Distortion (Vin = 100 mVrms)
THD
—
0.2
1.0
%
—
—
—
37
64
72
—
—
—
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)
—
—
3.0
14
—
—
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
Input Impedance at Pin 3
DC Bias Level (Pin 2)
Output DC Shift (Vin Changed from 0 to 100 mVrms)
dB
EXPANDER (Pin 12 = Low, unless noted)
Passthrough Gain (Pin 8 = High, Pin 12 = Low, Vin = 1.0 Vrms)
GPTE
–1.0
0
2.0
Muting (∆ Gain) with Pin 12 = High (Vin = 0.316 Vrms)
GMTE
60
76
—
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 Distortion (Vin = 100 mVrms)
THD
Page 3 of 12
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—
—
2.8
2.8
—
—
—
—
—
± 3.5
±1.0
± 4.0
—
—
—
—
0.2
1.0
dB
dB
dB
Vp-p
mA
%
Issue A
ML33111
LANSDALE Semiconductor, Inc.
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
—
—
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
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 Distortion (Vout = 1.0 Vrms, Unity Gain)
THD
—
0.02
0.2
—
—
1.5
1.7
2.0
—
—
1.5
—
Input Impedance at Pin 14
DC Bias Level (Pin 15)
Output DC Shift (Vin changed from 0 to 100 mVrms)
dB
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)
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
Page 4 of 12
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mA
Vdc
dB
40
70
—
—
96
—
60
100
—
—
97
—
Issue A
ML33111
LANSDALE Semiconductor, Inc.
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
tEMLH
tCMLH
tCMHL
tEMHL
Compressor
or Expander
Output
Figure 2. Passthrough Timing
Passthrough
Input
Compressor
Output
Expander
Output
Page 5 of 12
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Issue A
ML33111
LANSDALE Semiconductor, Inc.
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
– 20
Vin, INPUT VOLTAGE (mVrms)
Figure 5. Frequency Response (Compressor)
20
15
10
5.0
0
– 5.0
–10
–15
100
Vin = 1.0 mVrms
Vin = 10 mVrms
Vin = 100 mVrms
Vin = 1.0 Vrms
1000
20
Figure 6. Frequency Response (Expander)
15
OUTPUT RELATIVE TO INPUT (dB)
OUTPUT RELATIVE TO INPUT (dB)
25
0
Vin, INPUT VOLTAGE (dB)
10k
100k
Vin = 316 mVrms
5.0
Vin = 100 mVrms
0
– 5.0
Vin = 31.6 mVrms
–15
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)
90 mV
V2
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.
Page 6 of 12
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.
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Issue A
ML33111
LANSDALE Semiconductor, Inc.
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
60
20
20
Attack Time
0
0
1.0
2.0
3.0
4.0
0
0
5.0
2.0
3.0
4.0
5.0
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)
1.0
C, CAPACITANCE AT PIN 11 (µF)
0
Shaded area depicts typical drift range
1.0 mVrms ≤ Vin ≤ 1.0 Vrms
– 20
0
20
40
60
85
1.0
0
–1.0
– 2.0
– 40
TA, AMBIENT TEMPERATURE (°C)
Shaded area depicts typical drift range
10 mVrms ≤ Vin ≤ 316 mVrms
– 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 (%)
Attack Time
C, CAPACITANCE AT PIN 5 (µF)
1.0
–1.0
– 40
Decay Time
40
0.5
Compressor
Expander
0
– 40
– 20
0
20
40
60
85
80
60
40
0
0
TA, AMBIENT TEMPERATURE (°C)
Page 7 of 12
Pins 4, 8, 12
Vin ≤ VCC
20
2.0
4.0
6.0
7.0
Vin, INPUT VOLTAGE (V)
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Issue A
ML33111
LANSDALE Semiconductor, Inc.
FUNCTIONAL DESCRIPTION
Introduction
The ML33111 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
Input
7.5 k
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):
V out
0.3162 x V
in
In terms of dB levels, the relationship is:
Vo(dB) = 0.5 x Vi(dB)
where 0 dB = 100 mVrms (See Figures 3 and 4).
(1)
(2)
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
Page 8 of 12
Output
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.
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.
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Issue A
ML33111
LANSDALE Semiconductor, Inc.
Figure 16. Expander
11
40 k
1.0 µF
Rectifier
VCC
Input
14
20 k
ICONTROL
15 k
∆ Gain
15
Vb
Output
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
In terms of dB levels, the relationship is:
Vo(dB) = 2.0 x Vi(dB)
where 0 dB = 100 mVrms (See Figures 3 and 4).
flows into the pin. The outputs can typically supply a maximum of 3.7 mA load current (see Electrical Characteristics).
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:
(3)
CM
(Pin 4)
EM
(Pin 12)
PT
(Pin 8)
(4)
0
0
0
Normal Operation
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.
1
X
X
Compressor Mute
X
1
X
Expander Mute
0
0
1
Passthrough
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.
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
Page 9 of 12
Function
www.lansdale.com
Figure 17. Logic Input Stage
VCC
Pins
4, 8, 12
50 k
50 k
Issue A
ML33111
LANSDALE Semiconductor, Inc.
Power Supply
The ML33111 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.
LEGACY APPLICATIONS INFORMATION
Typical Application Circuit
Figure 18 indicates a typical implementation of the ML33111
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 micro
phone 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
ML33111. Any unused input should be connected to ground
and not left open.
Figure 18. Typical Application
Expander
Input
0.47
1.0 µF
Compressor
Input
14
15 k
11
∆ Gain
40 k
2
Compressor
Output
Vb
7.5 k
∆ Gain
5
Bias &
Reference
Generator
40 k
Rectifier
V+
10
9
Vb
Mute/
Passthrough
Logic
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
Page 10 of 12
Expander
Output
Vb
10 k
0.47
Microphone
15
Rectifier
3
1.0 µF
20 k
ML33111
6
16
4.7/
0.01
1
4
CM
12 EM
8
VCC
PT
µP or
Other Control Circuit
(See Text For Component Values)
level. At the receiving end, the signal is then expanded back to its
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 ML33111 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.
www.lansdale.com
Issue A
ML33111
LANSDALE Semiconductor, Inc.
Legacy Applications Information
The ML33111 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 fre-
quency 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
ML33111 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 ML33111 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 ML33111 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 ML33111 compander
involve voice transmission over RF links, care must be taken
in the design of the product to keep RF signals out of the
ML33111 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.
Page 11 of 12
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.
www.lansdale.com
Issue A
ML33111
LANSDALE Semiconductor, Inc.
OUTLINE DIMENSIONS
P DIP 16 = EP
(ML33111EP)
PLASTIC PACKAGE
CASE 648-08
-A16
9
1
8
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.
B
F
C
DIM
A
B
C
D
F
G
H
J
K
L
M
S
L
S
SEATING
PLANE
-TK
H
G
D 16 PL
0.25 (0.010)
M
M
J
T
A
M
SO 16 = -5P
(ML33111-5P)
PLASTIC PACKAGE
CASE 751B-05
-A-
-B-
P 8 PL
0.25 (0.010)
8
M
B
M
G
K
F
R X 45°
C
-TSEATING
PLANE
D 16 PL
0.25 (0.010)
M
M
T B
S
A
S
MILLIMETERS
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
18.80 19.55
6.85
6.35
4.44
3.69
0.53
0.39
1.77
1.02
2.54 BSC
1.27 BSC
0.38
0.21
3.30
2.80
7.74
7.50
10°
0°
0.51
1.01
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.
16
9
1
INCHES
J
DIM
A
B
C
D
F
G
J
K
M
P
R
MILLIMETERS
INCHES
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
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
Lansdale Semiconductor reserves the right to make changes without further notice to any products herein to improve reliability, function or design. Lansdale does not assume any liability arising out of the application or use of any product or circuit
described herein; neither does it convey any license under its patent rights nor the rights of others. “Typical” parameters which
may be provided in Lansdale data sheets and/or specifications can vary in different applications, and actual performance may
vary over time. All operating parameters, including “Typicals” must be validated for each customer application by the customer’s technical experts. Lansdale Semiconductor is a registered trademark of Lansdale Semiconductor, Inc.
Page 12 of 12
www.lansdale.com
Issue A