LC550.pdf

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Medium Power
Class B Amplifier
LC550 DATA SHEET
FEATURES
•
23 dB class A preamp & 40 dB class B output stage
•
1.0 V DC to 1.7 V DC operating range
•
2.2 k
Ω
on chip microphone decoupling resistor
•
350
µ
A typical quiescent current
•
400 Hz to 20 kHz frequency response
STANDARD PACKAGING
• 10 pin MICROpac
• 10 pin MINIpac
• 10 pin SLT
• 10 pin PLID
®
DESCRIPTION
The LC550 is a low voltage linear monolithic integrated
circuit amplifier. It is comprised of two separate amplifiers
on a single chip. The first is a 23 dB Class A preamp
followed by a 40 dB Class B output stage.
Both stages incorporate negative feedback to control
gain, minimize distortion and stabilize operation at very
low quiescent currents.
The preamp and output stage have their inputs and outputs
separately pinned out. This is an advantage as it allows
access to both stages, providing the designer with flexibility
and a full range volume control.
The combination of low quiescent current and a medium
power push-pull output makes the LC550 suitable for
medium power BTE hearing aids and for high power ITE
aids where efficiency and battery life are a premium
consideration.
• Chip (57 x 47 mils)
Au Bump
V
MIC
6
2.2k
9
V
B
5
8
IN A
23 dB
40 dB
1
OUT B2
OUT B1
10
GND
7
OUT A
3
IN B
2
DEC B1
4
DEC B2
All resistors in ohms, all capacitors in
µF
unless otherwise stated.
U.S. Patent No. 4,085,382, patented in other countries.
BLOCK DIAGRAM
Revision Date: December 1994
Document No. 500 - 37 - 8
GENNUM CORPORATION P.O. Box 489, Stn A, Burlington, Ontario, Canada L7R 3Y3
Japan Branch: A-302, M i yamae Vi l l age, 2–10–42 M i yamae, Suginami–ku, Tokyo 168, Japan
tel. (905) 632-2996 fax: (905) 632-5946
tel. (03) 3334-7700
fax (03) 3247-8839
ABSOLUTE MAXIMUM RATINGS
PIN CONNECTION
PARAMETER
Supply Voltage
Power Dissipation
Operating Temperature Range
Storage Temperature Range
VALUE/UNITS
3V
60 mW
-10° C to 60° C
-20° C to 70° C
OUT B2
DEC B2
IN B
DEC B1
OUT B1
1
5
TOP VIEW
6
V
MIC
OUT A
IN A
V
B
10
GND
CAUTION
CLASS 1 ESD SENSITIVITY
ELECTRICAL CHARACTERISTICS
All switches remain as shown in Test Circuit
Conditions: Supply voltage V
B
= 1.3 V DC, Temperature ambient = 25°C, Ground line resistance 0.03
Ωmax.,
Volume control setting max. gain
PARAMETER
Gain
Total Current (including
I
MIC
)
Input Referred Noise
Total Harmonic Distortion
O/P Swing at 7% Distortion
Stable with Battery Resistance to:
Preamp O/P Impedance
Preamp I/P Impedance
O/P Stage O/P Impedance
O/P Stage I/P Impedance
Start-Up Time
SYMBOL
A
V
I
TOT
IRN
THD
CONDITIONS
Output Level 0.707 V
RMS
S1 - open
NFB 0.2 to 10kHz at 12dB/Oct
Output Level 0.707 V
RMS
MIN
59
-
-
-
-
TYP
63
350
1.5
3.5
1.4
-
1.1
30
110
27
-
MAX
67
475
3
7.5
-
60
-
-
-
34
3
UNITS
dB
µA
µV
%
V
RMS
Ω
kΩ
kΩ
Ω
kΩ
sec
S4 - open
-
-
-
-
18
Refer to start up test sequence
-
START-UP TEST SEQUENCE
SEQUENCE
Power Supply
S1
S2 / S3
S1
CONDITIONS
Off
Open
Closed
Closed
Removes V
IN
Discharges C2 & C3
Applies V
IN
COMMENT
(V
IN
level is
determined from Gain Test)
S2 / S3
Power Supply
Open
On
Removes Short from C2 and C3
Gain must be within specification, within 3 seconds after Power Supply is turned on
500 - 37 - 8
2
4.7Ω
I
TOT
+
10
820
33K
I
MIC
S1 V11 3.3k
0.022
8
22k
V1
1
220
7
3
10k
1kHz
0.01
S2
0.047
C2
2.2
R
G
*
C3
2.2
S3
2
10
4
+
4.7
2.2kΩ
23dB
40dB
0.047
1kΩ
5
MIC SUPPLY
6
9
S4
V
B
R
B
+
1.3 V DC
BATTERY
SIMULATOR
V
O
MICROPHONE SIMULATOR
NOTES:
1. 42.13 dB of attenuation from V1 to V11
2 *RG (equivalent gnd resistance) should not exceed 30 mΩ (increasing RG increases distortion)
All resistors in ohms, all capacitors in
µF
unless otherwise stated.
Fig. 1 Test Circuit
+ 4.7
NOTE1
+
6
0.022
8
23dB
0.047
3
4
0.01
+
2.2
10
40dB
0.047
1
2k TYP
10k
2.2
9
7
2
5
V
B
1.3 V DC
NOTE:
1. 2.2
µF
when receiver is
≥
3kΩ
All resistors in ohms, all capacitors in
µF
unless otherwise stated.
Fig. 2 Typical Hearing Aid Application
3
9
2.2k
6
1
2
27k
33k
8
5
10
7
4
All resistors in ohms, all capacitors in
µF
unless otherwise stated.
U.S. Patent No. 4,085,382, patented in other countries.
Fig.3 Functional Schematic
3
500 - 37 - 8
0
35
30
25
20
15
10
5
0
0
20
40
60
80
100
0
20
40
60
80
100
RELATIVE VOLTAGE GAIN (dB)
0.1
0.2
0.3
0.4
0.5
0.6
0.7
DISTORTION ( % )
BATTERY RESISTANCE (Ω)
GROUND RESISTANCE ( mΩ )
Fig. 4 Gain vs Battery Resistance
Fig. 5 Distortion vs Ground Line Resistance
700
825
725
TOTAL CURRENT (µA) (with S1 open)
600
500
400
300
200
100
0
0.6
0.8
1.0
1.2
1.4
1.6
TOTAL CURRENT (µA)
625
525
425
325
225
125
-40
-20
0
20
o
40
60
SUPPLY VOLTAGE (V)
TEMPERATURE ( C)
Fig. 6 Total Current vs Supply Voltage
Fig. 7 Total Current vs Temperature
70
60
50
40
30
20
10
0
0.6
0.8
1.0
1.2
1.4
1.6
70
68
66
GAIN (dB)
GAIN (dB)
64
62
60
58
56
-40
-20
0
20
o
40
60
SUPPLY VOLTAGE (V)
TEMPERATURE ( C)
Fig. 8 Gain vs Supply Voltage
Fig. 9 Gain vs Temperature
500 - 37 - 8
4
3.5
3.0
10
0
VOLTAGE GAIN (dB)
2.5
-10
-20
-30
-40
-50
-60
POWER (mW)
2.0
1.5
1.0
0.5
0
100
1k
10k
100k
10
100
1k
10k
100k
LOAD IMPEDANCE (Ω)
FREQUENCY (Hz)
Fig. 10 Power Output vs Load Impedance
at 7% Distortion
Fig. 11 Voltage Gain vs Frequency
DOCUMENT
IDENTIFICATION
PRODUCT PROPOSAL
This data has been compiled for market investigation purposes
only, and does not constitute an offer for sale.
ADVANCE INFORMATION NOTE
This product is in development phase and specifications are
subject to change without notice. Gennum reserves the right to
remove the product at any time. Listing the product does not
constitute an offer for sale.
PRELIMINARY DATA SHEET
The product is in a preproduction phase and specifications are
subject to change without notice.
DATA SHEET
The product is in production. Gennum reserves the right to make
changes at any time to improve reliability, function or design, in
order to provide the best product possible.
REVISION NOTES
Correction to Fig. 1 Pb/Sn Bump removed
Gennum Corporation assumes no responsibility for the use of any circuits described herein and makes no representations that they are free from patent infringement.
© Copyright September 1981 Gennum Corporation.
All rights reserved.
Printed in Canada.
5
500 - 37 - 8

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