AD SSM2019

a
FEATURES
Excellent Noise Performance: 1.0 nV/÷Hz or
1.5 dB Noise Figure
Ultra-low THD: < 0.01% @ G = 100 Over the
Full Audio Band
Wide Bandwidth: 1 MHz @ G = 100
High Slew Rate: 16 V/s @ G = 10
10 V rms Full-Scale Input,
G = 1, VS = 18 V
Unity Gain Stable
True Differential Inputs
Subaudio 1/f Noise Corner
8-Lead PDIP or 16-Lead SOIC
Only One External Component Required
Very Low Cost
Extended Temperature Range: –40C to +85C
APPLICATIONS
Audio Mix Consoles
Intercom/Paging Systems
2-Way Radio
Sonar
Digital Audio Systems
GENERAL DESCRIPTION
The SSM2019 is a latest generation audio preamplifier, combining SSM preamplifier design expertise with advanced processing.
The result is excellent audio performance from a monolithic
device, requiring only one external gain set resistor or potentiometer. The SSM2019 is further enhanced by its unity gain stability.
Key specifications include ultra-low noise (1.5 dB noise figure) and
THD (<0.01% at G = 100), complemented by wide bandwidth
and high slew rate.
Applications for this low cost device include microphone preamplifiers and bus summing amplifiers in professional and consumer
audio equipment, sonar, and other applications requiring a low
noise instrumentation amplifier with high gain capability.
Self-Contained
Audio Preamplifier
SSM2019
FUNCTIONAL BLOCK DIAGRAM
V+
V–
+IN
1
–IN
RG1
5k
1
5k
RG2
5k
5k
OUT
5k
5k
REFERENCE
V–
PIN CONNECTIONS
8-Lead PDIP (N Suffix)
8-Lead Narrow Body SOIC (RN Suffix)*
RG1 1
8
SSM2019
RG2
V+
TOP VIEW
+IN 3 (Not to Scale) 6 OUT
–IN 2
V– 4
7
5
REFERENCE
16-Lead Wide Body SOIC (RW Suffix)
NC 1
16 NC
RG1 2
15 RG2
NC 3
–IN 4
14 NC
SSM2019
13 V+
TOP VIEW
+IN 5 (Not to Scale) 12 NC
NC 6
11 OUT
V– 7
10 REFERENCE
NC 8
9
NC
NC = NO CONNECT
*Consult factory for availability.
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
www.analog.com
Fax: 781/326-8703
© 2003 Analog Devices, Inc. All rights reserved.
V and –40C £ T £ +85C, unless otherwise noted. Typical specifications
SSM2019–SPECIFICATIONS (Vapply= 15
at T = 25C.)
S
A
A
Parameter
Symbol
Conditions
Min
Typ
Max
Unit
DISTORTION PERFORMANCE
Total Harmonic Distortion Plus Noise
NOISE PERFORMANCE
Input Referred Voltage Noise Density
Input Current Noise Density
DYNAMIC RESPONSE
Slew Rate
Small Signal Bandwidth
INPUT
Input Offset Voltage
Input Bias Current
Input Offset Current
Common-Mode Rejection
Power Supply Rejection
Input Voltage Range
Input Resistance
OUTPUT
Output Voltage Swing
Output Offset Voltage
Maximum Capacitive Load Drive
Short Circuit Current Limit
Output Short Circuit Duration
GAIN
Gain Accuracy
Maximum Gain
THD + N
en
in
SR
BW–3 dB
VIOS
IB
Ios
CMR
PSR
IVR
RIN
VO = 7 V rms
RL = 2 kW
f = 1 kHz, G = 1000
f = 1 kHz, G = 100
f = 1 kHz, G = 10
f = 1 kHz, G = 1
BW = 80 kHz
0.017
0.0085
0.0035
0.005
%
%
%
%
f = 1 kHz, G = 1000
f = 1 kHz, G = 100
f = 1 kHz, G = 10
f = 1 kHz, G = 1
f = 1 kHz, G = 1000
1.0
1.7
7
50
2
nV/÷Hz
nV/÷Hz
nV/÷Hz
nV/÷Hz
pA/÷Hz
G = 10
RL = 2 kW
CL = 100 pF
G = 1000
G = 100
G = 10
G=1
16
V/ms
200
1000
1600
2000
kHz
kHz
kHz
kHz
0.05
0.25
3
10
± 0.001 ± 1.0
mV
mA
mA
110
90
70
50
130
113
94
74
dB
dB
dB
dB
110
110
90
70
± 12
124
118
101
82
1
30
5.3
7.1
dB
dB
dB
dB
V
MW
MW
MW
MW
± 13.5
± 13.9
4
30
5000
± 50
Continuous
V
mV
pF
mA
sec
0.5
0.5
0.5
0.1
0.1
0.2
0.2
0.2
70
dB
dB
dB
dB
dB
10
± 12
1
kW
V
V/V
VCM = 0 V
VCM = 0 V
VCM = ± 12 V
G = 1000
G = 100
G = 10
G=1
VS = ± 5 V to ± 18 V
G = 1000
G = 100
G = 10
G=1
Differential, G = 1000
G=1
Common Mode, G = 1000
G=1
VO
VOOS
RL = 2 kW, TA = 25∞C
ISC
Output-to-Ground Short
RG =
10 kW
G–1
TA = 25∞C
RG = 10 W, G = 1000
RG = 101 W, G = 100
RG = 1.1 kW, G = 10
RG = , G = 1
G
REFERENCE INPUT
Input Resistance
Voltage Range
Gain to Output
POWER SUPPLY
Supply Voltage Range
Supply Current
VS
ISY
VCM = 0 V, RL = VCM = 0 V, VS = ± 18 V, RL = ±5
± 4.6
± 4.7
± 18
± 7.5
± 8.5
V
mA
mA
Specifications subject to change without notice.
–2–
REV. 0
SSM2019
ABSOLUTE MAXIMUM RATINGS 1
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 19 V
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . Supply Voltage
Output Short Circuit Duration . . . . . . . . . . . . . . . . . . . 10 sec
Storage Temperature Range . . . . . . . . . . . . –65∞C to +150∞C
Junction Temperature (TJ) . . . . . . . . . . . . . –65∞C to +150∞C
Lead Temperature Range (Soldering, 60 sec) . . . . . . . . 300∞C
Operating Temperature Range . . . . . . . . . . . –40∞C to +85∞C
Thermal Resistance2
8-Lead PDIP (N) . . . . . . . . . . . . . . . . . . . . . . . ␪JA = 96∞C/W
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ␪JC = 37∞C/W
16-Lead SOIC (RW) . . . . . . . . . . . . . . . . . . . . ␪JA = 92∞C/W
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ␪JC = 27∞C/W
ORDERING GUIDE
Model
Temperature
Range
Package
Description
Package
Option
SSM2019BN
SSM2019BRW
SSM2019BRWRL
SSM2019BRN*
SSM2019BRNRL*
–40∞C to +85∞C
–40∞C to +85∞C
–40∞C to +85∞C
–40∞C to +85∞C
–40∞C to +85∞C
8-Lead PDIP
16-Lead SOIC
16-Lead SOIC, Reel
8-Lead SOIC
8-Lead SOIC, Reel
N-8
RW-16
RW-16
RN-8
RN-8
*Consult factory for availability.
NOTES
1
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
2
qJA is specified for worst-case mounting conditions, i.e., qJA is specified for device
in socket for PDIP; qJA is specified for device soldered to printed circuit board for
SOIC package.
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the SSM2019 features proprietary ESD protection circuitry, permanent damage may occur on
devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are
recommended to avoid performance degradation or loss of functionality.
WARNING!
ESD SENSITIVE DEVICE
Typical Performance Characteristics
100
RTI, VOLTAGE NOISE DENSITY – nV/ Hz
0.1
G = 1000
G = 100
THD + N – %
0.01
G=1
G = 10
0.001
ⴞ15V VS ⴞ18V
7Vrms VO 10Vrms
RL 600⍀
BW = 80kHz
0.0001
10
20
100
1k
FREQUENCY – Hz
10
1
0.1
10k 20k
1
10
100
1k
10k
FREQUENCY – Hz
TPC 1. Typical THD + Noise vs. Gain
REV. 0
TA = 25ⴗC
VS = ⴞ15V
G = 1000
TPC 2. Voltage Noise Density vs. Frequency
–3–
SSM2019
100
TA = 25 C
VS = 15V
GAIN
80
IMPEDANCE – 10
f = 1kHz OR 10kHz
1
70
60
50
40
30
20
10
GAIN = 1
25
20
TA = 25 C
RL = 2k
VS = 15V
15
10
10
100
0
100
1k
GAIN
G
12
G=1
8
6
4
2
1k
10k
100
LOAD RESISTANCE – 10
30
20
10
30
20
SUPPLY VOLTAGE (V+ – V–) – V
150
G = 1000
125
100
+PSRR – dB
75
G=1
25
20
1k
10k
FREQUENCY– Hz
TPC 9. CMRR vs. Frequency
100k
0
10
G = 100
G = 10
G = 100
G=1
75
50
50
40
40
150
100
G=1
100
0
40
TPC 8. Output Voltage Range vs.
Supply Voltage
G = 10
60
10
5
0
10
125
G = 10
0
10
G = 1000
G = 100
80
20
15
TPC 7. Input Voltage Range vs.
Supply Voltage
VCM = 100mV
180 VS = 15V
TA = 25C
160
100
30
0
200
G = 1000
1M
TA = 25 C
SUPPLY VOLTAGE (V+ – V–) – V
TPC 6. Output Voltage vs. Load
Resistance
10k
100k
FREQUENCY – Hz
20
0
100k
1k
TPC 5. Maximum Output Swing
vs. Frequency
TA = 25 C
f = 100kHz
10
10
120
10
100
1M
40
TA = 25 C
14 VS = 15V
INPUT SWING (VIN+ – VIN–) – V
OUTPUT VOLTAGE – V
16
140
10k
100k
FREQUENCY – Hz
TPC 4. Output Impedance vs.
Frequency
TPC 3. RTI Voltage Noise Density
vs. Gain
0
10
1k
OUTPUT SWING (VOUT+ – VOUT–) – V
1
–PSRR – dB
0.1
CMRR – dB
30
90
PEAK-TO-PEAK VOLTAGE – V
RTI VOLTAGE NOISE DENSITY – nV/ Hz
100
VCM = 100mV
TA = 25 C
VS = 15V
100
25
1k
10k
FREQUENCY – Hz
100k
TPC 10. Positive PSRR vs. Frequency
–4–
0
10
VS = 100mV
TA = 25 C
VS = 15V
100
1k
10k
FREQUENCY – Hz
100k
TPC 11. Negative PSRR vs. Frequency
REV. 0
SSM2019
0.040
0
0.02
V+/V– =
TA = 25C
–1
0.030
0
–2
0.025
–0.01
–3
0.020
0.015
VOOS – mV
0.01
VIOS – mV
VIOS – mV
V+/V– = 15V
0.035
–0.02
–0.03
–4
–5
0.010
–0.04
–6
0.005
–0.05
–7
0
–50
–25
0
25
50
TEMPERATURE – C
75
100
–0.06
0
5
10 15 20 25 30 35
SUPPLY VOLTAGE (VCC – VEE) – V
–8
–50
40
TPC 13. VIOS vs. Supply Voltage
TPC 12. VIOS vs. Temperature
100
TA = 25C
4
4
0
3
IB – A
IB – A
VOOS – mV
75
5
10
IB+ OR IB–
3
2
2
–10
1
1
–20
0
–50
–30
0
5
10
15
20
25
30
35
SUPPLY VOLTAGE (VCC – VEE) – V
40
TPC 15. VOOS vs. Supply Voltage
0
–25
0
25
50
TEMPERATURE – C
75
100
TPC 16. IB vs. Temperature
8
8
6
6
0
I+ @ V+/V– = 15V
2
0
–2
I– @ V+/V– = 15V
–4
–6
I– @ V+/V– = 18V
–8
–50
–25
2
0
–2
–4
I–
–6
75
TPC 18. Supply Current vs.
Temperature
REV. 0
TA = 25 C
14
I+
4
–8
0
25
50
TEMPERATURE – C
100
40
16
SUPPLY CURRENT – mA
SUPPLY CURRENT – mA
I+ @ V+/V– = 18V
4
10
20
30
SUPPLY VOLTAGE (VCC – VEE) – V
TPC 17. IB vs. Supply Voltage
TA = 25C
SUPPLY CURRENT – mA
25
0
50
TEMPERATURE – C
6
V+/V– = 15V
TA = 25C
20
–25
TPC 14. VOOS vs. Temperature
5
30
15V
12
10
8
6
4
2
0
5
10
15
20
25
30
35
40
SUPPLY VOLTAGE (VCC – VEE) – V
TPC 19. Supply Current vs. Supply
Voltage
–5–
0
0
10
15
5
SUPPLY VOLTAGE – V
20
TPC 20. ISY vs. Supply Voltage
SSM2019
V+
VS = ⴞ15V
TA = 25ⴗC
+IN
SSM2019
VOLTAGE GAIN – dB
RG1
RG
OUT
RG2
REFERENCE
–IN
G=
VOUT
(+IN) – (– IN)
=
10k⍀
RG
+1
V–
60
40
20
0
Figure 1. Basic Circuit Connections
GAIN
1k
The SSM2019 only requires a single external resistor to set the
voltage gain. The voltage gain, G, is:
G=
For convenience, Table I lists various values of RG for common
gain levels.
Table I. Values of RG for Various Gain Levels
NC
4.7 k
1.1 k
330
100
32
10
0
10
20
30
40
50
60
1
3.2
10
31.3
100
314
1000
10M
The SSM2019 is a very low noise audio preamplifier exhibiting
a typical voltage noise density of only 1 nV/÷Hz at 1 kHz. The
exceptionally low noise characteristics of the SSM2019 are in
part achieved by operating the input transistors at high collector
currents since the voltage noise is inversely proportional to the
square root of the collector current. Current noise, however, is
directly proportional to the square root of the collector current.
As a result, the outstanding voltage noise performance of the
SSM2019 is obtained at the expense of current noise performance.
At low preamplifier gains, the effect of the SSM2019 voltage
and current noise is insignificant.
10 kW
G –1
dB
1M
NOISE PERFORMANCE
and the external gain resistor, RG , is:
RG (⍀) AV
100k
Figure 2. Bandwidth for Various Values of Gain
10 kW
+1
RG
RG =
10k
The total noise of an audio preamplifier channel can be calculated by:
E n = e n 2 + ( i n RS )2 + e t 2
where:
En = total input referred noise
en = amplifier voltage noise
in = amplifier current noise
The voltage gain can range from 1 to 3500. A gain set resistor is
not required for unity gain applications. Metal film or wire-wound
resistors are recommended for best results.
RS = source resistance
et = source resistance thermal noise
The total gain accuracy of the SSM2019 is determined by the
tolerance of the external gain set resistor, RG, combined with the
gain equation accuracy of the SSM2019. Total gain drift combines
the mismatch of the external gain set resistor drift with that of
the internal resistors (20 ppm/∞C typ).
For a microphone preamplifier, using a typical microphone
impedance of 150 W, the total input referred noise is:
Bandwidth of the SSM2019 is relatively independent of gain,
as shown in Figure 2. For a voltage gain of 1000, the SSM2019
has a small-signal bandwidth of 200 kHz. At unity gain, the
bandwidth of the SSM2019 exceeds 4 MHz.
1.93 nV / Hz @ 1 kHz
E n = (1 nV Hz )2 + 2( pA / Hz ¥ 150 W)2 + (1.6 nV / Hz )2 =
where:
en = 1 nV/÷Hz @ 1 kHz, SSM2019 en
in = 2 pA/÷Hz @ 1 kHz, SSM2019 in
RS = 150 W, microphone source impedance
et = 1.6 nV/÷Hz @ 1 kHz, microphone thermal noise
This total noise is extremely low and makes the SSM2019
virtually transparent to the user.
–6–
REV. 0
SSM2019
Although the SSM2019 inputs are fully floating, care must be
exercised to ensure that both inputs have a dc bias connection
capable of maintaining them within the input common-mode
range. The usual method of achieving this is to ground one side
of the transducer as in Figure 3a. An alternative way is to float
the transducer and use two resistors to set the bias point as in
Figure 3b. The value of these resistors can be up to 10 kW, but
they should be kept as small as possible to limit common-mode
pickup. Noise contribution by resistors is negligible since it is
attenuated by the transducer’s impedance. Balanced transducers
give the best noise immunity and interface directly as in Figure 3c.
INPUTS
The SSM2019 has protection diodes across the base emitter
junctions of the input transistors. These prevent accidental
avalanche breakdown, which could seriously degrade noise
performance. Additional clamp diodes are also provided to prevent
the inputs from being forced too far beyond the supplies.
(INVERTING)
SSM2019
TRANSDUCER
(NONINVERTING)
For stability, it is required to put an RF bypass capacitor directly
across the inputs, as shown in Figures 3 and 4. This capacitor
should be placed as close as possible to the input terminals. Good
RF practice should also be followed in layout and power supply
bypassing, since the SSM2019 uses very high bandwidth devices.
a. Single-Ended
R
TRANSDUCER
R
REFERENCE TERMINAL
SSM2019
The output signal is specified with respect to the reference terminal,
which is normally connected to analog ground. The reference
may also be used for offset correction or level shifting. A reference source resistance will reduce the common-mode rejection
by the ratio of 5 kW/RREF. If the reference source resistance is
1 W, then the CMR will be reduced to 74 dB (5 kW/1 W = 74 dB).
b. Pseudo-Differential
COMMON-MODE REJECTION
Ideally, a microphone preamplifier responds to only the difference
between the two input signals and rejects common-mode voltages
and noise. In practice, there is a small change in output voltage
when both inputs experience the same common-mode voltage
change; the ratio of these voltages is called the common-mode
gain. Common-mode rejection (CMR) is the logarithm of the ratio
of differential-mode gain to common-mode gain, expressed in dB.
SSM2019
TRANSDUCER
c. True Differential
Figure 3. Three Ways of Interfacing Transducers for
High Noise Immunity
PHANTOM POWERING
A typical phantom microphone powering circuit is shown in
Figure 4. Z1 to Z4 provide transient overvoltage protection for
the SSM2019 whenever microphones are plugged in or unplugged.
+48V
C1
+18V
+IN
R5
100
C3
47F
R3
6.8k
1%
R4
6.8k
1%
R1
10k
Z1
Z2
C4
200pF
R2
10k
RG1
RG
SSM2019
VOUT
RG2
Z3
Z4
–IN
–18V
C2
C1, C2: 22F TO 47F, 63V, TANTALUM OR ELECTROLYTIC
Z1–Z4: 12V, 1/2W
Figure 4. SSM2019 in Phantom Powered Microphone Circuit
REV. 0
–7–
SSM2019
critical, then the servo loop can be replaced by the diode biasing
scheme of Figure 5. If ac coupling is used throughout, then Pins 2
and 3 may be directly grounded.
BUS SUMMING AMPLIFIER
In addition to its use as a microphone preamplifier, the SSM2019
can be used as a very low noise summing amplifier. Such a circuit
is particularly useful when many medium impedance outputs
are summed together to produce a high effective noise gain.
The principle of the summing amplifier is to ground the SSM2019
inputs. Under these conditions, Pins 1 and 8 are ac virtual grounds
sitting about 0.55 V below ground. To remove the 0.55 V offset,
the circuit of Figure 5 is recommended.
SSM2019
VOUT
– IN
A2 forms a “servo” amplifier feeding the SSM2019 inputs. This
places Pins l and 8 at a true dc virtual ground. R4 in conjunction
with C2 removes the voltage noise of A2, and in fact just about
any operational amplifier will work well here since it is removed
from the signal path. If the dc offset at Pins l and 8 is not too
V
C1
R3
0.33F 33k
R2
6.2k
R5
10k
R4
5.1k
A2
C2
200F
TO PINS
2 AND 3
IN4148
C02718–0–2/03(0)
+ IN
Figure 5. Bus Summing Amplifier
OUTLINE DIMENSIONS
16-Lead Standard Small Outline Package [SOIC]
Wide Body
(RW-16)
8-Lead Plastic Dual In-Line Package [PDIP]
(N-8)
Dimensions shown in inches and (millimeters)
Dimensions shown in millimeters and (inches)
0.375 (9.53)
0.365 (9.27)
0.355 (9.02)
8
5
1
4
10.50 (0.4134)
10.10 (0.3976)
0.295 (7.49)
0.285 (7.24)
0.275 (6.98)
0.100 (2.54)
BSC
0.180
(4.57)
MAX
0.150 (3.81)
0.130 (3.30)
0.110 (2.79)
0.022 (0.56)
0.018 (0.46)
0.014 (0.36)
9
16
0.325 (8.26)
0.310 (7.87)
0.300 (7.62)
0.015
(0.38)
MIN
7.60 (0.2992)
7.40 (0.2913)
0.150 (3.81)
0.135 (3.43)
0.120 (3.05)
1.27 (0.0500)
BSC
0.015 (0.38)
0.010 (0.25)
0.008 (0.20)
SEATING
PLANE
0.060 (1.52)
0.050 (1.27)
0.045 (1.14)
0.30 (0.0118)
0.10 (0.0039)
COPLANARITY
0.10
10.65 (0.4193)
10.00 (0.3937)
8
1
0.51 (0.0201)
0.33 (0.0130)
0.75 (0.0295)
45
0.25 (0.0098)
2.65 (0.1043)
2.35 (0.0925)
SEATING
PLANE
0.32 (0.0126)
0.23 (0.0091)
8
0
1.27 (0.0500)
0.40 (0.0157)
COMPLIANT TO JEDEC STANDARDS MS-013AA
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
COMPLIANT TO JEDEC STANDARDS MO-095AA
CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
8-Lead Standard Small Outline Package [SOIC]*
Narrow Body
(RN-8)
PRINTED IN U.S.A.
Dimensions shown in millimeters and (inches)
5.00 (0.1968)
4.80 (0.1890)
4.00 (0.1574)
3.80 (0.1497)
8
5
1
4
1.27 (0.0500)
BSC
0.25 (0.0098)
0.10 (0.0040)
COPLANARITY
SEATING
0.10
PLANE
6.20 (0.2440)
5.80 (0.2284)
1.75 (0.0688)
1.35 (0.0532)
0.51 (0.0201)
0.33 (0.0130)
0.50 (0.0196)
45
0.25 (0.0099)
8
0.25 (0.0098) 0 1.27 (0.0500)
0.41 (0.0160)
0.19 (0.0075)
COMPLIANT TO JEDEC STANDARDS MS-012AA
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
*Consult factory for availability.
–8–
REV. 0