Datasheet

REV. 0
–8–
C02718–0–2/03(0)
PRINTED IN U.S.A.
SSM2019
OUTLINE DIMENSIONS
8-Lead Plastic Dual In-Line Package [PDIP]
(N-8)
Dimensions shown in inches and (millimeters)
SEATING
PLANE
0.180
(4.57)
MAX
0.150 (3.81)
0.130 (3.30)
0.110 (2.79)
0.060 (1.52)
0.050 (1.27)
0.045 (1.14)
8
1
4
5
0.295 (7.49)
0.285 (7.24)
0.275 (6.98)
0.100 (2.54)
BSC
0.375 (9.53)
0.365 (9.27)
0.355 (9.02)
0.150 (3.81)
0.135 (3.43)
0.120 (3.05)
0.015 (0.38)
0.010 (0.25)
0.008 (0.20)
0.325 (8.26)
0.310 (7.87)
0.300 (7.62)
0.022 (0.56)
0.018 (0.46)
0.014 (0.36)
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
COMPLIANT TO JEDEC STANDARDS MO-095AA
0.015
(0.38)
MIN
16-Lead Standard Small Outline Package [SOIC]
Wide Body
(RW-16)
Dimensions shown in millimeters and (inches)
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 MS-013AA
SEATING
PLANE
0.30 (0.0118)
0.10 (0.0039)
0.51 (0.0201)
0.33 (0.0130)
2.65 (0.1043)
2.35 (0.0925)
1.27 (0.0500)
BSC
16
9
8
1
10.65 (0.4193)
10.00 (0.3937)
7.60 (0.2992)
7.40 (0.2913)
10.50 (0.4134)
10.10 (0.3976)
0.32 (0.0126)
0.23 (0.0091)
8
0
0.75 (0.0295)
0.25 (0.0098)
 45
1.27 (0.0500)
0.40 (0.0157)
COPLANARITY
0.10
8-Lead Standard Small Outline Package [SOIC]*
Narrow Body
(RN-8)
Dimensions shown in millimeters and (inches)
0.25 (0.0098)
0.19 (0.0075)
1.27 (0.0500)
0.41 (0.0160)
0.50 (0.0196)
0.25 (0.0099)
 45
8
0
1.75 (0.0688)
1.35 (0.0532)
SEATING
PLANE
0.25 (0.0098)
0.10 (0.0040)
85
41
5.00 (0.1968)
4.80 (0.1890)
4.00 (0.1574)
3.80 (0.1497)
1.27 (0.0500)
BSC
6.20 (0.2440)
5.80 (0.2284)
0.51 (0.0201)
0.33 (0.0130)
COPLANARITY
0.10
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 MS-012AA
*Consult factory for availability.
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.
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
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.
– IN
V
OUT
SSM2019
R4
5.1k
R3
33k
C1
0.33F
R2
6.2k
C2
200F
+ IN
A2
R5
10k
V
IN4148
TO PINS
2 AND 3
Figure 5. Bus Summing Amplifier