SSM2404

REV. B

–8–

The circuit was tested with an SSM2131 high slew rate audio

amplifier and the results are shown in Figures 24 and 25. This

configuration yields excellent THD performance that is

primarily determined by the amplifier. Also, the headroom is

now +24 dBu (0 dBu = 0.775 V rms), which is due to the

amplifier’s output voltage swing. Thus, even though the

SSM2404 has a

±12 V limitation on its supplies, it can be used

in systems with much higher voltage ranges. For example, the

double-pole double-throw switch from Figure 22 can be

reconfigured in the virtual ground mode to allow higher voltage

swings, as shown in Figure 26. This application realizes the

excellent performance of Figures 24 and 25 while providing a

low cost switching solution.

+18V

–18V

SSM2131

SSM2404

SW1 A

SW1 B

+12V

–12V

13

1N914

R1

5k

Ω

R2

5k

Ω

AUDIO

OUT

AUDIO

IN

Figure 23. Virtual Ground Switching

Figure 24. Virtual Ground Switch THD+N vs. Frequency

80 kHz Filter)

SW2

SW1

SW2 CONTROL

SW3 CONTROL

DGND

SW1 CONTROL

SW4 CONTROL

SW3

SW4

AGND

SSM2404

V–

SWA/SWB

V+

17

10

8

13

2

R

OUT

9

12

19

13

18

14

20

11

16

5

4

15

6

5k

SSM2131

SSM2131

5k

5k

5k

5k

5k

Ω

Ω

Ω

Ω

Ω

Ω

Figure 26. Double-Pole, Double-Throw Stereo Switch

Using Virtual Ground Operation

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

Mini-DIP (P Suffix)

0.280 (7.11)

0.240 (6.10)

1.060 (26.90)

0.925 (23.50)

0.022 (0.558)

0.014 (0.356)

0.100 (2.54)

BSC

0.210

(5.33)

MAX

0.200 (5.05)

0.125 (3.18)

0.060 (1.52)

0.015 (0.38)

0.150

(3.81)

MIN

0.070 (1.77)

0.045 (1.15)

PLANE

SEATING

0.015 (0.381)

0.008 (0.204)

0.195 (4.95)

0.115 (2.93)

0.325 (8.25)

0.300 (7.62)

PIN 1

10

1

11

20

SOIC (S Suffix)

0.0500 (1.27)

BSC

0.0192 (0.49)

0.0138 (0.35)

0.0118 (0.30)

0.0040 (0.10)

0.0500 (1.27)

0.0157 (0.40)

0.1043 (2.65)

0.0926 (2.35)

0.0125 (0.32)

0.0091 (0.23)

0.4193 (10.65)

0.3937 (10.00)

0.2992 (7.60)

0.2914 (7.40)

0.5118 (13.00)

0.4961 (12.60)

110

20

11

PIN 1

0

0.0291 (0.74)

0.0098 (0.25)

X

45

°