SSM2000

REV. 0

–16–

VCF—minimum bandwidth) to their fully open positions. If

the VCA and VCF are fully opened then at least 1.5 seconds of

no signal is required for the VCA and VCF detectors to return

to the closed position. A series of 10 kHz pulses interspersed

with 1.5 seconds of no signal will accomplish this requirement.

The system’s attack and release times will be dominated by

VCA since the attack and release times of the VCA are slower

than the VCF’s. In addition, monitoring Pins 11 (VCF) and 12

(VCA) will ensure that the VCA and VCF are either fully

opened or fully closed.

As stated before, the most common cause of a failure to reduce

noise is fixed-frequency tones that are being detected by the

output. A solution for this condition is detailed in the “Precau-

tions, Limitations, and Observations” section.

In single-supply applications, ACOM should be driven with a

well regulated reference capable of both sinking and souring

current. Zener-resistor references are unacceptable, because of

their inability to sink significant amounts of current.

By following these simple suggestions, the common pitfalls to a

successful implementation of the HUSH noise reduction system

can be avoided.

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

24-Pin Plastic DIP

(N-24)

24

112

13

0.280 (7.11)

0.240 (6.10)

PIN 1

1.275 (32.30)

1.125 (28.60)

0.150

(3.81)

MIN

0.200 (5.05)

0.125 (3.18)

SEATING

PLANE

0.022 (0.558)

0.014 (0.356)

0.060 (1.52)

0.015 (0.38)

0.210

(5.33)

MAX

0.070 (1.77)

0.045 (1.15)

0.100 (2.54)

BSC

0.325 (8.25)

0.300 (7.62)

0.015 (0.381)

0.008 (0.204)

0.195 (4.95)

0.115 (2.93)

24 Pin SOIC

(SOL-24)

24

13

12

1

0.6141 (15.60)

0.5985 (15.20)

PIN 1

SEATING

PLANE

0.0118 (0.30)

0.0040 (0.10)

0.0192 (0.49)

0.0138 (0.35)

0.1043 (2.65)

0.0926 (2.35)

0.0500

(1.27)

BSC

0.0125 (0.32)

0.0091 (0.23)

0.0500 (1.27)

0.0157 (0.40)

8

°

0

°

0.0291 (0.74)

0.0098 (0.25)

x 45

°

promotional and descriptive literature. Rocktron Corp. reserves the right to

approve use of the HUSH logo and may require submission of a schematic

illustrating the use of the SSM2000; a physical sample of the end product may

also be required. Applications for approval of the use of the HUSH name and

logo may be obtained by contacting ADI.

IMPORTANT NOTICE—LICENSING

The SSM2000 is manufactured under a license granted to Analog Devices,

Inc., by Rocktron Corp. and embodies technology covered by the following

patents: 4696044, 4893099, 5124657, 5263091, 5402498, and 5493617. For-

eign patents are pending. Rocktron Corp. grants a royalty-free license to

purchasers of the SSM2000 for use in end equipment, and no further rights

are implied. The use of the HUSH logo is encouraged on products, packaging,