1784 Chessie Lane, Ottawa, IL 61350 • Tel: 800/252-7074, 815/434-7800 • FAX: 815/434-8176

e-mail: sales@freqdev.com • Web Address: http://www.freqdev.com

November 2000

Programmable Filters Modules

818, 824, 828, 828BP, 828BR, 854, 858, R854, R858

I. Scope

The following precautions are necessary when handling and installing Frequency Devices

programmable filter modules.

II. Digital Circuit Description

The digital input pins connect directly to 4000 series CMOS logic, such as the 4053 analog switch. The

power supply (Vss) for the digital logic on the module comes directly from the +15 Volt pin on the

module. This sets the threshold voltage at 11.0 V minimum to 15.0 V maximum for a "1" (High) level

and 0.0 V minimum to 4.0 V maximum for a "0" (Low) level. Applying a voltage between 4.0 and 11.0

V will produce unpredictable operation. Connecting 5 Volt or 3.3 V logic devices directly to the filter

module without using a voltage translator will result in erratic operation of the filter.

III. (VERY IMPORTANT) Power-Up and Power-Down Sequence

supplied to the + 15 V pin on the filter module before or at the same instance that any digital pin is

pulled High (> 0.0 V). Failure to do this will result in excessive current flowing through the digital input

pin and through a protection diode internal to the 4000 logic, which will result in damage to the module.

The proper power-up and power-down sequence is:

1. Connect filter module ground.

2. Connect filter module +15 V.

3. Connect filter module -15 V.

4. Connect the input signal.

All four of the above steps can also occur simultaneously. Power-down should occur in the reverse

order.

IV. ESD Issues

Like most modern electronic equipment, the modules can be damaged by electrostatic discharge (ESD).

The modules are shipped from the factory in sealed, anti-static packaging and should be kept in the

sealed package prior to mounting on a circuit board. The following additional rules should also be

observed when handling the modules after they are removed from the factory packaging:

1. Only a person wearing a properly grounded wrist strap should handle the modules.

2. Any work surface that the modules are placed on must be properly ESD grounded.

3. Any insulating materials capable of generating static charge (such as paper) should be kept

away from the modules.

Static generating clothing should be covered with an ESD-protective smock.

1

Product Handling

Procedure

Programmable Filter Modules Power Sequence & ESD