Product Handling
Procedure
Programmable Filter Modules Power Sequence & ESD
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
Do not plug-in or un-plug module while power is applied. It is imperative that power is
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.
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