ELM446
Pin Descriptions
VDD (pin 1)
circuit by applying a logic low level to it. While
held low, all outputs are placed in an open or
tristate condition. If unused, this pin should be
left open (as a pullup resistor is provided) or
connected to VDD.
This pin is the positive supply pin, and should
always be the most positive point in the circuit.
Internal circuitry connected to this pin is used to
provide power on reset of the microprocessor, so
an external reset signal is not required. Refer to
the Electrical Characteristics section for further
information.
50Hz (pin 6) and 50Hz (pin 5)
These pins provide complementary 50Hz
outputs. Each has a nominal 50% duty cycle.
XT1 (pin 2) and XT2 (pin 3)
A 3.579545MHz NTSC television colourburst
crystal is connected between these two pins.
Crystal loading capacitors (typically 27pF) will
also normally be connected between each of the
pins and VSS.
1Hz (pin 7)
The output on this pin is a 1Hz 50% duty cycle
signal.
VSS (pin 8)
Circuit common is connected to this pin. This is
the most negative point in the circuit.
reset (pin 4)
This pin can optionally be used to reset the
Ordering Information
These integrated circuits are available in either the 300 mil plastic DIP format, or in the 200 mil SOIC surface
mount type of package. To order, add the appropriate suffix to the part number:
300 mil Plastic DIP............................... ELM446P
200 mil SOIC..................................... ELM446SM
Absolute Maximum Ratings
Storage Temperature....................... -65°C to +150°C
Note:
Stresses beyond those listed here will likely damage
the device. These values are given as a design
guideline only. The ability to operate to these levels
is neither inferred nor recommended.
Ambient Temperature with
Power Applied....................................-40°C to +85°C
Voltage on VDD with respect to VSS............0 to +7.5V
Voltage on any other pin with
respect to VSS........................... -0.6V to (VDD + 0.6V)
All rights reserved. Copyright ©1999 Elm Electronics.
Every effort is made to verify the accuracy of information provided in this document, but no representation or warranty can be
given and no liability assumed by Elm Electronics with respect to the accuracy and/or use of any products or information
described in this document. Elm Electronics will not be responsible for any patent infringements arising from the use of these
products or information, and does not authorize or warrant the use of any Elm Electronics product in life support devices and/or
systems. Elm Electronics reserves the right to make changes to the device(s) described in this document in order to improve
reliability, function, or design.
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ELM446DSB
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