ELM412
Pin Descriptions
VDD (pin 1)
is convenient for interfacing to slowly changing
signals, as from an RC coupled circuit.
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.
Out2 (pin 6) and Out1 (pin 7)
These complementary outputs are used to drive
the piezo-electric element through a current
limiting resistor. The outputs switch between Vdd
and Vss with a combined duty cycle of
approximately 67% (see Figure 2). This results
in reduced harmonics in the output signal and
more energy to the fundamental. The output
always consists of complete cycles, as the cycle
that is in progress when the enable input goes
low will always be allowed to complete.
F2 (pin 2), F1 (pin 3) and F0 (pin 4)
These are the frequency select inputs. One of
eight frequencies are selected according to the
logic levels on these pins, as shown in Table 1.
Enable (pin 5)
VSS (pin 8)
This schmitt trigger input pin is used to control
the output. A high level at this input will allow the
outputs to appear at pins 6 and 7, while a low
level inhibits the output. The schmitt trigger input
Circuit common is connected to this pin. This is
the most negative point in the circuit.
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............................... ELM412P
200 mil SOIC..................................... ELM412SM
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.
2 of 4
ELM412DSB
Elm Electronics – Circuits for the Hobbyist
< http://www.elmelectronics.com/ >
ELM [ ELM ELECTRONICS ]
