ELM ELM460SM, ELM460P Datasheet

ELM460

1234876

5

Impossible Oscillator

Description

54726

3

Features

The ELM460 is a complete astable oscillator
circuit in an 8 pin package. The circuit (impossibly!)
requires no external components to operate, as all
timing is generated internally.

Immediately after power-up, the ELM460 begins
to oscillate continuously at a frequency determined
by the logic levels on the configuration inputs. At the
end of every period, the circuit again reads these
configuration settings, and automatically adapts to
any changes that are made.

Two outputs are provided, an active high output
and it’s logical inverse. The circuit output is always a
50msec pulse, independent of the time period
selected.

Applications

• Time Base Generator

• Power Gating Controller

• LED Flasher

• Programmable Timer

• Requires no external components

• Low power CMOS design - typically 1mA at 5V

• Wide supply range - 3.0 to 5.5 volt operation

• Provides periods from 0.1 to 600 seconds

• High current drive outputs - up to 25 mA

Connection Diagram

PDIP and SOIC

(top view)

VDD VSS

P1
P0

Out
Out
M0M1

Block Diagram

P1

P0

ELM460DSB

Base Period

Generator

Rate

Multiplier

M1

M0

P1 P0 Period

L

L
H
H

L

H 2 sec

L

H

1 sec

5 sec
6 sec

50ms Pulse

Generator

M1 M0

L

L
H
H

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L

H

L

H

Out

Out

Multiplier

0.1
1

10

100

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ELM460

Pin Descriptions

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.

VDD (pin 1)

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.

P1 (pin 2) and P0 (pin 3)

These two pins are used to select the base

period for oscillation. P1 is the most significant
bit, and P0 is the least. See the chart on page 1
for possible states of P1 and P0, and the
resulting periods.

M1 (pin 4) and M0 (pin 5)

These two pins determine the multiplier that

should be applied to the base period in order to

Ordering Information

determine the actual period of oscillation. Values
of 0.1, 1, 10 and 100 are possible as shown in
the chart on page 1.

Out (pin 6) and Out (pin 7)

These are the two output pins. Pin 6 is normally

held at a logical high level, and pin 7 at a logical
low. Each pin reverses its state for a period of
50ms at the beginning of each timing cycle,
independent of the overall period selected.

VSS (pin 8)

Circuit common is connected to this pin. This is

the most negative point in the circuit.

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............................... ELM460P 200 mil SOIC.....................................ELM460SM

Absolute Maximum Ratings

Storage Temperature.......................-65°C to +150°C

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.

Note:

ELM460DSB

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