ELM460
Impossible Oscillator
Description
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.
Features
• 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)
Applications
• Time Base Generator
• Power Gating Controller
• LED Flasher
• Programmable Timer
V
DD
P1
P0
M1
1
2
3
4
8
7
6
5
V
SS
Out
Out
M0
Block Diagram
Base Period
Generator
P1
P0
2
Rate
Multiplier
M1
M0
4
50ms Pulse
Generator
7
Out
6
Out
3
5
P1
L
L
H
H
P0
L
H
L
H
Period
1 sec
2 sec
5 sec
6 sec
M1
L
L
H
H
M0
L
H
L
H
Multiplier
0.1
1
10
100
ELM460DSB
Elm Electronics – Circuits for the Hobbyist
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