NE555/SA555/NA555
PRECISION TIMERS
Description
Pin Assignments
NEW PRODUCT
These devices are precision timing circuits capable of
producing accurate time delays or oscillation. In the timedelay or monostable mode of operation, the timed interval is
controlled by a single external resistor and capacitor network.
In the astable mode of operation, the frequency and duty
cycle can be controlled independently with two external
resistors and a single external capacitor.
The threshold and trigger levels normally are two-thirds and
one-third, respectively, of VCC. These levels can be altered
by use of the control-voltage terminal. When the trigger input
falls below the trigger level, the flip-flop is set, and the output
goes high. If the trigger input is above the trigger level and
the threshold input is above the threshold level, the flip-flop is
reset and the output is low. The reset (RESET) input can
override all other inputs and can be used to initiate a new
timing cycle. When RESET goes low, the flip-flop is reset,
and the output goes low. When the output is low, a lowimpedance path is provided between discharge (DISCH) and
ground.
(Top View)
GND
VCC
TRIG
DISCH
OUT
THRES
RESET
CONT
SO-8
The output circuit is capable of sinking or sourcing current up
to 200mA. Operation is specified for supplies of 5V to 15V.
With a 5-V supply, output levels are compatible with TTL
inputs.
Features
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Timing from microseconds to hours
Astable or monostable operation
Adjustable duty cycle
TTL compatible output can source or sink up to 200mA
“Green” Molding Compound (No Br, Sb)
Lead Free Finish/ RoHS Compliant (Note 1)
Notes:
1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
1 of 14
www.diodes.com
February 2012
© Diodes Incorporated
