1FEATURES
• Timing From Microseconds to Hours
• Astable or Monostable Operation
• Adjustable Duty Cycle
• TTL-Compatible Output Can Sink or Source up
to 100 mA
• QML-V Qualified, SMD 5962-98555
• Military Temperature Range (-55°C to 125°C)
• Rad-Tolerant: 25 kRad (Si) TID (1)
(1) Radiation tolerance is a typical value based upon initial device
qualification with dose rate = 10 mrad/sec. Radiation Lot
Acceptance Testing is available - contact factory for details.

DESCRIPTION/ORDERING INFORMATION
The SE555 is a precision timing circuit capable of producing accurate time delays or oscillation. In the time-delay
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 low-impedance path is provided between discharge (DISCH) and ground.
The output circuit is capable of sinking or sourcing current up to 100 mA. Operation is specified for supplies of
4.5 V to 16.5 V. With a 5-V supply, output levels are compatible with TTL inputs.