SE555-SP QML Class V Precision Timer |


QML Class V Precision Timer

QML Class V Precision Timer - SE555-SP


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.


  • 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.

View more

Parametrics Compare all products in Timer

Frequency (Max) (MHz)
VCC (Min) (V)
VCC (Max) (V)
Iq (Typ) (uA)
Operating Temperature Range (C)
Package Group
Package Size: mm2:W x L (PKG)
-55 to 125    
See datasheet (CDIP)    

Other qualified versions of SE555-SP

Version Part Number Definition
Catalog SE555 TI's standard catalog product
Military SE555M QML certified for Military and Defense Applications