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SE555DR

Texas Instruments · Timers / Clock Oscillators · SOIC-8

SE555DR from Texas Instruments, in a SOIC-8. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 GND power_in Ground reference (0 V). Return for all supply and signal currents.
2 TRIG input Trigger input. A negative-going pulse below VCC/3 (1/3 VCC) sets the internal flip-flop and drives the output HIGH. Typical trigger threshold ~1.67 V at VCC=5 V, ~5 V at VCC=15 V.
3 OUT output Push-pull output. Can source or sink up to 200 mA. Output HIGH is approximately VCC - 1.7 V (typ) at 100 mA sink; output LOW is ~0.1 V at 5 mA sink.
4 RESET input Active-low reset input. Forces the output LOW and discharge transistor ON regardless of other inputs when pulled below ~0.7 V. Tie to VCC if unused. Reset current typ 0.1 mA.
5 CONT input Control voltage input. Directly accesses the 2/3 VCC reference of the upper comparator, allowing external modulation of timing thresholds. Bypass to GND with 0.01 µF when unused. Nominal voltage 2/3 VCC (~3.33 V at 5 V, ~10 V at 15 V).
6 THRES input Threshold input. When the voltage on THRES rises above 2/3 VCC, the internal flip-flop resets, driving the output LOW and turning on the discharge transistor. Typical threshold ~3.33 V at VCC=5 V, ~10 V at VCC=15 V.
7 DISCH output Discharge output (open-collector NPN to GND). Provides a discharge path for the external timing capacitor when the output is LOW. Sinks the timing-capacitor current to GND; not driven high internally.
8 VCC power_in Positive supply voltage. Operating range 4.5 V to 18 V (SE555). Supply current typ 3 mA at VCC=5 V, 10 mA at VCC=15 V (output LOW).

Key specifications

Parameter Value
Manufacturer Texas Instruments
Package SOIC-8
Category RTC
Pins 8

Ordering variants

  • SE555DR
  • SE555DRD

CAD (KiCad official)

  • Symbol: SE555DR
  • Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
  • 3D model: SOIC-8 (KiCad packages3D, STEP)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Texas Instruments datasheet (None pp, sha256 c6f5275b8c31eb1d, retrieved 2026-08-17, tier: manufacturer)
  • Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF

Symbol & Footprint

Schematic Symbol

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PCB Footprint

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