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SA555M

HGSEMI · Timers / Clock Oscillators · SOP-8

SA555M from HGSEMI, in a SOP-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 / 0 V reference for the device. All internal timing, comparator, and output-stage return currents flow through this pin.
2 RTIG input Trigger input. A negative-going pulse below 1/3 VCC (typ. 1.67 V at VCC=5 V, 5 V at VCC=15 V) sets the internal flip-flop, driving OUT high and starting the timing cycle. Input current ~0.5 uA typ.
3 OUT output Push-pull output stage. Sources up to ~200 mA (VOH ≈ 12.5 V at VCC=15 V, IS=200 mA) or sinks up to ~200 mA (VOL ≈ 2.5 V at VCC=15 V, ISINK=200 mA). Rise/fall times ~100 ns.
4 R input Active-low reset input. Pulling below ~0.4-1 V (typ. 0.5 V) forces the internal flip-flop reset, discharging the timing capacitor and driving OUT low regardless of TRIG/THRES state. Reset current ~0.1 mA typ. Tie to VCC when unused.
5 CONTRIG input Control voltage (CV) input to the internal 2/3 VCC threshold reference. Nominally 2/3 VCC (typ. 3.33 V at VCC=5 V, 10 V at VCC=15 V). Bypass to GND with a 0.01 uF capacitor when unused; can be driven to modulate output pulse width (PWM/PPM).
6 CONTH input Threshold input. When the voltage on this pin rises above 2/3 VCC (typ. 0.667*VCC), the internal comparator resets the flip-flop, driving OUT low and turning on the discharge transistor. Input current ~0.1 uA typ.
7 DIS output Discharge open-collector output from an internal NPN transistor whose collector is tied here and emitter to GND. Provides the discharge path for the external timing capacitor when OUT is low. V7(SAT) ~180 mV at 15 mA sink; leakage ~20 nA typ.
8 VCC power_in Positive supply pin. Operating range 4.5 V to 16 V (absolute max 18 V). Typical quiescent current 3 mA at VCC=5 V, 10 mA at VCC=15 V (RL=∞).

Key specifications

Parameter Value
Manufacturer HGSEMI
Package SOP-8
Category RTC
Pins 8

Ordering variants

  • SA555MM/TR
  • SA555MM-4K/TR
  • SA555MN
  • SA555MMM/TR
  • SA555MDQ2/TR
  • SA555MDQ3/TR

CAD (KiCad official)

  • Symbol: SA555M
  • Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
  • 3D model: SOP-8 (KiCad packages3D, STEP)

Provenance

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

  • Datasheet: HGSEMI datasheet (None pp, sha256 aeacc0a1e25195ab, retrieved 2026-08-17, tier: lcsc)
  • Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
  • 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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