NA555DR 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). All voltages in the datasheet are with respect to this pin.
2	TRIG	input	Start-of-timing input. When TRIG falls below 1/2 of CONT (nominally 1/3 VCC), the internal flip-flop is set: OUT goes high and DISCH is released (open).
3	OUT	output	High-current timer output signal. Can sink or source up to 200 mA; TTL-compatible logic levels with a 5 V supply.
4	RESET	input	Active-low reset. Forces OUT low and DISCH low regardless of other inputs. Threshold ~0.7 V (min 0.3 V, max 1 V). Tie high (to VCC) when unused.
5	CONT	bidirectional	Control-voltage pin. Internally biased to 2/3 VCC and sets the comparator thresholds; can be overdriven by an external voltage or bypassed to GND with a 10 nF capacitor to reject supply noise.
6	THRES	input	End-of-timing input. When THRES rises above CONT (nominally 2/3 VCC), the flip-flop is reset: OUT goes low and DISCH is pulled low. Input current typ 30 nA (max 250 nA).
7	DISCH	output	Open-collector discharge output. Provides a low-impedance path to GND to discharge the external timing capacitor whenever OUT is low. On-state VCE ~0.15 V typ at 8 mA.
8	VCC	power_in	Positive supply. Recommended operating range 4.5 V to 16 V (SE555 up to 18 V). Absolute maximum 18 V.

Key specifications

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

Ordering variants

Same part, different packaging or reel option.

NA555DR
NA555DRD
NA555DRP

CAD (KiCad official)

Symbol: NA555DR
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 (39 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