component
NE555
Public Unreviewedby Ray
TI precision 555 timer, SOIC-8. Monostable / astable, 4.5-16 V, 200 mA output. Datasheet-verified.
3D Model
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Symbol & Footprint
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PCB Footprint
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Datasheet
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README
markdownNE555
Texas Instruments · Precision timer / oscillator · SOIC-8
The classic 555 precision timing circuit, in a SOIC-8 package. An external RC network sets accurate time delays (monostable) or oscillation (astable); the output sinks or sources up to 200 mA and is TTL-compatible at 5 V. It runs from 4.5 to 16 V. The default building block for delays, blinkers, PWM, tone generation, and simple clocks.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | GND | power_in | Ground reference (0 V). All voltages in the device are referenced to this pin. |
| 2 | TRIG | input | Trigger input. Starts the timing cycle: when TRIG falls below approximately 1/3 VCC (< 1/2 CONT), the internal flip-flop is set, the output goes high, and the discharge switch opens. |
| 3 | OUT | output | High-current timer output signal. Can sink or source up to 200 mA; TTL-compatible at VCC = 5 V. High level is approximately VCC - 1.7 V, low level is near GND. |
| 4 | RESET | input | Active-low reset input. When driven below approximately 0.7 V, the flip-flop is reset and the output is forced low regardless of TRIG/THRES. Tie to VCC when reset is not used. |
| 5 | CONT | bidirectional | Control voltage pin. Directly sets the upper comparator threshold (nominally 2/3 VCC) and indirectly the lower threshold (1/2 CONT). Bypass to GND with a 0.01 uF capacitor when not driven externally. |
| 6 | THRES | input | Threshold input. End of timing input: when THRES exceeds CONT (nominally 2/3 VCC), the flip-flop is reset, the output goes low and the discharge switch closes. |
| 7 | DISCH | output | Discharge. Open-collector output used to discharge the external timing capacitor. Sinks current to GND whenever the internal flip-flop is reset (output low). |
| 8 | VCC | power_in | Positive supply voltage. Recommended operating range 4.5 V to 16 V (SE555: up to 18 V). Bypass with a low-ESR ceramic capacitor to GND. |
Key specifications
| Parameter | Value |
|---|---|
| Type | Precision timer (555) |
| Modes | Monostable, astable |
| Supply voltage | 4.5-16 V |
| Output current | ±200 mA (TTL-compatible) |
| Timing | External RC network |
| Package | SOIC-8 |
| Body (L×W×H) | 4.9 × 3.9 × 1.75 mm |
Ordering variants
Same part, different packaging or reel option.
NE555D (SOIC-8, tube)NE555DR (SOIC-8, tape & reel)
CAD (KiCad official)
- Symbol:
Timer:NE555D - Footprint:
Package_SO:SOIC-8_3.9x4.9mm_P1.27mm - 3D model: SOIC-8 (KiCad packages3D)
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Texas Instruments datasheet (39 pp, sha256
dae2be1a919b0cfe, retrieved 2026-08-17, tier: manufacturer) - Extractor:
ds2sf(Claude) — every pin and dimension is cited to a datasheet page; refuses to fabricate. - CAD: KiCad official libraries (CC-BY-SA 4.0).