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SN74LS221DBR
Public Made by Adomby adom
Texas Instruments Monostable Multivibrators, SSOP-16-208mil. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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README
markdownSN74LS221DBR
Texas Instruments · Monostable Multivibrators · SSOP-16-208mil
SN74LS221DBR from Texas Instruments, in a SSOP-16-208mil. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | 1A | input | Monostable 1 negative-transition-triggered input, which can also be used as an inhibit input; unused inputs must be held at VCC or GND. |
| 2 | 1B | input | Monostable 1 positive-transition-triggered Schmitt-trigger input, which can also be used as an inhibit input. |
| 3 | 1CLR | input | Monostable 1 active-low overriding clear input that terminates the output pulse. |
| 4 | 1Q̄ | output | Monostable 1 complementary (inverted) totem-pole output, high when idle; IOL 8 mA max and IOH -400 µA for the SN74LS221. |
| 5 | 2Q | output | Monostable 2 totem-pole output, low when idle and high during the pulse; IOL 8 mA max and IOH -400 µA for the SN74LS221. |
| 6 | 2Cext | passive | Monostable 2 external timing capacitor connection; the Rext/Cext terminal is never more positive than this terminal. |
| 7 | 2Rext/Cext | passive | Monostable 2 external timing resistor/capacitor junction; Rext 1.4 kΩ min to 100 kΩ max for the SN74LS221, with tw ≈ 0.7·Cext·Rext. |
| 8 | GND | power_in | Ground. |
| 9 | 2A | input | Monostable 2 negative-transition-triggered input, which can also be used as an inhibit input. |
| 10 | 2B | input | Monostable 2 positive-transition-triggered Schmitt-trigger input, which can also be used as an inhibit input. |
| 11 | 2CLR | input | Monostable 2 active-low overriding clear input that terminates the output pulse. |
| 12 | 2Q̄ | output | Monostable 2 complementary (inverted) totem-pole output, high when idle; IOL 8 mA max and IOH -400 µA for the SN74LS221. |
| 13 | 1Q | output | Monostable 1 totem-pole output, low when idle and high during the pulse; IOL 8 mA max and IOH -400 µA for the SN74LS221. |
| 14 | 1Cext | passive | Monostable 1 external timing capacitor connection; the Rext/Cext terminal is never more positive than this terminal. |
| 15 | 1Rext/Cext | passive | Monostable 1 external timing resistor/capacitor junction; Rext 1.4 kΩ min to 100 kΩ max for the SN74LS221, with tw ≈ 0.7·Cext·Rext. |
| 16 | VCC | power_in | Supply voltage, 4.75 V to 5.25 V recommended for the SN74LS221 (7 V absolute maximum). |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SSOP-16-208mil |
| Category | Logic ICs |
| Pins | 16 |
CAD (KiCad official)
- Symbol:
SN74LS221DBR - Footprint:
Package_SO:SSOP-16_5.3x6.2mm_P0.65mm - 3D model: SSOP-16-208mil (KiCad packages3D, STEP)
- 3D model files:
sn74ls221dbr-etched.step/sn74ls221dbr-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);sn74ls221dbr.step/sn74ls221dbr.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Texas Instruments datasheet (31 pp, sha256
9d7f372b30430c70, retrieved 2026-10-08, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-sonnet-5-5(text+vision), consensusclaude-opus-5-5(agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish. - CAD: KiCad official libraries (CC-BY-SA 4.0).