component
SN74121D
Public Made by Adomby adom
Texas Instruments Monostable Multivibrators, SOIC-14. Datasheet-verified pinout, KiCad symbol/footprint/3D.
3D Model
Open in new tab ↗
Loads on click. Unloads only if this page sits in the background.
Symbol & Footprint
Schematic Symbol
Open full view ↗Loads on click. Unloads only if this page sits in the background.
PCB Footprint
Open full view ↗Loads on click. Unloads only if this page sits in the background.
Datasheet
Open in new tab ↗Loads on click. Unloads only if this page sits in the background.
README
markdownSN74121D
Texas Instruments · Monostable Multivibrators · SOIC-14
SN74121D from Texas Instruments, in a SOIC-14. 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 | ~Q | output | Complementary monostable output; goes high during quiescent state and low during output pulse. |
| 2 | NC | unconnected | No internal connection. |
| 3 | A1 | input | Negative-transition-triggered logic input A1; Req = 4 kΩ NOM; V_IH ≥ 2 V, V_IL ≤ 0.8 V. |
| 4 | A2 | input | Negative-transition-triggered logic input A2; Req = 4 kΩ NOM; V_IH ≥ 2 V, V_IL ≤ 0.8 V. |
| 5 | B | input | Schmitt-trigger positive-transition-triggered input (also used as inhibit); Req = 2 kΩ NOM, V_T+ typ 1.55 V, V_T- min 0.8 V, hysteresis typ 0.2 V. |
| 6 | Q | output | Non-inverting monostable output; goes low during quiescent state and high during output pulse; I_OH max -0.4 mA, I_OL max 16 mA. |
| 7 | GND | power_in | Ground reference for all voltage values in the device. |
| 8 | NC | unconnected | No internal connection. |
| 9 | RINT | passive | Internal timing resistor pin; connect to V_CC to use internal 2 kΩ NOM resistor; leave open or connect external resistor between this pin and R_ext/C_ext for external timing. |
| 10 | CEXT | passive | External timing capacitor connection (positive terminal); capacitor is connected between C_ext and R_ext/C_ext; C_ext range 0 to 1000 µF. |
| 11 | REXT_CEXT | passive | External timing resistor/capacitor node; connect external resistor R_T (2 kΩ to 40 kΩ for SN74121) between this pin and V_CC; also serves as negative terminal of C_ext. |
| 12 | NC | unconnected | No internal connection. |
| 13 | NC | unconnected | No internal connection. |
| 14 | VCC | power_in | Positive supply voltage; recommended operating range 4.75 V to 5.25 V (74 Family), absolute maximum 7 V. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOIC-14 |
| Category | Logic |
| Pins | 14 |
CAD (KiCad official)
- Symbol:
SN74121D - Footprint:
Package_SO:SOIC-14_3.9x8.7mm_P1.27mm - 3D model: SOIC-14 (KiCad packages3D, STEP)
- 3D model files:
sn74121d-etched.step/sn74121d-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);sn74121d.step/sn74121d.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Texas Instruments datasheet (26 pp, sha256
e2cda1e93d18a969, retrieved 2026-09-22, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.2, primaryclaude-sonnet-4-6(vision), consensusclaude-opus-4-7(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).