74HCT221
Dual non-retriggerable monostable multivibrator with reset
The 74HCT221 is a dual non-retriggerable monostable multivibrator. Each multivibrator features edge-triggered inputs (nA and nB), either of which can be used as an enable input. Pulse triggering occurs at a particular voltage level and is not directly related to the transition time of the input pulse. Schmitt-trigger input circuitry for the nB inputs allow jitter-free triggering from inputs with slow transition rates, providing the circuit with excellent noise immunity. Once triggered, the outputs (nQ, nQ) are independent of further transitions of nA and nB inputs. The output pulse width is defined by the following relationship:
- tW = 0.7 × CEXTREXT
The output pulses can be terminated by the active LOW reset inputs (nRD). Pulse width stability is achieved through internal compensation and is virtually independent of VCC and temperature. In most applications pulse stability will only be limited by the accuracy of the external timing components . This device features reduced input threshold levels to allow interfacing to TTL logic levels. Inputs also include clamp diodes, this enables the use of current limiting resistors to interface inputs to voltages in excess of VCC.
Features and benefits
Supply voltage range from 4.5 V to 5.5 V
CMOS low power dissipation
High noise immunity
Input levels:
For 74HCT221: TTL level
Pulse width variance is typically less than ±5%
Direct reset terminates output pulse
Schmitt-trigger action on nB inputs
Latch-up performance exceeds 100 mA per JESD 78 Class II Level B
- ESD protection:
HBM: ANSI/ESDA/JEDEC JS-001 class 2 exceeds 2000 V
CDM: ANSI/ESDA/JEDEC JS-002 class C3 exceeds 1000 V
Specified from -40 °C to +85 °C and from -40 °C to +125 °C
Parametrics
| Type number | VCC (V) | Logic switching levels | Output drive capability (mA) | tpd (ns) | Power dissipation considerations | Tamb (°C) | Rth(j-a) (K/W) | Ψth(j-top) (K/W) | Rth(j-c) (K/W) | Package name |
|---|---|---|---|---|---|---|---|---|---|---|
| 74HCT221D | 4.5 - 5.5 | TTL | ± 4 | 32 | low | -40~125 | 62 | 1 | 19 | SO16 |
Package
| Type number | Orderable part number, (Ordering code (12NC)) | Status | Marking | Package | Package information | Reflow-/Wave soldering | Packing |
|---|---|---|---|---|---|---|---|
| 74HCT221D | 74HCT221D,118 (933715110118) |
Active | 74HCT221D |
SO16 (SOT109-1) |
SOT109-1 |
SO-SOJ-REFLOW
SO-SOJ-WAVE WAVE_BG-BD-1 |
SOT109-1_118 |
Environmental information
| Type number | Orderable part number | Chemical content | RoHS | RHF-indicator |
|---|---|---|---|---|
| 74HCT221D | 74HCT221D,118 | 74HCT221D |
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Documentation (10)
| File name | Title | Type | Date |
|---|---|---|---|
| 74HCT221 | Dual non-retriggerable monostable multivibrator with reset | Data sheet | 2024-04-04 |
| AN90063 | Questions about package outline drawings | Application note | 2025-06-13 |
| SOT109-1 | 3D model for products with SOT109-1 package | Design support | 2020-01-22 |
| Nexperia_package_poster | Nexperia package poster | Leaflet | 2020-05-15 |
| SO16_SOT109-1_mk | plastic, small outline package; 16 leads; 1.27 mm pitch; 9.9 mm x 3.9 mm x 1.35 mm body | Marcom graphics | 2017-01-28 |
| SOT109-1 | plastic, small outline package; 16 leads; 1.27 mm pitch; 9.9 mm x 3.9 mm x 1.75 mm body | Package information | 2023-11-07 |
| 74HCT221D_Nexperia_Product_Reliability | 74HCT221D Nexperia Product Reliability | Quality document | 2025-03-20 |
| SO-SOJ-REFLOW | Footprint for reflow soldering | Reflow soldering | 2009-10-08 |
| SO-SOJ-WAVE | Footprint for wave soldering | Wave soldering | 2009-10-08 |
| WAVE_BG-BD-1 | Wave soldering profile | Wave soldering | 2021-09-08 |
Support
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Models
| File name | Title | Type | Date |
|---|---|---|---|
| SOT109-1 | 3D model for products with SOT109-1 package | Design support | 2020-01-22 |
Ordering, pricing & availability
Sample
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