74HC221; 74HCT221
Dual non-retriggerable monostable multivibrator with reset
The 74HC/74HCT221 are high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A.
The 74HC/HCT221 are dual non-retriggerable monostable multivibrators. Each multivibrator features an active LOW-going edge input (nA) and an active HIGH-going edge input (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 and are a function of the timing components. The output pulses can be terminated by the overriding active LOW reset inputs (nR D ). Input pulses may be of any duration relative to the output pulse.
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.
The output pulse width is defined by the following relationship:
tW=CEXT REXT In2
tW= 0.7CEXT REXT
Pin assignments for the '221' are identical to those of the '123' so that the '221' can be substituted for those products in systems not using the retrigger by merely changing the value of REXT and/or CEXT.
Features and benefits
Pulse width variance is typically less than ± 5%
Pin-out identical to '123'
Overriding reset terminates output pulse
nB inputs have hysteresis for improved noise immunity
Output capability: standard (except for nREXT /CEXT)
ICC category: MSI
Applications
參數(shù)類型
| 型號 | 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 |
封裝
| 型號 | 可訂購的器件編號，（訂購碼(12NC)） | 狀態(tài) | 標(biāo)示 | 封裝 | 外形圖 | 回流焊/波峰焊 | 包裝 |
|---|---|---|---|---|---|---|---|
| 74HCT221D | 74HCT221D,118 (933715110118) |
Active | 74HCT221D |
SO16 (SOT109-1) |
SOT109-1 |
SO-SOJ-REFLOW
SO-SOJ-WAVE WAVE_BG-BD-1 |
SOT109-1_118 |
文檔 (10)
| 文件名稱 | 標(biāo)題 | 類型 | 日期 |
|---|---|---|---|
| AN11044 | Pin FMEA 74HC/74HCT family | Application note | 2019-01-09 |
| AN90063 | Questions about package outline drawings | Application note | 2025-10-22 |
| 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 |
| SO-SOJ-REFLOW | Footprint for reflow soldering | Reflow soldering | 2009-10-08 |
| HCT_USER_GUIDE | HC/T User Guide | User manual | 1997-10-31 |
| SO-SOJ-WAVE | Footprint for wave soldering | Wave soldering | 2009-10-08 |
| WAVE_BG-BD-1 | Wave soldering profile | Wave soldering | 2021-09-08 |
支持
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模型
| 文件名稱 | 標(biāo)題 | 類型 | 日期 |
|---|---|---|---|
| SOT109-1 | 3D model for products with SOT109-1 package | Design support | 2020-01-22 |
Ordering, pricing & availability
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