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.
Name/Description | Modified Date |
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Dual non-retriggerable monostable multivibrator with reset (REV 3.0) PDF (199.0 kB) 74HCT221 [English] | 26 Oct 2016 |
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Live Insertion Aspects of Philips Logic Families (REV 1.0) PDF (73.0 kB) AN252 [English] | 13 Mar 2013 |
Pin FMEA 74HC/74HCT family (REV 1.0) PDF (51.0 kB) AN11044 [English] | 16 Mar 2011 |
Name/Description | Modified Date |
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HC/T User Guide (REV 1.0) PDF (508.0 kB) HCT_USER_GUIDE [English] | 01 Nov 1997 |
Name/Description | Modified Date |
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plastic small outline package; 16 leads; body width 3.9 mm (REV 1.0) PDF (192.0 kB) SOT109-1 [English] | 08 Feb 2016 |
Name/Description | Modified Date |
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SO16; Reel pack; SMD, 13" Q1/T1 Standard product orientation Orderable part number ending ,118 or J Ordering... (REV 4.0) PDF (210.0 kB) SOT109-1_118 [English] | 24 Apr 2013 |
Name/Description | Modified Date |
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Footprint for reflow soldering (REV 1.0) PDF (9.0 kB) SO-SOJ-REFLOW [English] | 08 Oct 2009 |
Footprint for wave soldering (REV 1.0) PDF (8.0 kB) SO-SOJ-WAVE [English] | 08 Oct 2009 |
Product | Status | Family | Function | VCC (V) | Logic switching levels | Description | Output drive capability (mA) | Package version | tpd (ns) | Power dissipation considerations | Tamb (Cel) | Rth(j-a) (K/W) | Ψth(j-top) (K/W) | Rth(j-c) (K/W) | Package name | No of pins |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
74HCT221D | Active | HC(T) | Multivibrators | 4.5 - 5.5 | TTL | TTL enabled | +/- 4 | SOT109-1 | 32 | low | -40~125 | 62 | 1.0 | 19 | SO16 | 16 |
Product ID | Package Description | Outline Version | Reflow/Wave Soldering | Packing | Product Status | Part NumberOrdering code(12NC) | Marking | Chemical Content | RoHS / Pb Free / RHF | LeadFree Conversion Date | EFR | IFR(FIT) | MTBF(hour) | MSL | MSL LF |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
74HCT221D | SOT109-1 | SO-SOJ-REFLOW
SO-SOJ-WAVE SO-SOJ-REFLOW SO-SOJ-WAVE | Reel 13" Q1/T1 | Active | 74HCT221D,118 (9337 151 10118) | 74HCT221D | 74HCT221D | week 4, 2004 | 84.9 | 6.62 | 1.51E8 | 1 | 1 | ||
Bulk Pack | Active | 74HCT221D,112 (9337 151 10112) | 74HCT221D | 74HCT221D | week 4, 2004 | 84.9 | 6.62 | 1.51E8 | 1 | 1 |