74HC_HCT4538_15 Datasheet, PDF (5/24 Pages) NXP Semiconductors – Dual retriggerable precision monostable multivibrator

NXP Semiconductors
74HC4538; 74HCT4538
Dual retriggerable precision monostable multivibrator
6. Functional description
Table 3.
Inputs
nA
↓
Function table
nB
L
nCD
H
Outputs
nQ
nQ
H
↑
H
X
X
L
L
H
[1] H = HIGH voltage level; L = LOW voltage level; X = don’t care;
↑ = positive-going transition; ↓ = negative-going transition;
= one HIGH level output pulse, with the pule width determined by C_EXT and R_EXT;
= one LOW level output pulse, with the pulse width determined by C_EXT and R_EXT.
(1)
nB input
(3)
nA input
nCD input
nREXT/CEXT input
V_ref1
V_ref2
nQ output
T
T
(5)
(1) Positive edge triggering.
(2) Positive edge re-triggering (pulse lengthening).
(3) Negative edge triggering.
(4) Reset (pulse shortening).
(5) T = 0.7 × R_EXT × C_EXT (see also Figure 6).
Fig 5. Timing diagram
(1)
(2)
(1)
(4)
V_ref1
V_ref2
T
001aae737
74HC_HCT4538_3
Product data sheet
Rev. 03 — 8 June 2009
© NXP B.V. 2009. All rights reserved.
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