74HC244; 74HCT244
Philips Semiconductors
Octal buffer/line driver; 3-state
Table 10: Dynamic characteristics type 74HCT244 …continued
GND = 0 V; tr = tf = 6 ns; CL = 50 pF unless otherwise specified; for test circuit see Figure 8.
Symbol Parameter
Conditions
Min
Typ
Max
Unit
Tamb = −40 °C to +85 °C
tPHL
tPLH
,
propagation delay nAn to nYn VCC = 4.5 V; see Figure 6
-
-
-
-
-
-
-
-
28
38
31
15
ns
ns
ns
ns
tPZH
tPZL
,
,
3-state output enable time
nOE to nYn
VCC = 4.5 V; see Figure 7
VCC = 4.5 V; see Figure 7
VCC = 4.5 V; see Figure 6
tPHZ
tPLZ
3-state output disable time
nOE to nYn
tTHL
,
output transition time
tTLH
Tamb = −40 °C to +125 °C
tPHL propagation delay nAn to nYn VCC = 4.5 V; see Figure 6
tPLH
tPZH
tPZL
tPHZ
tPLZ
tTHL
tTLH
,
-
-
-
-
-
-
-
-
33
45
38
18
ns
ns
ns
ns
,
,
3-state output enable time
nOE to nYn
VCC = 4.5 V; see Figure 7
VCC = 4.5 V; see Figure 7
VCC = 4.5 V; see Figure 6
3-state output disable time
nOE to nYn
,
output transition time
[1] CPD is used to determine the dynamic power dissipation (PD in µW):
PD = CPD × VCC2 × fi × N + ∑(CL × VCC2 × fo) where:
fi = input frequency in MHz;
fo = output frequency in MHz;
CL = output load capacitance in pF;
VCC = supply voltage in V;
N = number of inputs switching;
∑(CL × VCC2 × fo) = sum of outputs.
12. Waveforms
V
I
V
V
M
nAn input
GND
M
t
t
PHL
PLH
V
OH
90 %
V
V
nYn output
M
M
10 %
V
OL
t
t
TLH
THL
001aae013
Measurement points are given in Table 11.
VOL and VOH are typical voltage output drop that occur with the output load.
Fig 6. Propagation delay input (1An, 2An) to output (1Yn, 2Yn) and transition time output
(nYn)
74HC_HCT244_3
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Product data sheet
Rev. 03 — 22 December 2005
12 of 22
NXP [ NXP ]
