HD74AC HITACHI [Hitachi Semiconductor], HD74AC Datasheet - Page 7

• Manufacturer Part Number: HD74AC
• Description: HD74AC Series Common Information
• Manufacturer: HITACHI [Hitachi Semiconductor]

FACT Descriptions and Family Characteristics
We can calculate what current is required by looking at the Bergeron diagram. The quiescent voltage on
the line will be within 100 mV of either rail. We know what voltage is required to guarantee a valid
voltage at the receiver. This is either 70% or 30% of V
voltage required is | (V
required I
I
impedances greater than 50 , the current requirements are less and switching is still guaranteed.
It is important to note that the typical 24 mA drive specification is not adequate to guarantee incident wave
switching. The only way to guarantee this is to guarantee the current required to switch a transmission line
from the output quiescent point to the valid V
The performance charts in figures 5 to 7 are provided in order to aid the designer in determining dynamic
output current drive of FACT devices with various power supply voltage.
6
OL
is 75 mA at 1.65 V. FACT’s I/O specifications include these limits. For transmission lines with
OH
at 3.85 V is 75 mA. For the high-to-low transition, V
OQ
Figure 5 Output Characteristics V
Figure 6 Output Characteristics V
–V
200 mA
I
)/Z
V
–1
–2
CC
7
6
5
4
3
2
1
0
O
| at V
= 5.5 V
V
0
CC
V
150
= 5.0 V
CC
I
V
. For V
V
CC
= 4.5 V
CC
= 5.5 V
–50
= 4.5 V
IN
Current (mA)
OQ
level.
100
Current (mA)
= 100 mV, V
V
CC
–100
= 5.0 V
CC
. The formula for calculating the current and
50
IH
OH
OL
/I
= 3.85 V, V
/I
–150
QQ
OH
OL
= 5.4 V, V
, HD74AC00
, HD74AC00
0
–200 mA
7
6
5
4
3
2
1
0
–1
–2
CC
= 5.5 V and Z
IL
= 1.65 V, and Z
O
= 50 , the
O
= 50 ,