74lvc1t45gw NXP Semiconductors, 74lvc1t45gw Datasheet - Page 23

• Manufacturer Part Number: 74lvc1t45gw
• Description: Dual Supply Translating Transceiver; 3-state
• Manufacturer: NXP Semiconductors

NXP Semiconductors
74LVC_LVCH1T45_1
Product data sheet
14.2 Bidirectional logic level-shifting application
Figure 16
level-shifting application. Since the device does not have an output enable pin, the system
designer should take precautions to avoid bus contention between system-1 and
system-2 when changing directions.
Table 17
and then from system-2 to system-1.
Table 17.
[1]
State DIR CTRL I/O-1
1
2
3
4
Fig 16. Bidirectional logic level-shifting application
H = HIGH voltage level;
L = LOW voltage level;
Z = high-impedance OFF-state.
DIR CTRL
V
I/O-1
H
H
L
L
CC1
gives a sequence that will illustrate data transmission from system-1 to system-2
Pull-up or pull-down only needed for 74LVC1T45.
shows the 74LVC1T45; 74LVCH1T45 being used in a bidirectional logic
Description bidirectional logic level-shifting application
system-1
PULL-UP/DOWN
output
Z
Z
input
V
Rev. 01 — 11 May 2009
CC1
I/O-2
input
Z
Z
output
V
CC(A)
GND
A
74LVC1T45; 74LVCH1T45
1
2
3
Description
system-1 data to system-2
system-2 is getting ready to send data to system-1.
I/O-1 and I/O-2 are disabled. The bus-line state
depends on bus hold.
DIR bit is set LOW. I/O-1 and I/O-2 still are disabled.
The bus-line state depends on bus hold.
system-2 data to system-1
74LVCH1T45
74LVC1T45
Dual supply translating transceiver; 3-state
6
5
4
V
DIR
B
CC(B)
V
PULL-UP/DOWN
CC2
[1]
system-2
© NXP B.V. 2009. All rights reserved.
V
I/O-2
CC2
001aaj995
23 of 30