74LVX4245QSCX Fairchild Semiconductor, 74LVX4245QSCX Datasheet - Page 6

• Manufacturer Part Number: 74LVX4245QSCX
• Description: IC TXRX DUAL 8BIT 3ST 24-QSOP
• Manufacturer: Fairchild Semiconductor
• Series: 74LVXr
• Type: Transceiverr

Specifications of 74LVX4245QSCX

• Number Of Drivers/receivers: 8/8
• Voltage - Supply: 2.7 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 24-QSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Protocol: -
• Other names: 153093; Q1153093

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Applications: Mixed Mode Dual Supply Interface Solution
LVX4245 is designed to solve 3V/5V interfacing issues
when CMOS devices cannot tolerate I/O levels above their
applied V
P-Channel transistor in 3V ICs will conduct causing current
flow from I/O bus to the 3V power supply. The resulting
high current flow can cause destruction of 3V ICs through
latchup effects. To prevent this problem, a current limiting
resistor is used typically under direct connection of 3V ICs
and 5V ICs, but it causes speed degradation.
In a better solution, the LVX4245 configures two different
output levels to handle the dual supply interface issues.
The “A” port is a dedicated 5V port to interface 5V ICs. The
“B” port is a dedicated port to interface 3V ICs. Figure 2
shows how LVX4245 fits into a system with 3V subsystem
and 5V subsystem.
This device is also configured as an 8-bit 245 transceiver,
giving the designer 3-STATE capabilities and the ability to
select either bidirectional or unidirectional modes. Since
the center 20 pins are also pin compatible to 74 series 245,
as shown in Figure 1, the designer could use this device in
CC
. If an I/O pin of 3V ICs is driven by 5V ICs, the
FIGURE 2. LVX4245 Fits into a System with 3V Subsystem and 5V Subsystem
6
either a 3V system or a 5V system without any further work
to re-layout the board.
FIGURE 1. LVX4245 Pin Arrangement is Compatible to
20-Pin 74 Series 245