Applications: Mixed Mode Dual Supply Interface Solution

LVX3245 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 LVX3245 configures two different

output levels to handle the dual supply interface issues. The

“A” port is a dedicated 3V port to interface 3V ICs. The “B”

port is a dedicated port to interface 5V ICs.

Figure 1 shows

how LVX3245 fits into a system with 3V subsystem and 5V

subsystem.

DS101018-5

FIGURE 1. LVX3245 Fits into a System with 3V Subsystem and 5V Subsystem

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