XR17D152IM-F Datasheet, PDF (7/68 Pages) Exar Corporation – UNIVERSAL (3.3V AND 5V) PCI BUS DUAL UART

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REV. 1.2.0
XR17D152
UNIVERSAL (3.3V AND 5V) PCI BUS DUAL UART
1.0 APPLICATION EXAMPLES
The XR17D152 is designed to operate with VCC (voltage to the UART Core Logic) greater than or equal to
VIO. For a universal add-in card, it is usually unknown whether it will be plugged into a 3.3V or 5V PCI slot,
therefore VCC must be 5V to guarantee proper functionality in any PCI slot as shown in Figure 3. In an
embedded system, the designer can choose to use a 3.3V or 5V power supply for the UART core voltage. Of
course, the core voltage can be 3.3V only when the VIO is 3.3V. In Figure 4, examples 1-3 show valid
applications of the XR17D152 in an embedded system.
FIGURE 3. TYPICAL APPLICATION FOR A UNIVERSAL ADD-IN CARD
VIO
(3.3V or 5V)
CLK
(up to 33.34MHz)
UART Core Logic
VCC = 5V
PCI
Local
Bus
Interface
UART Channel 0
UART Channel 1
Max Crystal Frequency = 24MHz
Max External Clock = 50MHz
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