XR17D154 Exar Corporation, XR17D154 Datasheet - Page 7

• Manufacturer Part Number: XR17D154
• Description: Four-channel Pci-bus Uart
• Manufacturer: Exar Corporation

XR17D154
UNIVERSAL (3.3V AND 5V) PCI BUS QUAD UART
REV. P1.0.0
The XR17D154 will only function properly if VCC (voltage to the UART Core Logic) is 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
embedded system, the designer can choose to use a 5V power supply for the UART core voltage or 3.3V if the
VIO is also at 3.3V. In
system.
F
1.0 APPLICATION EXAMPLES
IGURE
3. T
YPICAL
(3.3V or 5V)
(up to 33MHz)
A
VIO
PPLICATION FOR A
CLK
Figure
4, examples 1-3 show valid applications of the XR17D154 in an embedded
Interface
U
Local
PCI
Bus
NIVERSAL
A
DD
M ax Crystal Frequency = 24M Hz
7
-
M ax External Clock = 50MHz
IN
UART Core Logic
C
UART Channel 0
UART Channel 1
UART Channel 2
UART Channel 3
ARD
VCC = 5V
PRELIMINARY
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Figure
3. In an