xr16l2550im Exar Corporation, xr16l2550im Datasheet - Page 5

• Manufacturer Part Number: xr16l2550im
• Description: Industry Smallest Package Uart With 2.25v To 5.5v Operation
• Manufacturer: Exar Corporation

Pin Description
REV. 1.1.2
Pin type: I=Input, O=Output, IO= Input/output, OD=Output Open Drain.
ANCILLARY SIGNALS
DTRB#
DSRB#
RESET
RTSB#
CTSB#
OP2B#
XTAL1
XTAL2
CDB#
N
RIB#
GND
GND
VCC
N.C.
AME
32-QFN
Center
P
9, 17
Pad
15
16
10
11
24
26
13
IN
-
-
-
-
-
#
44-PLCC
P
N/A
27
28
38
25
21
26
15
18
19
39
44
22
IN
-
#
48-TQFP
12, 24,
25, 37
P
N/A
22
23
35
20
16
21
13
14
36
42
17
IN
9
#
T
Pwr
Pwr
Pwr
YPE
O
O
O
O
I
I
I
I
I
I
UART channel B Request-to-Send (active low) or general pur-
pose output. This output must be asserted prior to using auto
RTS flow control, see EFR[6], MCR[1] and IER[6]. If it is not
used, leave it unconnected.
UART channel B Clear-to-Send (active low) or general purpose
input. It can be used for auto CTS flow control, see EFR[7] and
IER[7]. This input should be connected to VCC when not used.
UART channel B Data-Terminal-Ready (active low) or general
purpose output. If it is not used, leave it unconnected.
UART channel B Data-Set-Ready (active low) or general purpose
input. This input should be connected to VCC when not used.
This input has no effect on the UART.
UART channel B Carrier-Detect (active low) or general purpose
input. This input should be connected to VCC when not used.
This input has no effect on the UART.
UART channel B Ring-Indicator (active low) or general purpose
input. This input should be connected to VCC when not used.
This input has no effect on the UART.
Output Port 2 Channel B - The output state is defined by the user
and through the software setting of MCR[3]. INTB is set to the
active mode and OP2B# output to a logic 0 when MCR[3] is set to
a logic 1. INTB is set to the three state mode and OP2B# to a
logic 1 when MCR[3] is set to a logic 0. This output should not be
used as a general output else it will disturb the INTB output func-
tionality. If it is not used, leave it unconnected.
Crystal or external clock input.
Crystal or buffered clock output.
Reset (active high) - A longer than 40 ns logic 1 pulse on this pin
will reset the internal registers and all outputs. The UART trans-
mitter output will be held at logic 1, the receiver input will be
ignored and outputs are reset during reset period.
2.25V to 5.5V power supply. All inputs are 5V tolerant.
Power supply common, ground.
The center pad on the backside of the 32-QFN package is metal-
lic and should be connected to GND on the PCB. The thermal
pad size on the PCB should be the approximate size of this cen-
ter pad and should be solder mask defined. The solder mask
opening should be at least 0.0025" inwards from the edge of the
PCB thermal pad.
No Connection. These pins are open, but typically, should be con-
nected to GND for good design practice.
5
LOW VOLTAGE DUART WITH 16-BYTE FIFO
D
ESCRIPTION
XR16L2550