XR19L222 Datasheet, PDF (5/53 Pages) Exar Corporation – TWO CHANNEL INTEGRATED UART AND RS-232 TRANSCEIVER

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Pin Descriptions
XR19L222
TWO CHANNEL INTEGRATED UART AND RS-232 TRANSCEIVER
NAME
64-QFN
PIN#
TYPE
DESCRIPTION
ANCILLARY SIGNALS (CMOS/TTL Voltage Levels)
XTAL1
18
I _{Crystal or external clock input. This input is not 5V tolerant.}
XTAL2
19
O _{Crystal or buffered clock output. This output may be use to drive a clock buffer which can}
drive other device(s).
PwrSave 14
I _{Power-Save (active high). This feature isolates the L222’s data bus interface from the host}
preventing other bus activities that cause higher power drain during sleep mode. See Sleep
Mode with Auto Wake-up and Power-Save Feature section for details.
ACP
25
I _{Autosleep for Charge Pump (active HIGH). When this pin is HIGH, the charge pump is shut}
off if the L222 is already in partial sleep mode, i.e. the crystal oscillator is stopped. See
”Section 2.18, Sleep Modes and Power-Save Feature with Wake-Up Inter-
rupt” on page 20.
I/M#
30
I _{Intel or Motorola Bus Select.}
When I/M# pin is HIGH, 16 or Intel Mode, the device will operate in the Intel bus type of
interface.
When I/M# pin is LOW, 68 or Motorola mode, the device will operate in the Motorola bus
type of interface.
RESET
47
(RESET#)
I _{When I/M# pin is HIGH for Intel bus interface, this input becomes RESET (active high).}
When I/M# pin is LOW for Motorola bus interface, this input becomes RESET# (active low).
A 40 ns minimum active pulse on this pin will reset the internal registers and all outputs of
the UART. The UART transmitter output will be held HIGH, the receiver input will be ignored
and outputs are reset during reset period (see Table 16).
C2+
46
- _{Charge pump capacitors. As shown in Figure 1, a 0.1 uF capacitor should be placed}
C2-
45
between these 2 pins.
C1+
52
- _{Charge pump capacitors. As shown in Figure 1, a 0.1 uF capacitor should be placed}
C1-
51
between these 2 pins.
VREF+
53
Pwr _{+5.0V generated by the charge pump.}
VREF-
27
Pwr _{-5.0V generated by the charge pump.}
R_EN
24
I _{When the supply voltage is < 3.6V, connect R_EN to GND.}
When the supply voltage is > 3.6V, connect R_EN to VCC.
C3A
55
I _{When the supply voltage is 3.3 V, C3A and C3B should be connected to VCC.}
C3B
56
When the supply voltage is 5 V, C3A should be connected to C3B with a 1 uF capacitor to
GND.
RXBSEL
8
I _{When RXBSEL is HIGH, RXB is the input to the receiver of the UART.}
When RXBSEL is LOW, RXDB is the input to the receiver of the UART.
FAST
21
I _{When FAST is HIGH, the maximum serial data rate is 1 Mbps.}
When FAST is LOW, the maximum serial data rate is 250 Kbps.
VCC
48, 54 Pwr _{3.3V to 5.5V power supply. All CMOS/TTL input pins, except XTAL1, are 5V tolerant.}
GND 2, 17, 22, Pwr _{Power supply common, ground.}
35
5