XR21V1414
8
4-CH FULL-SPEED USB UART
REV. 1.3.0
NOTE: Pin type: I=Input, O=Output, I/O= Input/output, OD=Output Open Drain.
Miscellaneous Signals
LOWPOWER
2
O
Low power status output. The LOWPOWER pin will be asserted whenever
it is not safe to draw the amount of current from VBUS power requested in
the Device Max Power field of the Configuration Descriptor. The LOW-
POWER pin will behave differently for a low power device and a high power
device.
Low-power device (<= 1 unit load or 100 mA i.e. bMaxPower <= 0x32):
LOWPOWER pin is asserted when the USB UART is in
suspend mode.
High-power deivce (bMaxPower > 0x32): LOWPOWER pin is
asserted when the USB UART is in suspend mode or when it is not yet
configured.
The LOWPOWER pin will be de-asserted whenever it is safe to draw the
amount of current requested in the Device Maximum Power field.
This pin is sampled momentarily at power-up or at any USB bus reset to
configure the polarity of the LOWPOWER output during suspend mode. An
external (10K) pull-up resistor will cause the LOWPOWER pin to be
asserted HIGH during suspend mode. An external (3.3K) pull-down resistor
will cause the LOWPOWER pin to be asserted LOW during suspend mode.
Power / Ground Signals
VCC
5, 18, 33,
44, 45
Pwr
+3.3V power supply.
GND
1, 4, 19,
32, 40, 41
Pwr
Power supply common, ground.
Pin Description
NAME
48-QFN
PIN #
TYPE
DESCRIPTION