XR22404
5/14
REV1A
Pin Functions
QFN-24
Pin Number
SSOP-28
Pin Number
Pin Name Type Description
Center Pad 1 GND PWR Digital ground (in QFN package Center Pad must be connected to digital ground).
3 2 XTALOUT O 12 MHz crystal feedback output.
4 3 XTALIN I 12 MHz ± 50 ppm crystal input with load capacitance rating of 16-20 pF.
5 4 DM4 I/O Downstream port 4 USB D- data.
6 5 DP4 I/O Downstream port 4 USB D+ data.
7 6 DM3 I/O Downstream port 3 USB D- data.
8 7 DP3 I/O Downstream port 3 USB D+ data.
9 8 DM2 I/O Downstream port 2 USB D- data.
10 9 DP2 I/O Downstream port 2 USB D+ data.
11 10 DM1 I/O Downstream port 1 USB D- data.
12 11 DP1 I/O Downstream port 1 USB D+ data.
- 12 TEST2 - Leave unconnected for normal operation.
- 13 TEST3 - Leave unconnected for normal operation.
13 14 REXT I External bias resistor. Connect 2.7kΩ 1% resistor from this pin to GND.
14 15 UP_DM I/O Upstream port USB D- data.
15 16 UP_DP I/O Upstream port USB D+ data.
16 17 EXT_RST# I External reset input, active low. Must be asserted for a minimum of 10 µS.
17 18 VBUS_SENSE I
Active high. Indicates connection to USB host. Connect to VBUS power input from
USB host through series 10kΩ registor. A 100kΩ pull-down registor and 100nF shunt
capacitance are required on this pin.
18 19 BUS_PWR# I
Bus power indicator, active low. For bus powered mode, connect to ground. For self-
powered mode, connect to logic ‘1’.
19 20 VCC5 PWR 5V power to internal 5V to 3.3V regulator, unused when device is powered by 3.3V.
20 21 VCC33 PWR
3.3V power input, when device is powered by 3.3V. If device is powered by 5V to VCC5
pin, decouple this pin with 4.7 µF.
21 22
LED_CTL/
CHRGEN
I/O
LED hub active indicator or downstream port charge enable, active high. May also be
used in conjunction with port status LEDs. If sampled high during power up reset,
all downstream ports may be used as charging ports. Refer to Table 1.
22 23 LED1/SCL I/O
Port 1 LED indicator or I
2
C clock for external EEPROM. Max source current 3 mA. May be
used in conjunction with LED_CTL/CHRGEN pin.
23 24 LED2 I/O
Port 2 LED indicator. Max source current 3 mA. May be used in conjunction with DRV pin.
Refer to Figure 3.
24 25 PWR# O
Power enable for all downstream devices. Asserted when XR22404 device is configured
and OVC# is not asserted. Deasserted (high) if OVC# input is asserted or XR22404 is
not configured.
1 26 OVC# I Downstream port global overcurrent indicator, active low.
2 27 TEST#/SDA I
Test mode enable, active low or I
2
C serial data for external EEPROM. Tie to logic ‘1’ for
normal device operation or connect to serial data of I
2
C EEPROM.
- 28 TEST4 - Leave unconnected for normal operation.
NOTE:
Type: I = Input, O = Output, I/O = Input/Output, PWR = Power, OD = Open-Drain.
