USB2422
DS00001726B-page 10 2013 - 2015 Microchip Technology Inc.
2.4 Buffer Type Descriptions
2.5 Strap Pin Configuration
If a pin's strap function is enabled through hub configuration selection (Table 4-1), the strap pins must be pulled either
high or low using the values provided in Table 2-4. Each strap option is dependent on the pin’s buffer type, as outlined
in the sections that follow.
POWER, GROUND, and NO CONNECTS
1
9
18
VDD33 3.3 V power to the chip.
A 1.0 μF low-ESR capacitor to VSS is required on pin 9 as close as
possible to the pin. A 0.1 μF low-ESR capacitor to VSS is required on
pin 1 as close as possible to the pin.
10 CRFILT VDD Core Regulator Filter Capacitor:
This pin requires a 1.0 μF low-ESR capacitor to VSS for proper
operation.
23 PLLFILT PLL Regulator Filter Capacitor:
This pin can have up to a 0.1 μF low-ESR capacitor to VSS, or be left
unconnected.
VSS Ground Pad/ePad:
The package slug is the only VSS for the device and must be tied to
ground with multiple vias.
TABLE 2-3: BUFFER TYPE DESCRIPTIONS
Buffer Description
I/O Input/Output
IPD Input with internal weak pull-down resistor
IPU Input with internal weak pull-up resistor
IS Input with Schmitt trigger
I/O12 Input/Output buffer with 12 mA sink and 12 mA source
ICLKx XTAL clock input
OCLKx XTAL clock output
I-R RBIAS
I/O-U Analog Input/Output defined in USB specification
TABLE 2-4: STRAP OPTION SUMMARY
Strap Option Resistor Value Buffer Type Notes
Non-Removable 47 - 100 kΩ I/O
Internal Pull-Down (IPD)
10 kΩ IPD
• Only applicable to port power pins
• Contains a built-in resistor
LED 47 - 100 kΩ I/O
TABLE 2-2: USB2422 PIN DESCRIPTIONS (CONTINUED)
Pin # Symbol Buffer Type Description
