SMSC USB2502 - Manual (Page 14)

2-Port USB 2.0 Hub Controller
Datasheet
Revision 2.3 (08-27-07) 14 SMSC USB2502
DATASHEET
Analog Test
&
Internal 1.8V
voltage
regulator
enable
ATEST/
REG_EN
AIO This signal is used for testing the analog section of the
chip, and to enable or disable the internal 1.8v regulator.
This pin must be connected to VDDA33 to enable the
internal 1.8V regulator, or to VSS to disable the internal
regulator.
When the internal regulator is enabled, the 1.8V power
pins must be left unconnected, except for the required
bypass capacitors.When the PHY is in test mode, the
internal regulator is disabled and the ATEST pin
functions as a test pin.
Table 4.4 Power, Ground, and No Connect
NAME SYMBOL TYPE FUNCTION
VDDCORE3P3 VDD33CR +3.3V I/O Power.
If the internal core 1.8V regulator is enabled, then this pin
acts as the regulator input
VDD1P8 VDD18 +1.8V core power.
If the internal regulator is enabled, then VDD18 pin 27
must have a 4.7
μ
F (or greater) ±20% (ESR <0.1
Ω)
capacitor to VSS
VDDAPLL3P3 VDDA33PLL +3.3V Filtered analog power for the internal PLL
If the internal PLL 1.8V regulator is enabled, then this pin
acts as the regulator input
VDDAPLL1P8 VDDA18PLL +1.8V Filtered analog power for internal PLL.
If the internal regulator is enabled, then this pin must
have a 4.7
μ
F (or greater) ±20% (ESR <0.1
Ω)
capacitor
to VSS
VDDA3P3 VDDA33 +3.3V Filtered analog power.
VSS VSS Ground.
Table 4.5 Buffer Type Descriptions
BUFFER DESCRIPTION
I Input.
IPD Input, with a weak Internal pull-down.
IPU Input, with a weak Internal pull-up.
IS Input with Schmitt trigger.
I/O8 Input/Output 8mA
O8 Output 8mA
Table 4.3 Miscellaneous Pins (continued)
NAME SYMBOL TYPE FUNCTION