55.32 USB Electrical Specifications

Table 55-45. USB Electrical Specifications
AC CHARACTERISTICSStandard Operating Conditions: VDD = AVDD = 1.71V to 3.63V (unless otherwise stated)

Operating temperature:

-40°C ≤ TA ≤ +85°C for Industrial Temperature

Param. No.SymbolCharacteristics(1)Min.Typ.Max.UnitsConditions
USB_1VDDUSBUSB Transceiver Voltage3—3.6VVoltage on VDD must be in this range for proper USB operation
VBUS Supply
USB_7VILUSBInput Low Voltage for USB Buffer——0.8V—
USB_9VIHUSBInput High Voltage for USB Buffer2——V—
USB_11VDIFSDifferential Input Sensitivity0.2——VThe difference between D+ and D- must exceed this value while VCM is met
USB_13VCMDifferential Common Mode Range0.8—2.5VVDDUSB = 3.0V-to-3.6V
USB_15ZOUTDriver Output Impedance28—44Ω—
USB_17VOLUSBVoltage Output Low——0.3V1.425 kΩ load connected to VUSB=3.6V
USB_19VOHUSBVoltage Output High2.8——V14.25 kΩ load connected to ground w/VUSB=3.0V
USB_23USBCLKSUSB Clock Source (1) GCLK_USB of 48 MHz ± 0.25%—48—MHzGCLK_USB = 48 MHz ± 0.25%
USB_25USBAHBMin. AHB Clock for USB Operations12——MHz—
Note:
  1. External Crystal or clock oscillator ppm ≤ 50 w/FDPLL only for GCLK_USB_ of 48 MHz ± 0.25%.
Table 55-46. USB Clock Configuration
USB Clock configurationStandard Operating Conditions: VDD = AVDD = 1.71V to 3.63V (unless otherwise stated)

Operating temperature:

-40°C ≤ TA ≤ +85°C for Industrial Temperature

Param. No.SymbolCharacteristicsDevice mode operation.Host mode operation.
USB_30USB_GCLK_SRCDFLL48M Open loopNoNo
DFLL48M Close loop, Ref. internal OSC sourceNoNo
DFLL48M Close loop, Ref. external XOSC sourceYesNo
DFLL48M Close loop, Ref. SOF (USB recovery mode)Yes (1)N/A
FDPLL internal OSC (32K, 8M…)NoNo
FDPLL external OSC (<1MHz)YesNo
FDPLL external OSC (>1MHz)Yes (2)Yes
Note:
  1. When using DFLL48M in USB recovery mode, the Fine Step value must be 0x0A to guarantee a USB clock at +/-0.25% before 11ms after a resume. Only usable in LDO regulator mode.
  2. FDPLL lock time is short when the clock frequency source is high (>1 MHz). Therefore, FDPLL and external OSC can be stopped during USB suspend mode to reduce consumption and guarantee a USB resume signal time (See USB specification).