USB

The USB of JH-7110 has the following analog power characteristics.
  • VDDA connects to sys_top
  • VCCA18/VCCA33 generates output from pad, and supports board level switch control
Table 1. USB ASIC Transceiver Analog IO PAD Signals
Name Dir Description
VCCA33 P 3.3V power supply(only Full speed driver)
VCCA18 P 1.8V power supply
VDDA P 0.9V power supply
AGND G Ground IO for both 3.3V,1.8V and 0.9V

Power Up Sequence

There are three powers and they are VCCA33(3.3V)、VCCA18(1.8V) and VDDA(0.9V), IP supports power up sequence in any combination because it has power-off protection design between the three powers. But there is a over voltage case that 1.8V MOSFET works under 3.3V power, the IP has breakdown voltage design to protect the 1.8V MOSFET, but anyway we suggest to power up VCCA33(3.3V) finally for protecting the 1.8V MOSFET during the power-on period.
Figure 1. USB Power Up Sequence 1
Figure 2. USB Power Up Sequence 2
Table 2. USB Power Up Parameter
Name Description Min Typ Max Unit
tup the time of power-up 200 us
td the delay of two power-up >0 us

Power Down Sequence

There are three powers and they are VCCA33(3.3V)、VCCA18(1.8V) and VDDA(0.9V), IP supports power up sequence in any combination because it has power-off protection design between the three powers. But there is a over voltage case that 1.8V MOSFET works under 3.3V power, the IP has breakdown voltage design to protect the 1.8V MOSFET, but anyway we suggest to power down VCCA33(3.3V) first for protecting the 1.8V MOSFET during the power-on period.
Figure 3. USB Power Down Sequence 1
Figure 4. USB Power Down Sequence 2