Post Go back to editing

ADuM3160: any problem with VBUS2 being 3.3 V?

Category: Datasheet/Specs
Product Number: ADuM3160

The ADuM3160 datasheet is somewhat ambiguous about whether or not VBUS2 can be supplied from 3.3 V.  The specifications in Table 1 refer to both VBUS1 and VBUS2 having a range of 4.5 to 5.5 V, but Figure 5 shows VBUS2 tied to VDD2, which is then tied to 3.3 V.  Can VBUS2 be 3.3 V comfortably?



  • Hi Scott, 

    The VBUS pins are essentially LDO inputs. They will take the 5V power typically available with the USB bus and regulate it down to the required 3.3V for the isolator's internal circuitry. In this case, you make no external connection to the VDD pin besides the required bypass cap. 

    If the application circuit will supply 3.3V, then that 3.3V supply will be connected to both the VBUS and VDD pins. In this configuration the LDO goes unused and 3.3V power will be supplied directly to the VDD pin.