Nxp Semiconductors OM11043 Data Sheet

LPC1769_68_67_66_65_64_63

All information provided in this document is subject to legal disclaimers.

© NXP Semiconductors N.V. 2014. All rights reserved.

Remark: The USB controller is available as a device/Host/OTG controller on parts 
LPC1769/68/66/65 and as device-only controller on part LPC1764.

If the LPC1769/68/67/66/65/64/63 V

DD

 is always greater than 0 V while V

BUS

 = 5 V, the 

V

BUS

 pin can be connected directly to the V

BUS

 pin on the USB connector.

This applies to bus powered devices where the USB cable supplies the system power. For 
systems where V

DD

 can be 0 V and V

BUS

 is directly applied to the V

BUS

 pin, precautions 

must be taken to reduce the voltage to below 3.6 V.

 

The maximum allowable voltage on the V

BUS

 pin is 3.6 V. One method is to use a voltage 

divider to connect the V

BUS

 pin to the V

BUS

 on the USB connector.

The voltage divider ratio should be such that the V

BUS

 pin will be greater than 0.7V

DD

 to 

indicate a logic HIGH while below the 3.6 V allowable maximum voltage.

Use the following operating conditions:

VBUS

max

 = 5.25 V

V

DD

 = 3.6 V

The voltage divider would need to provide a reduction of 3.6 V/5.25 V or ~0.686 V.

V

DD(3V3)

R1
1.5 k

Ω

R2

USB_UP_LED

USB-B
connector

USB_D+

USB_D

−

V

BUS

V

SS 

RS = 33 

Ω

RS = 33 

Ω