bc41b143a07 ETC-unknow, bc41b143a07 Datasheet - Page 66

• Manufacturer Part Number: bc41b143a07
• Description: Single Chip Bluetooth
• Manufacturer: ETC-unknow

9.5.4
In self-powered mode, the circuit is powered from its own power supply and not from the VBUS (5V) line of the USB
cable. It draws only a small leakage current (below 0.5mA) from VBUS on the USB cable. This is the easier mode for
which to design, as the design is not limited by the power that can be drawn from the USB hub or root port. However,
it requires that VBUS be connected to BlueCore4-ROM via a resistor network (R
can detect when VBUS is powered up. BlueCore4-ROM will not pull USB_DP high when VBUS is off.
Self-powered USB designs (powered from a battery or PSU) must ensure that a PIO line is allocated for USB pull-up
purposes. A 1.5kΩ 5% pull-up resistor between USB_DP and the selected PIO line should be fitted to the design.
Failure to fit this resistor may result in the design failing to be USB compliant in self-powered mode. The internal pull-up
in BlueCore is only suitable for bus-powered USB devices, e.g., dongles.
The terminal marked USB_ON can be any free PIO pin. The PIO pin selected must be registered by setting
PSKEY_USB_PIO_VBUS to the corresponding pin number.
Note:
9.5.5
In bus-powered mode, the application circuit draws its current from the 5V VBUS supply on the USB cable.
BlueCore4-ROM negotiates with the PC during the USB enumeration stage about how much current it is allowed to
consume.
For Class 2 Bluetooth applications, CSR recommends that the regulator used to derive 3.3V from VBUS is rated at
100mA average current and should be able to handle peaks of 120mA without foldback or limiting. In bus-powered
mode, BlueCore4-ROM requests 100mA during enumeration.
CS-101564-DSP12
Identifier
R
R
R
s
vb1
vb2
USB_ON is shared with BlueCore4-ROM PIO terminals.
Self-Powered Mode
Bus-Powered Mode
Figure 9.11: USB Connections for Self-Powered Mode
Value
27Ω nominal
22kΩ 5%
47kΩ 5%
Table 9.7: USB Interface Component Values
Production Information
© CSR plc 2003-2007
Function
Impedance matching to USB cable
VBUS ON sense divider
VBUS ON sense divider
vb1
and R
vb2
Device Terminal Descriptions
), so BlueCore4-ROM
Page 66 of 97