BC41B143A-ANN-E4 ETC, BC41B143A-ANN-E4 Datasheet - Page 64

• Manufacturer Part Number: BC41B143A-ANN-E4
• Description: Bluecore 4-rom CSP EDR Single Chip Bluetooth v2.0 + EDR System
• Manufacturer: ETC

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 PIO number.
11.5.5 Bus-powered Mode
In bus-powered mode the application circuit draws its current from the 5V VBUS supply on the USB cable.
BlueCore4-ROM CSP 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 CSP requests 100mA during enumeration.
When selecting a regulator, be aware that VBUS may go as low as 4.4V. The inrush current (when charging
reservoir and supply decoupling capacitors) is limited by the USB specification (see USB specification v1.1,
Section 7.2.4.1). Some applications may require soft start circuitry to limit inrush current if more than 10μF is
present between VBUS and GND.
The 5V VBUS line emerging from a PC is often electrically noisy. As well as regulation down to 3.3V and 1.8V,
applications should include careful filtering of the 5V line to attenuate noise that is above the voltage regulator
bandwidth. Excessive noise on the 1.8V supply to the analogue supply pins of BlueCore4-ROM CSP will result in
reduced receive sensitivity and a distorted RF transmit signal.
Note:
BC41B143A-ds-002Pd
USB_ON is shared with BlueCore4-ROM CSP PIO terminals.
Figure 11.12: USB Connections for Self Powered Mode
Figure 11.13: USB Connections for Bus-Powered Mode
This material is subject to CSR’s non-disclosure agreement
BlueCore4-ROM CSP
BlueCore4-ROM CSP
© Cambridge Silicon Radio Limited 2005
USB_ON
USB_DP
USB_DN
PIO
USB_ON
USB_DP
USB_DN
Production Information
1.5kΩ 5%
R
R
R
R
vb1
s
s
vb2
Regulator
22 to 27Ω
22 to 27Ω
Voltage
22kΩ 5%
47kΩ 5%
R
R
s
s
22 to 27Ω
22 to 27Ω
USB cable
D+
D-
VBUS
GND
D+
D-
VBUS
GND
Device Terminal Descriptions
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