BC41B143A-DS-003PC Datasheet, PDF (83/94 Pages) List of Unclassifed Manufacturers – BlueCore 4-ROM Plug-n-Go Single Chip Bluetooth v2.0 + EDR System

Device Terminal Descriptions
10.12 Power Supply
10.12.1 Voltage Regulator (Plug-n-Go)
An on-chip linear voltage regulator can be used to power the 1.8V dependent supplies. It is advised that a smoothing
circuit using a 2.2µF low ESR capacitor and 2.2Ω resistor be placed on the output VDD_ANA.
In the Plug-n-Go package, an internal 2.2Ω resistor is provided between the regulator output VDD_ANA and
VDD_DIG.
The regulator is switched into a low power mode when the device is sent into Deep Sleep mode. When the on-chip
regulator is not required VDD_ANA is a 1.8V input and VREG_IN must be either open circuit or tied to VDD_ANA.
10.12.2 Sequencing
It is recommended that VDD_CORE, VDD_RADIO and VDD_ANA be powered at the same time. The order of
powering supplies for VDD_CORE, VDD_PIO, VDD_PADS and VDD_USB is not important. However, if VDD_CORE
is not present, all inputs have a weak pull-down irrespective of the reset state.
10.12.3 Sensitivity to Disturbances
CSR recommends if supplying BlueCore4-ROM Plug-n-Go from an external voltage source that VDD_ANA and
VDD_RADIO should have less than 10mV rms noise levels between 0 to 10MHz. In addition, avoid single tone
frequencies. CSR recommends a simple RC filter for VDD_CORE, as this reduces transients put back onto the power
supply rails.
The remaining supplies VDD_MEM, VDD_PIO, VDD_PADS and VDD_USB can be connected together with the
VREG_IN to the 3.3V supply and simply decoupled as shown in Figure 13.1.
The transient response of the regulator is also important. At the start of a packet, power consumption will jump to high
levels. See the average current consumption section. The regulator should have a response time of 20µs or less; it is
essential that the power rail recovers quickly.
10.12.4 VREG_EN Pin
The regulator enable pin, VREG_EN, can be used to enable and disable the BlueCore4-ROM Plug-n-Go device if the
on-chip regulator is being used. The pin is active high and has an internal weak pull-up to enable the regulator if
VREG_EN is not connected.
BC41B143A-ds-003Pc
Advance Information
© Cambridge Silicon Radio Limited 2005
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