BC41B143A-DS-001PE Datasheet, PDF (87/102 Pages) List of Unclassifed Manufacturers – BlueCpre 4-ROM Single Chip Bluetooth v2.0 System with EDR

Device Terminal Descriptions
10.12 Power Supplies
BlueCore4-ROM contains a 1.8V regulator which may be used to power the 1.8V supplies of the device. The
device pin VREG_EN is used to enable and disable the regulator. Alternatively an external 1.8V voltage source
may be used.
10.12.1 Supply Domains and Sequencing
The 1.8V supplies are VDD_ANA, VDD_VCO, VDD_RADIO and VDD_CORE. It is recommended that the 1.8V
supplies are all powered at the same time. The order of powering the 1.8V supplies relative to the other IO
supplies (VDD_PIO, VDD_PADS, VDD_USB) is not important, however if the IO supplies are powered before the
1.8V supplies all digital IO will have a weak pull-down irrespective of the reset state.
10.12.2 External Voltage Source
If the 1.8V rails of BlueCore4-ROM are supplied from an external voltage source, it is recommended that
VDD_VCO, VDD_RADIO, and VDD_ANA, should have less than 10mV rms noise levels between 0 to 10MHz.
Single tone frequencies are also to be avoided.
The transient response of any regulator used should be 20μs or less. It is essential that the power rail recovers
quickly at the start of a packet, where the power consumption will jump to high levels (see average current
consumption section).
10.12.3 Linear Regulator
The on-chip 1.8V linear regulator may be used to power the 1.8V dependent supplies. It is advised that a
smoothing circuit using a series connected 2.2μF low ESR capacitor and a 2.2Ω resistor to ground is placed on
the output of the regulator VDD_ANA.
The regulator is switched into a low power mode when the device is sent into deep-sleep mode.
When this regulator is not used the terminal VREG_IN must be connected to VDD_ANA or left unconnected.
10.12.4 VREG_EN Pin
The regulator enable pin, VREG_EN, can be used to enable and disable the BlueCore4-ROM device if one of the
on-chip regulators is being used. The pin is active high, and has a weak pull-up to the active regulator input.
BC41B143A-ds-001Pe
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Production Information
© Cambridge Silicon Radio Limited 2005
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