BC41B143A-ANN-E4 ETC, BC41B143A-ANN-E4 Datasheet - Page 50

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

11.1.1 Transmit RF Power Control for Class 1 Applications
An 8-bit voltage DAC (AUX_DAC) can be used to control the amplification level of an external PA for Class 1
operation. The DAC output is derived from the on-chip band gap voltage reference and is virtually independent of
temperature and supply voltage. The output voltage is given by either:
for a load current ≤10mA (sourced from the device) or:
for no load current.
BlueCore4-ROM CSP enables the external PA only when transmitting. Before transmitting, the IC normally ramps
up the power to the internal PA, then it ramps it down again afterwards. However, if a suitable external PA is
used, it may be possible to ramp the power externally by driving the gain pin on the PA from AUX_DAC.
The PS Key PSKEY_TX_GAINRAMP controls the delay (in units of μs) between the end of the transmit power
ramp and the start of modulation. In this period the carrier is transmitted, which gives the transmit circuitry time to
fully settle to the correct frequency.
Bits [15:8] define a delay, t
modulation. In this period an unmodulated carrier is transmitted, which aids interoperability with some other
vendor equipment which is not strictly Bluetooth compliant.
BC41B143A-ds-002Pd
Modulation
TX Power
V
AUX
Equation 11.1: Output Voltage with Load Current ≤ 10mA
carrier
Equation 11.2: Output Voltage with No Load Current
_
DAC
This material is subject to CSR’s non-disclosure agreement
, (in units of μs), between the end of the transmit power ramp and the start of
V
AUX
=
MIN
Figure 11.2: Internal Power Ramping
_
t
carrier
DAC
© Cambridge Silicon Radio Limited 2005
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3
=
3 .
MIN
V
Production Information
×
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CNTRL
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3
3 .
V
×
255
CNTRL
_
WORD
255
_
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WORD
,
(
VDD
_
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,
PIO
VDD
−
_
0
3 .
PIO
Device Terminal Descriptions
V
)
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