ACPM-7311-TR1 查看數據表（PDF） - Avago Technologies
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ACPM-7311-TR1 Datasheet PDF : 18 Pages
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CoolPAM
Avago Technologies’ CoolPAM is stage-bypass PA tech-
nology which saves more power compared with conven-
tional PA. With this technology, the ACPM-7311 has very
low quiescent current and efficiencies at low and medium
output power ranges are very high.
Mode control pins
Vmode0 and Vmode1 are digitally controlled pins and
they control operating mode of PA and truth table is sum-
marized in table 3. These pins do not require constant
voltage for interface, but high voltage input range is 1.9
though 2.9V
Incorporation of bias circuit
Application on mobile board
The ACPM-7311 has internal bias circuit, which removes
the need for external constant voltage source (LDO). PA
on/off is controlled by Ven. This is digitally control pin.
3-mode power control with two mode control pins
Figure 16 shows one application example on mobile
board. C4 and C5 should be placed nearby pin5 and
pin6. Transmission line length after PA output should be
minimized to reduce conduction loss.
The ACPM-7311 supports three power modes (low power
mode/mid power mode/high power mode) with two
mode control pins (Vmode0 and Vmode1). This control
scheme enables the ACPM-7311 to save more power,
which accordingly gives extended talk time.
PDF (probability density function) in Figure 15 showing
distribution of output power of mobile in real field gives
motivation for stage-bypass PA. Output power is less
than 16dBm for most of operating time (during talking),
so it is important to save power consumption at low and
medium output power ranges
BB
PA_ON
PA_R0
PA_R1
C2
C3
RF In
TX filter
C9
C4
C1
ACPM-7311
Ven
GND
Vmoce0 GND
Vmode1 OUT
IN
GND
Vc1
Vcc2
C5
output matching circuit
C8
RF Out
Coupler
C7
L1
C6
VBATT
Figure 16. Peripheral Circuits
Figure 15. PDF and Current
Average current & Talk time
Average current consumed by PA can be calculated by
summing up current at each output power weighted
with probability. So it is expressed with integration of
multiplication of current and probability at each output
power.
Average current = ∫ (PDF x Current)dp
Talk time is extended more as average current consump-
tion is lowered.
Load Insensitivity
With the trend to remove the isolator from the Tx chain
in UMTS handsets, the performance demands of Load
Insensitivity become dependent on the combined per-
formance of the remaining elements in the TX chain: the
power amplifier, coupler, antenna as well as the physical
layout on the phone board. The ACPM-7311, as part of
optimized design, meets the necessary linearity require-
ments over a 4:1 VSWR mismatch at the antenna plane.
In the case of the ACPM-7311, the output stage has been
designed for slightly higher Pout to provide the necessary
margin to meet linearity under the mismatch experienced
at the PA output port resulting from the forced antenna
mismatch. Documentation is available that provides a
more complete description of the system considerations
and measurement considerations.
To illustrate the system performance using the ACPM-
7311, Figure 17 shows measurement of TX chain with
VSWR fixed at 4:1. ACLR1 is kept higher than -38dBc over
all phases and gain variance is about 2dB.
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