Option A
ACPM-7891 Test Board
24
4
C5
Figure 3 shows the schematic for
the ACPM-7891 Test Board
which provides a straightfor-
ward method of testing and
evaluating the ACPM-7891.
External RF sources, power and
Vapc supplies are used.
23
26
2
C4
C7
C9
7
EGSM RFin
EGSM Vapc
EGSM RFout
C8
Vdd
Gnd
20
14
C2
Option B
Power Control Loop Design
21
18
16
C3
C14
C11
C13
The implementation of a trans-
mitter power control is one of the
most engineering-intensive and
time-consuming aspects of GSM
handset design. It dictates the
correct transmit power level and
burst shaping in a GSM network.
The use of an off-the-shelf power
control IC helps simplify the
engineering effort and shorten
the design cycle time.
11
DCS/PCS RFin
DCS/PCS Vapc
DCS/PCS RFout
1, 3, 5, 6, 8, 9, 10, 12, 13, 15, 17, 19, 22, 25
Figure 3. Schematic of ACPM-7891 Test Board.
Component
Label
Component
Value
The ACPM-7891 PA Control
Board includes the ACPM-7891
PA, Linear Technology
C2
.033 µF
12 pF
C3
LTC1758-2 power control IC,
EGSM/DCS/PCS directional cou-
plers, tri-band diplexer and a
20-pin interface socket designed
to work with an LTC1758 demo
board from Linear Technology.
C4
220 pF
.033 µF
220 pF
33 pF
C5
C7
C8
C9
.033 µF
33 pF
C11
C13
C14
.033 µF
27 pF
14
HP [ HEWLETT-PACKARD ]
