MOTOROLA CONFIDENTIAL - PROPRIETARY
6881036B20
November 20, 2000
19
Level 3 Service Manual
Circuit Description
.
In TX background mode the Communicator requires the same current as in standby
mode, with 50mA supporting the unit and 350mA charging the battery. During TX
background, however, the EXT B+ FET
Q905
is switched off causing the charger
current to be directed through the charging FET
Q900
.
In TX background, MIDRATE_1 = 0 and MIDRATE_2 = 1
During transmission, the communicator requires up to 1.5A to be supplied during
each burst. During a TX pulse the full 400mA from the charger supports B+ in
addition to approximately 1.1A from the battery.
In TX burst, MIDRATE_1 = 1 and MIDRATE_2 = 1
Deep Sleep Mode
Deep sleep mode saves battery life by intermittently shutting off part of the PCB
as follows: STBY_DL is generated from Whitecap IC
Pin F1
, through a standby
delay circuit consisting of diode
CR912
and logic gate
U906
which provides a short
delay between activation of STBY_PC5 and STBY_DL. This is a hardware patch
for timing issues related to the Whitecap IC's deep sleep module (DSM). The
resulting signal is passed onto
Q911
and
Q912
which, in turn:
• Grounds VREF, making Magic IC inoperable.
• Grounds V2, switching off Magic IC, Front END IC and inhibits the Transmit
path through RF_V2.
Deep sleep mode shutdown is only for a fraction of a second and, during that time,
the GCAP Clock supports the logic side of the unit. The GCAP clock is generated
000723-O
Figure 11. Transmit Operation Battery Charging
TX Background
Current
I supply = I radio B
+
+ I chrg
400mA = 50mA + 350mA
I Tx burst = I I batt contrib
1.5A = 400mA + 1.1A
Tx burst
Summary of Contents for 38C V100
Page 1: ...Level 3 Service Manual Model V100 GSM Technology Product Family 38C Personal Communicator ...
Page 2: ......
Page 73: ...V100 BOARD LAYOUT PAGE 1 2 ...
Page 74: ...V100 BOARD LAYOUT PAGE 2 2 ...
Page 77: ...V100 CONNECTOR SCHEMATICS ...
Page 78: ...V100 DISPLAY SCHEMATICS ...
Page 79: ...V100 FM SCHEMATICS ...
Page 81: ......
Page 83: ......