Motorola 38C V100 Service Manual page 22

Circuit Description
18
LS3_TX_PA_B+ to Whitecap IC Pin F3 DAT0_TX.
• RX: Data from Whitecap IC Pin B5 DATA0_RX to GCAP II Pin H8
LS3_RX where the signal is level-shifted to desired voltage and output
on Pin J8 SIM I/O to SIM contacts J803 Pin 6 SIM I/O.
• SIM_PD. From BATT_THERM battery contact. With no batteries present, the
unit will not power-up. If batteries are present, but colder than -15° C and no
card is inserted, the output of the comparator Q905 stays high and the unit
displays INSERT CARD. When the battery temperature is above -15° C
(BATT_THERM voltage approximately 2.51V), but the SIM card is either not
inserted or faulty, CHECK CARD displays.
Charger Circuit
Either the mid-rate charger or the full rate charger may be used. (See also "Charger
Power Source" on page 14.)
In standby, Q905 is opened to provide the approximately 50mA required by the
PF38C Personal Communicator circuitry. Q900 also opens, controlled by CHRGC
(GCAP II Pin E8) to provide a charge of 350mA to the battery. The charger is
capable of supplying the 400mA of current required to support the Personal
Communicator in standby while, at the same time, charging its internal battery.
Charging current is monitored at GCAP II Pin D9 I_SENSE by monitoring the
voltage drop across current sense resistor R913.
In standby, MIDRATE_1 = 0 and MIDRATE_2 = 0
Figure 10. Standby Operation Battery Charging
MOTOROLA CONFIDENTIAL - PROPRIETARY
November 20, 2000
Product Family 38C
000722-O
6881036B20