Motorola MTP700 Detailed Service Manual page 146

4.2 - 24
VREF2 Linear Regulator
VREF2 is a programmable linear regulator. It is programmed using RedCap2 SPIB bus
from 0.95V to 2.775V. For this radio, it is programmed to 2.775V which supplies the
Tx/Rx LED, backlights and display.
TS_REF Linear Regulator
TS_REF is a fixed output linear regulator. It is supplied internally from the V2 linear regu-
lator. It is set to 2.3V. The radio uses TS_REF for the AD voltage dividers. It is not active
at POR.
5.5V Linear Regulator
This is an external linear regulator used to supply GCAP3 DSC regulator, and a 4.5V lin-
ear regulator in ESCORT section. Its supplies comes from SWB+.
DSC Linear Regulator
DSC is a fixed output linear regulator. This regulator is active during POR in the 5V mode.
DSC is supplied from an external 5.5V linear regulator. DSC 5V is used to supply the
WPIC and ODCT charge pump circuits. It is also used by ESCORT and Main VCO sec-
tions.
Current Limit
The SWB+ current limit regulator provides power from the phone battery to clip-on acces-
sories. It is enabled only when the phone is powered up and an accessory which requires
power from the phone is connected.
MTP700 Portable Radio / Detailed Service Manual TRANSCEIVER 800 MHz