Nokia 636, 638 服务手册
After Sales
Technical Documentation
System Module
NHA–2
Original 06/97
Page 4–23
Regulators
Transistors V901 and V902 form a voltage regulator for RF parts. It is realized
with discrete transistors because the output noise has to be very low. The 3.3 V
reference voltage (VREF) comes from the logic module. This regulated voltage
goes directly to RX part and also to RX synthesizer. TX synthesizer get it’s sup-
ply voltage via a switch. The switch is realized with transistors V651 and
V654.It is controlled over digital line TXS from the logic module.
with discrete transistors because the output noise has to be very low. The 3.3 V
reference voltage (VREF) comes from the logic module. This regulated voltage
goes directly to RX part and also to RX synthesizer. TX synthesizer get it’s sup-
ply voltage via a switch. The switch is realized with transistors V651 and
V654.It is controlled over digital line TXS from the logic module.