Rf Description; Rf Introduction; Regulators; Block Diagrams - Nokia n80 User Manual

RM-91; RM-92
Nokia Customer Care System Module

RF description

RF introduction

This section describes the RF modules of the RM-91/92 engine. RM-92 uses RF ASIC N7500 and RM-91 uses RF
ASIC N7505.
The RF is controlled by digital baseband circuitry via a serial bus (RFBus). The RFBus is for mode selection,
frequency synthesizer control, RX AGC setting, RF regulator control, TX power control loop and PA bias control.
In addition to RFBus there are also several other interface signals coming from BB. TX power control (TXC),
VCTCXO frequency control (AFC) and some other control signals (voltage and current references, WCDMA TX
power detection, PA combination detection).

Regulators

All RF regulators, except one, are located in the EM ASIC N2200 in the baseband section or in the RF ASIC of
the device. The discreet regulator, N7541, feeds the WCDMA PA. The EM ASIC N2200 has three regulators for
RF:
• 2.5 V regulator VXO
• 4.75 V regulator VCP (VCP1 & VCP2)
• 1.35 V regulator, VB_EXT, which is the reference voltage.

Block diagrams

Figure 111 RF block diagram RM-92 using RF ASIC N7500
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