User Guide

Back-up battery interface electrical characteristics

Table 29 Back-up battery connections

Pin name I/O Connection Notes

G2200,

VBack

-> N2200,

VBack

Back-up battery G2200 is

connected to N2200

Table 30 Back-up battery electrical characteristics

Description Parameter Min Typ Max Unit

Back-Up

Battery

Voltage

Vback 0 2.5 2.7 V

RF description

RF introduction

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.

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