Nokia NSE–3 SERIES Service Manual

Contents

Nokia NSE–3 SERIES Service Manual Manual pdf 29 page image

PAMSTechnical DocumentationNSE–3System ModulePage 3 – 23Original 11/97Battery TemperatureThe battery temperature is measured with a NTC inside the battery pack.The BTEMP line inside transceiver has a 100k pullup to VREF. The MCUcan calculate the battery temperature by reading the BTEMP line DC–voltage level with a CCONT (N100) A/D–converter.100kVREFTRANSCEIVERR TBATTERYBTEMPBGNDBSIBVOLT10nNTC 1kMADBTEMP CCONTVibraPWM10k1kMCUGenIO4Supply Voltage RegulatorsThe heart of the power distrubution is the CCONT. It includes all the volt-age regulators and feeds the power to the whole system. The basebanddigital parts are powered from the VBB regulator which provides 2.8Vbaseband supply. The baseband regulator is active always when thephone is powered on. The VBB baseband regulator feeds MAD and me-mories, COBBA digital parts and the LCD driver in the UI section. There isa separate regulator for a SIM card. The regulator is selectable between3V and 5V and controlled by the SIMPwr line from MAD to CCONT. TheCOBBA analog parts are powered from a dedicated 2.8V supply VCOB-BA. The CCONT supplies also 5V for RF and for flash VPP. The CCONTcontains a real time clock function, which is powered from a RTC backupwhen the main battery is disconnected.