Siemens A55 Repair Documentation

Also see for A52: User guide

V 1.10 Page 28of 45 ICM MP CCQ GRMA52/A55/C55 IFX Company Confidential © Copyright Siemens AG 08/03Functions PinRequirementsSequenceVoltage SupplyLogicsREG3(2.65V)The linear controller is designed for2.65V(±3%) and a maximum load current of220 mA.It will consist basically of an internal operationamplifier, an integrated p-channel outputtransistor as well as a capacitor (C = 2.2μF) forstabilizing the voltage. The required referencevoltage for the regulating circuit will begenerated internally via a bandgap. Thenegative feedback of the regulating circuit shallbe done via chip-internal resistances.Voltage SupplyRFVREGRF1,RF_EN,RESET_NThe linear controller is designed for 2.85V(min.2.79V, max. 2.91V) and a maximum loadcurrent of 120 mA.Voltage and current for RF-VCO andTransceiver is supplied from the internal 2.85VLDO. The operating voltage RF12LDO is keptconstant up to the maximum rated load current.A reference voltage for the regulator circuit isgenerated from a bandgap reference. A lownoise must be guaranteed.RF1LDO is controlled by RF_EN. If it is set tohigh, the regulator is enabled. The controlmethod can be modified by TWI interfacebetween external and internal control mode. Ifinternal control mode is set, RF1LDO can onlybe enabled by TWI bit. In external mode,RF1LDO can only be enabled by RF_EN.RF1LDO is released with rising edge ofRESET_N signal.Voltage SupplyRFVREGRF2,SLEEP1_N,SLEEP2_N,POWER_ONThe linear controller is designed for 2.85V(min.2.79V, max. 2.91V) and a maximum loadcurrent of 180 mA.Voltage and current for RF-VCO andTransceiver is supplied from the internal 2.85VLDO. The operating voltage RF2LDO is keptconstant up to the maximum rated load current.A reference voltage for the regulator circuit isgenerated from a bandgap reference. A lownoise must be guaranteed.RF2LDO is controlled by VCXO_EN (PinH1). Ifit is set to high, the regulator is enabled. Thecontrol method can be modified by TWIinterface between external and internal controlmode. If internal control mode is set, RF2LDOcan only be enabled by TWI bit. In externalmode, RF2LDO can only be enabled byVCXO_EN (PinH1).RF2LDO is released with rising edge ofPOWER_ON signal.