Panasonic EB-X70 Service Manual

Also see for EBX70 - CELL PHONE: Operating instructions Operating instructions Technical information Service manual

TECHNICAL DESCRIPTIONPMCD030901C8 Section 4 Issue 1Service Manual – 21 – Revision 04.8.3 Power On / Off ControlThe power on sequence can begin when VBAT >2.6 V or VBACKUP >2.6 V. In this state SYREN (U120) is in Power OnCondition and internal supply UPR is active. RESPWRONZ signal to CALYPSO+ (U100) is released high.If SYREN is in the Power On Condition, one of following conditions start the Power Up sequence.• Power key is pushed for more than 30 ms.• EXTPWR voltage is higher than (VBAT+0.4) V.• CALYPSO+ RTC ALARM signal goes high.The Power Up sequence is as follows:1. SYREN internal band gap reference is activated.2. If VBAT < 3.2 V after a timeout of 51.2 ms Power Up sequence is aborted.3. All regulators (VRDBB, VRMEM, VRRAM, VRIO & VRABB) are enabled.4. Power Up status bit and internal Reset bits are set.5. ONNOFF signal is set to activate CALYPSO+.6. ARM in CALYPSO+ starts running software using 32 kHz clock, and also starts 26 MHz clock.The following Power Down sequence can only be started by CALYPSO+ setting the DEVICE_OFF bit in SYREN or, inemergency case, when VBAT < 2.7 V (or VBAT < Vbackup & VBAT < 2.8 V):1. If emergency case, INT1 is set low by SYREN.2. SYREN starts an internal 150 μs watchdog timer to allow CALYPSO+ to shutdown.3. ONNOFF signal is reset to deactivate CALYPSO+.4. All regulators (VRDBB, VRMEM, VRRAM, VRIO, VRABB & VRRAM) are disabled.5. SYREN internal band gap reference is deactivated.4.8.4 Power Source Detection FailureIf the power fails (i.e. battery removal) the software detects INT1 and asserts the MODE pin of the PSRAM low to back up thecontents.4.8.5 Voltage RegulationThe voltage regulators for I/O and memories have a nominal output of 2.8 V, and are designed to provide a minimum 2.7 Voutput over all load, transients and temperature conditions.Each power source is specified as follows.• D15V: (SYREN VRDBB) Power supply for the CALYPSO+ (Lead Mega Module) LMM block.This power supply provides the power for CALYPSO+ internal RAM, ASIC modules, LMM and ARM Blocks, and isselectable from 1.3 V, 1.5 V and 1.8 V.• D28VB: SYREN (VR10) Power supply for SYREN ASIC I/O and CALYPSO+ .This is the main power supply for the baseband digital sections (I/O and LCD) and some analogue sections. It is also usedfor the digital I/O ring on both CALYPSO+ and SYREN.Voltage 1.5 V ±0.15 VCurrent 170 mA max.Dropout 100 mV max (load max)Supply VBATVoltage 2.8 V ±0.1 VCurrent 100 mA max.Dropout 100 mV max (load max)Supply VBAT