Siemens A70 - Page 38

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Copyright 2005© Siemens AG
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TD_Repair_L2.5_A70_A75_R1.0.pdf Release 1.0
Functions Pin Requirements Implementation/Sequence
Voltage Supply
Logics
REG2
(1,5V)
The linear controller is designed for 1.5V (±2%) and a
maximum load current of 300 mA.
The output voltage can be adjusted to four different values
with TWI register by the µC. The selectable values are
1.5(default), 1.82, 1.92 and 2.0V.
The REG2 supplies the Baseband Processor.
Voltage Supply
Logics
REG3
(2.65V)
The linear controller is designed for 2.65V(±3%) and a
maximum load current of 140 mA.
It will consist basically of an internal operation amplifier, an
integrated p-channel output transistor as well as a capacitor
(C = 2.2µF) for stabilising the voltage. The required reference
voltage for the regulating circuit will be generated internally
via a band gap. The negative feedback of the regulating
circuit shall be done via chip-internal resistances.
Voltage Supply
RF
VREGRF1,
SLEEP1_N,
SLEEP2_N,
POWER_ON
The linear controller is designed for 2.755V (±2%) and a
maximum load current of 150 mA. The output voltage can be
adjusted to three different values with TWI register by the µC.
The selectable values are 2.755V(default), 2.54V, and 2.85V.
Voltage and current for RF-VCO and Transceiver is supplied
from the internal 2.755V LDO. The operating voltage RF1LDO
is kept constant up to the maximum rated load current. A
reference voltage for the regulator circuit is generated from a
bandgap reference. A low noise must be guaranteed.
RF1LDO is controlled by SLEEP1_N and SLEEP2_N. If one
of them is set to high, the regulator is enabled. The control
method can be modified by TWI interface between external
and internal control mode. If internal control mode is set,
RF1LDO can only be enabled by TWI bit. In external mode,
RF1LDO can only be enabled by SLEEP1_N or SLEEP2_N.
RF1LDO is released with rising edge of POWER_ON signal.
Voltage Supply
RF
VREGRF2,
RF_EN,
RESET_N
The linear controller is designed for 1.53V (±2%) and a
maximum load current of 180 mA. The output voltage can be
adjusted to three different values with TWI register by the µC.
The selectable values are 1.53V(default), 2.70V, and 2.85V.
Voltage and current for RF-VCO and Transceiver is supplied
from the internal 1.53V LDO. The operating voltage RF2LDO
is kept constant up to the maximum rated load current. A
reference voltage for the regulator circuit is generated from a
bandgap reference. A low noise must be guaranteed.
RF2LDO is controlled by RF_EN. If it is set to high, the
regulator is enabled. The control method can be modified by
TWI interface between external and internal control mode. If
internal control mode is set, RF2LDO can only be enabled by
TWI bit. In external mode, RF2LDO can only be enabled by
RF_EN.
RF2LDO is released with rising edge of RESET_N signal.
Voltage Supply
Audio
VREGA The linear controller is designed for 2.9V(min. 2.84V, max.
2.96V) and a maximum load current of 190 mA.
VDDA is used for the whole stereo analog supply. The DAC
digital (VDDDAC), Low Noise Bandgap, Mono- and
Stereoamplifier supplies are connected to VREGA or VBAT or
an external LDO at 2.9V +/-5%. The AUDIO performances are
guaranteed only, if the VREGA supplies all the stereo path.
VREGA is controlled with TWI registers directly by the µC.