M
ODEL
SL599 V
ERSION
V_1.0
P
REPARED BY
H/W
D
ATE
2007.04.11
S
UBJECT
T
ECHNICAL
M
ANUAL
P
AGE
40/52
SL599
T
ECHNICAL
M
ANUAL
The Analog LDO is a regulator that could source 150mA with 2.8V output voltage. It supplies the
Analog sections of the baseband chipsets. The LDO is optimized for low frequency ripple rejection in
order to reject the ripple coming from the RF Power Amplifier burst frequency at 217Hz. The
Decoupling Capacitor C150 must be higher than X5R type.
5.
TCXO LDO ( Vtcxo)
The TCXO LDO is a regulator that could source 20mA with 2.8V output voltage. It supplies the
temperature compensated crystal oscillator, which needs its own ultra low noise supply and very good
ripple rejection ratio. The Decoupling Capacitor C151 must be higher than X5R type.
6.
RTC LDO ( Vrtc)
The RTC LDO is a regulator that could source 200uA with 1.2V output voltage with Pin3 GND. If
Pin3 is not GND, The Output Voltage is 1.5V. It charges up a capacitor-type backup coin cell to run
the real-time clock module. The LDO features the reverse current protection.
7.
Memory LDO ( Vmem)
The memory LDO is a regulator that could source 150mA with 1.8V or 2.8V output voltage selection
based on the supply specs of memory chips. It supplies the memory circuitry in the handset.
8.
SIM LDO (Vsim)
The SIM LDO is a regulator that could source 20mA with 1.8V or 3.0V output voltage selection based
on the supply specs of subscriber identity modules card. The LDO is controlled independently of the
others LDO.
9.
SIM card interface
It provides level shifting needs for low voltage GSM controller to communicate with either 1.8V or 3V
SIM cards. In SL599, 3V SIM card is applied. All SIM cards contain a clock input, a reset input, and a
bi-directional data input/output. The clock and reset inputs to SIM cards are level shifted from the
supply of digital IO of baseband chipset to the SIM supply.
Figure 26. Status of Mobile Handset and LDOs.
