MOBILE COMMUNICATIONS DIVISION
CUSTOMER SERVICES
Version 1.0 22/11/2006
Created by Konrad Szombara
Page 75 of 103
6.5.2 POWER SOURCE
The battery used is a single Lithium-Ion (Li-Ion) cell with a nominal voltage of 3.7
V and 700-mAh capacity. T Li-Ion type of battery has an advantage in weight and
size over Nickel Metal Hydride (NiMH) cells.
6.5.3 REGULATOR CONTROL
The voltage regulators are enabled or disabled based on the remaining capacity
of the battery. If the AD6537B is in Deep Discharge Lockout (DDLO), Under-
Voltage Lockout (UVLO) or Thermal Shutdown Mode, only the Real-Time Clock
regulator is active. If the battery is not in Deep Discharge Lockout, Under-Voltage
Lockout, or Thermal Shutdown, the Real-Time Clock regulator and the voltage
reference regulator are always enabled. Other regulators are enabled or disabled
based on the input of the user or software. If user presses the power-on key
(KEYON pin of AD6537B),or a charger is plugged(CHGDET pin of AD6537B), the
regulators required to boot the system are enabled. If the software asserts the
DBBON signal, the regulators required to maintain the software state are enabled.
The VCXOEN signal enables the VCXO regulator for system clock power supply.
The analog regulator (VABB) can be enabled or disabled by writing registers.
6.5.4 VOLTAGE REGULATION
Following is the description of each power sources:
Digital Core Regulator (VCORE): 1.8 V
The digital core regulator supplies the baseband digital circuitry in the handset
(baseband processor and baseband converter). The regulator has been
optimized for very low quiescent current at light load since this regulator is always
turned-on whenever the handset is switched on.
Memory Regulator (VMEM): 2.8 V
The memory regulator supplies the system memory as well as the sub-systems of
the baseband processor including memory IO, and display interfaces. It is
capable of delivering up to
150 mA of current and is available for either 1.8 V or 3 V based systems. The
regulator has also been optimized for low quiescent current and its turn on timing
is the same time as the core regulator.
Analogue Baseband Regulator (VABB): 2.45 V
This regulator has the same features as the memory regulator. It has been further
optimized for better low frequency ripple rejection for use with the baseband
converter sections in order to reject the ripple coming from the RF power amplifier.
VABB is rated to 170 mA, which is sufficient to supply the analog section of the
baseband converter such as the AD6537B.
