LG B2000 Service Manual page 35

3. TECHNICAL BRIEF
AD6537B
VBAT
KEYON
VRTC
DBBON
VEXT
VCXOEN
2. LDO Block
1. There are 8 LDOsin the AD6537B.
-VCORE : supplies Digital basebandProcessor core and AD6537B digital core
-VMEM : supplies external memory and the interface to the external memory on the
-VEXT : supplies Radio digital interface and high voltage interface (2.8V, 170mA)
-VSIM : supplies the SIM interface circuitry on the digital processor and SIM card
(2.85V, 20mA)
-VRTC : supplies the Real-Time Clock module (1.8 V, 20 •A)
-VABB : supplies the analog portions of the AD6537B
-VMIC : supplies the microphone interface circuitry (2.5 V, 1 mA)-VVCXO : supplies the
voltage controlled crystal oscillator ( 2.75 V, 10 mA)
THERM
Thermal
Shutdown
DDLO
UVLO
CHGDET
Figure 3-17 AD6537B POWER MODE LOGIC
(1.8V, 80mA)
digitalbasebandprocessor (1,8V or 2.8V, 150mA)
Enable
Mode
Enable
Mode
Enable
VEXT mode
Control Bit
Mode
VSIMEn
Enable
Control Bit
Mode
Enable
POWERMODE
Mode
VCORE Comparator
VCORECP
low: VCORE < 1.6V
high:VCORE > 1.6V
VMEM Comparator
VMEMCP
low: VMEM < 2.6V or 1.6V
high:VMEM > 2.6V or 1.6V
VEXT Comparator
VEXTCP
low: VEXT < 2.6V
high: VEXT > 2.6V
- 34 -
VCORE
Digital Core
LDO Regulator
VMEM
Memory Interface
LDO Regulator
VEXT
External Interface
LDO Regulator
VSIM
SIM Interface
LDO Regulator
VVCXO
VCXO
LDO Regulator
VCORE
VMEM
VEXT