XC9210 Series
Synchronous Step-Down DC / DC Controller ICs
July 4 , 2003 Ver. 3
APPLICATIONS
Synchronous Step-Down DC/DC Conrollers
Input Voltage Range
2.0V ~ 10V
Maximum Duty Cycle
Output Voltage Externally Set-up
Oscillation Frequency
300kHz (Accuracy ±15%)
PWM, PWM/PFM Externally Selectable
100% (TYP.)
Synchronous Rectification Control
High Efficiency
95% (TYP.)
Small MSOP-8A Packaging
GENERAL DESCRIPTION
The XC9210 is a synchronous PWM, PWM/PFM controller designed
for low voltage step-down DC/DC converter applications. High
efficiency is obtained through the use of a synchronous rectification
topology. Efficiencies are maximised by using the low RDSon N-
Channel MOSFET switch which replaces the catch diode used in
standard buck circuits.
The operation of the XC9210 series can be switched between PWM
and PWM/PFM externally using the MODE pin. In PWM/PFM mode
the XC9210 automatically switches from PWM to PFM during light
loads and high efficiencies can be achieved over a wide range of load
conditions. Output noise is reduced in PWM operation as the
frequency is fixed.
The XC9210 has an 0.9V (±2.0%) internal voltage, and using
externally connected components, the output voltage can be set
freely between 0.9V to 6.0V. With an internal switching frequency of
300kHz and 180kHz (custom) smaller, low cost external components
can also be used.
Soft-start time is internally set to 10msec offering protection against
in-rush currents during start-up and preventing voltage overshoot.
PDAs
Palmtop computers
Portable audios
Various power supplies
FEATURES
Input Voltage Range
Output Voltage Range
: 2.0V ~ 10V
: 0.9V ~ 6.0V
Can be set freely with 0.9V
(±2.0%) of reference voltage supply
and external components.
: 300kHz
±15%
Oscillation Frequency
(180kHz is available as custom)
Output Current
: More than 2A
(VIN = 5.0V, VOUT=3.3V)
Stand-By Function
Package
Soft-start internally set-up
: 3.0µA (MAX.)
: MSOP-8A
: 10 ms (internally set-up)
TYPICAL APPLICATION CIRCUIT
<XC9210B093, VOUT:3.3V)
Tr1:Pch MOSFET
:CPH3308
L:22µH
CDRH125
V
OUT
:3.3V
Tr2:Nch MOSFET
:CPH3408
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs. Output Current
XC9210B093K (300kHz, 3.3V)
Tr1:CPH3308, Tr2:CPH3408
L=22uH(CDRH125), CL=94uF(Tantalum)
100
90
80
70
60
50
40
30
20
10
0
0.1
C
IN
:47µF
CFB
:62pF
EXT1
VDD
PWM
CE
V
IN
:3.3V~10V
PWM
CE
EXT2
GND
FB
MODE
MODE
RFB
:75kΩ
RFB1
:200kΩ
CL:
47µFX2
Efficiency EFFI (%)
VIN=5.0V
8.0V
PWM/PFM Switching Control
Synchronous PWM Control
1
10
100
1000
Output Current I
OUT
(mA)
10000
1
Semiconductor Ltd.
TOREX [ TOREX SEMICONDUCTOR ]
