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July 4 , 2003 Ver. 3
APPLICATIONS
Synchronous Step-Down DC/DC Conrollers
Input Voltage Range
Maximum Duty Cycle
Output Voltage Externally Set-up
Oscillation Frequency
PWM, PWM/PFM Externally Selectable
Synchronous Rectification Control
High Efficiency
Small MSOP-8A Packaging
2.0V ~ 10V
z
PDAs
z
Palmtop computers
300kHz (Accuracy ±15%)
100% (TYP.)
z
Portable audios
95% (TYP.)
z
Various power supplies
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.
FEATURES
Input Voltage Range
: 2.0V ~ 10V
Output Voltage Range
: 0.9V ~ 6.0V
Can be set freely with 0.9V
(
±
2.0%) of reference voltage supply
and external components.
Oscillation Frequency
: 300kHz
±
15%
(180kHz is available as custom)
Output Current
: More than 2A
(VIN = 5.0V, VOUT=3.3V)
Stand-By Function
: 3.0
μ
A (MAX.)
Package
: MSOP-8A
Soft-start internally set-up
: 10 ms (internally set-up)
TYPICAL APPLICATION CIRCUIT
<XC9210B093, VOUT:3.3V)
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs. Output Current
1
Synchronous Step-Down DC / DC Controller ICs
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.
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.
XC9210 Series
Soft-start time is internally set to 10msec offering protection against
in-rush currents during start-up and preventing voltage overshoot.
VDD
EXT1
PWM
CE
GND
EXT2
FB
MODE
PWM
CE
MODE
L:22
μ
H
CDRH125
Tr1:Pch MOSFET
:CPH3308
RFB
:75k
Tr2:Nch MOSFET
:CPH3408
C
IN
:47
μ
F
V
IN
:3.3V~10V
CL:
47
FX2
RFB1
:200k
CFB
:62pF
V
OUT
:3.3V
XC9210B093K (300kHz, 3.3V)
0
10
20
30
40
50
60
70
80
90
100
0.1
1
10
100
1000
10000
Output Current I
OUT
(mA)
E
8.0V
VIN=5.0V
Tr1:CPH3308, Tr2:CPH3408
L=22uH(CDRH125), CL=94uF(Tantalum)
PWM/PFM Switching Control
Synchronous PWM Control
Semiconductor Ltd.