XC9106_1 Datasheet, PDF (1/11 Pages) Torex Semiconductor – PWM Control,PWM/PFM Switching Control, Step-Up DC/DC Converters, Externally Applied Vref

XC9106/XC9107 Series
ETR0405_002
PWM Control,PWM/PFM Switching Control,
Step-Up DC/DC Converters, Externally Applied Vref
■GENERAL DESCRIPTION
☆GO-Compatible
The XC9106 / 07 series are step-up DC/DC controller ICs with an externally applied reference voltage (Vref).
Output voltage will be set with external resistors (RFB1 and 2) and Vref value. The series make it easy to control output
voltage externally and are suited to software applications that need to vary voltage, such as LCD power supply for PDA.
Output will be stable no matter which load capacitors are used but if a low ESR capacitor is used, RSENSE of about 0.1Ω will
be required and phase compensation will be achieved. This makes the use of ceramic capacitors much easier, and allows for
lower output ripple and reduced PCB area requirements. Tantalum and electrolytic capacitors can also be used, in which
case, RSENSE becomes unnecessary.
Oscillation frequencies of high clock, low ripple 300kHz and low supply current 100kHz are available.
The XC9107 series are PWM/PFM automatic switching controlled. Control switches from PWM to PFM during light loads with
the XC9107 and the series is highly efficient from light loads to large output currents. By bringing the whole circuit down
while the series is in the stand-by mode (CE/PWM pin: low), supply current can be reduced to less than 1.0μA.
■APPLICATIONS
●Power supply for LCDs
●PDAs
●Cellular phones
●Palmtop computers
●Portable audio systems
●Various multi-function power supplies
■FEATURES
Input Voltage
: 0.9V ~ 10V
Power
Supply Voltage Range : 1.8V~10.0V and more than
VREF Input Range
Output Voltage
Vref+0.7V
: 0.8V~2.5V (±2.0%)
: Vref x external split resistor ratio
VOUT=Vref x (RFB1+RFB2)/RFB2
Oscillation Frequency : 300kHz, 100kHz (±15%)
Output Current
: More than 30mA
(VIN=3.3V, VOUT=20V,
when external components are
Controls
used as in the circuits below.)
: PWM (XC9106)
: PWM/PFM auto-switching
(XC9107)
High Efficiency
: 85% (TYP.)
Stand-by Current
: ISTB = 1.0μA (MAX.)
Load Capacitors
: Low ESR capacitors compatible
Externally Applied Reference Voltage (Vref)
Packages
: SOT-25, USP-6B
■TYPICAL APPLICATION CIRCUIT
RSENSE : 100m Ω
for Ceramic CL _{SD : MA737}
*
CFB : 27pF
VOUT = 8V~25V RFB1 : RFB2 :
IOUT = 30mA ^270k Ω ^30k Ω
Ceramic CL :
1
5
10μF
2
3
4
CE/Vref
0.8V~2.5V
D/A converter
L : 10μH
CIN
Nch Pow er
MOS FET
2SK2159
VIN = 3.3V
* RSENSE is of no use in light load (uncontinuous mode)
applications such as a small LCD, even using ceramic
capacitor.
■TYPICAL PERFORMANCE
CHARACTERISTICS
XC9107D003M R
Circuit as lef t
30
VDD=VIN=3.3V, IOUT=30mA
25
20
15
10
5
0
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Vref (V)
XC9107D003M R
30
Circuit as left
VDD=VIN=3.3V
25
2.5V
20
2.0V
15
1.5V
10
5
V r e f=0.8V
0
0.1
1
10
100
IOUT (mA)
1000
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