XC910607 Datasheet, PDF (1/7 Pages) Torex Semiconductor – PWM Control, PWM/PFM Switching Control, Step-up DC/DC Converters

XC9106 / 07 Series
Preliminary
PWM Control, PWM/PFM Switching Control,
Step-up DC/DC Converters
Externally Applied Reference Voltage (Vref)
May 23, 2002 Ver. 1-1
‹ Externally Applied Reference Voltage (Vref)
‹ Ceramic Capacitors Compatible
‹ Input Voltage Range: 0.9V~10.0V
‹ Oscillation Frequency: 300kHz, 100kHz (±15%)
‹ PWM Control (XC9106)
PWM/PFM Automatic Switching Control (XC9107)
‹ SOT-25 / USP-6B Package
„ Applications
z Power Supply for LCD
z PDAs
z Cellular Phones
z Palmtop Computers
z Portable Audio Systems
z Various Multi-function Power Supplies
„ General Description
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.
„ Features
Input Voltage Range:
0.9V ~ 10.0V
Power Supply Voltage Range: 1.8V ~ 10.0V and more than Vref+0.7V
VREF Input Range:
0.8V ~ 2.5V (±2.0%)
Output Voltage:
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 peripheral
components are used as in the circuits
below .)
Controls:
High Efficiency:
Stand-by Current:
Load Capacitors:
Packages:
PWM (XC9106)
PWM/PFM auto-switching (XC9107)
85% (TYP.)
ISTB=1.0µA (MAX.)
Low ESR capacitors compatible
SOT-25, USP-6B
„ Typical Application Circuit
„ Electrical Characteristics
RSENSE : 100m Ω
for Ceramic CL _{SD : MA737}
*
L : 10µH
XC9107D003MR
Circuit as left
30
VDD=VIN=3.3V, IOUT=30mA
25
20
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
CIN
Nch Power
MOS FET
2SK2159
VIN = 3.3V
15
10
5
0
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Vref (V)
XC9107D003MR
30
25
20
15
10
Circuit as left
VDD=VIN=3.3V
2.5V
2.0V
1.5V
* RSENSE is of no use in light load (uncontinuous mode)
applications such as a small LCD, even using ceramic capacitor.
5
0
0.1
Vref=0.8V
1
10
100
IOUT (mA)
1000
1