Preliminary

June 26, 2003 Ver. 2

! Externally Applied Reference Voltage (Vref)

" APPLICATIONS

! Ceramic Capacitors Compatible

# Power Supply for LCD

! Input Voltage Range: 0.9V~10.0V

# PDAs

! Oscillation Frequency: 300kHz, 100kHz (±15%)

# Cellular Phones

! PWM Control (XC9106)

# Palmtop Computers

PWM/PFM Automatic Switching Control (XC9107)

# Portable Audio Systems

! SOT-25 / USP-6B Packages

# Various Multi-function Power Supplies

" GENERAL DESCRIPTION

" 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

Controls:

PWM (XC9106)

PWM/PFM auto-switching (XC9107)

High Efficiency:

85% (TYP.)

Stand-by Current:

ISTB=1

.0µA (MAX.)

Load Capacitors:

Low ESR capacitors compatible

Packages:

SOT-25, USP-6B

" TYPICAL APPLICATION CIRCUIT

" TYPICAL APPLICATION PERFORMANCE

1

PWM Control, PWM/PFM Switching Control,

Step-up DC/DC Converters

Externally Applied Reference Voltage (Vref)

XC9106 / 07 Series

(VIN=3.3V, VOUT=20V, when peripheral

components are used as in the circuits below .)

* RSENSE is of no use in light load (uncontinuous mode) applications such

as a small LCD, even using ceramic capacitor.

0

5

10

15

20

25

30

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Vref (V)

0

5

10

15

20

25

30

0.1

1

10

100

1000

2.0V

Vref=0.8V

1.5V

2.5V

Circuit as left

XC9107D003MR

XC9107D003MR

Circuit as left

L : 10

µH

SD : MA737

CFB : 27pF

Nch Power

MOS FET

2SK2159

RFB2 :

30k

Ω

RFB1 :

270k

Ω

D/A converter

Ceramic CL :

10

µF

CE/Vref

CIN

RSENSE : 100m

Ω

for Ceramic CL

0.8V~2.5V

3

2

15

4

*

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

0.1

Ω 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 1.0

µA.

Semiconductor Ltd.