XC9128/XC9129 Series
ETR0411-011
1A Driver Transistor Built-In, Step-Up DC/DC Converters
☆GreenOperation Compatible
■GENERAL DESCRIPTION
The XC9128/XC9129 series are synchronous step-up DC/DC converters with a 0.2Ω (TYP.) N-channel driver transistor and a
synchronous 0.2Ω (TYP.) P-channel switching transistor built-in. A highly efficient and stable current can be supplied up to
1.0A by reducing ON resistance of the built-in transistors. With a high switching frequency of 1.2MHz, a small inductor is
selectable making the series ideally suited for applications requiring low profile or space saving solutions. With the MODE
pin, the series provides mode selection of PWM control or PFM/PWM automatic switching control. In the PWM/PFM
automatic switching mode, the series switches from PWM to PFM to reduce switching loss when load current is small.
When load current is large, the series switches automatically to the PWM mode so that high efficiency is achievable over a
wide range of load conditions. The series also provides small output ripple from light to large loads by using the built-in
circuit which enables the smooth transition between PWM and PFM. With a adaptor enable function of the XC9128 series,
when a voltage higher than the input voltage is applied to the output, the input and the output become isolated making it
possible for the IC to work in parallel with the likes of an AC adaptor.
■ FEATURES
■APPLICATIONS
High Efficiency, Large Current Step-Up Converter
Output Current
: 150mA＠VOUT=3.3V, VIN=0.9V
500mA＠VOUT=3.3V, VIN=1.8V
Input Voltage Range
: 0.8V~6.0V
Output Voltage Setting
: 1.8V~5.3V (Externally set)
Range
Set up freely with a reference voltage
supply of 0.45V (±0.010V) & external
components
Oscillation Frequency
: 1.2MHz (Fixed oscillation frequency
accuracy ±15%)
Input Current
: 1.0A
Maximum Current Limit
: 1.2A (MIN.), 2.0A (MAX.)
Control
: PWM, PWM/PFM control
externally selectable
High Speed
:100mV @ VOUT=3.3V,
Transient Response
VIN=1.8V, IOUT=10mA→100mA
Protection Circuits
: Thermal shutdown
Integral latch method (Over current
limit)
Soft-Start Time
: 5ms (TYP.) internally set
●Digital audio equipment
●Digital still cameras / Camcorders
●Computer Mouses
●Multi-function power supplies
Ceramic Capacitor Compatible
Adaptor Enable Function (XC9128 series)
Flag Output (XC9128 series) : Open-drain output
Operating Ambient Temperature : - 40℃∼+85℃
Packages
: MSOP-10, USP-10B
Environmentally Friendly
: EU RoHS Compliant, Pb Free
■TYPICAL APPLICATION CIRCUIT
■TYPICAL PERFORMANCE
CHARACTERISTICS
●Efficiency vs. Output Current
XC9128B45CD
CIN
VOUT
VOUT
10
2
Lx
MODE
9
3
VIN
L
BAT
FB
8
EN
4
EN
FO
5
FO
AGND
AEN/
MODE
CFB
RFB1
7
6
RFB2
100
90
CL
(ceramic)
Efficiency: EFFI (%)
PGND
1
L=4.7μH(LTF5022-LC),CL =30μF(LMK212BJ106KG ×3)
VO UT=3.3V,VEN=6V,VFO =OPEN,VAEN/ =0V
RFB1 =270kΩ,RFB2 =43kΩ,CFB=12pF,CIN=10μF
80
70
1.8V
60
3.0V
50
40
30
20
PWM/PFM (VMO DE=0V)
10
PWM (VMODE=VO UT)
0
0.1
1
10
100
Output Current: I OUT (mA)
1000
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