XC9128_1 Datasheet, PDF (1/13 Pages) Torex Semiconductor – 1A Driver Transistor Built-In, Step-Up DC/DC Converters

XC9128/XC9129 Series
1A Driver Transistor Built-In, Step-Up DC/DC Converters
ETR0411-006
■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.
■APPLICATIONS
●Digital audio equipment
●Digital cameras, Video equipment
●Computer Mice
●Various multi-function power supplies using alkali cells (1
to 3 cells), nickel hydride batteries, or single lithium cells
■TYPICAL APPLICATION CIRCUIT
CIN
1
PGND
VIN
2 Lx
L
3 BAT
EN
4 EN
FO
5 FO
VOUT 10
MODE
MODE 9
CFB
RFB1
FB 8
AGND
7
AEN/ 6
RFB2
VOUT
CL
(ceramic)
■ FEATURES
High Efficiency, Large Current Step-Up Converter
Output Current
Input Voltage Range
Output Voltage Setting
Range
Oscillation Frequency
Input Current
Maximum Current Limit
Control
High Speed
Transient Response
Protection Circuits
Soft-Start Time
: 150mAï¼ V_OUT=3.3V, V_IN=0.9V
500mAï¼ V_OUT=3.3V, V_IN=1.8V
: 0.8V~6.0V
: 1.8V~5.3V (Externally set)
Set up freely with a reference voltage
supply of 0.45V (±0.010V) & external
components
: 1.2MHz (Fixed oscillation frequency
accuracy ±15%)
: 1.0A
: 1.2A (MIN.), 2.0A (MAX.)
: PWM, PWM/PFM control
externally selectable
:100mV @ V_OUT=3.3V,
V_IN=1.8V, I_OUT=10mA→100mA
: Thermal shutdown
: Integral latch method (Over current
limit)
: 5ms (TYP.) internally set
Ceramic Capacitor Compatible
Adaptor Enable Function (XC9128 series)
Packages
: MSOP-10, USP-10B, SOP-8
Flag Output (XC9128 series) : Open-drain output
■TYPICAL PERFORMANCE
CHARACTERISTICS
●Efficiency vs. Output Current
XC9128B45CDx
V_OUT=5.0V, f_OSC=1.2MHz
100
L=4.7μH (CDRH4D28C), C_IN=10μF, C_L=32μF
80
60
3.7V
40
VIN=1.8V
20
0
0.1
PWM(MODE:H)
PWM/PFM(MODE:L)
1
10
100
Ou_Ot_up_tu_pt_uC_{t C}ur_ur_re_ren_nt_t:_{: I}IO_OUU_TT_(m(m_A)A)
1000
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