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30V Operation
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Low Power Consumption
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Step-down DC/DC Controller IC
XC9252 Series
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The XC9252 series is a 30V operation step-down DC/DC controller IC. The external P-ch driver transistor
is used to achieve a stable operation under low input voltage. Low ESR capacitors such as ceramic capacitors can be used for the load capacitor (CL). A 0.8V reference voltage source is incorporated, and the output
voltage can be set freely from 1.5V using external resistors (RFB1, RFB2). 280kHz to 550kHz can be
selected for the switching frequency by connecting an external resistor to the ROSC pin. The generation of
unneeded noise can be reduced by this synchronization with an external CLK within ±25% of the internal
clock using the MODE/SYNC pin. In automatic PWM/PFM control, the IC operates by PFM control when
the load is light to achieve high efficiency over the full load range from light to heavy. The soft start time can
be set as desired by adding an external capacitance to the SS pin. With the built-in UVLO function, the
driver transistor is forced OFF when input voltage becomes 2.5V or lower. Internal protection circuits include
over current protection, short-circuit protection, and thermal shutdown circuits to enable safe use.
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USP-10B
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Achieves high efficiency at light loads
1
Microcomputers have a standby mode to reduce
battery consumption, and the efficiency of the
DC/DC converter plays an important role in this.
■Example
Capable of operation from a low voltage
2
Output is not shut down even when the battery
voltage drops suddenly due to environment or
other factors.
■Example
Even though a car is stopped,
some power from a battery is consumed.
Dramatic voltage drop happens due to a cranking or a cold cranking.
■XC9252 Advantage
■XC9252 Advantage
In this case, the low power consumption feature is important for a
power management IC.
Even though an input voltage drops dramatically.
XC9252 can ease the impact because the power SW for XC9252 is P-FET.
Input Voltage (MIN.) 3.0V
⇒ XC9252; Iq:30μA, PFM control is selectable.
Waveform when VIN is lower than V_nominal
Efficiency vs. Output Current
f=460kHz, VIN=13V & 16V, VOUT=5.7V, IOUT=2.5A
VIN=5V, VOUT=5V, IOUT=500mA
VIN
VIN (red): 1V/div
XC9252 VOUT (light green): 1V/div
Low Input Current=0.6mA (16V), 0.5mA (13V)
VOUT (blue) of regular DC/DC with
internal N-ch driver
VIN=5.0V VOUT=4.85V
XC9252
(P-ch Driver)
⇒Lower
Dropout
Efficiency: EFFI (%)
100
80
Buck with
N-ch driver
VOUT=4.25V
GND
60
40
VIN=13V (PWM)
VIN=16V (PWM)
VIN=13V (PWM/PFM)
VIN=16V (PWM/PFM)
20
0
0.0001
0.001
0.01
0.1
Output Current: IOUT (A)
1
10
Most high-withstand voltage DC/DC converters use an N-ch driver IC.
When an input voltage less than the set voltage is applied to an N-ch
driver IC, the output voltage drops dramatically due to the MAX Duty limit.
The XC9252 Series uses a P-ch driver. When an input voltage
lower than the set voltage is applied, the MAX Duty limit is 100%
and the output voltage drop is smaller than with an N-ch driver.
Memory protection when voltage drops due to cranking of vehicle
Supply from backup power supply of industrial equipment.
Features
Input Voltage Range
Load Dump Transients
3.0V ~ 30V ( Maximum Rating: 36V)
46V, 400ms
FB Voltage
Supply Current
0.8V (±2.0%)
30μA (@300kHz)
Oscillation Frequency
280kHz ~ 550kHz (External Resistor)
Ext. CLK Synchronization ±25% of the internal CLK
Control Method
PWM (Mode: H) , PWM/ PFM (Mode: L)
Soft-start
Protection Circuit
External set (External C)
Over current limit (External Resistor)
Integral latch protection
Auto-return
Packages
Thermal shutdown
TSSOP-16, USP-10B
Environmentally friendly EU RoHS Compliant, Pb Free
www.torex.co.jp/english/ October 2013 ②
● Values shown in this sheet can be changed without any prior notice.