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PDF XC9254R Data sheet ( Hoja de datos )

Número de pieza XC9254R
Descripción Synchronous Step-Down DC/DC Converter
Fabricantes Torex Semiconductor　
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No Preview Available ! XC9254R Hoja de datos, Descripción, Manual

XC9254R Series
ETR0529-003
600mA Driver Tr. Built-In, Synchronous Step-Down DC/DC Converter
GreenOperation Compatible
GENERAL DESCRIPTION
The XC9254R series is a group of synchronous-rectification type DC/DC converters with a built-in 0.42 P-channel MOS driver
transistor and 0.52 N-channel MOS switching transistor, designed to allow the use of ceramic capacitors. Operating voltage
range is from 2.0V to 6.0V. The XC9254R001 type has a fixed output voltage of 1.2V (accuracy: 2.0%). The device provides
a high efficiency, stable power supply with an output current of 600mA to be configured using only a coil and two capacitors
connected externally. With the built-in oscillator, 1.2MHz is fixed internally. As for operation mode, the XC9254R series is
automatic PWM/PFM switching control allowing fast response, low ripple and high efficiency over the full range of loads (from
light load to heavy load).
The soft start and current control functions are internally optimized. During stand-by, all circuits are shutdown to reduce current
consumption to as low as 1.0 A or less. With the built-in UVLO (Under Voltage Lock Out) function, the internal P-channel
MOS driver transistor is forced OFF when input voltage becomes 1.4V or lower.
Two types of package SOT-25 and USP-6C are available.
APPLICATIONS
Smart phones / Mobile phones
Bluetooth
Mobile devices / terminals
Portable game consoles
Digital still cameras / Camcorders
Digital audio equipments
Note PCs / Tablet PCs
FEATURES
Driver Transistor Built-In
: 0.42 P-ch driver transistor
0.52 N-ch switch transistor
Input Voltage
: 2.0V ~ 6.0V
Output Voltage
: 1.2V
High Efficiency
: 92% (TYP.)
Output Current
: 600mA
Oscillation Frequency
: 1.2MHz (+15%)
Maximum Duty Cycle
: 100%
Control Methods
: PWM/PFM Auto
Function
: Current Limiter Circuit Built-In
(Constant Current & Latching)
Capacitor
Operating Ambient Temperature
Packages
CL Discharge
: Low ESR Ceramic Capacitor
: -40 +85
: SOT-25, USP-6C
Environmentally Friendly
: EU RoHS Compliant, Pb Free
* Performance depends on external components and wiring on the PCB.
TYPICAL APPLICATION CIRCUIT
CE
1/17

1 page




XC9254R pdf
XC9254R
Series
ELECTRICAL CHARACTERISTICS (Continued)
XC9254R Series, VOUT=1.2V, fOSC=1.2MHz, Ta=25
PARAMETER
Output Voltage
SYMBOL
VOUT
CONDITIONS
When connected to external components,
VIN=VCE=5.0V, IOUT=30mA
MIN. TYP. MAX. UNIT CIRCUIT
1.176 1.200 1.224 V
Operating Voltage Range
VIN
2.0 - 6.0 V
Maximum Output Current
UVLO Voltage
Supply Current
Stand-by Current
Oscillation Frequency
IOUTMAX
VUVLO
IDD
ISTB
fOSC
VIN=VOUT(E)+2.0V, VCE=1.0V,
When connected to external components (*8)
VCE =VIN, VOUT=VOUT(E) 0.5V (*11)
Voltage which Lx pin holding “L” level (*1, *10)
VIN=VCE=5.0V, VOUT=VOUT(E) 1.1V
VIN=5.0V, VCE=0V, VOUT=VOUT(E) 1.1V
When connected to external components,
VIN=VOUT(E)+2.0V, VCE =1.0V, IOUT=100mA
PFM Switching Current
PFM Duty Limit
Maximum Duty Cycle
Minimum Duty Cycle
Efficiency (*2)
Lx SW "H" ON Resistance 1
Lx SW "H" ON Resistance 2
Lx SW "L" ON Resistance 1
Lx SW "L" ON Resistance 2
Lx SW "H" Leak Current (*5)
Current Limit (*9)
Output Voltage
Temperature Characteristics
CE "H" Voltage
IPFM
When connected to external components,
VIN=VOUT(E)+2.0V, VCE =VIN, IOUT=1mA
DTYLIMIT_PFM
DTYMAX
DTYMIN
VCE=VIN=2.0V, IOUT=1mA
VIN=VCE=5.0V, VOUT=VOUT(E)
VIN=VCE=5.0V, VOUT=VOUT(E)
0.9V
1.1V
EFFI
RLxH
RLxH
RLxL
RLxL
ILeakH
ILIM
VOUT/
(VOUT Topr)
VCEH
When connected to external components,
VCE=VIN=VOUT(E)+1.2V, IOUT=100mA
VIN=VCE=5.0V, VOUT (E)
VIN=VCE=3.6V, VOUT (E)
VIN=VCE=5.0V (*4)
VIN=VCE=3.6V (*4)
0.9V , ILx=100mA (*3)
0.9V , ILx=100mA (*3)
VIN=VOUT=5.0V, VCE=0V, Lx=0V
VIN=VCE=5.0V, VOUT=VOUT(E) 0.9V (*7)
IOUT=30mA, -40 Topr 85
VOUT= VOUT(E)×0.9V, Applied voltage to VCE,
Voltage changes Lx to “H” level (*10)
CE "L" Voltage
CE "H" Current
CE "L" Current
Soft Start Time
Latch Time
Short Protection Threshold
Voltage
CL Discharge
VCEL
ICEH
ICEL
tSS
tLAT
VSHORT
RDCHG
VOUT= VOUT(E)×0.9V, Applied voltage to VCE ,
Voltage changes Lx to “L” level (*10)
VIN=VCE=5.0V, VOUT= VOUT(E)×0.9V
VIN=5.0V, VCE=0V, VOUT= VOUT(E)×0.9V
When connected to external components,
VCE=0V VIN, IOUT=1mA
VIN=VCE=5.0V, VOUT=0.8 VOUT(E),
Short Lx at 1 resistance (*6)
Sweeping VOUT, VIN=VCE=5.0V, Short Lx at
1 resistance, VOUT voltage which Lx becomes “L”
level within 1ms
VIN=5.0V, LX=5.0V, VCE=0V, VOUT=open
600
1.00
-
-
1020
140
100
-
-
-
-
-
-
-
900
-
0.65
VSS
- 0.1
- 0.1
0.5
1.0
0.675
200
-
1.40
15
0
1200
180
200
-
-
92
0.35
0.42
0.45
0.52
0.01
1050
100
-
-
-
-
1.0
-
0.900
300
- mA
1.78
33
1.0
1380
V
A
A
kHz
240 mA
%
-%
0%
-%
0.55
0.67
0.66
0.77
1.0
1350
A
mA
- ppm/
6.0 V
0.25
0.1
0.1
2.5
20.0
V
A
A
ms
ms
1.150
450
V
-
Test conditions: Unless otherwise stated, VIN=5.0V, VOUT(E)=Nominal Voltage, applied voltage sequence is VOUT VIN VCE
NOTE:
*1: Including hysteresis operating voltage range.
*2: EFFI = { ( output voltage output current ) ( input voltage input current) } 100
*3: ON resistance ( )= (VIN - Lx pin measurement voltage) 100mA
*4: R&D value
*5: When temperature is high, a current of approximately 10 A (maximum) may leak.
*6: Time until it short-circuits VOUT with GND via 1 of resistor from an operational state and is set to Lx=0V from current limit pulse generating.
*7: When VIN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance.
*8: When the difference between the input and the output is small, some cycles may be skipped completely before current maximizes.
If current is further pulled from this state, output voltage will decrease because of P-ch driver ON resistance.
*9: Current limit denotes the level of detection at peak of coil current.
*10: “H”=VIN~VIN-1.2V, “L”=+0.1V~-0.1V
*11: VIN is applied when VOUT (E) x 0.5V becomes more than VIN.
5/17

5 Page





XC9254R arduino
XC9254R
Series
NOTE ON USE
1. The XC9254R series is designed for use with ceramic output capacitors. If, however, the potential difference is too large
between the input voltage and the output voltage, a ceramic capacitor may fail to absorb the resulting high switching energy
and oscillation could occur on the output. If the input-output potential difference is large, connect an electrolytic capacitor
in parallel to compensate for insufficient capacitance.
2. Spike noise and ripple voltage arise in a switching regulator as with a DC/DC converter. These are greatly influenced by
external component selection, such as the coil inductance, capacitance values, and board layout of external components.
Once the design has been completed, verification with actual components should be done.
3. Depending on the input-output voltage differential, or load current, some pulses may be skipped, and the ripple voltage may
increase.
4. When the difference between VIN and VOUT is large in PWM control, very narrow pulses will be outputted, and there is the
possibility that some cycles may be skipped completely.
5. When the difference between VIN and VOUT is small, and the load current is heavy, very wide pulses will be outputted and
there is the possibility that some cycles may be skipped completely.
6. With the IC, the peak current of the coil is controlled by the current limit circuit. Since the peak current increases when
dropout voltage or load current is high, current limit starts operation, and this can lead to instability. When peak current
becomes high, please adjust the coil inductance value and fully check the circuit operation. In addition, please calculate
the peak current according to the following formula:
Ipk = (VIN - VOUT) x OnDuty / (2 x L x fOSC) + IOUT
L: Coil Inductance Value
fOSC: Oscillation Frequency
7. When the peak current which exceeds limit current flows within the specified time, the built-in Pch MOS driver transistor
turns off. During the time until it detects limit current and before the built-in transistor can be turned off, the current for limit
current flows; therefore, care must be taken when selecting the rating for the external components such as a coil.
8. When VIN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance.
9. Care must be taken when laying out the PC Board, in order to prevent misoperation of the current limit mode. Depending
on the state of the PC Board, latch time may become longer and latch operation may not work. In order to avoid the effect of
noise, the board should be laid out so that input capacitors are placed as close to the IC as possible.
10. Use of the IC at voltages below the recommended voltage range may lead to instability.
11. This IC should be used within the stated absolute maximum ratings in order to prevent damage to the device.
12. When the IC is used in high temperature, output voltage may increase up to input voltage level at no load because of the
leak current of the driver transistor.
13. The current limit is set to 1350mA (MAX.) at typical. However, the current of 1350mA or more may flow. In case that the
current limit functions while the VOUT pin is shorted to the GND pin, when Pch MOS driver transistor is ON, the potential
difference for input voltage will occur at both ends of a coil. For this, the time rate of coil current becomes large. By
contrast, when Nch MOS driver transistor is ON, there is almost no potential difference at both ends of the coil since the
VOUT pin is shorted to the GND pin. Consequently, the time rate of coil current becomes quite small. According to the
repetition of this operation, and the delay time of the circuit, coil current will be converged on a certain current value,
exceeding the amount of current, which is supposed to be limited originally. Even in this case, however, after the over
current state continues for several ms, the circuit will be latched. A coil should be used within the stated absolute
maximum rating in order to prevent damage to the device.
Current flows into Pch MOS driver transistor to reach the current limit (ILIM).
The current of ILIM or more flows since the delay time of the circuit occurs during from the detection of the current limit to
OFF of Pch MOS driver transistor.
Because of no potential difference at both ends of the coil, the time rate of coil current becomes quite small.
Lx oscillates very narrow pulses by the current limit for several ms.
The circuit is latched, stopping its operation.
LX
ILIM
ILX
Delay
Limit >
mmsS
11/17

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