XC9244/XC9245 Series
ETR0520-006
400mA Synchronous Step-Down DC/DC Converters
■GENERAL DESCRIPTION
☆GreenOperation Compatible
The XC9244/XC9245 series is a group of synchronous-rectification type step-down DC/DC converters with a built-in
0.65Ω P-channel MOS driver transistor and 0.45Ω N-channel MOS switching transistor, designed to allow the use of
ceramic capacitors. Output current of 400mA (MAX.) to be configured using only a coil and capacitor connected externally.
The output voltage can be set from 0.8V to 4.0V in increments of 0.05V (accuracy: ±2.0%). With an internal switching
frequency of 1.2MHz, small external components can be used. USPN-6 package is suitable for the application which
requires low profile and small-footprint.
The XC9244 series is PWM fixed frequency control, and the XC9245 series is PWM/PFM, which automatically switches
from PWM to PFM during light loads, high efficiency can be achieved over a wide range of load conditions. When
stand-by mode, due to stop all operation, supply current is reduced to 1μA or less. The integrated CL discharge function
which enables the electric charge at the output capacitor CL to be discharged via the internal discharge switch located
between the VOUT and VSS pins. The CL discharge function prevents malfunction on VOUT connecting application during
stand-by mode.
The XC9244/XC9245 series has a high speed soft-start as fast as 0.25ms in typical for quick turn-on. Current limiter
circuit (Constant Current & Latching) is built-in for preventing from thermal destruction. With UVLO (Under Voltage Lock
Out) function, the internal P channel driver transistor is forced OFF when input voltage becomes 2.25V or lower.
■FEATURES
■APPLICATIONS
●Smart
phones / Mobile phones
devices / terminals
●Portable
●Digital
●Note
:
Input Voltage
:
0.65Ω P-ch Driver Transistor
0.45Ω N-ch Synchronous Switch Transistor
●Bluetooth
●Mobile
Driver Transistor Built-In
game consoles
still cameras / Camcorders
PCs / Tablet PCs
2.3V ~ 6.0V
Output Voltage Selectable
:
0.8V ~ 4.0V (0.05V Increments)
High Efficiency
:
90% (TYP.)＊
Output Current
:
400mA
Oscillation Frequency
:
1.2MHz ±15%
Maximum Duty Cycle
:
100%
Function
:
Current Limiter Circuit
(Constant Current & Latching)
CL High Speed Discharge
Soft Start Circuit
Capacitor
:
Low ESR Ceramic Capacitor
Control Methods
:
PWM (XC9244)
Operating Ambient Temperature
:
-40℃∼+85℃
PWM/PFM Auto (XC9245)
Package
:
USPN-6
Environmentally Friendly
:
EU RoHS Compliant, Pb Free
* The characteristics change with external parts, substrate wiring, etc.
■TYPICAL APPLICATION CIRCUIT
■TYPICAL PERFORMANCE
CHARACTERISTICS
XC9244/XC9245A33C
L
VIN
CE
CIN
(ceramic)
CIN=4.7μF(LMK212BJ475)
VOUT
400mA
CE
VOUT
VSS
CL
(ceramic)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
100
Lx
Efficiency : EFFI (%)
VIN
80
60
VIN=4.2V
40
VIN=5.0V
20
PWM Control
VIN=4.2V
5.0V
0
0.1
1
10
100
1000
Output Current : IOUT (mA)
1/24
XC9244/XC9245 Series
■BLOCK DIAGRAM
XC9244/XC9245 Series, Type A
■PRODUCT CLASSIFICATION
●Ordering Information
XC9244①②③④⑤⑥-⑦ Fixed PWM control
XC9245①②③④⑤⑥-⑦ PWM / PFM automatic switching control
DESIGNATOR
ITEM
SYMBOL
①
Type
A
Output Voltage
②③
Oscillation
Frequency
Package (Order Unit)
④
⑤⑥-⑦
(*1)
08∼40
(*1)
C
7R-G
DESCRIPTION
Refer to Selection Guide
Output voltage options
e.g. 1.2V → ②=1, ③=2
1.25V → ②=1, ③=C
0.05V increments: 0.05=A, 0.15=B, 0.25=C, 0.35=D, 0.45=E,
0.55=F, 0.65=H, 0.75=K, 0.85=L, 0.95=M
Refer to “Stadard Voltage”
1.2MHz
USPN-6 (5,000/Reel)
The “-G” suffix denotes Halogen and Antimony free as well as being fully EU RoHS compliant.
Selection Guide
TYPE
OUTPUT
VOLTAGE
CL
AUTO-DISCHARGE
LATCH
UVLO
CHIP
ENABLE
CURRENT
LIMIT
SOFT-START TIME
A
Fixed
Yes
Yes
Yes
Yes
Yes
Fixed
Standard Voltage
VOUT（V）
1.0V
1.2V
1.5V
1.8V
2.5V
2.8V
3.3V
PRODUCT NAME
Fixed PWM
PWM/PFM Auto
XC9244A10C7R-G
XC9244A12C7R-G
XC9244A15C7R-G
XC9244A18C7R-G
XC9244A25C7R-G
XC9244A28C7R-G
XC9244A33C7R-G
XC9245A10C7R-G
XC9245A12C7R-G
XC9245A15C7R-G
XC9245A18C7R-G
XC9245A25C7R-G
XC9245A28C7R-G
XC9245A33C7R-G
*For other voltages, please contact your local Torex sales office or representative.
2/24
XC9244/XC9245
Series
■PIN CONFIGURATION
VSS 6
1 VOUT
Lx 5
2 VSS
VIN 4
3 CE
USPN-6
(BOTTOM VIEW)
*If the pad needs to be connected to other pins, it should be connected to the VSS (No. 2 and 6) pin.
■PIN ASSIGNMENT
PIN NUMBER
USPN-6
PIN NAME
FUNCTION
4
2, 6
3
1
5
VIN
VSS
CE
VOUT
LX
Power Input
Ground
Chip Enable
Output Voltage Monitor
Switching Output
■FUNCTION
XC9244/XC9245 Series, Type A
PIN NAME
CE
SIGNAL
STATUS
L
Stand-by
H
Active
* Please do not leave the CE pin open.
■ABSOLUTE MAXIMUM RATINGS
Ta=25℃
PARAMETER
SYMBOL
RATINGS
UNITS
VIN Pin Voltage
VIN
-0.3∼+6.5
V
Lx Pin Voltage
VLx
-0.3∼VIN+0.3 or +6.5 (*1)
V
VOUT Pin Voltage
VOUT
-0.3∼VIN+0.3 or +6.5 (*1)
V
CE Pin Voltage
VCE
-0.3∼ +6.5
V
Lx Pin Current
ILx
±1500
mA
Pd
100
mW
Power Dissipation
USPN-6
Operating Ambient Temperature
Topr
-40∼+85
℃
Storage Temperature
Tstg
-55∼+125
℃
* All voltages are described based on the VSS pin.
(*1) The maximum value should be either VIN+0.3 or +6.5 in the lowest.
3/24
XC9244/XC9245 Series
■ELECTRICAL CHARACTERISTICS
XC9244/XC9245
Ta=25℃
PARAMETER
SYMBOL
Output Voltage
VOUT
Operating Voltage Range
VIN
Maximum Output Current
IOUTMAX
UVLO Voltage
VUVLO
Quiescent Current
Iq
Stand-by Current
ISTB
Oscillation Frequency
fOSC
PFM Switch Current
PFM Duty Limit
(*3)
IPFM
(*3)
DTYLIMIT_PFM
CONDITIONS
When connected to external components,
VIN=VCE=5.0V, IOUT=30mA
When connected to external components
(*1)
,VIN=VCE=VOUT(E)+2.0V,
VIN=VCE,VOUT=0V,Voltage which Lx pin
holding “L” level
(*2,*9)
MIN.
TYP.
MAX.
UNITS
CIRCUIT
V
①
2.3
-
6.0
V
①
400
-
-
mA
①
1.60
1.90
2.25
V
③
VIN=VCE=5.0V, VOUT=VOUT(E) × 1.1V
-
18
30
μA
②
VIN=5.0V, VCE=0V, VOUT=0V
-
0.0
1.0
μA
②
1020
1200
1380
kHz
①
125
180
235
mA
①
-
-
300
%
①
When connected to external components,
VIN=VCE=5.0V, IOUT=200mA
When connected to external components,
VIN=VCE = (C-1) , IOUT=1mA
VIN=VCE= (C-2), IOUT=1mA
Maximum Duty Cycle
DMAX
VIN=VCE =5.0V, VOUT=VOUT(E) × 0.9V
100
-
-
%
③
Minimum Duty Cycle
DMIN
VIN=VCE=5.0V, VOUT=VOUT(E) × 1.1V
-
-
0
%
③
Efficiency
EFFI
-
-
%
①
Lx SW”H”ON Resistance
RLXH
-
0.65
0.85
Ω
④
Ω
-
1.00
μA
⑤
Lx SW”L”ON Resistance
When connected to external components,
VIN=VCE=VOUT(E) +1.5V, IOUT =100mA
(*4)
VIN=VCE=5.0V, VOUT=0V, ILX=100mA
(*5)
RLXL
VIN=VCE=5.0V
-
Lx SW”H” Leakage Current
ILeakH
VIN=VOUT=5.0V, VCE=0V, VLX=0V
-
0.00
Lx SW”L” Leakage Current
(*7)
ILeakL
VIN=VOUT=5.0V, VCE=0V, VLX=5.0V
-
0.00
1.00
μA
⑤
ILIM
VIN=VCE=5.0V, VOUT=VOUT(E) ×0.9V
700
900
1200
mA
⑥
-
±100
-
ppm/℃
①
(*8)
0.65
(*6)
(*7)
Current Limit
0.45
(*6)
Output Voltage Temperature
ΔVOUT/
Characteristics
(VOUT・ΔTopr)
CE ”H” Voltage
VCEH
VIN=5.0V, VOUT=0V, Applied voltage to
(*9)
VCE,Voltage changes Lx to “H” level
1.20
-
6.00
V
③
CE ”L” Voltage
VCEL
VIN=5.0V, VOUT=0V, Applied voltage to
(*9)
VCE,Voltage changes Lx to “L” level
VSS
-
0.25
V
③
CE ”H” Current
ICEH
VIN=5.0V, VCE=5.0V, VOUT=0V
-0.1
-
0.1
μA
⑤
CE ”L” Current
ICEL
VIN=5.0V, VCE=0V, VOUT=0V
-0.1
-
0.1
μA
⑤
Soft-Start Time
tSS
-
0.25
-
ms
①
Latch Time
tLAT
0.50
1.00
5.00
ms
⑦
CL Discharge
RDCHG
50
120
200
Ω
⑧
IOUT=30mA, -40℃≦Topr≦85℃
When connected to external components,
VIN=5.0V, VCE=0V → 5.0V, IOUT=1mA
VIN=VCE=5.0V, VOUT=0.8×VOUT(E),
Short Lx at 1Ω resistance
(*10)
VIN=5.0V, VCE=0V, VOUT=5.0V
NOTE:
Unless otherwise stated, VIN=5.0V, VOUT(E)=Nominal Voltage
(*1) 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.
(*2) Including UVLO detect voltage, hysteresis operating voltage range for UVLO release voltage. UVLO release voltage is VIN voltage which is
Lx pin becomes “H”.
(*3) XC9244 series exclude IPFM and DTYLIMIT_PFM because those are only for the PFM control’s functions.
(*4) EFFI = { ( output voltage×output current ) / ( input voltage×input current) }×100
(*5) ON resistance= (VIN - Lx pin measurement voltage) / 100mA
(*6) Design value
(*7) When temperature is high, a current of approximately 10μA (maximum) may leak.
(*8）Current limit denotes the level of detection at peak of coil current.
(*9) "H"＝VIN∼VIN - 1.2V, "L"＝+ 0.1V ∼ - 0.1V
(*10) Time until it short-circuits VOUT with GND via 1Ωof resistor from an operational state and is set to Lx=0V from current limit pulse generating.
4/24
XC9244/XC9245
Series
■ELECTRICAL CHARACTERISTICS (Continued)
SPEC Table
1) IPFM,DTYLIMIT_PFM,VOUT,EFFI
NOMINAL
OUTPUT
IPFM
DTYLIMIT_PFM
VOLTAGE
VOUT
EFFI (TYP.)
MIN.
TYP.
MAX.
0.80
0.784
0.800
0.816
77
0.85
0.833
0.850
0.867
78
0.90
0.882
0.900
0.918
79
0.95
0.931
0.950
0.969
80
1.00
0.980
1.000
1.020
81
1.05
1.029
1.050
1.071
82
1.10
1.078
1.100
1.122
83
1.15
1.127
1.150
1.173
84
1.176
1.200
1.224
85
1.225
1.250
1.275
85
1.274
1.300
1.326
86
1.35
1.323
1.350
1.377
86
1.40
1.372
1.400
1.428
86
1.45
1.421
1.450
1.479
86
1.50
1.470
1.500
1.530
87
1.55
1.519
1.550
1.581
87
1.60
1.568
1.600
1.632
87
1.65
1.617
1.650
1.683
87
1.70
1.666
1.700
1.734
88
1.75
1.715
1.750
1.785
88
1.80
1.764
1.800
1.836
88
1.85
1.813
1.850
1.887
88
1.90
1.862
1.900
1.938
89
1.95
1.911
1.950
1.989
89
2.00
1.960
2.000
2.040
89
2.05
2.009
2.050
2.091
89
2.10
2.058
2.100
2.142
89
2.107
2.150
2.193
90
2.156
2.200
2.244
90
2.205
2.250
2.295
90
2.30
2.254
2.300
2.346
90
2.35
2.303
2.350
2.397
90
2.40
2.352
2.400
2.448
91
2.45
2.401
2.450
2.499
91
2.50
2.450
2.500
2.550
91
2.55
2.499
2.550
2.601
91
2.60
2.548
2.600
2.652
91
2.65
2.597
2.650
2.703
91
2.70
2.646
2.700
2.754
92
VOUT(E)
1.20
3.6V
1.25
2.3V
1.30
2.15
2.20
2.25
VOUT(E)+2.0V
VOUT(E)+0.5V
5/24
XC9244/XC9245 Series
■ELECTRICAL CHARACTERISTICS (Continued)
SPEC Table
1) IPFM,DTYLIMIT_PFM,VOUT,EFFI
NOMINAL
OUTPUT
IPFM
DTYLIMIT_PFM
VOLTAGE
EFFI
VOUT
(TYP.)
MIN.
TYP.
MAX.
2.75
2.695
2.750
2.805
92
2.80
2.744
2.800
2.856
92
2.85
2.793
2.850
2.907
92
2.90
2.842
2.900
2.958
92
2.95
2.891
2.950
3.009
92
3.00
2.940
3.000
3.060
92
3.05
2.989
3.050
3.111
92
3.10
3.038
3.100
3.162
93
3.15
3.087
3.150
3.213
93
3.20
3.136
3.200
3.264
93
3.25
3.185
3.250
3.315
93
3.30
3.234
3.300
3.366
93
3.283
3.350
3.417
93
VOUT(E)
3.35
3.40
VOUT(E)+2.0V
VOUT(E)+0.5V
3.332
3.400
3.468
93
3.45
3.381
3.450
3.519
93
3.50
3.430
3.500
3.570
93
3.55
3.479
3.550
3.621
93
3.60
3.528
3.600
3.672
93
3.65
3.577
3.650
3.723
93
3.70
3.626
3.700
3.774
93
3.75
3.675
3.750
3.825
94
3.80
3.724
3.800
3.876
94
3.85
3.773
3.850
3.927
94
3.90
3.822
3.900
3.978
94
3.95
3.871
3.950
4.029
94
4.00
3.920
4.000
4.080
94
6/24
XC9244/XC9245
Series
■TYPICAL APPLICATION CIRCUIT
L
VIN
VIN
CE
CIN
VOUT
400mA
Lx
CE
VOUT
CL
(ceramic)
VSS
(ceramic)
●External Components
L
CIN
CL
MANUFACTURE
PRODUCT NUMBER
RATED VOLTAGE / INDUCTANCE
DIMENTION (mm)
TDK
SPM3012-4R7
4.7μH
3.2 x 3.0 x h1.2
TAIYO YUDEN
NR3015-4R7
4.7μH
3.0 x 3.0 x h1.5
Coilcraft
EPL3015-4R7
4.7μH
3.2 x 3.2 x h1.55
TAIYO YUDEN
LMK212ABJ475KG
10V / 4.7μF
2.0 x 1.25 x h1.4
CM105X5R475K10A
10V / 4.7μF
1.6 x 0.8 x h1.0
LMK212ABJ106KG
10V / 10μF
2.0 x 1.25 x h1.4
CM105X5R106M10A
10V / 10μF
1.6 x 0.8 x h1.0
KYOCERA
TAIYO YUDEN
KYOCERA
7/24
XC9244/XC9245 Series
■OPERATIONAL DESCRIPTION
The XC9244/XC9245 series consists of a reference voltage source, ramp wave circuit, error amplifier, PWM comparator, phase compensation
circuit, output voltage adjustment resistors, P-channel MOS driver transistor, N-channel MOS switching transistor for the synchronous switch,
current limiter circuit, UVLO circuit and others.
(See the block diagram below.)
The series ICs compare, using the error amplifier, the voltage of the internal voltage reference source with the feedback voltage from the VOUT
pin through split resistors, R1 and R2.
Phase compensation is performed on the resulting error amplifier output, to input a signal to the PWM
comparator to determine the turn-on time during PWM operation.
The PWM comparator compares, in terms of voltage level, the signal from the
error amplifier with the ramp wave from the ramp wave circuit, and delivers the resulting output to the buffer driver circuit to cause the Lx pin to
output a switching duty cycle.
This process is continuously performed to ensure stable output voltage.
The current feedback circuit monitors
the P-channel MOS driver transistor current for each switching operation, and modulates the error amplifier output signal to provide multiple
feedback signals.
This enables a stable feedback loop even when a low ESR capacitor such as a ceramic capacitor is used ensuring stable
output voltage.
XC9244/XC9245 Series, Type A
Phase
Compensation
VOUT
Current Feedback
Current Limit
CFB
R1
Error Amp.
PWM
Comparator
Logic
CEB
R2
Vref with
Soft Start,
CE
VIN
Synch.
Buffer
Drive
Lx
PWM/PFM
Selector
UVLO Comparator
Ramp Wave
Generator
OSC
UVLO
R3
R4
CEB
CE
Control
Logic
CE
VSS
The reference voltage source provides the reference voltage to ensure stable output voltage of the DC/DC converter.
The ramp wave circuit determines switching frequency.
The frequency is fixed internally as1.2MHz.
Clock pulses generated in this circuit are
used to produce ramp waveforms needed for PWM operation, and to synchronize all the internal circuits.
The error amplifier is designed to monitor output voltage.
internal split resistors, R1 and R2.
increases.
The amplifier compares the reference voltage with the feedback voltage divided by the
When a voltage lower than the reference voltage is fed back, the output voltage of the error amplifier
The gain and frequency characteristics of the error amplifier output are fixed internally to deliver an optimized signal to the mixer.
The error amplifier output signal optimized in the mixer is modulated with the current feedback signal.
compatator.
8/24
This signal is delivered to the PWM
XC9244/XC9245
Series
■OPERATIONAL DESCRIPTION (Continued)
The current limiter circuit of the XC9244/XC9245 series monitors the current flowing through the P-channel MOS driver transistor connected to
the Lx pin, and features a combination of the current limit mode and the operation suspension mode.
① When the driver current is greater than a specific level, the current limit function operates to turn off the pulses from the Lx pin at any given
timing.
② When the P-channel MOS driver transistor is turned off, the limiter circuit is then released from the current limit detection state.
③ At the next pulse, the P-channel MOS driver transistor is turned on. However, the P-channel MOS driver transistor is immediately turned off
in the case of an over current state.
④ When the over current state is eliminated, the IC resumes its normal operation.
The IC waits for the over current state to end by repeating the steps ① through ③. If an over current state continues for a few ms and the
above three steps are repeatedly performed, the IC performs the function of latching the OFF state of the P-channel MOS driver transistor,
and goes into operation suspension mode. Once the IC is in suspension mode, operations can be resumed by either turning the IC off via
the CE/MODE pin, or by restoring power to the VIN pin. The suspension mode does not mean a complete shutdown, but a state in which
pulse output is suspended; therefore, the internal circuitry remains in operation. The current limit of the XC9244/XC9245 series can be set
at 900mA at typical. Besides, 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.
When the VIN voltage becomes 1.6V or lower, the P-ch MOS driver transistor output driver transistor is forced OFF to prevent false pulse output
caused by unstable operation of the internal circuitry. When the VIN pin voltage becomes 2.25V or higher, switching operation takes place. By
releasing the UVLO function, the IC performs the soft start function to initiate output startup operation. The soft start function operates even
when the VIN pin voltage falls momentarily below the UVLO operating voltage. The UVLO circuit does not cause a complete shutdown of the IC,
but causes pulse output to be suspended; therefore, the internal circuitry remains in operation.
(*1)
In PFM control operation, until coil current reaches to a specified level (IPFM), the IC keeps the P-ch MOS driver transistor on.
that the P-ch MOS driver transistor is kept on (tON) can be given by the following formula.
tON= L×IPFM / (VIN−VOUT) →IPFM①
In this case, time
< PFM Duty Limit > (*1)
In PFM control operation, the PFM duty limit (DTYLIMIT_PFM) is set to 300% (MAX.).
Therefore, under the condition that the duty increases (e.g. the condition that the step-down ratio is small), it’s possible for P-ch MOS driver
transistor to be turned off even when coil current doesn’t reach to IPFM. →IPFM②
(* 1) XC9244 series exclude.
9/24
XC9244/XC9245 Series
■OPERATIONAL DESCRIPTION (Continued)
XC9244/ XC9245 series can quickly discharge the electric charge at the output capacitor (CL) when a low signal to the CE pin which enables a
whole IC circuit put into OFF state, is inputted via the N-ch MOS switch transistor located between the VOUT pin and the VSS pin. When the IC is
disabled, electric charge at the output capacitor (CL) is quickly discharged so that it may avoid application malfunction. Discharge time of the
output capacitor (CL) is set by the CL auto-discharge resistance (R) and the output capacitor (CL). By setting time constant of a CL auto-discharge
resistance value [RDCHG] and an output capacitor value (CL) as τ(τ= CL×RDCHG), discharge time of the output voltage after discharge via the
N-channel transistor is calculated by the following formulas.
V = VOUT(E)×e
-t /τ
or
t = τln (VOUT(E) /V)
Output Voltage Dischage Characteristics
RDCHG=120Ω(TYP)
100
V: Output voltage after discharge
CL=10μF
CL=20μF
CL=50μF
Output Voltage (Relative Value)
100 = Setting Voltage Value
90
VOUT(E): Output voltage
t: Discharge time
τ: CL×RDCHG
CL: Capacitance of Output capacitor
RDCHG: CL auto-discharge resistance
80
70
60
50
40
30
20
10
0
0
10
20
30
40
50
Discharge Time t (ms)
The operation of the XC9244/XC9245 series will enter into the shut down mode when a low level signal is input to the CE pin. During the
shutdown mode, the current consumption of the IC becomes 0μA (TYP.), with a state of high impedance at the Lx pin and CL high speed
discharge at VOUT pin. The IC starts its operation by inputting a high level signal to the CE pin. The input to the CE pin is a CMOS input and the
sink current is 0μA (TYP.).
1) XC9244/XC9245 series - Examples of how to use CE pin
(A)
SW_CE
STATUS
ON
Stand-by
OFF
Operation
SW_CE
STATUS
ON
Stand-by
OFF
Operation
(B)
The XC9244/ XC9245 series provide 0.25ms (TYP).
time when the VCE is turned on.
10/24
Soft start time is defined as the time interval to reach 90% of the output voltage from the
XC9244/XC9245
Series
■NOTE ON USE
1.
Please use this IC within the stated maximum ratings. For temporary, transitional voltage drop or voltage rising phenomenon, the IC is liable
to malfunction should the ratings be exceeded.
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. 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.
4. 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.
V OUT：100mV/div
ILx：100mA/div
V Lx：5V/div
Horizon：200μsec/div
5. 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.
inductance value and fully check the circuit operation.
When peak current becomes high, please adjust the coil
In addition, please calculate the peak current according to the following formula:
Ipk = (VIN - VOUT)×OnDuty / (2×L×fOSC) + IOUT
L: Coil Inductance Value
fOSC: Oscillation Frequency
6. When the peak current which exceeds limit current flows within the specified time, the built-in P-ch 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.
7. 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.
8. Please do not use the IC at voltages below the recommended voltage range.
9. This IC should be used within the stated absolute maximum ratings in order to prevent damage to the device.
10. 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.
11. The current limit is set to 1200mA (MAX.) at typical. However, the current of 1200mA or more may flow. In case that the current limit
functions while the VOUT pin is shorted to the GND pin, when P-ch 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 N-ch 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.
①Current flows into P-ch MOS driver transistor to reach the current limit (ILIM).
②The 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 P-ch MOS driver transistor.
③Because of no potential difference at both ends of the coil, the time rate of coil current becomes quite small.
④Lx oscillates very narrow pulses by the current limit for several ms.
⑤The circuit is latched, stopping its operation.
11/24
XC9244/XC9245 Series
■NOTE ON USE (Continued)
12. In order to stabilize VIN’s voltage level, we recommend that a by-pass capacitor (CIN) be connected as close as possible to the VIN & VSS pins.
13. In case of VIN＜2.5V, the maximum load current may be decreased less than 400mA due to the characteristics of current limit.
14. Torex places an importance on improving our products and their reliability.
We request that users incorporate fail-safe designs and post-aging protection treatment when using Torex products in their systems.
●Instructions of pattern layouts
1. In order to stabilize VIN voltage level, we recommend that a by-pass capacitor (CIN) be connected as close as possible to the VIN & VSS pins.
2. Please mount each external component as close to the IC as possible.
3. Wire external components as close to the IC as possible and use thick, short connecting traces to reduce the circuit impedance.
4. Make sure that the PCB GND traces are as thick as possible, as variations in ground potential caused by high ground currents at the time of
switching may result in instability of the IC.
5. This series’ internal P-ch driver transistors bring on heat because of the output current and ON resistance of driver transistors.
●Recommended Pattern Layout
st
1 Layer
PCB
12/24
nd
2 Layer
XC9244/XC9245
Series
■TEST CIRCUITS
13/24
XC9244/XC9245 Series
■TYPICAL PERFORMANCE CHARACTERISTICS
(1)
Efficiency
vs. Output Current (Compare to different coil)
(1)効率
- 出力電流特性例（コイル別比較）
XC9244A12C(VIN=3.6V)
XC9245A12C(VIN=3.6V)
CIN=4.7μF(LMK212BJ475)
L=4.7μH,CL=10μF(LMK212BJ106)
80
60
SPM3012(TDK)
NR3015(TAIYO YUDEN)
EPL3015(Coilcraft)
40
20
L=4.7μH,CL=10μF(LMK212BJ106)
100
Efficiency : EFFI (%)
100
Efficiency : EFFI (%)
CIN=4.7μF(LMK212BJ475)
80
60
SPM3012(TDK)
NR3015(TAIYO YUDEN)
EPL3015(Coilcraft)
40
20
0
0
0.1
1
10
100
0.1
1000
1
10
100
1000
Output Current : IOUT (mA)
Output Current : IOUT (mA)
(1)
Efficiency
vs. Output Current
(1)効率
- 出力電流特性例
XC9244/XC9245A12C
100
XC9244/XC9245A18C
CIN=4.7μF(LMK212BJ475)
CIN=4.7μF(LMK212BJ475)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
100
80
60
4.2V
3.6V
40
20
PWM Control
VIN=2.3V
3.6V
4.2V
Efficiency : EFFI (%)
Efficiency : EFFI (%)
VIN=2.3V
0
10
100
1000
4.2V
40
PWM Control
VIN=3.6V
4.2V
3.6V
20
0.1
1
10
100
Output Current : IOUT (mA)
Output Current : IOUT (mA)
XC9244/XC9245A33C
(2) Output Voltage
vs. Output Current
(2)出力電圧
- 出力電流特性例
XC9244/XC9245A12C
1000
CIN=4.7μF(LMK212BJ475)
CIN=4.7μF(LMK212BJ475)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
80
60
VIN=4.2V
40
VIN=5.0V
20
PWM Control
VIN=4.2V
5.0V
1.30
Output Voltage : VOUT (V)
Efficiency : EFFI (%)
1
0
1.28
1.25
VIN=2.3V,3.6V,4.2V
1.23
1.20
1.18
1.15
1.13
1.10
0.1
1
10
100
Output Current : IOUT (mA)
14/24
60
0
0.1
100
80
1000
0.1
1
10
100
Output Current : IOUT (mA)
1000
XC9244/XC9245
Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(2)
Output Voltage- vs.
Output Current (Continued)
(2)出力電圧
出力電流特性例
XC9244/XC9245A18C
CIN=4.7μF(LMK212BJ475)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
1.88
VIN=3.6V,4.2V
1.85
3.40
Output Voltage : VOUT (V)
Output Voltage : VOUT (V)
1.90
XC9244/XC9245A33C
CIN=4.7μF(LMK212BJ475)
1.83
1.80
1.78
1.75
1.73
1.70
3.38
3.35
VIN=4.2V,5.0V
3.33
3.30
3.28
3.25
3.23
3.20
0.1
1
10
100
1000
0.1
1
10
100
1000
Output Current : IOUT (mA)
Output Current : IOUT (mA)
(3)
Ripple Voltage vs. -Output
Current
(3)リップル電圧
出力電流特性例
XC9244/XC9245A12C
XC9244/XC9245A18C
CIN=4.7μF(LMK212BJ475)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
PWM/PFM Automatic
Switching Control
VIN=2.3V
PWM Control
3.6V
VIN=2.3V,3.6V,4.2V
4.2V
80
60
40
20
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
100
Ripple Voltage : Vr (mV)
100
Ripple Voltage : Vr (mV)
CIN=4.7μF(LMK212BJ475)
80
60
PWM Control
VIN=3.6V,4.2V
PWM/PFM Automatic
Switching Control
VIN= 3.6V
4.2V
40
20
0
0
0.1
1
10
100
0.1
1000
Output Current : IOUT (mA)
1
10
100
1000
Output Current : IOUT (mA)
(4) Output Voltage
vs. Ambient Temperature
(4)出力電圧
- 周囲温度特性例
XC9244/XC9245A33C
CIN=4.7μF(LMK212BJ475)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
80
60
PWM Control
VIN=4.2V,5.0V
40
PWM/PFM Automatic
Switching Control
VIN=4.2V
5.0V
20
1.98
Output Voltage :Vout (V)
Ripple Voltage : Vr (mV)
100
CIN=4.7μF(LMK212BJ475)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
1.94
1.90
VIN=2.3V,3.6V,5.0V
1.86
1.82
1.78
1.74
1.70
1.66
1.62
0
0.1
1
10
100
Output Current : IOUT (mA)
1000
-50
-25
0
25
50
75
100
Ambient temperture: Ta (℃)
15/24
XC9244/XC9245 Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
1.5
(6) Oscillation Frequency
vs. Input Voltage
(6)発振周波数
- 入力電圧特性例
CIN=4.7μF(LMK212BJ475)
CIN=4.7μF(LMK212BJ475)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
1.4
VIN=2.3V
VIN=3.6V
1.3
Oscillation Freqency : fOSC(MHz)
Oscillation Freqency : fOSC(MHz)
(5)(5)発振周波数
Oscillation Frequency
vs. Ambient Temperature
- 周囲温度特性例
1.2
1.1
1.0
VIN=5.0V
0.9
0.8
-50
-25
0
25
50
75
1.5
1.4
Ta=25℃,85℃
1.3
1.2
1.1
1.0
Ta=-40℃
0.9
0.8
100
1.5
2.5
40
40
35
35
VIN=2.3V,3.6V,5.0V
25
20
15
10
5
0
6.5
30
Ta=25℃,85℃
25
20
15
10
Ta=-40℃
5
0
-50
-25
0
25
50
75
100
1.5
2.5
(9) CE "H" Voltage vs. Ambient Temperature
CE"H" Voltage : VCEH (V)
VIN=2.3V
VIN=3.6V
VIN=5.0V
-50
-25
0
25
50
4.5
5.5
6.5
(10) CE "H" Voltage vs. Input Voltage
(10)CE"H"電圧
- 入力電圧特性例
(9)CE"H"電圧 - 周囲温度特性例
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
3.5
Input Voltage: VIN (V)
Ambient temperture: Ta (℃)
CE"H" Voltage : VCEH (V)
5.5
(8) Quiescent
Current -vs.
Input Voltage
(8)消費電流
入力電圧特性例
Quiescent Current : Iq (μA)
Quiescent Current : Iq (μA)
(7)(7)消費電流
Quiescent Current
vs. Ambient Temperature
- 周囲温度特性例
75
Ambient temperture: Ta (℃)
16/24
4.5
Input Voltage: VIN (V)
Ambient temperture: Ta (℃)
30
3.5
100
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Ta=-40℃
Ta=85℃
Ta=25℃
1.5
2.5
3.5
4.5
5.5
Input Voltage: VIN (V)
6.5
XC9244/XC9245
Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
1.6
1.4
VIN=2.3V
1.2
1.0
VIN=3.6V
0.8
0.6
0.4
0.2
VIN=5.0V
0.0
-50
-25
0
25
50
75
(12)
Lx SWSW
"H" ON
Resistance vs.
Input Voltage
(12)Lx
"H"ON抵抗
- 入力電圧特性例
Lx SW "H"ON Resistance : RLxH (Ω)
Lx SW "H"ON Resistance : RLxH (Ω)
(11)
Lx SW "H"
ON"H"ON抵抗
Resistance vs. -Ambient
Temperature
(11)Lx
SW
周囲温度特性例
1.6
1.4
1.2
Ta=25℃
1.0
Ta=85℃
0.8
0.6
0.4
Ta=-40℃
0.2
0.0
100
1.5
2.5
Ambient temperture: Ta (℃)
1.4
1.2
1.0
VIN=3.6V
0.6
0.4
0.2
VIN=5.0V
0.0
-50
-25
0
25
50
75
1.4
1.2
1.0
Ta=-40℃
Ta=25℃
0.8
Ta=85℃
0.6
0.4
0.2
0.0
100
1.5
2.5
4.5
5.5
6.5
(16)
CL Discharge
vs. Input
Voltage
(16)C
- 入力電圧特性例
L放電抵抗
300
300
250
250
CL Discharge : RDCHG(Ω)
CL Discharge : RDCHG(Ω)
3.5
Input Voltage: VIN (V)
(15)
CL Discharge
vs. Ambient
Temperature
- 周囲温度特性例
(15)C
L放電抵抗
VIN=2.3V
150
100
50
6.5
1.6
Ambient temperture: Ta (℃)
200
5.5
(14)
Lx SW SW
"L" ON
Resistance vs.- Input
Voltage
(14)"Lx
"L"ON抵抗
入力電圧特性例
Lx SW "L"ON Resistance : RLxL (Ω)
Lx SW "L"ON Resistance : RLxL (Ω)
1.6
VIN=2.3V
4.5
Input Voltage: VIN (V)
(13)
Lx SW "L"
ON"L"ON抵抗
Resistance vs. -Ambient
Temperature
(13)Lx
SW
周囲温度特性例
0.8
3.5
VIN=3.6V,5.0V
0
200
Ta=25℃
Ta=85℃
150
100
50
Ta=-40℃
0
-50
-25
0
25
50
75
Ambient temperture: Ta (℃)
100
1.5
2.5
3.5
4.5
5.5
6.5
Input Voltage: VIN (V)
17/24
XC9244/XC9245 Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(17)
PFM Switch Current vs. Ambient
Temperature
(17)PFMスイッチ電流
- 周囲温度特性例
(18)
PFM Switch Current vs. Input
Voltage
(18)PFMスイッチ電流
- 入力電圧特性例
VOUT(E)=0.8V,CIN=4.7μF(LMK212BJ475)
PFM Switch Current : IPFM (mA)
VIN=2.3V
VIN=3.6V
VIN=5.0V
-50
-25
0
25
50
75
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
250
230
210
190
170
150
130
110
90
70
50
PFM Switch Current : IPFM (mA)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
250
230
210
190
170
150
130
110
90
70
50
VOUT(E)=0.8V,CIN=4.7μF(LMK212BJ475)
Ta=-40℃
Ta=25℃
Ta=85℃
1.5
100
2.5
4.5
5.5
6.5
Input Voltage: VIN (V)
Ambient temperture: Ta (℃)
(19)
Current Limit vs. -Ambient
Temperature
(19)電流制限
周囲温度特性例
(20)
Current Limit vs.
Input Voltage
(20)電流制限
- 入力電圧特性例
1200
1200
1100
1100
Current Limit : ILIM (mA)
Current Limit : ILIM (mA)
3.5
1000
Ta=85℃
1000
900
VIN=3.6V
800
VIN=5.0V
700
600
VIN=2.3V
500
400
900
800
Ta=25℃
700
Ta=-40℃
600
500
400
-50
-25
0
25
50
75
100
1.5
2.5
3.5
4.5
5.5
6.5
Input Voltage: VIN (V)
Ambient temperture: Ta (℃)
(21)
UVLO Voltage vs. Ambient
Temperature
(21)UVLO電圧
- 周囲温度特性例
(22)
Soft Start Time vs. Input Voltage
(22)ソフトスタート時間
- 周囲温度特性例
CIN=4.7μF(LMK212BJ475)
2.2
Soft Start Time: tSS (μs)
UVLO Voltage : UVLO (V)
2.3
2.1
2.0
1.9
1.8
1.7
1.6
1.5
-50
-25
0
25
50
75
Ambient temperture: Ta (℃)
18/24
100
500
450
400
350
300
250
200
150
100
50
0
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
VOUT=2.0V
VOUT=4.0V
VOUT=0.8V
-50
-25
0
25
50
75
Ambient temperture: Ta (℃)
100
XC9244/XC9245
Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(23)
Rise Wave Form
(23)起動波形例
XC9244/XC9245A12C
XC9244/XC9245A18C
CIN=4.7μF(LMK212BJ475)
CIN=4.7μF(LMK212BJ475)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
VIN=5.0V
IOUT=1mA
VIN=5.0V
IOUT=1mA
VOUT ：0.5V/div
VOUT ：0.5V/div
CE ：0V⇒5.0V
CE ：0V⇒5.0V
100μs/div
100μs/div
XC9244/XC9245A33C
CIN=4.7μF(LMK212BJ475)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
VIN=5.0V
IOUT=1mA
VOUT ：1.0V/div
CE ：0V⇒5.0V
100μs/div
19/24
XC9244/XC9245 Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(24)
Load Transient Response
(24)負荷過渡応答特性例
XC9244A18C
XC9244A18C
CIN=4.7μF(LMK212BJ475)
CIN=4.7μF(LMK212BJ475)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
IOUT=1mA⇒100mA
VOUT ：50mV/div
50μs/div
IOUT=1mA⇒300mA
VOUT ：50mV/div
XC9244A18C
XC9244A18C
CIN=4.7μF(LMK212BJ475)
CIN=4.7μF(LMK212BJ475)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
IOUT=300mA⇒1mA
IOUT=100mA⇒1mA
VOUT ：50mV/div
VOUT ：50mV/div
200μs/div
20/24
50μs/div
200μs/div
XC9244/XC9245
Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(24)
Load Transient Response (Continued)
(24)負荷過渡応答特性例
XC9245A18C
XC9245A18C
CIN=4.7μF(LMK212BJ475)
CIN=4.7μF(LMK212BJ475)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
IOUT=1mA⇒300mA
IOUT=1mA⇒100mA
VOUT ：50mV/div
50μs/div
VOUT ：50mV/div
XC9245A18C
50μs/div
XC9245A18C
CIN=4.7μF(LMK212BJ475)
CIN=4.7μF(LMK212BJ475)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)
IOUT=100mA⇒1mA
IOUT=300mA⇒1mA
VOUT ：50mV/div
VOUT ：50mV/div
200μs/div
200μs/div
21/24
XC9244/XC9245 Series
■PACKAGING INFORMATION
●USPN-6
Reference Pattern Layout
●USPN-6
0.15
22/24
●USPN-6
Reference Metal Mask Design
0.25
0.2
0.25
0.2
0.2
0.2
6
5
4
6
5
4
1
0.45
2
0.45
3
0.15
0.1
1
0.45
2 0.45 3
0.1
XC9244/XC9245
Series
■MARKING RULE
① represents product series and output voltage
XC9244 Series
●USPN-6
1
① ②
3
③ ④
2
6
5
4
MARK
OUTPUT
VOLTAGE
VOLTAGE
INCREMENT
PRODUCT SERIES
A
0.8∼3.7
0.1
XC9244A08C**-G ∼ XC9244A37C**-G
B
0.85∼3.75
0.05
XC9244A0LC**-G ∼ XC9244A3KC**-G
C
3.8∼4.0
0.1
XC9244A38C**-G ∼ XC9244A40C**-G
C
3.85∼3.95
0.05
XC9244A3LC**-G ∼ XC9244A3MC**-G
VOLTAGE
INCREMENT
PRODUCT SERIES
XC9245 Series
MARK
OUTPUT
VOLTAGE
D
0.8∼3.7
0.1
XC9245A08C**-G ∼ XC9245A37C**-G
E
0.85∼3.75
0.05
XC9245A0LC**-G ∼ XC9245A3KC**-G
F
3.8∼4.0
0.1
XC9245A38C**-G ∼ XC9245A40C**-G
F
3.85∼3.95
0.05
XC9245A3LC**-G ∼ XC9245A3MC**-G
② represents product function
MARK
OUTPUT VOLTAGE
MARK
OUTPUT VOLTAGE
0
0.8
0.85
F
2.3
2.35
1
0.9
0.95
H
2.4
2.45
2
1.0
1.05
K
2.5
2.55
3
1.1
1.15
L
2.6
2.65
4
1.2
1.25
M
2.7
2.75
5
1.3
1.35
N
2.8
2.85
6
1.4
1.45
P
2.9
2.95
7
1.5
1.55
R
3.0
3.05
8
1.6
1.65
S
3.1
3.15
9
1.7
1.75
T
3.2
3.25
A
1.8
1.85
3.8
U
3.3
3.35
B
1.9
1.95
3.9
V
3.4
3.45
C
2.0
2.05
4.0
X
3.5
3.55
D
2.1
2.15
3.85
Y
3.6
3.65
E
0.8
0.85
3.95
Z
3.7
3.75
③④ represents production lot number
01 to 09, 0A to 0Z, 11 to 9Z, AA to AZ, B1 to ZZ repeated.
(G, I, J, O, Q, W excluded)
*No character inversion used.
23/24
XC9244/XC9245 Series
1. The products and product specifications contained herein are subject to change without
notice to improve performance characteristics.
Consult us, or our representatives
before use, to confirm that the information in this datasheet is up to date.
2. We assume no responsibility for any infringement of patents, patent rights, or other
rights arising from the use of any information and circuitry in this datasheet.
3. Please ensure suitable shipping controls (including fail-safe designs and aging
protection) are in force for equipment employing products listed in this datasheet.
4. The products in this datasheet are not developed, designed, or approved for use with
such equipment whose failure of malfunction can be reasonably expected to directly
endanger the life of, or cause significant injury to, the user.
(e.g. Atomic energy; aerospace; transport; combustion and associated safety
equipment thereof.)
5. Please use the products listed in this datasheet within the specified ranges.
Should you wish to use the products under conditions exceeding the specifications,
please consult us or our representatives.
6. We assume no responsibility for damage or loss due to abnormal use.
7. All rights reserved. No part of this datasheet may be copied or reproduced without the
prior permission of TOREX SEMICONDUCTOR LTD.
24/24
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