XC9248 Series
ETR05022-004
18V Driver Transistor Built-In Synchronous Step-Down DC/DC Converter
■GENERAL DESCRIPTION
The XC9248 series is 18V bootstrap synchronous step-down DC/DC converter with built-in Nch-Nch driver transistors.
With an input voltage range from 4.5V to 18V and a maximum output current of 2.2A, the series is suitable for digital home
appliance power supplies and can be used with small ceramic capacitors.
The series has a 0.8V reference voltage, and using externally connected resistors, the output voltage can be set freely from
1.0V to 12V.
The control method is synchronous PWM (Source/ Sink). The soft start time is internally set to 2.8ms (TYP.), also can be
adjusted using external capacitor.
With UVLO (Under Voltage Lock Out) function, the internal driver transistors are forced OFF when input voltage falls down
below 3.8V (TYP.).
The series includes over current protection, VOUT short-circuit protection, Lx short-circuit protection, VOUT overvoltage
protection and thermal shutdown.
■FEATURES
■APPLICATIONS
Input Voltage
： 4.5V ～ 18V
Output Voltage
： 1.0V～12V (VFB=0.8V±1.5%)
●Office automation equipment
Output Current
： 2.2A
●Notebook computers
Efficiency
： 93.8%
Oscillation Frequency
： 500kHz
Maximum Duty Cycle
： 79%
Soft-Start Time
： Fixed2.8ms, set by external capacitor
Protection Circuit
： UVLO
●Digital home appliance
●Car accessories power supplies
(*1)
(*1)
@VIN=12V,VOUT=5V, IOUT=700mA
High side over current protection
Low side over current protection
VOUT Short-circuit Protection
LX Short-circuit Protection
VOUT Over voltage protection
Thermal shutdown
Package
： SOP-8FD
Environmentally Friendly
： EU RoHS Compliant, Pb Free
(*1)
Performance depends on external components and wiring on the PCB.
■TYPICAL APPLICATION CIRCUIT
■TYPICAL PERFORMANCE
CHARACTERISTICS
Efficiency vs. Output Current
L
VIN
LX
EN
EN
GND
SS
BST
FB
VL
CIN
CSS
VOUT
90
CBST
CVL
Ta=25°C
100
CFB
CL
RFB1
RFB2
80
Efficiency [%]
VIN
70
VIN=12V , VOUT=5V
60
50
VIN=12V , VOUT=3.3V
40
30
20
10
0
0
500
1000
1500
Output Current : IOUT [mA]
2000
1/21
XC9248 Series
■BLOCK DIAGRAM
* Internal diodes include an ESD protection diode and a parasitic diode.
■PRODUCT CLASSIFICATION
●Ordering Information
XC9248①②③④⑤⑥-⑦
DESIGNATOR
ITEM
①
TYPE
SYMBOL
A
DESCRIPTION
Refer to Selection Guide
B
FB Voltage
08
FB voltage is fixed in 0.8V
Oscillation Frequency
5
500kHz
Package
QR-G
②③
④
⑤⑥-⑦
(*1)
(*1)
SOP-8FD (1,000/Reel)
The “-G” suffix denotes Halogen and Antimony free as well as being fully RoHS compliant.
●Selection Guide
(*1)
(*2)
LATCH FOR
LATCH FOR
LATCH FOR
CURRENT LIMITER
VOUT-SHORT
LX-SHORT
TYPE
CURRENT LIMITER
A
YES
B
YES
NO
TYPE
ENABLE
UVLO
A
YES
B
YES
YES
(*1)
YES
YES
NO
YES
(*2)
CL
THERMAL
AUTO-DISCHARGE
SHUTDOWN
YES
YES
YES
YES
YES
YES
The over-current protection latch is an integral latch type.
To prevent an extremely large rush current from flowing in the event that Lx is short-circuited, both the A & B types have an Lx short
protection latch function.
2/21
XC9248
Series
■PIN CONFIGURATION
VIN 1
8 LX
EN 2
7 GND
SS 3
6 BST
FB 4
5 VL
SOP-8FD
(TOP VIEW)
* The dissipation pad for the SOP-8FD package should be solder-plated in recommended mount pattern and metal masking so as
to enhance mounting strength and heat release. If the pad needs to be connected to other pins, it should be connected to the
GND (No.7) pin.
■PIN CONFIGURATION
PIN NAME
FUNCTIONS
1
VIN
Power Input
2
EN
Enable
3
SS
External Soft-start
4
FB
FB Voltage Monitor
5
VL
Internal Regulator Output
6
BST
Pre Driver Supply
7
GND
Ground
8
LX
Switching Output
PIN NUMBER
■FUNCTION
PIN NAME
SIGNAL
STATUS
L
Stand-by
EN
H
Active
OPEN
(*1)
Undefined State
(*1)
On the XC9248 series, causes unspecified behavior and thus is prohibited.
3/21
XC9248 Series
■ABSOLUTE MAXIMUM RATINGS
Ta=25℃
PARAMETER
SYMBOL
RATINGS
UNITS
VIN Pin Voltage
VIN
-0.3 ～ +20
V
EN Pin Voltage
VEN
-0.3 ～ +20
V
(*1)
LX Pin Voltage
VLX
BST Pin Voltage
VBST
VL Pin Voltage
VVL
FB Pin Voltage
VFB
-0.3 ～ +5.5
V
SS Pin Voltage
VSS
-0.3 ～ +5.5
V
LX Pin Current
ILX
±5
A
VL Pin Current
IVL
85
mA
-0.3 ～ VIN +0.3 or +20
VL-0.3～VL+20
V
VLX -0.3～ VLX +5.5
-0.3 ～ VIN +0.3 or +5.5
V
(*2)
V
Power Dissipation
Pd
300
mW
Operating Ambient Temperature
Topr
-40～+105
°C
Storage Temperature
Tstg
-50～+125
°C
All voltages are described based on the ground voltage.
(*1)
The maximum value should be either VIN+0.3 or +20V in the lowest.
(*1)
The maximum value should be either VIN+0.3 or +5.5V in the lowest.
4/21
XC9248
Series
■ELECTRICAL CHARACTERISTICS
XC9248 Series
PARAMETER
Ta=25℃
SYMBOL
CONDITIONS
MIN.
TYP.
MAX.
UNITS
CIRCUIT
4.5
-
18
V
①
0.788
0.800
0.812
V
②
ppm/℃
②
When connected to external components
Operating Voltage Range
VIN
FB Voltage
VFB
FB Voltage
VFB/
Temperature Characteristics
(VFB・ΔTopr)
Maximum Output Current
IOUTMAX
Supply Current
Iq
VIN ≦7V: Setup VOUT=3.3V
VIN >7V: Setup VOUT=5V
VFB=Sweep (0.812V→0.788V), VSS=OPEN
±40
-40℃≦Topr≦105℃
When connected to external components
VIN=VEN=18V, VFB=0.9V
(*1)
2.2
-
-
-
A
①
0.76
1.10
mA
③
Stand-by Current
ISTB
VIN=18V, VEN=0V, VFB=OPEN
-
38
51
μA
③
Oscillation Frequency
fOSC
VFB=0.7V, VSS=OPEN
450
500
550
kHz
②
Maximum Duty Cycle
Dmax
VFB=0.7V, VSS=OPEN
74
79
-
%
②
3.50
3.80
4.45
V
④
3.55
3.90
4.50
V
④
2.1
-
-
A
⑦
0.4
1.1
1.8
ms
⑤
-
2.8
-
ms
②
2
4
6
μA
⑥
1.2
1.8
2.4
V
②
-
0.9
1.2
V
②
-
93.8
-
%
⑧
VIN=Sweep (4.5V→3.5V) , VEN=2V, VFB=0.9V
UVLO Detection Voltage
VUVLOD
Voltage when VL pin changes from
“H” level to “L” level
(*2)
VIN=Sweep (3.5V→4.5V), VEN=2V, VFB=0.9V
UVLO Release Voltage
VUVLOR
Voltage when VL pin changes from
“L” level to “H” level
Low side Current Limit
Integral Latch Time
(Type A)
ILIMLS
VOUT=4.5V (Forced), Bottom point of LX pin current
VFB=0.9V, ILX = ILIMLS
tLAT
Time until SS pin changes from
“H” level to “L” level
tSS
SS Terminal Current
ISS
SS Threshold Voltage
VSSTH
OVP Detection Voltage
VOVPD
EFFI
(*2)
VIN=12V, VEN=2V, VFB=0.72V, VSS=OPEN
Internal Soft-start Time
Efficiency
(*2)
Time until LX pin oscillates
VSS=0V, VLX=VFB=OPEN
(*3)
VFB=0.72V, VSS=OPEN
Voltage when LX pin oscillates
VFB=Sweep (0.788V→1.2V), VSS=OPEN
Setup VOUT=5V, IOUT=0.7A
When connected to external components
Lx SW ”H” ON Resistance
RLXH
-
0.12
(*4)
-
Ω
-
Lx SW ”L” ON Resistance
RLXL
-
0.12
(*4)
-
Ω
-
VIN=12V, VFB=0.9V, VEN=Sweep (0.2V→1.4V)
EN ”H” Voltage
VENH
Voltage when VL pin changes from
“L” level to “H” level
1.4
-
-
V
④
-
-
0.2
V
④
-1
0
-
μA
⑥
⑥
(*2)
VIN=12V, VFB=0.9V, VEN=Sweep (1.4V→0.2V)
EN ”L” Voltage
VENL
Voltage when VL pin changes from
“H” level to “L” level
(*2)
LX ”L” Current
ILXL
VIN=18V , VEN=VLX=0V , VFB=VSS=OPEN
EN ”H” Current
IENH
VIN=VEN=18V , VLX=VFB=VSS=OPEN
-
16
21
μA
EN ”L” Current
IENL
VIN=18V , VEN=0V , VLX=VFB=VSS=OPEN
-0.1
-
0.1
μA
⑥
FB ”H” Current
IFBH
VIN=18V , VEN=0V , VFB=5V , VLX=VSS=OPEN
-0.1
-
0.1
μA
⑥
FB ”L” Current
IFBL
VIN=18V , VEN=VFB=0V , VLX=VSS=OPEN
-0.1
-
0.1
μA
⑥
Thermal Shutdown Temperature
TTSD
-
150
-
°C
-
Hysteresis Width
THYS
-
25
-
°C
-
CL Discharge Resistance
RDCHG
VIN=12V , VEN=0V , VLX=2V , VFB=VSS=OPEN
-
300
-
Ω
⑥
CL Discharge Current
IDCHG
VIN=12V , VEN=0V , VLX=12V , VFB=VSS=OPEN
-
9
-
mA
⑥
Unless otherwise stated, VIN=VEN=12V
Mount conditions affect heat dissipation. Maximum output current is not guaranteed when Thermal Shutdown starts to operate earlier.
(*2)
“H”=4.3V～5V, “L”=－0.1V～0.1V
(*3)
EFFI = {[(output voltage)×(output current)]÷[(input voltage)×(input current)]}×100
(*4)
Design value
(*1)
5/21
XC9248 Series
■TEST CIRCUITS
CIRCUIT①
CIRCUIT②
CIRCUIT③
CIRCUIT④
CIRCUIT⑤
CIRCUIT⑥
CIRCUIT⑦
Wave Form Measurement Point
(Current Probe)
L
VIN
VOUT
LX
CBST
EN
RFB1
CFB
BST
FB
CIN
CL
RFB2
VL
SS
CVL
GND
CIRCUIT⑧
6/21
CIN : 10μF 2parallel(ceramic)
CVL : 0.1μF(ceramic)
CBST : 0.1μF(ceramic)
CL : 22μF 2parallel(ceramic)
L : 6.8μH
RFB1 : 43kΩ
RFB2 : 8.2kΩ
CFB : 470pF
XC9248
Series
■TYPICAL APPLICATION CIRCUIT
【Typical Examples】
L
CIN (*1)
CL (*1)
MANUFACTURER
PART NUMBER
TDK
CLF10040T100N
10μH
TDK
CLF7045T6R8N
6.8μH
TAIYO YUDEN
NR6045T4R5M
4.5μH
TAIYO YUDEN
NR6028T2R2N
2.2μH
C2012X5R1E106K
10μF/25V 2parallel
C3216X7R1E106K
10μF/25V 2parallel
C2012X5R1A226M
22μF/10V 2parallel
C3216X5R1E226M
22μF/25V 2parallel
C3225X7R1C226M
22μF/16V 2parallel
C4532X7R1E226M
22μF/25V 2parallel
TDK
TDK
CSS
VALUE
0.1μF
(*2)
/10V
CBST
0.1μF/10V
CVL
0.1μF/10V
(*1)
Select components appropriate to the usage conditions (ambient temperature, input & output voltage).
(*2)
For the coil capacitance value, please refer to P.8 < External soft-start setting >.
<Coil current setting >
For stable operation by current feedback control, the XC9248 series is optimum when the peak-to-peak current (Ipk) in the coil
is set approximately between 0.5A to 1A. The Ipk value can be calculated by using the following equation:
Ipk[A] = (VIN－VOUT ) × VOUT / VIN / 0.5 / L[μH]
L : Coil Inductance
【Examples】
VIN[V]
VOUT[V]
L[μH]
Ipk[A]
5.0
1.0
2.2
0.73
5.0
2.5
3.3
0.76
12.0
3.3
6.8
0.70
12.0
5.0
6.8
0.86
18.0
5.0
10.0
0.72
18.0
12.0
10.0
0.80
7/21
XC9248 Series
■TYPICAL APPLICATION CIRCUIT (Continued)
<VOUT setting>
The output voltage can be set by connecting external dividing resistors. The output voltage is determined by the values of RFB1
and RFB2 as given in the equation below. The total of RFB1 and RFB2 should be less than 150kΩ. Output voltage range can be
set freely from 1.0V to 12V with a 0.8V reference voltage.
VOUT=0.8×(RFB1+RFB2)/RFB2
Adjust the value of the phase compensation speed-up capacitor CFB so that fzfp=1 / (2 × π × CFB x RFB1) is about 7kHz.
Adjustments are required from 5kHz to 50kHz depending on the application, value of inductance (L), and value of load
capacitance (CL).
【Examples】
RFB1=47kΩ, RFB2=15kΩ, VOUT=0.8V×(47kΩ+15kΩ) /15kΩ =3.3V
CFB=470pF, fzfb=1/(2×π×470pF×47kΩ)=7.2kHz
< Minimum VOUT >
The Minimum VOUT is set by MINDUTY. The MINDUTY changes by the external inductance(L).
For the L value, please choose the optimal value – see P.7 <Coil current setting>. The Minimum VOUT can be calculated by
using the following equation:
VOUT= VIN × MINDUTY / 100
【L vs. MINDUTY】
L[μH]
MINDUTY[%]
2.2
18
3.3
20
4.7
21
6.8
21
10
22
<External soft-start setting>
A capacitor can be connected to the SS pin to set a time longer than the internal soft-start time voluntarily.
By setting the EN pin to the VENH voltage or higher, a current ISS=4μA (TYP.) flows to the SS pin and charges the capacitor.
When the SS pin voltage attains the SS threshold voltage VSSTH=1.8V (TYP.), the output voltage reaches about 90% of the set voltage.
External soft-start can be calculated by using the following equation:
External soft-start time=VSSTH × CSS / ISS
【Examples】
CSS=0.1μF, External soft-start time=1.8V × 0.1μF / 4μA × 1000=45ms
External soft-start time
2000ms
450ms
200ms
45ms
20ms
4.5ms
0.01
μF
0.047
μF
0.1
μF
0.47
μF
CSS
8/21
1
μF
4.7
μF
XC9248
Series
■OPERATIONAL EXPLANATION
The XC9248 series consists of a reference voltage source, an internal reference voltage source, ramp wave circuit, error
amplifier, PWM comparator, phase compensation circuit, Nch MOS driver transistor, current limiter circuit, UVLO, short
protection circuit, thermal shutdown circuit, over voltage protection and others. (See the block diagram below.)
By using the error amplifier, the FB pin voltage is compared with the internal reference voltage. The signal is input into the
PWM comparator to determine the on time of switching. The signal from the error amplifier is compared with the ramp wave
from the ramp wave circuit, and the resulting output is delivered to the output buffer circuit to provide on-time of the duty cycle at
the LX pin. This process is continuously performed to ensure stable output voltage.
The current feedback circuit monitors the Nch 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 using a low
ESR capacitor such as ceramic, which results in ensuring stable output voltage.
XC9248 Series
<Reference Voltage Source>
The reference voltage source provides the reference voltage to ensure stable output voltage of the DC/DC converter.
<Ramp Wave Circuit>
The ramp wave circuit determines switching frequency. The frequency is fixed 500kHz internally. Clock pulses generated in
this circuit are used to produce ramp waveforms needed for PWM operation, and to synchronize all the internal circuits.
<Error Amplifier>
The error amplifier is designed to monitor output voltage. The amplifier compares the reference voltage with the feedback
voltage. When a voltage lower than the reference voltage is fed back, the output voltage of the error amplifier increases. 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. This signal is delivered to
the PWM comparator.
9/21
XC9248 Series
■OPERATIONAL EXPLANATION (Continued)
<Current limiting>
The current limiting circuit of the XC9248 series monitors the current that flows through the Low side and High side Nch MOS
driver Tr, and when over-current is detected, the current limiting function activates.
① Low side driver current limiting
The current in the Low side driver Tr. is detected to equivalently monitor the bottom value of the coil current.
The Low side driver current limiting function prohibits the High side driver Tr. from turning on in an over-current state where the
bottom value of the coil current is higher than the Low side driver current limit value ILIMLS.
Control to lower the switching frequency fOSC is also performed. When the over-current state is released, normal operation
resumes.
② High side driver current limiting + Low side driver current limiting
The current in the High side driver Tr. is detected to equivalently monitor the peak value of the coil current.
The High side driver current limiting function forcibly turns off the High side driver Tr. when the peak value of the coil current
reaches the High side driver current limit value ILIMHS. ILIMLS < ILIMHS is set inside the IC, and therefore the Low side driver current
limiting function of ① above also detects the over-current state at this time. When the over-current state is released, normal
operation resumes.
③ Over-current latch (Type A)
Type A turns off the High side and Low side driver transistors when state ① or ② continues for 1.1 ms (TYP.). The LX pin is in
the CL discharged state, and is latch-stopped at the GND level (0V).
The latch-stopped state only stops the pulse output from the Lx pin; the internal circuitry of the IC continues to operate.
To restart after latch-stopping, L level and then H level must be input into the EN pin, or VIN pin re-input must be performed
(after lowering the voltage below the UVLO detection voltage) to resume operation by soft start.
The over-current latch function may occasionally be released from the current limit detection state by the effects of ambient
noise, and it may also happen that the latch time becomes longer or latching does not take place due to board conditions. For
this reason, place the input capacitor as close as possible to the IC.
Type B is an automatic recovery type that performs the operation of ① or ② until the over-current state is released.
Low side driver current limit value ILIMLS=2.1A (MIN.)
High side driver current limit value ILIMHS=4.1A (TYP.)
10/21
XC9248
Series
■OPERATIONAL EXPLANATION (Continued)
<Thermal Shutdown>
For protection against heat damage of the ICs, thermal shutdown function monitors chip temperature. The thermal shutdown
circuit starts operating and the Nch MOS driver transistor will be turned off when the chip’s temperature reaches 150℃. The LX
pin enters the CL discharged state and stops functioning at GND level (0V). When the temperature drops to 125℃ or less after
shutting of the current flow, the IC performs the soft-start function to initiate output startup operation.
<UVLO Circuit>
When the VIN voltage becomes 3.8V (TYP.) or lower, the Nch MOS driver transistor is forced OFF. The LX pin enters the CL
discharged state and stops functioning at GND level (0V). When the VIN voltage becomes 3.9V (TYP.) 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 voltage falls momentarily below the UVLO detect 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.
<Bootstrap method>
An Nch MOS driver Tr. is used for the High side driver, and a voltage higher than the VIN voltage is needed to turn the driver on.
For that purpose, the bootstrap method is used to generate a voltage higher than the VIN voltage. The CBST capacitance is
connected between BST and LX, and because the VLX voltage is lower than the 4.6V (TYP.) VL voltage that is the internal power
supply, CBST is charged from VL.
<VOUT short-circuit protection>
With the A type, when the output voltage VOUT is shorted to GND or is near a shorted state (the FB voltage is1/2 or lower), and
a current over the current limit flows to the High side or Low side driver Tr., a VOUT short circuit is detected and the High side and
Low side driver Trs. are immediately turned off and latched. The LX pin enters the CL discharged state and stops functioning at
GND level (0V). Once in the latched state, operation is resumed by either turning the IC off and restarting with the EN pin, or by
re-input into the VIN pin (the voltage is lowered below the under-voltage lockout detection voltage once).
<LX short-circuit protection>
If the event that the LX pin shorts to GND, LX short-circuit protection activates for protection from over-current due to rush
current and to protect the IC.
If the LX pin shorts to GND, High side current limiting will activate due to rush current when the High side driver Tr. turns on.
The High side driver Tr. turn offs, and the Low side driver Tr. turns on at the same time. At this time, if Low side current limiting
did not activate, an LX short-circuit is detected, and the Low side driver is turned off and latched at the same time as the High
side driver Tr. Once in the latched state, operation is resumed by either turning the IC off and restarting with the EN pin, or by
re-input into the VIN pin (the voltage is lowered below the under-voltage lockout detection voltage once).
<VOUT over-voltage protection>
To minimize output voltage overshoot, VOUT over-voltage protection activates when VOUT overshoot occurs due to the output
resistance changing from a heavy load to a light load or otherwise. When VOUT overshoot occurs and the FB voltage that senses
VOUT rises to 0.9V (TYP.) or more, the High side driver Tr. is immediately turned off and the Low side driver Tr. is turned on to
prevent VOUT overshoot. When the FB voltage falls to 0.8V (TYP.) or less due to hysteresis, the High side driver Tr. turns on at
the next clock cycle.
11/21
XC9248 Series
■OPERATIONAL EXPLANATION (Continued)
<CL high-speed discharge function>
When L level is input into the EN pin and the IC enters the standby state, the charge on the output capacitor CL can be
discharged at high speed with the Nch MOS switch Tr. incorporated between LX and GND. This enables the prevention of
application malfunctioning due to CL charge remaining when the IC stops.
The CL discharge time can be calculated from the equation below. Note that the equation varies depending on the set voltage
VOUT(E).
(1) Equation when the set voltage VOUT(E) is 1V to 4V.
The CL discharge time is determined by CL and RDCHG. If the time constant of CL and RDCHG is τ(τ= CL×RDCHG), the output
voltage discharge time can be calculated by using the following equation:
V = VOUT(E) × e -t / τ or t = τln ( VOUT(E) / V )
V : Output voltage after discharge
VOUT(E) : Output voltage
t : Discharge time
τ: CL×RDCHG
(2) Equation when the set voltage VOUT(E) is 4.1V to 12V.
The CL discharge time is determined by constant current until VOUT(E) is 4 V. When 4V or less, it is determined by CL and RDCHG
as in (1). If τ(τ= CL×RDCHG) is the time constant of CL and RDCHG and the CL discharge current is IDCHG, the discharge time of
the output voltage can be calculated by using the following equation:
t = τln ( 4 / V ) + CL × (VOUT(E) - 4) / IDCHG
V : Output voltage after discharge
VOUT(E) : Output voltage,
t: Discharge time
τ: CL×RDCHG
IDCHG : CL : Discharge time
12/21
XC9248
Series
■NOTE ON USE
1. For temporary, transitional voltage drop or voltage rising phenomenon, the IC is liable to malfunction should the ratings be
exceeded.
2. The DC/DC converter characteristics depend greatly on the externally connected components as well as on the
characteristics of this IC, so refer to the specifications and typical standard circuit examples of each component when
carefully considering which components to select. Be especially careful of the capacitor characteristics and use B
characteristics (JIS standard) or X7R, X5R (EIA standard) ceramic capacitors.
3. Where wiring impedance is high, operations may become unstable due to noise and/or phase lag depending on output current.
Please wire the input capacitor (CIN) and the output capacitor (CL) as close to the IC as possible.
4. This IC monitors Peak to Peak current in the coil by means of a Low side driver current limiting circuit and a High side driver
current limiting circuit. The Peak to Peak current varies depending on the difference between the input voltage and the
output voltage as well as the L value of the coil and thus, in some cases, current limiting may activate too frequently and
cause operation to become unstable or the current may not reach the maximum output current.
5. With the A type, when a sharp load fluctuation occurs, the VOUT voltage drop is conveyed directly to the FB pin through CFB,
and short-circuit protection may activate at a voltage higher than 1/2 the VOUT voltage.
6. The VL pin is the output of the internal regulator for operation of the DC/DC control block. For stable operation, always
connect an external capacitor CVL to the VL pin. Do not use the VL pin for external power supply, as it has been optimized as a
local power supply.
7. With this IC, operation may become unstable at the minimum operating voltage or less.
8. Make sure that the absolute maximum ratings of the external components and of this IC are not exceeded.
9. 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.
13/21
XC9248 Series
■NOTE ON USE (Continued)
10. Instructions for 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 and GND 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 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) Internal driver transistors bring on heat because of the output current (IOUT) and ON resistance of the Nch MOS driver transistors.
<Reference Pattern Layout>
st
1 Layer
PCB mounted
14/21
nd
2 Layer
XC9248
Series
■TYPICAL PERFORMANCE CHARACTERISTICS
(1) Efficiency vs. Output current
XC9248(VIN=12V , VOUT=3.3V)
XC9248(VIN=12V , VOUT=5V)
L=6.8μF(CLF7045T6R8N)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
100
100
90
90
80
80
Efficiency :EFFI[%]
Efficiency :EFFI[%]
L=6.8μF(CLF7045T6R8N)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
70
60
50
40
30
20
10
60
50
40
30
20
10
0
0
1
10
100
1000
10000
1
10
100
1000
Output Current :IOUT[mA]
Output Current :IOUT[mA]
XC9248(VIN=9V , VOUT=4V)
XC9248(VIN=5V , VOUT=1V)
L=4.5μF(NR6045T4R5M)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
100
100
90
90
80
80
70
60
50
40
30
20
10000
L=2.2μF(NR6028T2R2N)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
Efficiency :EFFI[%]
Efficiency :EFFI[%]
70
10
70
60
50
40
30
20
10
0
0
1
10
100
1000
10000
1
Output Current :IOUT[mA]
10
100
1000
10000
Output Current :IOUT[mA]
(2) Output Voltage vs. Output Currnt
XC9248(VIN=12V , VOUT=3.3V)
XC9248(VIN=12V , VOUT=5V)
L=6.8μF(CLF7045T6R8N)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
3.40
5.10
3.38
5.08
Output Voltage : VOUT[V]
Output Voltage : VOUT[V]
L=6.8μF(CLF7045T6R8N)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
3.36
3.34
3.32
3.30
3.28
3.26
3.24
3.22
5.04
5.02
5.00
4.98
4.96
4.94
4.92
4.90
3.20
1
10
100
1000
1
10000
10
100
1000
Output Current :IOUT[mA]
Output Current :IOUT[mA]
XC9248(VIN=9V , VOUT=4V)
XC9248(VIN=5V , VOUT=1V)
L=4.5μF(NR6045T4R5M)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
4.10
1.10
4.08
1.08
4.06
4.04
4.02
4.00
3.98
3.96
3.94
3.92
3.90
10000
L=2.2μF(NR6028T2R2N)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
Output Voltage : VOUT[V]
Output Voltage : VOUT[V]
5.06
1.06
1.04
1.02
1.00
0.98
0.96
0.94
0.92
0.90
1
10
100
1000
Output Current :IOUT[mA]
10000
1
10
100
1000
Output Current :IOUT[mA]
10000
15/21
XC9248 Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(3) Ripple Voltage vs. Output Current
XC9248(VIN=12V , VOUT=3.3V)
XC9248(VIN=12V , VOUT=5V)
L=6.8μF(CLF7045T6R8N)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
L=6.8μF(CLF7045T6R8N)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
10
Ripple Voltage :Vr[mV]
Ripple Voltage :Vr[mV]
10
8
6
4
2
0
6
4
2
0
1
10
100
1000
10000
1
10
100
10000
Output Current :IOUT[mA]
XC9248(VIN=9V , VOUT=4V)
XC9248(VIN=5V , VOUT=1V)
L=2.2μF(NR6028T2R2N)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
10
Ripple Voltage :Vr[mV]
10
8
6
4
2
0
8
6
4
2
0
1
10
100
1000
10000
1
10
Output Current :IOUT[mA]
100
1000
10000
Output Current :IOUT[mA]
(4) FB Voltage vs. Ambient Temperature
(5) UVLO Voltage vs. Ambient Temperature
XC9248
XC9248
4.5
0.812
0.810
0.808
0.806
0.804
0.802
0.800
0.798
0.796
0.794
0.792
0.790
0.788
VIN=4.5V
VIN=12V
VIN=18V
-50
-25
0
25
50
75
100
125
UVLO Voltage :VUVLOD,VUVLOR[V]
FB Voltage :VFB[V]
1000
Output Current :IOUT[mA]
L=4.5μF(NR6045T4R5M)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
Ripple Voltage :Vr[mV]
8
4.4
4.3
4.2
4.1
4.0
3.9
3.8
Detection
3.7
Release
3.6
3.5
Ambient Temperature :Ta[℃]
-50
-25
0
25
50
75
100
125
Ambient Temperature :Ta[℃]
(6) Oscillation Frequency vs. Ambient Temperature
(7) Supply Current vs. Ambient Temperature
XC9248
550
0.80
540
0.75
530
520
510
500
490
VIN=4.5V
480
VIN=12V
470
VIN=18V
0.70
0.65
0.60
VIN=4.5V
0.55
VIN=12V
0.50
VIN=18V
0.45
460
0.40
450
-50
16/21
Supply Current :Iq[mA]
Oscillation Frequency
:fosc[kHz]
XC9248
-25
0
25
50
75
100
Ambient Temperature :Ta[℃]
125
-50
-25
0
25
50
75
100
Ambient Temperature :Ta[℃]
125
XC9248
Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(8) Stand-by Current vs. Ambient Temperature
(9) Lx SW"L" ON Resistance vs. Ambient Temperature
XC9248
XC9248
0.20
45
0.18
Lx SW"L" ON Resistance
:RLXL[Ω]
Stand-by Current :ISTB[μA]
40
35
30
25
20
VIN=4.5V
15
VIN=12V
10
VIN=18V
5
0.16
0.14
0.12
0.10
VIN=4.5V
VIN=12V
0.08
VIN=18V
0.06
0
-50
-25
0
25
50
75
100
-50
125
Ambient Temperature :Ta[℃]
-25
0
25
50
75
(10) Lx "L" Current vs. Ambient Temperature
XC9248
XC9248
30
VIN=4.5V
EN "H" Current :IENH[μA]
Lx "L" Current :ILXL[μA]
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
VIN=4.5V
-0.6
VIN=12V
VIN=18V
-0.8
VIN=12V
25
VIN=18V
20
15
10
5
0
-1.0
-50
-25
0
25
50
75
100
-50
125
-25
0
25
50
75
100
125
Ambient Temperature :Ta[℃]
Ambient Temperature :Ta[℃]
(12) EN "H" Voltage vs. Ambient Temperature
(13) EN "L" Voltage vs. Ambient Temperature
XC9248
XC9248
1.4
1.4
1.2
EN "L" Voltage :VENL[V]
EN "H" Voltage :VENH[V]
125
(11) EN "H" Current vs. Ambient Temperature
1.0
1.0
0.8
0.6
VIN=4.5V
0.4
VIN=12V
0.2
VIN=18V
0.0
1.2
1.0
0.8
0.6
VIN=4.5V
0.4
VIN=12V
VIN=18V
0.2
0.0
-50
-25
0
25
50
75
100
125
-50
Ambient Temperature :Ta[℃]
-25
0
25
50
75
100
125
Ambient Temperature :Ta[℃]
(14) Internal Soft-Start Time vs. Ambient Temperature
(15) SS Terminal Current vs. Ambient Temperature
XC9248
XC9248
4.0
6.0
SS Terminal Current :ISS[μA]
Internal Soft-Start Time
:tSS[ms]
100
Ambient Temperature :Ta[℃]
3.5
3.0
2.5
2.0
VIN=4.5V
VIN=12V
1.5
VIN=18V
1.0
5.5
5.0
4.5
4.0
3.5
VIN=4.5V
3.0
VIN=12V
2.5
VIN=18V
2.0
-50
-25
0
25
50
75
100
Ambient Temperature :Ta[℃]
125
-50
-25
0
25
50
75
100
125
Ambient Temperature :Ta[℃]
17/21
XC9248 Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(16) SS Threshold Voltage vs. Ambient Temperature
SS Threshold Voltage :VSSTH[V]
XC9248
2.4
2.2
2.0
1.8
1.6
VIN=4.5V
VIN=12V
1.4
VIN=18V
1.2
-50
-25
0
25
50
75
100
125
Ambient Temperature :Ta[℃]
(17) Load Transient Response
XC9248
XC9248
VIN=12V, VOUT=3.3V, IOUT=No Load→1000mA
VIN=12V, VOUT=3.3V, IOUT=1000mA→No Load
L=6.8μF(CLF7045T6R8N)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
L=6.8μF(CLF7045T6R8N)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
50μs/div
50μs/div
VOUT: 500mV/div
VOUT: 500mV/div
IOUT=No Load→1000mA
IOUT=1000mA→No Load
XC9248
XC9248
VIN=9V, VOUT=4V, IOUT=No Load→1000mA
VIN=9V, VOUT=4V, IOUT=1000mA→No Load
L=4.5μF(NR6045T4R5M)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
L=4.5μF(NR6045T4R5M)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
50μs/div
50μs/div
VOUT: 500mV/div
VOUT: 500mV/div
IOUT=No Load→1000mA
IOUT=1000mA→No Load
XC9248
XC9248
VIN=5V, VOUT=1V, IOUT=No Load→1000mA
VIN=5V, VOUT=1V, IOUT=1000mA→No Load
L=2.2μF(NR6028T2R2N)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
L=2.2μF(NR6028T2R2N)
CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K)
50μs/div
18/21
50μs/div
VOUT: 500mV/div
VOUT: 500mV/div
IOUT=No Load→1000mA
IOUT=1000mA→No Load
XC9248
Series
■PACKAGING INFORMATION
●SOP-8FD (unit: mm)
0.22±0.03
4.9±0.1
0.1
(1.27）
0.42±0.09
(3.3)
BOTTOM VIEW
4.88
2.3
4.88
●SOP-8FD Reference Metal Mask Design (unit: mm)
1.52
1.62
2.4
●SOP-8FD Reference Pattern Layout (unit: mm)
19/21
XC9248 Series
■MARKING RULE
SOP-8FD
8
7
6
5
① represents products series
MARK
PRODUCT SERIES
B
XC9248******-G
① ② ③
④ ⑤
② represents products type
1
2
3
4
MARK
PRODUCT SERIES
A
B
XC9248A*****-G
XC9248B*****-G
③ represents FB voltage and oscillation frequency
MARK
VOLTAGE (V)
OSCILLATION
FREQUENCY
PRODUCT SERIES
5
0.8
500kHz
XC9248*085**-G
④⑤ represents production lot number
01～09、0A～0Z、11～9Z、A1～A9、AA～AZ、B1～ZZ in order.
(G, I, J, O, Q, W excluded)
* No character inversion used.
20/21
XC9248
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.
21/21