XC9257/XC9258 Series is Not Recommended for New Designs.
XC9257/XC9258 Series
ETR05040-003
COT Control, 1.0A Synchronous Step-Down DC/DC Converters
☆GreenOperation-compatible
■GENERAL DESCRIPTION
The XC9257/XC9258 series is a group of synchronous-rectification type DC/DC converters with a built-in P-channel MOS driver
transistor and N-channel MOS switching transistor, designed to allow the use of ceramic capacitors. Output voltage is internally
set in a range from 0.8V to 3.6V (accuracy: ±2.0%) increments of 0.05V. The device provides a high efficiency, stable power supply
with an output current of 1.0A to be configured using only a coil and two capacitors connected externally. Oscillation frequency is
set to 1.2MHz or 6.0MHz can be selected for suiting to your particular application.
As for operation mode HiSAT-COT (*) control excellent in transient response, the XC9257 series is PWM control, the XC9258
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).
During stand-by, all circuits are shutdown to reduce current consumption to as low as 1.0μA or less. As for the soft-start function
as fast as 0.3ms in typical for quick turn-on. With the built-in UVLO (Under Voltage Lock Out) function, the internal P-channel MOS
driver transistor is forced OFF when input voltage becomes 2.00V or lower. The B types integrate CL High Speed discharge function
which enables the electric charge at the output capacitor CL to be discharged via the internal discharge.
Two types of package SOT-25, USP-6C are available.
(*)
HiSAT-COT is an original Torex term for High Speed Transient Response.
■FEATURES
■APPLICATIONS
●Smart phones / Mobile phones
●Bluetooth
●Portable game consoles
●Digital still cameras / Camcorders
Input Voltage Range
Output Voltage Range
Oscillation Frequency
Output Current
Control Methods
:
:
:
:
:
Protection Circuits
:
Functions
:
Capacitor
Operating Ambient Temperature
Packages
Environmentally Friendly
:
:
:
:
●Point-of-Load (POL)
●Wearable devices
2.5V～5.5V
0.8V～3.6V (±2.0%)
1.2MHz, 6.0MHz
1A
HiSAT-COT Control
100% Duty Cycle
PWM Control (XC9257)
PWM/PFM Auto (XC9258)
Thermal Shutdown
Current Limit (Pendent character)
Short Circuit Protection (Type B)
Soft-Start
UVLO
CL High Speed Discharge (Type B)
Ceramic Capacitor
- 40℃ ～ + 105℃
SOT-25, USP-6C
EU RoHS Compliant, Pb Free
■TYPICAL APPLICATION CIRCUIT ■TYPICAL PERFORMANCE
CHARACTERISTICS
XC9257B18C/XC9258B18C
L =LTF5022T-4R7N2R0(4.7μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF(GRM155R61A106M)
100
L
VIN
CE
CIN
Lx
80
VOUT
CE
VSS
VIN=3.7V
90
CL
Efficiency: EFFI (%)
VIN
VOUT
1.0A
70
VIN=5.0V
60
50
VIN=3.7V
40
VIN=5.0V
30
20
XC9258
10
0
XC9257
0.1
1
10
100
1000
Output Current: IOUT (mA)
1/30
XC9257/XC9258 Series is
Not Recommended for New Designs.
XC9257/XC9258 Series
■ BLOCK DIAGRAM
1)
XC9257/XC9258 Series Type A (SOT-25)
R1
Phase
Compensation
CFB
Error Amp.
VOUT
+
VSS
Q
Logic
R
Synch.
Buffer
Driver
Error Amp.
+
Lx
+
Vref with
Soft Start
S
Q
Logic
R
Minimum
On Time
Generator
CE Control Logic,
UVLO,
Thermal Shutdown
CE
PWM/PFM
Selector
High Side
Current Limit
VIN
Comparator
-
R2
VIN
VOUT
Short
Protection
Phase
Compensation
CFB
VSS
Minimum
On Time
Generator
CE Control Logic,
UVLO,
Thermal Shutdown
R1
VOUT
S
+
Vref with
Soft Start
XC9257/XC9258 Series Type B (SOT-25)
VIN
Comparator
-
R2
CE
High Side
Current Limit
2)
Synch.
Buffer
Driver
Lx
VIN
VOUT
PWM/PFM
Selector
(*) The XC9257 offers a fixed PWM control, a Control Logic of PWM/PFM Selector is fixed at “PWM” internally.
The XC9258 control scheme is a fixed PWM/PFM automatic switching, a Control Logic of PWM/PFM Selector is fixed at “PWM/PFM
automatic switching” internally.
Diodes inside the circuit are an ESD protection diode and a parasitic diode.
3)
XC9257/XC9258 Series Type A (USP-6C)
R1
Phase
Compensation
CFB
VOUT
Error Amp.
+
-
R2
Vref with
Soft Start
VSS
CE
(*)
CE Control Logic,
UVLO,
Thermal Shutdown
High Side
Current Limit
4)
VIN
Comparator
+
S
Q
Logic
R
Minimum
On Time
Generator
Synch.
Buffer
Driver
PWM/PFM
Selector
R1
Phase
Compensation
CFB
VOUT
Error Amp.
+
Lx
R2
VSS
VIN
VOUT
XC9257/XC9258 Series Type B (USP-6C)
Vref with
Soft Start
VSS
CE
CE Control Logic,
UVLO,
Thermal Shutdown
Short
Protection
High Side
Current Limit
VIN
Comparator
+
S
Q
Logic
R
Minimum
On Time
Generator
Synch.
Buffer
Driver
Lx
VSS
VIN
VOUT
PWM/PFM
Selector
The XC9257 offers a fixed PWM control, a Control Logic of PWM/PFM Selector is fixed at “PWM” internally.
The XC9258 control scheme is a fixed PWM/PFM automatic switching, a Control Logic of PWM/PFM Selector is fixed at “PWM/PFM
automatic switching” internally.
Diodes inside the circuit are an ESD protection diode and a parasitic diode.
2/30
XC9257/XC9258
XC9257/XC9258 Series is Not Recommended for New Designs.
Series
■PRODUCT CLASSIFICATION
1) Ordering Information
XC9257①②③④⑤⑥-⑦ PWM Control
XC9258①②③④⑤⑥-⑦ PWM/PFM Automatic switching control
DESIGNATOR
ITEM
①
Type
A
Output Voltage
④
Oscillation Frequency
08～36
Packages (Order Unit)
(*1)
DESCRIPTION
Refer to Selection Guide
B
②③
⑤⑥-⑦
(*1)
SYMBOL
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
C
1.2MHz
E
6.0MHz
MR-G
SOT-25 (3,000pcs/Reel)
ER-G
USP-6C (3,000pcs/Reel)
The “-G” suffix denotes Halogen and Antimony free as well as being fully EU RoHS compliant.
2) Selection Guide
TYPE
OUTPUT VOLTAGE
CL AUTO-DISCHARGE
SHORT PROTECTION
(LATCH)
UVLO
A
Fixed
No
No
Yes
B
Fixed
Yes
Yes
Yes
TYPE
CHIP ENABLE
CURRENT LIMIT
SOFT-START TIME
THERMAL SHUTDOWN
A
Yes
Yes
Fixed
Yes
B
Yes
Yes
Fixed
Yes
3/30
XC9257/XC9258 Series is
Not Recommended for New Designs.
XC9257/XC9258 Series
■PIN CONFIGURATION
Lx
VOUT
5
4
2
1
VIN
VIN 6
1 Lx
VSS 5
2 VSS
CE 4
3 VOUT
3
USP-6C
(BOTTOM VIEW)
VSS
CE
SOT - 25
(TOP VIEW)
* The dissipation pad for the USP-6C 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. 2 and 5) pin.
■PIN ASSIGNMENT
PIN NUMBER
PIN NAME
FUNCTIONS
6
VIN
Power Input
2
2,5
VSS
Ground
3
4
CE
Chip Enable
4
3
VOUT
Output Voltage Monitor
5
1
Lx
Switching Output
SOT-25
USP-6C
1
■FUNCTION
CE PIN Function
PIN NAME
CE
SIGNAL
STATUS
L
Stand-by
H
Active
Please do not leave the CE pin open.
4/30
XC9257/XC9258 Series is Not Recommended for New Designs.
XC9257/XC9258
Series
■ABSOLUTE MAXIMUM RATINGS
Ta=25℃
PARAMETER
SYMBOL
RATINGS
UNITS
VIN Pin Voltage
VIN
-0.3～+6.2
V
Lx Pin Voltage
VLx
-0.3～VIN+0.3 or +6.2(*1)
V
VOUT Pin Voltage
VOUT
-0.3～VIN+0.3 or +4.0(*2)
V
CE Pin Voltage
VCE
-0.3～+6.2
V
Pd
250
600 (40mm x 40mm Standard board) (*3)
120
1000 (40mm x 40mm Standard board) (*3)
1250(JEDEC board) (*3)
mW
Operating Ambient Temperature
Topr
-40～+105
℃
Storage Temperature
Tstg
-55～+125
℃
SOT-25
Power Dissipation
USP-6C
* All voltages are described based on the GND (VSS) pin.
(*1)
The maximum value should be either VIN+0.3V or +6.2V in the lowest.
(*2)
The maximum value should be either VIN+0.3V or +4.0V in the lowest.
(*3)
The power dissipation figure shown is PCB mounted and is for reference only.
Please see the power dissipation page for the mounting condition.
5/30
XC9257/XC9258 Series is
Not Recommended for New Designs.
XC9257/XC9258 Series
■ELECTRICAL CHARACTERISTICS
XC9257/XC9258 Series
PARAMETER
SYMBOL
Output Voltage
VOUT
Operating Voltage Range
VIN
CONDITIONS
When connected to external components,
IOUT=30mA
-
MIN.
TYP.
MAX.
UNITS
Ta=25℃
CIRCUIT
V
①
2.5
-
5.5
V
①
1000
-
-
mA
①
1.35
2.0
2.48
V
③
fOSC=1.2MHz
-
15.0
25.0
fOSC=6.0MHz
-
40.0
70.0
μA
②
fOSC=1.2MHz
-
250
450
fOSC=6.0MHz
-
400
825
μA
②
-
0.0
1.0
μA
②
ns
①
Maximum Output Current
IOUTMAX
When connected to external components (*1),
VIN =
UVLO Voltage (*2)
VUVLO
VOUT=0.6V,Voltage which Lx pin holding “L” level(*6)
Quiescent Current
(XC9258)
Iq
VOUT =VOUT(T) × 1.1V
Quiescent Current
(XC9257)
Iq
VOUT =VOUT(T) × 1.1V
Stand-by Current
ISTB
Minimum ON time
tONmin
When connected to external components,
VIN = , IOUT = 1mA
Thermal shutdown
TTSD
-
-
150
-
℃
①
Thermal shutdown
hysteresis
THYS
-
-
30
-
℃
①
Lx SW ”H” ON Resistance
RLXH
VOUT=0.6V, ILX=100mA (*3)
-
0.24
0.37
Ω
④
Lx SW ”L” ON
Resistance (*4)
RLXL
VOUT=VOUT(T) V × 1.1, ILX=100mA (*3)
-
0.16
0.30
Ω
④
Lx SW ”H” Leakage Current
ILeakH
VIN=5.5V, VCE=0V, VOUT=0V, VLX=5.5V
-
0.0
30.0
μA
⑤
Lx SW ”L” Leakage Current
IleakL
VIN=5.5V, VCE=0V, VOUT=0V, VLX=0.0V
-
0.0
1.0
μA
⑤
ILIMH
VOUT=0.6V, ILx until Lx pin oscillates
1.3
1.5
2.5
A
⑥
-
±100
-
ppm/℃
①
1.40
-
5.5
V
③
VSS
-
0.30
V
③
Current Limit
(*5)
VCE=0.0V
Output Voltage
Temperature
Characteristics
ΔVOUT/
(VOUT・ΔTopr)
CE ”H” Voltage
VCEH
CE ”L” Voltage
VCEL
CE ”H” Current
ICEH
VIN=5.5V, VCE=5.5V, VOUT=0.0V
-0.1
-
0.1
μA
⑤
CE ”L” Current
ICEL
VIN=5.5V, VCE=0.0V, VOUT=0.0V
-0.1
-
0.1
μA
⑤
Soft-start Time
tSS
VCE=0.0V → 5.0V VOUT=VOUT(T)V × 0.9
After "H" is fed to CE, the time by when clocks are
generated at Lx pin.
0.10
0.30
0.50
ms
③
Short Protection
Threshold
Voltage (Type B)
VSHORT
Sweeping VOUT, VOUT voltage which Lx becomes “L”
level(*6)
0.17
0.27
0.37
V
③
CL Discharge (Type B)
RDCHG
VCE=0V, VOUT=4.0V
50
210
300
Ω
⑦
IOUT=30mA, -40℃≦Topr≦105℃
VOUT=0.6V, Applied voltage to VCE,
Voltage changes Lx to “H” level (*6)
VOUT=0.6V, Applied voltage to VCE,
Voltage changes Lx to “L” level (*6)
Unless otherwise stated, VIN=5V, VCE=5V, VOUT(T)=Nominal Value,
NOTE:
(*1)
When the difference between the input and the output is small, 100% duty might come up and internal control circuits keep P-ch driver
turning on even though the output current is not so large.
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.
(*3)
RLXH= (VIN - Lx pin measurement voltage) / 100mA, RLXL= Lx pin measurement voltage / 100mA
(*4)
Design value for the XC9258 series.
(*5)
Current limit denotes the level of detection at peak of coil current.
(*6)
"H"=VIN ~ VIN - 1.2V, "L"=- 0.1V ~ + 0.1V
6/30
XC9257/XC9258 Series is Not Recommended for New Designs.
XC9257/XC9258
Series
■ELECTRICAL CHARACTERISTICS (Continued)
SPEC Table
NOMINAL
tONmin
VOUT
OUTPUT
fOSC = 1.2MHz
fOSC = 6.0MHz
VOLTAGE
VOUT(T)
MIN.
TYP.
MAX.
VIN
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
0.80
0.784
0.800
0.816
2.70
173
247
321
16
53
91
0.85
0.833
0.850
0.867
2.70
184
262
341
18
57
95
0.90
0.882
0.900
0.918
2.70
194
278
361
21
60
99
0.95
0.931
0.950
0.969
2.70
205
293
381
23
63
104
1.00
0.980
1.000
1.020
2.70
216
309
401
26
67
108
1.05
1.029
1.050
1.071
2.70
227
324
421
29
70
112
1.10
1.078
1.100
1.122
2.70
238
340
441
31
73
115
1.15
1.127
1.150
1.173
2.70
248
355
461
35
77
119
1.20
1.176
1.200
1.224
2.70
259
370
481
38
80
122
1.25
1.225
1.250
1.275
2.70
270
386
502
41
83
126
1.30
1.274
1.300
1.326
2.70
281
401
522
45
87
129
1.35
1.323
1.350
1.377
2.70
292
417
542
48
90
132
1.40
1.372
1.400
1.428
2.70
302
432
562
52
93
135
1.45
1.421
1.450
1.479
2.70
313
448
582
56
97
137
1.50
1.470
1.500
1.530
2.70
324
463
602
60
100
140
1.55
1.519
1.550
1.581
2.70
335
478
622
60
100
140
1.60
1.568
1.600
1.632
2.70
346
494
642
60
100
140
1.65
1.617
1.650
1.683
2.75
350
500
650
60
100
140
1.70
1.666
1.700
1.734
2.83
350
500
650
60
100
140
1.75
1.715
1.750
1.785
2.92
350
500
650
60
100
140
1.80
1.764
1.800
1.836
3.00
350
500
650
60
100
140
1.85
1.813
1.850
1.887
3.08
350
500
650
60
100
140
1.90
1.862
1.900
1.938
3.17
350
500
650
60
100
140
1.95
1.911
1.950
1.989
3.25
350
500
650
60
100
140
2.00
1.960
2.000
2.040
3.33
350
500
650
60
100
140
2.05
2.009
2.050
2.091
3.42
350
500
650
60
100
140
2.10
2.058
2.100
2.142
3.50
350
500
650
60
100
140
2.15
2.107
2.150
2.193
3.58
350
500
650
60
100
140
2.20
2.156
2.200
2.244
3.67
350
500
650
60
100
140
2.25
2.205
2.250
2.295
3.75
350
500
650
60
100
140
2.30
2.254
2.300
2.346
3.83
350
500
650
60
100
140
2.35
2.303
2.350
2.397
3.92
350
500
650
60
100
140
2.40
2.352
2.400
2.448
4.00
350
500
650
60
100
140
2.45
2.401
2.450
2.499
4.08
350
500
650
60
100
140
2.50
2.450
2.500
2.550
4.17
350
500
650
60
100
140
2.55
2.499
2.550
2.601
4.25
350
500
650
60
100
140
2.60
2.548
2.600
2.652
4.33
350
500
650
60
100
140
2.65
2.597
2.650
2.703
4.42
350
500
650
60
100
140
2.70
2.646
2.700
2.754
4.50
350
500
650
60
100
140
7/30
XC9257/XC9258 Series is
Not Recommended for New Designs.
XC9257/XC9258 Series
■ELECTRICAL CHARACTERISTICS (Continued)
SPEC Table
NOMINAL
tONmin
VOUT
OUTPUT
fOSC=1.2MHz
fOSC=6.0MHz
VOLTAGE
VOUT(T)
MIN.
TYP.
MAX.
VIN
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
2.75
2.695
2.750
2.805
4.58
350
500
650
60
100
140
2.80
2.744
2.800
2.856
4.67
350
500
650
60
100
140
2.85
2.793
2.850
2.907
4.75
350
500
650
60
100
140
2.90
2.842
2.900
2.958
4.83
350
500
650
60
100
140
2.95
2.891
2.950
3.009
4.92
350
500
650
60
100
140
3.00
2.940
3.000
3.060
5.00
350
500
650
60
100
140
3.05
2.989
3.050
3.111
5.08
350
500
650
60
100
140
3.10
3.038
3.100
3.162
5.17
350
500
650
60
100
140
3.15
3.087
3.150
3.213
5.25
350
500
650
60
100
140
3.20
3.136
3.200
3.264
5.33
350
500
650
60
100
140
3.25
3.185
3.250
3.315
5.42
350
500
650
60
100
140
3.30
3.234
3.300
3.366
5.50
350
500
650
60
100
140
3.35
3.283
3.350
3.417
5.50
355
508
660
61
102
142
3.40
3.332
3.400
3.468
5.50
361
515
670
62
103
144
3.45
3.381
3.450
3.519
5.50
366
523
680
63
105
146
3.50
3.430
3.500
3.570
5.50
371
530
689
64
106
148
3.55
3.479
3.550
3.621
5.50
377
538
699
65
108
151
3.60
3.528
3.600
3.672
5.50
382
545
709
65
109
153
8/30
XC9257/XC9258
XC9257/XC9258 Series is Not Recommended for New Designs.
Series
■TEST CIRCUITS
< Circuit No.① >
< Circuit No.② >
Wave Form Me asure Point
L
A
VIN
VOUT
CE
CIN
A
LX
V
CL
VSS
※ External Components
fOS C = 1.2MHz
L : 4.7μH(LTF5022T-4R7N2R0-LC)
CIN : 10μF(ceramic)
CL : 10μF(ceramic)
RL
1μF
VIN
LX
VOUT
CE
VSS
※ External Components
fOS C = 6.0MHz
L : 0.47μH(LQM2MPNR47MGH)
CIN : 2.2μF(ceramic)
CL : 4.7μF(ceramic)
< Circuit No.④ >
< Circuit No.③ >
Wave Form Me asure Point
1uF
VIN
LX
CE
VOUT
VIN
Rpulldow n
200Ω
1μF
LX
VOUT
CE
V
ILX
VSS
VSS
RLXH = (VIN -VLx)/ILX
RLXL = VLx/ILX
< Circuit No.⑤ >
1μF
ILeak H
VIN
LX
CE
VOUT
IC EH
A
< Circuit No.⑥ >
A
VIN
LX
CE
VOUT
ILIMH
ILeak L
1μF
VSS
Wave Form Me asure Point
V
VSS
IC EL
< Circuit No.⑦ >
B TYPE
VIN
LX
1μF
VOUT
CE
A
VSS
9/30
XC9257/XC9258 Series
XC9257/XC9258 Series is
Not Recommended for New Designs.
■TYPICAL APPLICATION CIRCUIT
L
VIN
VIN VIN
VOUT
1.0A
LLx
X
CE
VVOUT
OUT
CE CE
VSS
CL
CIN
【Typical Examples】(*1)fOSC=1.2MHz
MANUFACTURER
L
PRODUCT NUMBER
VALUE
murata
LQH5BPN4R7NT0L
4.7μH
TDK
LTF5022T-4R7N2R0-LC
4.7μH
Coilcraft
XFL4020-472MEC
4.7μH
MANUFACTURER
PRODUCT NUMBER
VALUE
murata
LQM2MPNR47MGH
0.47μH
ALPS
GLCLKR4701A
0.47μH
TAIYO YUDEN
MAKK2016TR47M
0.47μH
TDK
MLP2520HR47MT0S1
0.47μH
【Typical Examples】(*1)fOSC=6.0MHz
L
【Typical Examples】(*1) fOSC=1.2MHz
MANUFACTURER
CIN
CL
【Typical
CIN
CL
(*1)
PRODUCT NUMBER
VALUE
murata
GRM155R61A106M
10μF/10V
murata
GRM21BR71A106KE51
10μF/10V
TAIYO YUDEN
LMK212AB7106MG
10μF/10V
murata
GRM155R61A106M
10μF/10V
murata
GRM21BR71A106KE51
10μF/10V
TAIYO YUDEN
LMK212AB7106MG
10μF/10V
Examples】(*1)
fOSC = 6.0MHz
MANUFACTURER
PRODUCT NUMBER
VALUE
murata
GRM155R61A106M
10μF/10V
murata
GRM21BR71A106KE51
10μF/10V
TAIYO YUDEN
LMK212AB7106MG
10μF/10V
murata
GRM155R61A106M
10μF/10V 2parallel
murata
GRM21BR71A226KE51
22μF/10V
TAIYO YUDEN
LMK212AB7226MG
22μF/10V
Select components appropriate to the usage conditions (ambient temperature, input & output voltage).
10/30
XC9257/XC9258 Series is Not Recommended for New Designs.
XC9257/XC9258
Series
■OPERATIONAL EXPLANATION
The XC9257/XC9258 series consists of a reference voltage source, error amplifier, comparator, phase compensation, minimum
on time generation circuit, output voltage adjustment resistors, P-channel MOS driver transistor, N-channel MOS switching
transistor for the synchronous switch, current limiter circuit, UVLO circuit, thermal shutdown circuit, short protection circuit,
PWM/PFM selection circuit and others. (See the BLOCK DIAGRAM below.)
R1
VOUT
Error Amp.
+
-
R2
Vref with
Soft Start
VSS
CE
CE Control Logic,
UVLO,
Thermal Shutdown
High Side
Current Limit
Phase
Compensation
CFB
VIN
Comparator
+
S
Q
Logic
R
Minimum
On Time
Generator
VIN
VOUT
Synch.
Buffer
Driver
Lx
Low Side
Current Limit
PWM/PFM
Selector
BLOCK DIAGRAM XC9257/XC9258 Series Type B (SOT-25)
The method is HiSAT-COT (High Speed circuit Architecture for Transient with Constant On Time) control, which features on time
control method and a fast transient response that also achieves low output voltage ripple.
The on time (ton) is determined by the input voltage and output voltage, and turns on the Pch MOS driver Tr. for a fixed time.
During the off time (toff), the voltage that is fed back through R1 and R2 is compared to the reference voltage by the error amp,
and the error amp output is phase compensated and sent to the comparator. The comparator compares this signal to the reference
voltage, and if the signal is lower than the reference voltage, sets the SR latch. On time then resumes. By doing this, PWM
operation takes place with the off time controlled to the optimum duty ratio and the output voltage is stabilized. The phase
compensation circuit optimizes the frequency characteristics of the error amp, and generates a ramp wave similar to the ripple
voltage that occurs in the output to modulate the output signal of the error amp. This enables a stable feedback system to be
obtained even when a low ESR capacitor such as a ceramic capacitor is used, and a fast transient response and stabilization of
the output voltage are achieved.
Generates an on time that depends on the input voltage and output voltage (ton). The on time is set as given by the equations
below.
fOSC≒1.2MHz type
ton (μs) = VOUT/VIN×0.833
fOSC≒6.0MHz type
ton (μs) = VOUT/VIN×0.167
The switching frequency can be obtained from the on time (ton), which is determined by the input voltage and output voltage, and
the PWM controlled off time (toff) as given by the equation below.
fOSC (MHz) = VOUT(V) / (VIN(V)×ton(μs))
When the load current is heavy and the voltage difference between input voltage and output voltage is small, 100% duty cycle
mode is activated and it keeps the Pch MOS driver Tr. keep on. 100% duty cycle mode attains a high output voltage stability and
a high-speed response under all load conditions, from light to heavy, even in conditions where the dropout voltage is low.
The error amp monitors the output voltage. The voltage divided by the internal R1 and R2 resistors is a feedback voltage for
Error Amp. and compared to the reference voltage. The output voltage of the error amp becomes higher when the feedback
voltage is higher than the reference voltage. The frequency characteristics of the error amp are optimized internally.
11/30
XC9257/XC9258 Series is
Not Recommended for New Designs.
XC9257/XC9258 Series
■OPERATIONAL EXPLANATION (Continued)
The reference voltage forms a reference that is used to stabilize the output voltage of the IC.
After “H” level is fed to CE pin, the reference voltage connected to the error amp increases linearly during the soft start interval.
This allows the voltage divided by the internal R1 and R2 resistors and the reference voltage to be controlled in a balanced manner,
and the output voltage rises in proportion to the rise in the reference voltage. This operation prevents rush input current and
enables the output voltage to rise smoothly.
If the output voltage does not reach the set output voltage within the soft start time, such as when the load is heavy or a large
capacity output capacitor is connected, the balancing of the voltage divided by the internal resistors R1 and R2 and the reference
voltage is lost, however, the current restriction function activates to prevent an excessive increase of input current, enabling a
smooth rise of the output voltage.
Regarding XC9257 which has PWM control method, it works with a continuous conduction mode, and operates at a stable
switching frequency by means of an on time (ton) that is determined by the input voltage and output voltage regardless of the load.
Regarding XC9258 which has PWM/PFM auto switching control method, it works with a discontinuous conduction mode at light
loads, and lowers the switching frequency to reduce switching loss and improve efficiency.
Operation starts when “H” voltage is input into the CE pin. The IC can be put in the shutdown state by inputting “L” voltage into
the CE pin. In the shutdown state, the supply current of the IC is 0μA (TYP.), and the Pch MOS driver Tr. and Nch MOS switch Tr.
for synchronous rectification turn off. The CE pin is a CMOS input and the sink current is 0μA.
When the VIN voltage becomes 2.00V (TYP.) 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 2.10V (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 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.
For protection against heat damage of the ICs, thermal shutdown function monitors chip temperature. The thermal shutdown
circuit starts operating and the P-ch MOS driver and N-ch MOS driver transistor will be turned off when the chip’s temperature
reaches 150℃. When the temperature drops to 120℃ or less after shutting of the current flow, the IC performs the soft-start
function to initiate output startup operation.
The B type short-circuit protection circuit protects the device that is connected to this product and to the input/output in situations
such as when the output is accidentally shorted to GND. The short-circuit protection circuit monitors the output voltage, and when
the output voltage falls below the short-circuit protection threshold voltage, it turns off the Pch MOS driver Tr and latches it. Once
in the latched state, operation is resumed by turning off the IC from the CE pin and then restarting, or by re-input into the VIN pin.
The B type 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 GND
pin. When the IC is disabled, electric charge at the output capacitor (CL) is quickly discharged so that it may avoid application
malfunction.
Output Voltage Dischage characteristics
R DCHG = 210Ω(TY P) C L=10μF
12/30
5.0
4.5
Output Voltage: VOUT(V)
V=VOUT(T)×e – t /τ
t=τln (VOUT(T) / V)
V: Output voltage after discharge
VOUT(T): Output voltage
t: Discharge time
τ: CL×RDCHG
CL: Capacitance of Output capacitor
RDCHG: CL auto-discharge resistance,
but it depends on supply voltage.
VOUT = -1.2V
VOUT = 1.8V
-VOUT = 3.3V
---
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0
2
4
6
8
10 12
14 16
Discharge Time: t(ms)
18 20
XC9257/XC9258 Series is Not Recommended for New Designs.
XC9257/XC9258
Series
■OPERATIONAL EXPLANATION (Continued)
The current limiter circuit of the XC9257/XC9258 series monitors the current flowing through the P-channel MOS driver
transistor connected to the Lx pin. 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. When the over current state is eliminated, the IC resumes its normal
operation.
■NOTE ON USE
1. For the phenomenon of temporal and transitional voltage decrease or voltage increase, the IC may be damaged or deteriorated
if IC is used beyond the absolute MAX. specifications.
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. 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 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.
4. Make sure that the PCB GND traces are as thick and wide as possible. The VSS pin fluctuation caused by high ground current
at the time of switching may result in instability of the IC. Therefore, the GND traces close to the VSS pin is important.
5. Mount external components as close as possible to the IC. Keep the wiring short and thick to lower the wiring impedance.
6. A feature of HiSAT-COT control is that it controls the off time in order to control the duty, which varies due to the effects of power
loss. In addition, changes in the on time due to 100% duty cycle mode are allowed. For this reason, caution must be exercised
as the characteristics of the switching frequency will vary depending on the external component characteristics, board layout,
input voltage, output voltage, load current and other parameters.
7. Due to propagation delay inside the product, the on time generated by the minimum on time generation circuit is not the same
as the on time that is the ratio of the input voltage to the output voltage.
8. With regard to the current limiting value, the actual coil current may at times exceed the electrical characteristics due to
propagation delay inside the product.
9. The CE pin is a CMOS input pin. Do not use with the pin open. If connecting to the input or ground, use the resistor not more
than 1MΩ or less. To prevent malfunctioning of the device connected to this product or the input/output due to short circuiting
between pins, it is recommended that a resistor be connected.
10. In the B type, if the output voltage drops below the short circuit protection threshold voltage at the end of the soft start interval,
operation will stop.
11. Regarding XC9258 which has PWM/PFM auto switching control method, it works with a discontinuous conduction mode at
light loads, and in this case where the voltage difference between input voltage and output voltage is low or the coil inductance
is higher than the value indicated in the standard circuit example, the coil current may reverse when the load is light, and thus
pulse skipping will not be possible and light load efficiency will worsen.
12. When the input voltage is close to the minimum input voltage, the current limit circuit might not be able to work.
13. When the voltage difference between input voltage and output voltage is low, the load stability feature may deteriorate.
13/30
XC9257/XC9258 Series is
Not Recommended for New Designs.
XC9257/XC9258 Series
■NOTE ON USE (Continued)
14. If the capacitance value is not sufficient by degrading CL due to the low temp. condition and DC bias feature, 100% duty cycle
might come up for the load transient condition. Add capacitance value for CL if necessary. (Refer to Fig14-1, Fig14-2, Fig143, Fig.14-4)
Ta＝-40℃,VIN=3.6V,VOUT=1.5V
fOSC=1.2MHz,IOUT=1000mA→10mA
L : 4.7μH,CIN : 10μF (ceramic),CL : 10μF (ceramic)
Ta＝-40℃,VIN=3.6V,VOUT=1.5V
fOSC=1.2MHz,IOUT=1000mA→10mA
L : 4.7μH,CIN : 10μF (ceramic),CL : 20μF (ceramic)
IOUT : 1A/div
IOUT : 1A/div
VOUT : 100mV/div
VOUT : 100mV/div
LX : 5V/div
5μsec/div
Fig.14-1 Insufficient CL (Ta=-40℃,CL=10μF )
Ta＝-40℃,VIN=3.6V,VOUT=1.5V
fOSC=1.2MHz,IOUT=10mA→1000mA
L : 4.7μH,CIN : 10μF (ceramic),CL : 10μF (ceramic)
IOUT : 1A/div
5μsec/div
Fig.14-2 Sufficient CL (Ta=-40℃,CL=20μF)
Ta＝-40℃,VIN=3.6V,VOUT=1.5V
fOSC=1.2MHz,IOUT=10mA→1000mA
L : 4.7μH,CIN : 10μF (ceramic),CL : 20μF (ceramic)
IOUT : 1A/div
VOUT : 100mV/div
LX : 5V/div
LX : 5V/div
VOUT : 100mV/div
5μsec/div
Fig.14-3 Insufficient CL (Ta=-40℃,CL=10μF )
LX : 5V/div
5μsec/div
Fig.14-4 Sufficient CL (Ta=-40℃,CL=20μF)
15. If the capacitance value is not sufficient by degrading CL due to the low temp. condition and DC bias feature, the duty cycle
might not be stable. Add capacitance value for CL if necessary. (Refer to Fig.15-1, Fig.15-2)
Ta＝25℃,VIN=2.5V,VOUT=0.8V
fOSC=6.0MHz,IOUT=300mA
L :0. 47μH,CIN : 10μF (ceramic),CL : 10μF (ceramic)
VOUT : 20mV/div
VOUT : 20mV/div
LX : 5V/div
Ta＝25℃,VIN=2.5V,VOUT=0.8V
fOSC=6.0MHz,IOUT=300mA
L :0. 47μH,CIN : 10μF (ceramic),CL : 20μF (ceramic)
200nsec/div
Fig.15-1 Insufficient CL (CL=10μF )
LX : 5V/div
200nsec/div
Fig.15-2 Sufficient CL (CL=20μF)
16. 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.
14/30
XC9257/XC9258 Series is Not Recommended for New Designs.
XC9257/XC9258
Series
■NOTE ON USE (Continued)
17. Instructions of pattern layouts
The operation may become unstable due to noise and/or phase lag from the output current when the wire impedance is
high,
please place the input capacitor(CIN) and the output capacitor (CL) as close to the IC as possible.
(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 pin, VSS pin.
(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) This series’ internal driver transistors bring on heat because of the output current and ON resistance of P-channel and Nchannel MOS driver transistors. Please consider the countermeasures against heat if necessary.
SOT-25
PCB mounted
USP-6C
PCB mounted
1st
Layer
1st
Layer
2nd
2nd
Layer
Layer
15/30
XC9257/XC9258 Series
XC9257/XC9258 Series is
Not Recommended for New Designs.
■NOTE ON USE (Continued)
< Estimation for the power consumption >
The power loss of a total buck DC/DC system (P_all) is as follows.
P_all (W) = VIN×IIN-VOUT×IOUT
= VOUT×IOUT/EFFI-VOUT×IOUT
=-VOUT×IOUT×(1-1/EFFI)
VIN：Input voltage, VOUT：Output voltage, IIN：Input current, IOUT：Output current, EFFI：Efficiency
The power loss at a coil (P_coil) is as follows.
P_coil (W) = IOUT2×DCR
DCR：The direct current resistance of a coil
The power loss at IC (P_IC) can be calculated by subtracting the power loss at a coil from the one of a total buck DC/DC
system.
P_IC (W) = P_all – P_coil
The temperature of IC (Tj) can be calculated by the function below.
Tj = Ta + R×P_IC
R：Thermal resistance
The temperature resistance varies based on the power dissipation of a PC board and so on.
Please note that Tj should be lower than 125℃
・Calculation Example
Conditions :
VIN=2.5V, VOUT=1.8V, IOUT=800mA, EFFI=81.4%
R=100℃/W
DCR=0.06Ω
The power loss of a total buck DC/DC system (P_all) =-VOUT×IOUT×(1-1/EFFI)
=-1.8×0.8×(1-1/0.814)
≒0.329(W)
The power loss at a coil (P_coil) = IOUT2×DCR
= 0.82×0.06
≒0.038 (W)
The power loss at IC (P_IC) = P_all - P_coil
= 0.329 -0.038
= 0.290 (W)
The temperature of IC (Tj) = The ambient temperature so that Tj becomes125℃ (Ta) = Tj-R*P_IC
= 125-100×0.290
= 96.0℃
In this case, under the condition above, the ambient temperature up to 96℃ is acceptable.
・Reference example
Ta-IOUTMAX feature example with SOT-25 recommendation PCB pattern
1. Measurement Condition
Maximum Output : IOUTMAX(mA)
VOUT(T)=1.8V
1200
Condition:
Mount on a board
Ambient:
Natural convection
Soldering:
1000
Board:
800
Copper thickness:
VIN=2.5V
400
Material:
VIN=3.6V
200
Thickness:
VIN=5.5V
-50
-25
0
25
50
Through-hole
75
100 125
Ambient Temperatuer : Ta(℃）
16/30
Dimensions 40 x 40 mm (1600 mm2 in one side)
(Reference pattern layout of SOT-25:
Refer to page 15)
600
0
Lead (Pb) free
18μm(Cu)+20μm(plating)=38μm
Glass Epoxy (FR-4)
0.8mm
8 x 0.3 Diameter
4 x 0.8 Diameter
14 x 1.0 Diameter
XC9257/XC9258
XC9257/XC9258 Series is Not Recommended for New Designs.
Series
■TYPICAL PERFORMANCE CHARACTERISTICS
(1) Efficiency vs. Output Current
XC9257B08C/XC9258B08C
XC9257B08E/XC9258B08E
L =GLCLKR4701A(0.47μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF×2(GRM155R61A106M)
100
100
90
90
80
60
50
VIN=5.0V
40
VIN=5.0V
30
VIN=3.7V
20
0
10
100
VIN=5.0V
60
50
40
XC9258
XC9257
0
1000
0.1
Output Current: IOUT (mA)
100
1000
L =LTF5022T-4R7N2R0(4.7μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF(GRM155R61A106M)
100
100
VIN=3.7V
90
VIN=3.7V
80
80
70
Efficiency: EFFI (%)
Efficiency: EFFI (%)
10
XC9257B18C/XC9258B18C
XC9257B18E/XC9258B18E
VIN=5.0V
60
50
40
VIN=5.0V
30
VIN=3.7V
20
70
60
50
10
100
XC9258
1000
XC9257
0.1
10
100
1000
XC9257B33C/XC9258B33C
XC9257B33E/XC9258B33E
L = GLCLKR4701A(0.47μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF×2(GRM155R61A106M)
L =LTF5022T-4R7N2R0(4.7μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF(GRM155R61A106M)
100
90
90
80
80
70
70
Efficiency: EFFI (%)
100
60
VIN=5.0V
VIN=5.0V
40
1
Output Current: IOUT (mA)
Output Current: IOUT (mA)
50
VIN=5.0V
30
0
0
1
VIN=3.7V
40
10
XC9257
0.1
VIN=5.0V
20
XC9258
10
Efficiency: EFFI (%)
1
Output Current: IOUT (mA)
L = GLCLKR4701A(0.47μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF×2(GRM155R61A106M)
90
VIN=5.0V
VIN=3.7V
30
10
XC9257
1
70
20
XC9258
10
0.1
VIN=3.7V
80
VIN=3.7V
70
Efficiency: EFFI (%)
Efficiency: EFFI (%)
L =LTF5022T-4R7N2R0(4.7μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF(GRM155R61A106M)
30
20
60
50
40
30
VIN=5.0V
20
XC9258
10
VIN=5.0V
XC9258
10
XC9257
XC9257
0
0
0.1
1
10
Output Current: IOUT (mA)
100
1000
0.1
1
10
100
1000
Output Current: IOUT (mA)
17/30
XC9257/XC9258 Series is
Not Recommended for New Designs.
XC9257/XC9258 Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(2) Output Voltage vs. Output Current
XC9257B18E/XC9258B18E
XC9257B33E/XC9258B33E
L = GLCLKR4701A(0.47μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF×2(GRM155R61A106M)
L = GLCLKR4701A(0.47μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF×2(GRM155R61A106M)
3.6
2.0
Output Voltage: VOUT (V)
Output Voltage: VOUT (V)
XC9257
1.8
VIN = 3.7V
1.7
1.6
0.1
1
XC9258
3.5
XC9258
1.9
10
100
XC9257
3.4
3.3
3.2
3
1000
VIN = 5.0V
3.1
0.1
Output Current: IOUT (mA)
1
10
100
1000
Output Current: IOUT (mA)
(3) Ripple Voltage vs. Output Current
XC9257B33E/XC9258B33E
XC9257B18E/XC9258B18E
L = GLCLKR4701A(0.47μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF×2(GRM155R61A106M)
L = GLCLKR4701A(0.47μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF×2(GRM155R61A106M)
100
100
80
XC9258
90
XC9258
XC9257
80
XC9257
Ripple Voltage: Vr(mV)
Ripple Voltage: Vr(mV)
90
70
60
50
40
30
VIN = 3.7V
20
60
50
40
30
VIN = 5.0V
20
10
10
0
70
0.1
1
10
100
0
1000
0.1
1000
L =LTF5022T-4R7N2R0(4.7μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF(GRM155R61A106M)
L =LTF5022T-4R7N2R0(4.7μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF(GRM155R61A106M)
100
100
90
XC9258
90
XC9258
80
XC9257
80
XC9257
Ripple Voltage: Vr(mV)
Ripple Voltage: Vr(mV)
100
XC9257B33C/XC9258B33C
XC9257B18C/XC9258B18C
70
60
50
40
VIN = 3.7V
30
20
70
60
50
VIN = 5.0V
40
30
20
10
10
0
10
Output Current: IOUT (mA)
Output Current: IOUT (mA)
0.1
1
10
Output Current: IOUT (mA)
18/30
1
100
1000
0
0.1
1
10
Output Current: IOUT (mA)
100
1000
XC9257/XC9258
XC9257/XC9258 Series is Not Recommended for New Designs.
Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(4) Output Voltage vs. Ambient Temperature
(5) UVLO Voltage vs. Ambient Temperature
XC9257B08E
2.00
3.0
1.95
2.8
1.90
UVLO Voltage: UVLO (V)
Output Voltage:VOUT (V)
XC9257B18E
VIN = 3.7V
1.85
1.80
1.75
1.70
1.65
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.60
1.0
-50
-25
0
25
50
75
100
125
-50
-25
Ambient Temperature: Ta (℃)
0
25
50
75
100
125
100
125
100
125
Ambient Temperature: Ta (℃)
(6) Quiescent Current vs. Ambient Temperature
XC9258B08E
XC9258B08C
100
90
80
Quiescent Current: Iq (μA)
Quiescent Current: Iq (μA)
100
VIN = 5.0V, 3.7V, 2.5V
70
60
50
40
30
20
80
70
60
50
VIN = 5.0V, 3.7V, 2.5V
40
30
20
10
10
0
90
-50
-25
0
25
50
75
100
0
125
-50
-25
0
XC9257B08E
75
XC9257B08C
1000
1000
900
Quiescent Current: Iq (μA)
Quiescent Current: Iq (μA)
50
Ambient Temperature: Ta (℃)
Ambient Temperature: Ta (℃)
VIN = 5.0V
VIN = 3.7V
VIN = 2.5V
800
700
600
500
400
300
200
900
800
VIN = 5.0V
VIN = 3.7V
VIN = 2.5V
700
600
500
400
300
200
100
100
0
25
-50
-25
0
25
50
75
Ambient Temperature: Ta (℃)
100
125
0
-50
-25
0
25
50
75
Ambient Temperature: Ta (℃)
19/30
XC9257/XC9258 Series is
Not Recommended for New Designs.
XC9257/XC9258 Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(7) Stand-by Current vs. Ambient Temperature
(8) Oscillation Frequency vs. Output Current
XC9257B08E
XC9257B08E
L = GLCLKR4701A(0.47μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF×2(GRM155R61A106M)
8.0
Oscillation Freqency: fOSC (MHz)
Standby Current: ISTB (μA)
5.0
4.0
3.0
VIN = 5.0V
2.0
VIN = 3.7V, 2.5V
1.0
0.0
-50
-25
0
25
50
75
100
7.5
6.0
5.5
5.0
VIN = 5.0V
4.5
0
200
600
800
1000
XC9257B33E
L = GLCLKR4701A (0.47μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF×2(GRM155R61A106M)
L = GLCLKR4701A (0.47μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF×2(GRM155R61A106M)
8.0
8.0
VIN = 3.6V
VIN = 3.0V
7.5
Oscillation Freqency: fOSC (MHz)
Oscillation Freqency: fOSC (MHz)
XC9257B18E
7.0
6.5
6.0
VIN = 5.0V
5.5
5.0
4.5
4.0
0
200
400
600
800
7.5
6.5
6.0
5.5
VIN = 4.2V
5.0
4.5
4.0
1000
VIN = 5.0V,5.5V
7.0
0
200
Output Current: IOUT (mA)
Oscillation Freqency: fOSC (MHz)
VIN = 3.0V
2.0
1.5
VIN = 3.6V
VIN = 5.0V
0.5
0.0
0
200
400
800
1000
L = LTF5022T-4R7N2R0-LC(4.7μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF(GRM155R61A106M)
3.0
1.0
600
XC9257A18C
L = LTF5022T-4R7N2R0-LC(4.7μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF(GRM155R61A106M)
2.5
400
Output Current: IOUT (mA)
XC9257A08C
Oscillation Freqency: fOSC (MHz)
400
Output Current: IOUT (mA)
Ambient Temperature: Ta (℃)
600
Output Current: IOUT (mA)
20/30
VIN = 3.6V
6.5
4.0
125
VIN = 3.0V
7.0
800
1000
3.0
2.5
VIN = 3.0V,3.6V,5.0V
2.0
1.5
1.0
0.5
0.0
0
200
400
600
Output Current: IOUT (mA)
800
1000
XC9257/XC9258
XC9257/XC9258 Series is Not Recommended for New Designs.
Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(8) Oscillation Frequency vs. Output Current (Continued)
(9) Pch Driver ON Resistance vs. Ambient Temperature
XC9257A08E
XC9257A33C
Lx SW Pch ON Resistance: RLxH (mΩ)
L = LTF5022T-4R7N2R0-LC(4.7μH)
CIN = 10μF(GRM155R61A106M) CL = 10μF(GRM155R61A106M)
Oscillation Freqency: fOSC (MHz)
3.0
2.5
VIN = 5.0V,5.5V
2.0
1.5
1.0
VIN = 4.2V
0.5
0.0
0
200
400
600
800
500
450
400
350
300
250
VIN = 5.0V
VIN = 3.7V
VIN = 2.5V
200
150
100
1000
-50
-25
Output Current: IOUT (mA)
0
100
125
XC9257A08E
400
10.0
LxSW”L” Leakage Current: ILxL (μA)
Lx SW Nch ON Resistance: RLxL (mΩ)
75
(11) LxSW ”L” Leakage Current vs. Ambient Temperature
XC9257A08E
VIN = 5.0V
VIN = 3.7V
VIN = 2.5V
350
300
250
200
150
-50
-25
0
25
50
75
100
125
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
VIN = 5.5V
1.0
0.0
-50
-25
Ambient Temperature: Ta (℃)
25
50
75
100
125
(13) CE ”H” Voltage vs. Ambient Temperature
XC9257A08E
XC9257B08E
1.4
10.0
CE”H” Voltage VCEH (V)
9.0
8.0
7.0
6.0
5.0
4.0
VIN = 5.5V
3.0
2.0
1.2
1.0
0.8
0.6
VIN = 5.0V
VIN = 3.7V
VIN = 2.5V
0.4
0.2
1.0
0.0
0
Ambient Temperature : Ta (℃)
(12) LxSW ”H” Leakage Current vs. Ambient Temperature
LxSW”H” Leakage Current: ILxH (μA)
50
Ambient Temperature: Ta (℃)
(10) Nch Driver ON Resistance vs. Ambient Temperature
100
25
-50
-25
0
25
50
75
100
Ambient Temperature : Ta (℃)
125
0.0
-50
-25
0
25
50
75
100
125
Ambient Temperature: Ta (℃)
21/30
XC9257/XC9258 Series is
Not Recommended for New Designs.
XC9257/XC9258 Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(14) CE”L” Voltage vs. Ambient Temperature
(15) Soft-Start Time vs. Ambient Temperature
XC9257B08E
XC9257B08E
500
Soft-Start Time: tSS (μs)
CE”L” Voltage VCEL (V)
1.4
VIN = 5.0V
1.2
1.0
0.8
0.6
VIN = 3.7V
VIN = 2.5V
0.4
400
350
VIN = 5.0V
300
250
200
150
100
0.2
0.0
450
50
-50
-25
0
25
50
75
100
0
125
-50
-25
Ambient Temperature: Ta (℃)
CL Discharge Resistance: RDCHG (Ω)
Current Limit: ILIM (mA)
2250
VIN = 5.0V
VIN = 3.0V
VIN = 3.7V
1750
1500
1250
1000
0
25
50
75
100
125
Ambient Temperature : Ta (℃)
Short Protection Threshold VSHORT (mV)
XC9257B08E
500
400
300
200
100
VIN = 5.0V, 3.7V, 2.5V
0
-25
0
25
50
75
100
Ambient Temperature: Ta (℃)
22/30
100
125
300
250
200
VIN = 5.0V
150
100
50
0
-50
-25
0
25
50
75
100
Ambient Temperature: Ta (℃)
(18) Short Protection Threshold vs. Ambient Temperature
-50
75
XC9257B08E
2500
-25
50
(17) CL Discharge Resistance vs. Ambient Temperature
XC9257B08E
-50
25
Ambient Temperature: Ta (℃)
(16) Current Limit vs. Ambient Temperature
2000
0
125
125
XC9257/XC9258 Series is Not Recommended for New Designs.
XC9257/XC9258
Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(19) Load Transient Response
XC9257A12E
VIN = 5.0V VOUT = 1.2V fOSC = 6.0MHｚ IOUT = 10mA ⇒ 600mA
L = GLCLKR4701A(0.47μH)CIN = 10μF(GRM155R61A106M)
CL = 10μF×2(GRM155R61A106M)
XC9258A12E
VIN = 5.0V VOUT = 1.2V fOSC = 6.0MHｚ IOUT = 10mA ⇒ 600mA
L = GLCLKR4701A(0.47μH)CIN = 10μF(GRM155R61A106M)
CL = 10μF×2(GRM155R61A106M)
IOUT : 600mA
IOUT : 600mA
IOUT : 10mA
IOUT : 10mA
VOUT : 50mV/div
VOUT : 50mV/div
20μs/div
XC9257A18E
VIN = 5.0V VOUT = 1.8V fOSC = 6.0MHｚ IOUT = 10mA ⇒ 600mA
L = GLCLKR4701A(0.47μH)CIN = 10μF(GRM155R61A106M)
CL = 10μF×2(GRM155R61A106M)
20μs/div
XC9258A18E
VIN = 5.0V VOUT = 1.8V fOSC = 6.0MHｚ IOUT = 10mA ⇒ 600mA
L = GLCLKR4701A(0.47μH))CIN = 10μF(GRM155R61A106M)
CL = 10μF(GRM155R61A106M)
IOUT : 600mA
IOUT : 600mA
IOUT : 10mA
IOUT : 10mA
VOUT : 50mV/div
VOUT : 50mV/div
50μs/div
XC9257A33E
VIN = 5.0V VOUT = 3.3V fOSC = 6.0MHｚ IOUT = 10mA ⇒ 600mA
L = GLCLKR4701A(0.47μH)CIN = 10μF(GRM155R61A106M)
CL = 10μF×2(GRM155R61A106M)
IOUT : 10mA
50μs/div
XC9258A33E
VIN = 5.0V VOUT = 3.3V fOSC = 6.0MHｚ IOUT = 10mA ⇒ 600mA
L = GLCLKR4701A(0.47μH)CIN = 10μF(GRM155R61A106M)
CL = 10μF×2(GRM155R61A106M)
IOUT : 600mA
IOUT : 600mA
IOUT : 10mA
VOUT : 50mV/div
VOUT : 50mV/div
50μs/div
50μs/div
23/30
XC9257/XC9258 Series
XC9257/XC9258 Series is
Not Recommended for New Designs.
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(19) Load Transient Response
XC9257A12C
VIN = 5.0V VOUT = 1.2V fOSC = 1.2MHｚ IOUT = 10mA ⇒ 600mA
L = LTF5022T-4R7N2R0-LC(4.7μH)CIN = 10μF(GRM155R61A106M)
CL = 10μF(GRM155R61A106M)
XC9258A12C
VIN = 5.0V VOUT = 1.2V fOSC = 1.2MHｚ IOUT = 10mA ⇒ 600mA
L = LTF5022T-4R7N2R0-LC(4.7μH)CIN = 10μF(GRM155R61A106M)
CL = 10μF(GRM155R61A106M)
IOUT : 600mA
IOUT : 600mA
IOUT : 10mA
IOUT : 10mA
VOUT : 100mV/div
VOUT : 100mV/div
50μs/div
50μs/div
XC9257A18C
VIN = 5.0V VOUT = 1.8V fOSC = 1.2MHｚ IOUT = 10mA ⇒ 600mA
L = LTF5022T-4R7N2R0-LC(4.7μH)CIN = 10μF(GRM155R61A106M)
CL = 10μF(GRM155R61A106M)
IOUT : 10mA
XC9258A18C
VIN = 5.0V VOUT = 1.8V fOSC = 1.2MHｚ IOUT = 10mA ⇒ 600mA
L = LTF5022T-4R7N2R0-LC(4.7μH)CIN = 10μF(GRM155R61A106M)
CL = 10μF(GRM155R61A106M)
IOUT : 600mA
IOUT : 600mA
IOUT : 10mA
VOUT : 100mV/div
VOUT : 100mV/div
50μs/div
50μs/div
XC9257A33C
VIN = 5.0V VOUT = 3.3V fOSC = 1.2MHｚ IOUT = 10mA ⇒ 600mA
L = LTF5022T-4R7N2R0-LC(4.7μH)CIN = 10μF(GRM155R61A106M)
CL = 10μF(GRM155R61A106M)
XC9258A33C
VIN = 5.0V VOUT = 3.3V fOSC = 1.2MHｚ IOUT = 10mA ⇒ 600mA
L = LTF5022T-4R7N2R0-LC(4.7μH)CIN = 10μF(GRM155R61A106M)
CL = 10μF(GRM155R61A106M)
IOUT : 600mA
IOUT : 600mA
IOUT : 10mA
IOUT : 10mA
VOUT : 200mV/div
VOUT : 200mV/div
50μs/div
24/30
50μs/div
XC9257/XC9258
XC9257/XC9258 Series is Not Recommended for New Designs.
Series
■PACKAGING INFORMATION
●SOT-25 (unit: mm)
●USP-6C (unit: mm)
2.9±0.2
1.8±0.05
+0.1
0.4 -0.05
2.0±0.05
4
1pin INDENT
3
0.6MAX
+0.1
0.15 -0.05
(0.95)
1.9±0.2
0.30±0.05
1.3MAX
(0.1)
1.0±0.05
0.20±0.05
(0.50)
0.10±0.05
Reference Pattern Layout (unit: mm)
●USP-6C
Reference Metal Mask Design (unit: mm) (unit: mm)
2.4
2.3
2
5
0.25
4
0.25
0.5
6
0.6
4
0.225
0.25
3
1
0.5
5
0.35
0.5
0.25
2
1.8
6
1.6
1
0.25
0.35
3
0.15
0.05
0.05
1.4
0.45
0.5
0.225
0.45
1.2
●USP-6C
1.4±0.05
0.25
1.1±0.1
0.05
0.25±0.05
2
1
0.2MIN
1.6
+0.2
-0.1
2.8±0.2
0～0.1
0.70±0.05
5
0.15
0.8
1.0
25/30
XC9257/XC9258 Series is
Not Recommended for New Designs.
XC9257/XC9258 Series
●SOT-25 Power Dissipation (40mm x 40mm Standard board)
Power dissipation data for the SOT-25 is shown in this page.
The value of power dissipation varies with the mount board conditions.
Please use this data as the reference data taken in the following condition.
1. Measurement Condition
40.0
Condition： Mount on a board
28.9
Ambient： Natural convection
Soldering： Lead (Pb) free
Board： Dimensions 40 x 40 mm
Copper (Cu) traces occupy 50% of the board
40.0
28.9
(1600 mm2 in one side)
area In top and back faces
Package heat-sink is tied to the copper traces
(Board of SOT-26 is used.)
Material： Glass Epoxy (FR-4)
Through-hole： 4 x 0.8 Diameter
2.54
2.5
Thickness： 1.6mm
1.4
Evaluation Board (Unit：mm)
2.Power Dissipation vs. Ambient Temperature
Board Mount (Tj max = 125℃)
Ambient Temperature（℃）
Power Dissipation Pd（mW）
Thermal Resistance (℃/W)
25
105
600
120
166.67
Pd vs. Ta
Power Dissipation Pd (mW)
700
600
500
400
300
200
100
0
26/30
25
45
65
85
105
Ambient Temperature Ta (℃)
125
XC9257/XC9258
XC9257/XC9258 Series is Not Recommended for New Designs.
Series
●USP-6C Power Dissipation (40mm x 40mm Standard board)
Power dissipation data for the USP-6C is shown in this page.
The value of power dissipation varies with the mount board conditions.
Please use this data as the reference data taken in the following condition.
1. Measurement Condition
40.0
28.9
Condition： Mount on a board
Ambient： Natural convection
Soldering： Lead (Pb) free
Board： Dimensions 40 x 40 mm
Copper (Cu) traces occupy 50% of the board
40.0
28.9
(1600 mm2 in one side)
area In top and back faces
Package heat-sink is tied to the copper traces
Material： Glass Epoxy (FR-4)
2.54
1.4
2.5
Thickness： 1.6mm
Through-hole： 4 x 0.8 Diameter
Evaluation Board (Unit：mm)
2.Power Dissipation vs. Ambient Temperature
Board Mount (Tj max = 125℃)
Ambient Temperature（℃）
Power Dissipation Pd（mW）
Thermal Resistance (℃/W)
25
105
1000
200
100.00
Pd vs Ta
Power Dissipation Pd (mW)
1200
1000
800
600
400
200
0
25
45
65
85
105
125
Ambient Temperature Ta (℃)
27/30
XC9257/XC9258 Series is
Not Recommended for New Designs.
XC9257/XC9258 Series
●USP-6C Power Dissipation (JEDEC board)
Power dissipation data for the USP-6C is shown in this page.
The value of power dissipation varies with the mount board conditions.
Please use this data as one of reference data taken in the described condition.
76.2
1. Measurement Condition (Reference data)
Condition : Mount on a board
Ambient : Natural convection
Soldering : Lead (Pb) free
Board : The board using 4 copper layer.
(76.2mm×114.3mm・・・Area: about 8700mm2）
1st layer : No copper foil (Signal layer)
2nd layer : 70mm×70mm_Connected to heat-sink.
3rd layer : 70mm×70mm_Connected to heat-sink.
114.3
4th layer : No copper foil (Signal layer)
Material : Glass Epoxy（FR-4）
Thickness : 1.6mm
8.74
Through-hole : φ0.2mm x 60pcs
Evaluation Board (Unit：mm)
2.Power Dissipation vs. Ambient temperature
Board Mount(Tjmax = 125℃)
AmbientTemperature（℃） PowerDissipation Pd（mW)
25
105
1250
250
θja(℃/W)
80.00
Power DissipationPd（mW）
Pd-Ta
1400
1200
1000
800
600
400
200
0
25
45
65
85
Ta（℃）
28/30
105
125
XC9257/XC9258 Series is Not Recommended for New Designs.
■MARKING RULE
XC9257/XC9258
Series
SOT-25(Under dot)
●SOT-25(Under dot)/USP-6C
4
② ③
1
2
④
⑤
3
③
3
②
② represents integer and oscillation frequency of the output voltage Type
MARK TYPE OUTPUT VOLTAGE (V)
OSCILLATION FREQUENCY (MHz)
8
0.x
9
1.x
1.2
E
2.x
F
3.x
A
H
0.x
K
1.x
6.0
L
2.x
M
3.x
N
0.x
P
1.x
1.2
R
2.x
S
3.x
B
T
0.x
U
1.x
6.0
V
2.x
X
3.x
2
⑤
Magnified
拡大
1
①
①
USP-6C
④
① represents products series
MARK
PRODUCT SERIES
7
XC9257******-G
8
XC9258******-G
5
6
5
4
PRODUCT SERIES
XC9257A0*C**-G / XC9258A0*C**-G
XC9257A1*C**-G / XC9258A1*C**-G
XC9257A2*C**-G / XC9258A2*C**-G
XC9257A3*C**-G / XC9258A3*C**-G
XC9257A0*E**-G / XC9258A0*E**-G
XC9257A1*E**-G / XC9258A1*E**-G
XC9257A2*E**-G / XC9258A2*E**-G
XC9257A3*E**-G / XC9258A3*E**-G
XC9257B0*C**-G / XC9258B0*C**-G
XC9257B1*C**-G / XC9258B1*C**-G
XC9257B2*C**-G / XC9258B2*C**-G
XC9257B3*C**-G / XC9258B3*C**-G
XC9257B0*E**-G / XC9258B0*E**-G
XC9257B1*E**-G / XC9258B1*E**-G
XC9257B2*E**-G / XC9258B2*E**-G
XC9257B3*E**-G / XC9258B3*E**-G
③ represents decimal number of the output voltage
OUTPUT VOLTAGE (V)
MARK
PRODUCT SERIES
X.0
0
XC9257**0***-G / XC9258**0***-G
X.05
A
XC9257**A***-G / XC9258**A***-G
X.1
1
XC9257**1***-G / XC9258**1***-G
X.15
B
XC9257**B***-G / XC9258**B***-G
X.2
2
XC9257**2***-G / XC9258**2***-G
X.25
C
XC9257**C***-G / XC9258**C***-G
X.3
3
XC9257**3***-G / XC9258**3***-G
X.35
D
XC9257**D***-G / XC9258**D***-G
X.4
4
XC9257**4***-G / XC9258**4***-G
X.45
E
XC9257**E***-G / XC9258**E***-G
X.5
5
XC9257**5***-G / XC9258**5***-G
X.55
F
XC9257**F***-G / XC9258**F***-G
X.6
6
XC9257**6***-G / XC9258**6***-G
X.65
H
XC9257**H***-G / XC9258**H***-G
X.7
7
XC9257**7***-G / XC9258**7***-G
X.75
K
XC9257**K***-G / XC9258**K***-G
X.8
8
XC9257**8***-G / XC9258**8***-G
X.85
L
XC9257**L***-G / XC9258**L***-G
X.9
9
XC9257**9***-G / XC9258**9***-G
X.95
M
XC9257**M***-G / XC9258**M***-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.
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XC9257/XC9258 Series
XC9257/XC9258 Series is
Not Recommended for New Designs.
1.
The product 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.
The information in this datasheet is intended to illustrate the operation and characteristics of our
products. We neither make warranties or representations with respect to the accuracy or
completeness of the information contained in this datasheet nor grant any license to any intellectual
property rights of ours or any third party concerning with the information in this datasheet.
3.
Applicable export control laws and regulations should be complied and the procedures required by
such laws and regulations should also be followed, when the product or any information contained in
this datasheet is exported.
4.
The product is neither intended nor warranted for use in equipment of systems which require
extremely high levels of quality and/or reliability and/or a malfunction or failure which may cause loss
of human life, bodily injury, serious property damage including but not limited to devices or equipment
used in 1) nuclear facilities, 2) aerospace industry, 3) medical facilities, 4) automobile industry and
other transportation industry and 5) safety devices and safety equipment to control combustions and
explosions. Do not use the product for the above use unless agreed by us in writing in advance.
5.
Although we make continuous efforts to improve the quality and reliability of our products;
nevertheless Semiconductors are likely to fail with a certain probability. So in order to prevent personal
injury and/or property damage resulting from such failure, customers are required to incorporate
adequate safety measures in their designs, such as system fail safes, redundancy and fire prevention
features.
6.
Our products are not designed to be Radiation-resistant.
7.
Please use the product listed in this datasheet within the specified ranges.
8.
We assume no responsibility for damage or loss due to abnormal use.
9.
All rights reserved. No part of this datasheet may be copied or reproduced unless agreed by Torex
Semiconductor Ltd in writing in advance.
TOREX SEMICONDUCTOR LTD.
30/30
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