TOREX XC9237B3ACMR

XC9235/XC9236/XC9237 Series
ETR0514-007
600mA Driver Tr. Built-In, Synchronous Step-Down DC/DC Converters
☆GreenOperation Compatible
■GENERAL DESCRIPTION
The XC9235/XC9236/XC9237 series is a group of synchronous-rectification type DC/DC converters with a built-in 0.42Ω
P-channel driver transistor and 0.52ΩN-channel switching transistor, designed to allow the use of ceramic capacitors. The ICs
enable a high efficiency, stable power supply with an output current of 600mA to be configured using only a coil and two
capacitors connected externally. Operating voltage range is from 2.0V to 6.0V. Output voltage is internally set in a range from
0.8V to 4.0V in increments of 50mV (accuracy: ±2.0%). With the built-in oscillator, ether 1.2MHz or 3.0MHz can be selected
for suiting to your particular application. As for operation mode, the XC9235 series is PWM control, the XC9236 series is
automatic PWM/PFM switching control and the XC9237 series can be manually switched between the PWM control mode and
the automatic PWM/PFM switching control mode, allowing fast response, low ripple and high efficiency over the full range of
loads (from light load to heavy load).
The soft start and current control functions are internally optimized. During stand-by, all circuits are shutdown to reduce
current consumption to as low as 1.0μA or less. With the built-in UVLO (Under Voltage Lock Out) function, the internal
P-channel driver transistor is forced OFF when input voltage becomes 1.4V or lower.
The XC9235B/XC9236B/XC9237B series provide short-time turn-on by the soft start function internally set in 0.25 ms (TYP).
The XC9235B(C)/XC9236B(C)/XC9237B(C) integrate CL auto discharge function which enables the electric charge at the output
capacitor CL to be discharged via the internal auto-discharge switch located between the LX and VSS pins. When the devices
enter stand-by mode, output voltage quickly returns to the VSS level as a result of this function.
Two types of package SOT-25 and USP-6C are available.
■APPLICATIONS
●Mobile phones
●Bluetooth equipment
●PDAs, portable communication modem
●Portable games
●Digital cameras, video cameras
●Cordless phones
●Notebook computers
■FEATURES
P-ch Driver Transistor Built-In
N-ch Driver Transistor Built-In
Input Voltage
Output Voltage
High Efficiency
Output Current
Oscillation Frequency
Maximum Duty Cycle
Control Methods
: ON resistance 0.42Ω
: ON resistance 0.52Ω
: 2.0V ~ 6.0V
: 0.8V ~ 4.0V
: 92% (TYP.)
: 600mA
: 1.2MHz, 3.0MHz (+15%)
: 100%
: PWM (XC9235)
PWM/PFM Auto (XC9236)
PWM/PFM Manual (XC9237)
Soft-Start Circuit Built-In
Current Limiter Circuit Built-In (Constant Current & Latching)
Low ESR Ceramic Capacitor Compatible
Packages
: SOT-25, USP-6C
CL High Speed Discharge
（XC9235B(C)/XC9236B(C)/XC9237B(C) Series）
High Speed Soft Start
（XC9235B/XC9236B/XC9237B Series）
* Performance depends on external components and wiring on the PCB.
■TYPICAL APPLICATION CIRCUIT ■TYPICAL PERFORMANCE
CHARACTERISTICS
●Efficiency vs. Output Current（FOSC=1.2NHz, VOUT=1.8V）
100
PWM/PFM Automatic Sw itching Control
90
Efficiency:
EFFI (%)
Efficency:EFFI(%)
80
VIN= 4.2V
70
60
50
PWM Control
VIN= 4.2V
3.6V
2.4V
3.6V
2.4V
40
30
20
10
0
0.1
1
10
100
1000
Output Current:IOUT(mA)
1/28
XC9235/XC9236/XC9237 Series
■PIN CONFIGURATION
Lx
VOUT
5
4
2
VIN
VSS
Lx
6
VSS
5
2
VSS
4
3
VOUT
CE/MODE
1
1
VIN
3
CE/MODE
SOT-25
(Top View)
* Please short the VSS pin (No. 2 and 5).
* 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 VSS (No. 5) pin.
USP-6C
(BOTTOM VIEW)
■PIN ASSIGNMENT
PIN NUMBER
SOT-25
USP-6C
1
6
2
2, 5
3
4
4
3
5
1
PIN NAME
FUNCTION
VIN
VSS
CE / MODE
VOUT
Lx
Power Input
Ground
Chip Enable Mode Switch
Output Voltage Sense
Switching Output
■PRODUCT CLASSIFICATION
●Ordering Information
XC9235①②③④⑤⑥
XC9236①②③④⑤⑥
XC9237①②③④⑤⑥
PWM fixed control
PWM / PFM automatic switching control
PWM fixed controlQPWM / PFM automatic switching, manual switching
DESIGNATOR
DESCRIPTION
SYMBOL
A
: CE input logic High Active
①.
Transistor built-in,
Output voltage internally set
(VOUT product),
Soft-start internally set
B
: CE input logic High Active, high speed soft start, CL discharge
C
②
Output Voltage
0~4
③
Output Voltage
0~9, A~M
: CE input logic High Active, CL discharge
: Integer number of output voltage
e.g. VOUT=2.8V→②=2, VOUT=3.3V→②=3
: Decimal number of output voltage
50mV 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
e.g. VOUT=2.8V→②=2, ③=8
VOUT=2.85V→②=2, ③=L
④
Oscillation Frequency
⑤
Packages
⑥
Device Orientation
2/28
DESCRIPTION
C
: 1.2MHz
D
: 3.0MHz
M
: SOT-25 (SOT-23-5)
E
: USP-6C
R
: Embossed tape, standard feed
L
: Embossed tape, reverse feed
XC9235/XC9236/XC9237
Series
■BLOCK DIAGRAM
●XC9235A / XC9236A / XC9237A
●XC9235B(C) / XC9236B(C) / XC9237B(C)
NOTE: The signal from CE/MODE Control Logic to PWM/PFM Selector is being fixed to "L" level inside,
and XC9235 series chooses only PWM control.
The signal from CE/MODE Control Logic to PWM/PFM Selector is being fixed to "H" level inside,
and XC9236 series chooses only PWM/PFM automatic switching control.
Diodes inside the circuit are ESD protection diodes and parasitic diodes.
■ABSOLUTE MAXIMUM RATINGS
Ta=25℃
PARAMETER
SYMBOL
RATINGS
UNIT
VIN Pin Voltage
Lx Pin Voltage
VOUT Pin Voltage
CE / MODE Pin Voltage
Lx Pin Current
Power Dissipation
SOT-25
(*Ta=25℃)
USP-6C
Operating Temperature Range
Storage Temperature Range
VIN
VLx
VOUT
VCE
ILx
- 0.3 ~ 6.5
- 0.3 ~ VIN + 0.3 or 6.5V
- 0.3 ~ 6.5
- 0.3 ~ 6.5
±1500
250
100
- 40 ~ + 85
- 55 ~ + 125
V
V
V
V
mA
Pd
Topr
Tstg
mW
O
O
C
C
3/28
XC9235/XC9236/XC9237 Series
■ELECTRICAL CHARACTERISTICS
XC9237A18Cxx, VOUT=1.8V, FOSC=1.2MHz, Ta=25℃
PARAMETER
SYMBOL
Output Voltage
VOUT
Operating Voltage Range
VIN
Maximum Output Current
IOUTMAX
U.V.L.O. Voltage
VUVLO
Supply Current
Stand-by Current
IDD
ISTB
Oscillation Frequency
FOSC
PFM Switching Current
IPFM
Maximum IPFM Limit
Maximum Duty Cycle
Minimum Duty Cycle
MAXIPFM
MAXDTY
MINDTY
Efficiency
(*2)
Lx SW "H" ON Resistance 1
Lx SW "H" ON Resistance 2
Lx SW "L" ON Resistance 1
Lx SW "L" ON Resistance 2
Lx SW "H" Leak Current (*5)
Lx SW "L" Leak Current (*5)
Current Limit (*10)
Output Voltage
EFFI
CONDITIONS
When connected to external components,
VIN=VCE=5.0V, IOUT=30mA
MIN.
TYP.
1.764
1.800 1.836
2.0
VIN=VOUT(E)+2.0V, VCE=1.0V,
600
When connected to external components (*9)
VCE =VIN, VOUT=0V,
1.00
Voltage which Lx pin holding “L” level (*1, *11)
VIN=VCE=5.0V, VOUT=VOUT(E)×1.1V
VIN=5.0V, VCE=0V, VOUT=VOUT(E)×1.1V
When connected to external components,
1020
VIN=VOUT(E)+2.0V, VCE =1.0V, IOUT=100mA
When connected to external components,
120
(*12)
VIN=VOUT(E)+2.0V, VCE =VIN, IOUT=1mA
(*12)
VCE=VIN=(C-1), IOUT=1mA
VIN=VCE=5.0V, VOUT=VOUT(E)×0.9V
100
VIN=VCE=5.0V, VOUT=VOUT(E)×1.1V
When connected to external components,
VCE=VIN=VOUT(E)+1.2V, IOUT=100mA
(*3)
VIN=VCE=5.0V, VOUT=0V, ILx=100mA
(*3)
VIN=VCE=3.6V, VOUT=0V, ILx=100mA
VIN=VCE=5.0V (*4)
VIN=VCE=3.6V (*4)
VIN=VOUT=5.0V, VCE=0V, Lx=0V
VIN=VOUT=5.0V, VCE=0V, Lx=5.0V
VIN=VCE=5.0V, VOUT=VOUT(E)×0.9V (*8)
900
RLxH
RLxH
RLxL
RLxL
ILeakH
ILeakL
ILIM
△VOUT
I =30mA, -40℃≦Topr≦85℃
Temperature Characteristics VOUT・△topr OUT
VOUT=0V, Applied voltage to VCE,
CE "H" Voltage
VCEH
(*11)
Voltage changes Lx to “H” level
VOUT=0V, Applied voltage to VCE ,
CE "L" Voltage
VCEL
Voltage changes Lx to “L” level (*11)
When connected to external components,
IOUT=1mA (*6), Voltage which oscillation
PWM "H" Level Voltage
VPWMH
frequency becomes 1020 kHz≦FOSC≦
(*13)
1380kHz
When connected to external components,
PWM "L" Level Voltage
VPWML
IOUT=1mA (*6), Voltage which oscillation
frequency becomes FOSC＜1020kHz (*13)
CE "H" Current
ICEH
VIN=VCE=5.0V, VOUT=0V
CE "L" Current
ICEL
VIN=5.0V, VCE=0V, VOUT=0V
When connected to external components,
Soft Start Time
TSS
VCE=0V → VIN, IOUT=1mA
VIN=VCE=5.0V, VOUT=0.8×VOUT(E),
Latch Time
TLAT
(*7)
Short Lx at 1Ω resistance
Sweeping VOUT, VIN=VCE=5.0V, Short Lx at
Short Protection
VSHORT
1Ω resistance, VOUT voltage which Lx
Threshold Voltage
becomes “L” level within 1ms
MAX.
UNIT CIRCUIT
V
①
-
6.0
V
①
-
-
mA
①
1.40
1.78
V
②
15
0
33
1.0
μA
μA
③
③
1200
1380
kHz
①
160
200
mA
①
200
-
0
%
%
%
①
②
②
92
-
%
①
0.35
0.42
0.45
0.52
0.01
0.01
1050
0.55
0.67
0.66
0.77
1.0
1.0
1350
Ω
Ω
Ω
Ω
μA
μA
mA
④
④
④
⑤
⑤
⑥
-
±100
-
ppm/℃
①
0.65
-
VIN
V
③
VSS
-
0.25
V
③
-
-
VIN 1.0
V
①
VIN –
0.25
-
-
V
①
- 0.1
- 0.1
-
0.1
0.1
μA
μA
⑤
⑤
0.5
1.0
2.5
ms
①
1.0
-
20.0
ms
⑦
V
⑦
0.675 0.900 1.150
Test conditions: Unless otherwise stated, VIN=5.0V, VOUT(E)=Setting Voltage
NOTE:
*1: Including hysteresis operating voltage range.
*2: EFFI = { ( output voltage×output current ) / ( input voltage×input current) }×100
*3: ON resistance (Ω)= (VIN - Lx pin measurement voltage) / 100mA
*4: R&D value
*5: When temperature is high, a current of approximately 10μA (maximum) may leak.
*6: The CE/MODE pin of the XC9237A series works also as an external switching pin of PWM control and PWM/PFM control. When the IC is in the
operation, control is switched to the automatic PWM/PFM switching mode when the CE/MODE pin voltage is equal to or greater than VIN minus
0.3V, and to the PWM mode when the CE/MODE pin voltage is equal to or lower than VIN minus 1.0V and equal to or greater than VCEH.
*7: 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.
*8: When VIN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance.
*9: 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.
*10: Current limit denotes the level of detection at peak of coil current.
*11: “H”=VIN~VIN-1.2V, “L”=+0.1V~-0.1V
*12: XC9235 series exclude IPFM and MAXIPFM because those are only for the PFM control’s functions.
*13: XC9235/9236 series exclude VPWMH and VPWML because those are only for the XC9237 series’ functions.
4/28
XC9235/XC9236/XC9237
Series
■ELECTRICAL CHARACTERISTICS (Continued)
XC9237A18Dxx, VOUT=1.8V, FOSC=3.0MHz, Ta=25℃
PARAMETER
SYMBOL
Output Voltage
VOUT
Operating Voltage Range
VIN
Maximum Output Current
IOUTMAX
U.V.L.O. Voltage
VUVLO
Supply Current
Stand-by Current
IDD
ISTB
Oscillation Frequency
FOSC
PFM Switching Current
IPFM
Maximum IPFM Limit
Maximum Duty Cycle
Minimum Duty Cycle
MAXIPFM
MAXDTY
MINDTY
Efficiency
EFFI
Lx SW "H" ON Resistance 1
Lx SW "H" ON Resistance 2
Lx SW "L" ON Resistance 1
Lx SW "L" ON Resistance 2
Lx SW "H" Leak Current (*5)
Lx SW "L" Leak Current (*5)
Current Limit (*10)
Output Voltage
CONDITIONS
When connected to external components,
VIN=VCE=5.0V, IOUT=30mA
MIN.
TYP.
1.764
1.800 1.836
2.0
VIN=VOUT(E)+2.0V, VCE=1.0V,
600
When connected to external components (*9)
VCE=VIN, VOUT=0V,
1.00
Voltage which Lx pin holding “L” level (*1,*11)
VIN=VCE=5.0V, VOUT=VOUT(E)×1.1V
VIN=5.0V, VCE=0V, VOUT=VOUT(E)×1.1V
When connected to external components,
2550
VIN=VOUT(E)+2.0V, VCE=1.0V, IOUT=100mA
When connected to external components,
170
VIN=VOUT(E)+2.0V, VCE=VIN, IOUT=1mA (*12)
(*12)
VCE=VIN=(C-1), IOUT=1mA
VIN=VCE=5.0V, VOUT=VOUT(E)×0.9V
100
VIN=VCE=5.0V, VOUT=VOUT(E)×0.1V
When connected to external components,
VCE=VIN＝VOUT(E)+1.2V, IOUT=100mA
(*3)
VIN=VCE=5.0V, VOUT =0V, ILx=100mA
VIN=VCE=3.6V, VOUT =0V, ILx=100mA (*3)
VIN=VCE=5.0V (*4)
VIN=VCE=3.6V (*4)
VIN=VOUT=5.0V, VCE=0V, Lx=0V
VIN=VOUT=5.0V, VCE=0V, Lx=5.0V
VIN=VCE=5.0V, VOUT=VOUT(E)×0.9V (*8)
900
RLxH
RLxH
RLxL
RLxL
ILeakH
ILeakL
ILIM
△VOUT
I =30mA, -40℃≦Topr≦85℃
Temperature Characteristics VOUT・△topr OUT
VOUT=0V, Applied voltage to VCE,
CE "H" Voltage
VCEH
Voltage changes Lx to “H” level (*11)
VOUT=0V, Applied voltage to VCE,
CE "L" Voltage
VCEL
(*11)
Voltage changes Lx to “L” level
When connected to external components,
IOUT=1mA (*6), Voltage which oscillation
PWM "H" Level Voltage
VPWMH
frequency becomes 2550kHz≦FOSC≦
3450kHz (*13)
When connected to external components,
PWM "L" Level Voltage
VPWML
IOUT=1mA (*6), Voltage which oscillation
frequency becomes FOSC＜2550kHz (*13)
CE "H" Current
ICEH
VIN=VCE=5.0V, VOUT=0V
CE "L" Current
ICEL
VIN=5.0V, VCE=0V, VOUT=0V
When connected to external components,
Soft Start Time
TSS
VCE=0V → VIN, IOUT=1mA
VIN=VCE=5.0V, VOUT=0.8×VOUT(E),
Latch Time
TLAT
Short Lx at 1Ω resistance (*7)
Sweeping VOUT, VIN=VCE=5.0V, Short Lx at
Short Protection
1Ω resistance, VOUT voltage which Lx
VSHORT
Threshold Voltage
becomes “L” level within 1ms (*4)
MAX. UNIT CIRCUIT
V
①
-
6.0
V
①
-
-
mA
①
1.40
1.78
V
③
21
0
35
1.0
μA
μA
②
②
3000
3450
kHz
①
220
270
mA
①
200
-
300
0
%
%
%
①
③
③
86
-
%
①
0.35
0.42
0.45
0.52
0.01
0.01
1050
0.55
0.67
0.66
0.77
1.0
1.0
1350
Ω
Ω
Ω
Ω
μA
μA
mA
④
④
⑤
⑤
⑥
-
±100
-
ppm/℃
①
0.65
-
VIN
V
③
VSS
-
0.25
V
③
-
-
VIN 1.0
V
①
VIN –
0.25
-
-
V
①
- 0.1
- 0.1
-
0.1
0.1
μA
μA
⑤
⑤
0.5
0.9
3.0
ms
①
1.0
-
20
ms
⑦
V
⑦
0.675 0.900 1.150
Test conditions: Unless otherwise stated, VIN=5.0V, VOUT(E)=Setting Voltage
NOTE:
*1: Including hysteresis operating voltage range.
*2: EFFI = { ( output voltage×output current ) / ( input voltage×input current) }×100
*3: ON resistance (Ω)= (VIN - Lx pin measurement voltage) / 100mA
*4: R&D value
*5: When temperature is high, a current of approximately 10μA (maximum) may leak.
*6: The CE/MODE pin of the XC9237A series works also as an external switching pin of PWM control and PWM/PFM control. When the IC is in the
operation, control is switched to the automatic PWM/PFM switching mode when the CE/MODE pin voltage is equal to or greater than VIN minus
0.3V, and to the PWM mode when the CE/MODE pin voltage is equal to or lower than VIN minus 1.0V and equal to or greater than VCEH.
*7: 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.
*8: When VIN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance.
*9: 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.
*10: Current limit denotes the level of detection at peak of coil current.
*11: “H”=VIN~VIN-1.2V, “L”=+0.1V~-0.1V
*12: XC9235 series exclude IPFM and MAXIPFM because those are only for the PFM control’s functions.
*13: XC9235/9236 series exclude VPWMH and VPWML because those are only for the XC9237 series’ functions.
5/28
XC9235/XC9236/XC9237 Series
■ELECTRICAL CHARACTERISTICS (Continued)
XC9237B(C)18Cxx, VOUT=1.8V, FOSC=1.2MHz, Ta=25℃
PARAMETER
SYMBOL
Output Voltage
VOUT
Operating Voltage Range
VIN
Maximum Output Current
IOUTMAX
U.V.L.O. Voltage
VUVLO
Supply Current
Stand-by Current
IDD
ISTB
Oscillation Frequency
FOSC
PFM Switching Current
IPFM
Maximum IPFM Limit
Maximum Duty Cycle
Minimum Duty Cycle
MAXIPFM
MAXDTY
MINDTY
Efficiency (*2)
EFFI
Lx SW "H" ON Resistance 1
Lx SW "H" ON Resistance 2
Lx SW "L" ON Resistance 1
Lx SW "L" ON Resistance 2
Lx SW "H" Leak Current (*5)
Current Limit (*10)
Output Voltage
CONDITIONS
When connected to external components,
VIN=VCE=5.0V, IOUT=30mA
VPWML
CE "H" Current
CE "L" Current
ICEH
ICEL
Soft Start Time (B Series)
TSS
Soft Start Time (C Series)
TSS
Latch Time
TLAT
Short Protection
Threshold Voltage
VSHORT
CL Discharge
Rdischg
TYP.
1.764
1.800 1.836
2.0
VIN=VOUT(E)+2.0V, VCE=1.0V,
600
When connected to external components (*9)
VCE =VIN, VOUT=0V,
1.00
Voltage which Lx pin holding “L” level (*1, *11)
VIN=VCE=5.0V, VOUT=VOUT(E)×1.1V
VIN=5.0V, VCE=0V, VOUT=VOUT(E)×1.1V
When connected to external components,
1020
VIN=VOUT(E)+2.0V, VCE =1.0V, IOUT=100mA
When connected to external components,
120
VIN=VOUT(E)+2.0V, VCE =VIN, IOUT=1mA (*12)
(*12)
VCE=VIN=(C-1), IOUT=1mA
VIN=VCE=5.0V, VOUT=VOUT(E)×0.9V
100
VIN=VCE=5.0V, VOUT=VOUT(E)×1.1V
When connected to external components,
VCE=VIN=VOUT(E)+1.2V, IOUT=100mA
(*3)
VIN=VCE=5.0V, VOUT=0V, ILx=100mA
(*3)
VIN=VCE=3.6V, VOUT=0V, ILx=100mA
VIN=VCE=5.0V (*4)
VIN=VCE=3.6V (*4)
VIN=VOUT=5.0V, VCE=0V, Lx=0V
VIN=VCE=5.0V, VOUT=VOUT(E)×0.9V (*8)
900
RLxH
RLxH
RLxL
RLxL
ILeakH
ILIM
△VOUT
I =30mA, -40℃≦Topr≦85℃
Temperature Characteristics VOUT・△topr OUT
VOUT=0V, Applied voltage to VCE,
CE "H" Voltage
VCEH
Voltage changes Lx to “H” level (*11)
VOUT=0V, Applied voltage to VCE ,
CE "L" Voltage
VCEL
Voltage changes Lx to “L” level (*11)
When connected to external components,
PWM "H" Level Voltage
VPWMH
IOUT=1mA (*6), Voltage which oscillation frequency
becomes 1020 kHz≦FOSC≦1380kHz (*13)
PWM "L" Level Voltage
MIN.
When connected to external components,
IOUT=1mA (*6), Voltage which oscillation frequency
becomes FOSC＜1020kHz (*13)
VIN=VCE=5.0V, VOUT=0V
VIN=5.0V, VCE=0V, VOUT=0V
When connected to external components,
VCE=0V → VIN, IOUT=1mA
When connected to external components,
VCE=0V → VIN, IOUT=1mA
VIN=VCE=5.0V, VOUT=0.8×VOUT(E),
Short Lx at 1Ω resistance (*7)
Sweeping VOUT, VIN=VCE=5.0V, Short Lx at
1Ω resistance, VOUT voltage which Lx
becomes “L” level within 1ms
VIN=5.0V, LX=5.0V, VCE=0V, VOUT=open
MAX.
UNIT CIRCUIT
V
①
-
6.0
V
①
-
-
mA
①
1.40
1.78
V
②
15
0
33
1.0
μA
μA
③
③
1200
1380
kHz
①
160
200
mA
①
200
-
0
%
%
%
①
②
②
92
-
%
①
0.35
0.42
0.45
0.52
0.01
1050
0.55
0.67
0.66
0.77
1.0
1350
Ω
Ω
Ω
Ω
μA
mA
④
④
④
⑤
⑥
-
±100
-
ppm/℃
①
0.65
-
VIN
V
③
VSS
-
0.25
V
③
-
-
VIN 1.0
V
①
VIN –
0.25
-
-
V
①
- 0.1
- 0.1
-
0.1
0.1
μA
μA
⑤
⑤
-
0.25
0.40
ms
①
0.5
1.0
2.5
ms
①
1.0
-
20.0
ms
⑦
V
⑦
Ω
⑧
0.675 0.900 1.150
200
300
450
Test conditions: Unless otherwise stated, VIN=5.0V, VOUT(E)=Setting Voltage
NOTE:
*1: Including hysteresis operating voltage range.
*2: EFFI = { ( output voltage×output current ) / ( input voltage×input current) }×100
*3: ON resistance (Ω)= (VIN - Lx pin measurement voltage) / 100mA
*4: R&D value
*5: When temperature is high, a current of approximately 10μA (maximum) may leak.
*6: The CE/MODE pin of the XC9237A series works also as an external switching pin of PWM control and PWM/PFM control. When the IC is in the
operation, control is switched to the automatic PWM/PFM switching mode when the CE/MODE pin voltage is equal to or greater than VIN minus
0.3V, and to the PWM mode when the CE/MODE pin voltage is equal to or lower than VIN minus 1.0V and equal to or greater than VCEH.
*7: 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.
*8: When VIN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance.
*9: 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.
*10: Current limit denotes the level of detection at peak of coil current.
*11: “H”=VIN~VIN-1.2V, “L”=+0.1V~-0.1V
*12: XC9235 series exclude IPFM and MAXIPFM because those are only for the PFM control’s functions.
*13: XC9235/9236 series exclude VPWMH and VPWML because those are only for the XC9237 series’ functions.
6/28
XC9235/XC9236/XC9237
Series
■ELECTRICAL CHARACTERISTICS (Continued)
XC9237B(C)18Dxx, VOUT=1.8V, FOSC=3.0MHz, Ta=25℃
PARAMETER
SYMBOL
Output Voltage
VOUT
Operating Voltage Range
VIN
Maximum Output Current
IOUTMAX
U.V.L.O. Voltage
VUVLO
Supply Current
Stand-by Current
IDD
ISTB
Oscillation Frequency
FOSC
PFM Switching Current
IPFM
Maximum IPFM Limit
Maximum Duty Cycle
Minimum Duty Cycle
MAXIPFM
MAXDTY
MINDTY
Efficiency
EFFI
Lx SW "H" ON Resistance 1
Lx SW "H" ON Resistance 2
Lx SW "L" ON Resistance 1
Lx SW "L" ON Resistance 2
Lx SW "H" Leak Current (*5)
Current Limit (*10)
Output Voltage
CONDITIONS
When connected to external components,
VIN=VCE=5.0V, IOUT=30mA
MIN.
TYP.
1.764
1.800 1.836
2.0
VIN=VOUT(E)+2.0V, VCE=1.0V,
600
When connected to external components (*9)
VCE=VIN, VOUT=0V,
1.00
Voltage which Lx pin holding “L” level (*1,*11)
VIN=VCE=5.0V, VOUT=VOUT(E)×1.1V
VIN=5.0V, VCE=0V, VOUT=VOUT(E)×1.1V
When connected to external components,
2550
VIN=VOUT(E)+2.0V, VCE=1.0V, IOUT=100mA
When connected to external components,
170
(*12)
VIN=VOUT(E)+2.0V, VCE=VIN, IOUT=1mA
(*12)
VCE=VIN=(C-1), IOUT=1mA
VIN=VCE=5.0V, VOUT=VOUT(E)×0.9V
100
VIN=VCE=5.0V, VOUT=VOUT(E)×0.1V
When connected to external components,
VCE=VIN＝VOUT(E)+1.2V, IOUT=100mA
(*3)
VIN=VCE=5.0V, VOUT =0V, ILx=100mA
VIN=VCE=3.6V, VOUT =0V, ILx=100mA (*3)
VIN=VCE=5.0V (*4)
VIN=VCE=3.6V (*4)
VIN=VOUT=5.0V, VCE=0V, Lx=0V
VIN=VCE=5.0V, VOUT=VOUT(E)×0.9V (*8)
900
RLxH
RLxH
RLxL
RLxL
ILeakH
ILIM
△VOUT
I =30mA, -40℃≦Topr≦85℃
Temperature Characteristics VOUT・△topr OUT
VOUT=0V, Applied voltage to VCE,
CE "H" Voltage
VCEH
Voltage changes Lx to “H” level (*11)
VOUT=0V, Applied voltage to VCE,
CE "L" Voltage
VCEL
Voltage changes Lx to “L” level (*11)
When connected to external components,
IOUT=1mA (*6), Voltage which oscillation
PWM "H" Level Voltage
VPWMH
frequency becomes 2550kHz≦FOSC≦
3450kHz (*13)
When connected to external components,
(*6)
IOUT=1mA , Voltage which oscillation
PWM "L" Level Voltage
VPWML
frequency becomes FOSC＜2550kHz (*13)
CE "H" Current
ICEH
VIN=VCE=5.0V, VOUT=0V
CE "L" Current
ICEL
VIN=5.0V, VCE=0V, VOUT=0V
When connected to external components,
Soft Start Time (B Series)
TSS
VCE=0V → VIN, IOUT=1mA
When connected to external components,
Soft Start Time (C Series)
TSS
VCE=0V → VIN, IOUT=1mA
VIN=VCE=5.0V, VOUT=0.8×VOUT(E),
Latch Time
TLAT
Short Lx at 1Ω resistance (*7)
Sweeping VOUT, VIN=VCE=5.0V, Short Lx at
Short Protection
VSHORT
1Ω resistance, VOUT voltage which Lx
Threshold Voltage
becomes “L” level within 1ms
VIN=5.0V, LX=5.0V, VCE=0V, VOUT=open
CL Discharge
Rdischg
MAX. UNIT CIRCUIT
V
①
-
6.0
V
①
-
-
mA
①
1.40
1.78
V
③
21
0
35
1.0
μA
μA
②
②
3000
3450
kHz
①
220
270
mA
①
200
-
300
0
%
%
%
①
③
③
86
-
%
①
0.35
0.42
0.45
0.52
0.01
1050
0.55
0.67
0.66
0.77
1.0
1350
Ω
Ω
Ω
Ω
μA
mA
④
④
⑤
⑥
-
±100
-
ppm/℃
①
0.65
-
VIN
V
③
VSS
-
0.25
V
③
-
-
VIN 1.0
V
①
VIN –
0.25
-
-
V
①
- 0.1
- 0.1
-
0.1
0.1
μA
μA
⑤
⑤
-
0.32
0.50
ms
①
0.5
0.9
2.5
ms
①
1.0
-
20
ms
⑦
V
⑦
Ω
⑧
0.675 0.900 1.150
200
300
450
Test conditions: Unless otherwise stated, VIN=5.0V, VOUT(E)=Setting Voltage
NOTE:
*1: Including hysteresis operating voltage range.
*2: EFFI = { ( output voltage×output current ) / ( input voltage×input current) }×100
*3: ON resistance (Ω)= (VIN - Lx pin measurement voltage) / 100mA
*4: R&D value
*5: When temperature is high, a current of approximately 10μA (maximum) may leak.
*6: The CE/MODE pin of the XC9237A series works also as an external switching pin of PWM control and PWM/PFM control. When the IC is in the
operation, control is switched to the automatic PWM/PFM switching mode when the CE/MODE pin voltage is equal to or greater than VIN minus
0.3V, and to the PWM mode when the CE/MODE pin voltage is equal to or lower than VIN minus 1.0V and equal to or greater than VCEH.
*7: 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.
*8: When VIN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance.
*9: 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.
*10: Current limit denotes the level of detection at peak of coil current.
*11: “H”=VIN~VIN-1.2V, “L”=+0.1V~-0.1V
*12: XC9235 series exclude IPFM and MAXIPFM because those are only for the PFM control’s functions.
*13: XC9235/9236 series exclude VPWMH and VPWML because those are only for the XC9237 series’ functions.
7/28
XC9235/XC9236/XC9237 Series
■ELECTRICAL CHARACTERISTICS (Continued)
●PFM Switching Current (IPFM) by Oscillation Frequency and Setting Voltage
(mA)
SETTING VOLTAGE
VOUT(E) ≦1.2V
1.2V＜VOUT(E) ≦1.75V
1.8V≦VOUT(E)
MIN.
1.2MHz
TYP.
MAX.
MIN.
3.0MHz
TYP.
MAX.
140
130
120
180
170
160
240
220
200
190
180
170
260
240
220
350
300
270
●Input Voltage (VIN) for Measuring Maximum PFM Switching Current (MAXIPFM) Limit
FOSC
C-1
1.2MHz
VOUT(E)+0.5V
3.0MHz
VOUT(E)+1.0V
Minimum operating voltage is 2.0V.
ex.) Although when VOUT(E) is 1.2V and FOSC is 1.2MHz, (C-1) should be 1.7V, (C-1) becomes 2.0V for the minimum operating voltage 2.0V.
●Soft-Start Time, Setting Voltage（XC9235B/36B/37B Series only）
SERIES
XC9235B/XC9237B
XC9236B
XC9235B/
XC9236B/XC9237B
FOSC
SETTING VOLTAGE
MIN.
TYP.
MAX.
1200kHz
0.8≦V OUT(E)<1.5
-
250
400μs
1200kHz
1.5≦V OUT(E)<1.8
-
320
500μs
1200kHz
1.8≦V OUT(E)<2.5
-
280
400μs
1200kHz
2.5≦V OUT(E)<4.0
-
320
500μs
1200kHz
0.8≦V OUT(E)<2.5
-
280
400μs
1200kHz
2.5≦V OUT(E)<4.0
-
320
500μs
3000kHz
0.8≦V OUT(E)<1.8
-
280
400μs
3000kHz
1.8≦V OUT(E)<4.0
-
320
500μs
■TYPICAL APPLICATION CIRCUIT
●FOSC=3.0MHz
L:
1.5μH
CIN:
4.7μF
CL:
10μF
●FOSC=1.2MHz
L:
4.7μH
CIN:
4.7μF
CL:
10μF
8/28
(NR3015, TAIYO YUDEN)
(Ceramic)
(Ceramic)
(NR4018, TAIYO YUDEN)
(Ceramic)
(Ceramic)
XC9235/XC9236/XC9237
Series
■OPERATIONAL DESCRIPTION
The XC9235/XC9236/XC9237 series consists of a reference voltage source, ramp wave circuit, error amplifier, PWM
comparator, phase compensation circuit, output voltage adjustment resistors, P-channel MOSFET driver transistor, N-channel
MOSFET switching transistor for the synchronous switch, current limiter circuit, U.V.L.O. circuit and others. (See the block
diagram above.) 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.
<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 internally and can be selected from 1.2MHz or
3.0MHz. 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 divided by the internal split resistors, R1 and R2. 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.
<Current Limit>
The current limiter circuit of the XC9235/XC9236/XC9237 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 driver transistor is turned off, the limiter circuit is then released from the current limit detection state.
③ At the next pulse, the driver transistor is turned on. However, the 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
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 XC9235/XC9236/XC9237 series can be set at 1050mA 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.
9/28
XC9235/XC9236/XC9237 Series
■OPERATIONAL DESCRIPTION (Continued)
<Short-Circuit Protection>
The short-circuit protection circuit monitors the internal R1 and R2 divider voltage from the VOUT pin (refer to FB point in
the block diagram shown in the previous page). In case where output is accidentally shorted to the Ground and when
the FB point voltage decreases less than half of the reference voltage (Vref) and a current more than the ILIM flows to
the driver transistor, the short-circuit protection quickly operates to turn off and to latch the driver transistor. In latch
mode, the operation can be resumed by either turning the IC off and on via the CE/MODE pin, or by restoring power
supply to the VIN pin.
When sharp load transient happens, a voltage drop at the VOUT is propagated to the FB point through CFB, as a result,
short circuit protection may operate in the voltage higher than 1/2 VOUT voltage.
<U.V.L.O. Circuit>
When the VIN pin voltage becomes 1.4V or lower, the P-channel 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 1.8V or higher,
switching operation takes place. By releasing the U.V.L.O. 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
U.V.L.O. operating voltage. The U.V.L.O. circuit does not cause a complete shutdown of the IC, but causes pulse output
to be suspended; therefore, the internal circuitry remains in operation.
<PFM Switch Current>
In PFM control operation, until coil current reaches to a specified level (IPFM), the IC keeps the P-ch MOSFET on. In this
case, time that the P-ch MOSFET is kept on (TON) can be given by the following formula.
TON= L×IPFM (VIN−VOUT)
→IPFM①
<Maximum IPFM Limit>
In PFM control operation, the maximum duty ratio (MAXIPFM) is set to 200% (TYP.). 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 MOSFET to be turned off even
when coil current doesn’t reach to IPFM.
→IPFM②
IPFM②
IPFM①
Ton
FOSC
M axum um IPFM Current
Lx
Lx
I Lx
10/28
IPFM
0mA
I Lx
IPFM
0mA
XC9235/XC9236/XC9237
Series
■OPERATIONAL DESCRIPTION (Continued)
＜CL High Speed Discharge＞
XC9235B(C)/ XC9236B(C)/ XC9237B(C) 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-channel transistor
located between the LX 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 [R] and an output capacitor value (CL) as τ(τ=C x R), discharge time of the output voltage after discharge via the N
channel transistor is calculated by the following formulas.
V = VOUT(E) x e –t/τ, or t=τln (VOUT(E) / V)
V : Output voltage after discharge
VOUT(E) : Output voltage
t: Discharge time,
τ: C x R
C= Capacitance of Output capacitor (CL)
R= CL auto-discharge resistance
Output Voltage Dischage Characteristics
Rdischg = 300Ω（ TYP）
100
90
CL=10uF
80
CL=20uF
70
CL=50uF
60
50
40
30
20
10
0
0
10
20
30
40
50
60
70
80
90
100
Discharge Time t (ms)
11/28
XC9235/XC9236/XC9237 Series
■OPERATIONAL DESCRIPTION (Continued)
<CE/MODE Pin Function>
The operation of the XC9235/XC9236/XC9237 series will enter into the shut down mode when a low level signal is input to the
CE/MODE 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 VOUT pin. The IC starts its operation by inputting a high level signal to the CE/MODE pin. The
input to the CE/MODE pin is a CMOS input and the sink current is 0μA (TYP.).
●XC9235/XC9236 series - Examples of how to use CE/MODE pin
(A)
SW＿CE
STATUS
ON
Stand-by
OFF
Operation
SW＿CE
STATUS
ON
Operation
OFF
Stand-by
(B)
(A)
(B)
●XC9237 series - Examples of how to use CE/MODE pin
(A)
SW＿CE
SW＿PWM/PFM
STATUS
ON
*
PWM/PFM Automatic Switching Control
OFF
ON
PWM Control
OFF
OFF
Stand-by
SW＿CE
SW＿PWM/PFM
STATUS
(B)
ON
*
Stand-by
OFF
ON
PWM Control
OFF
OFF
PWM/PFM Automatic Switching Control
(A)
Intermediate voltage can be generated by RM1 and RM2. Please set the value of each R1, R2, RM1, RM2 from
few hundreds kΩ to few hundreds MΩ. For switches, CPU open-drain I/O port and transistor can be used.
12/28
(B)
XC9235/XC9236/XC9237
Series
■OPERATIONAL DESCRIPTION (Continued)
＜Soft Start＞
Soft start time is available in two options via product selection.
The XC9235A/XC9236A/XC9237A/XC9235C/XC9236C/XC9237C series provide 1.0ms (TYP). The XC9225B/XC9236B/XC9237B series
provide 0.25ms (TYP). Soft start time is defined as the time to reach 90% of the output setting voltage when the CE pin is turned on.
90% of setting voltage
■FUNCTION CHART
CE/MODE
VOLTAGE LEVEL
OPERATIONAL STATES
XC9235
XC9236
Synchronous
PWM/PFM
Automatic Switching
H Level (*1)
Synchronous
PWM Fixed Control
M Level (*2)
━
━
L Level (*3)
Stand-by
Stand-by
XC9237
Synchronous
PWM/PFM
Automatic Switching
Synchronous
PWM Fixed Control
Stand-by
Note on CE/MODE pin voltage level range
(*1) H level: 0.65V < H level < VIN V (for XC9235/XC9236)
H level: VIN – 0.25V < H level < VIN (for XC9237)
(*2) M level: 0.65V < M level < VIN - 1.0V (for XC9237)
(*3) L level: 0V < L level < 0.25V
13/28
XC9235/XC9236/XC9237 Series
■NOTE ON USE
1. The XC9235/XC9236/XC9237 series is designed for use with ceramic output capacitors. If, however, the potential
difference is too large between the input voltage and the output voltage, a ceramic capacitor may fail to absorb the resulting
high switching energy and oscillation could occur on the output. If the input-output potential difference is large, connect an
electrolytic capacitor in parallel to compensate for insufficient capacitance.
2. Spike noise and ripple voltage arise in a switching regulator as with a DC/DC converter. These are greatly influenced by
external component selection, such as the coil inductance, capacitance values, and board layout of external components.
Once the design has been completed, verification with actual components should be done.
3. Depending on the input-output voltage differential, or load current, some pulses may be skipped, and the ripple voltage may
increase.
4. When the difference between VIN and VOUT is large in PWM control, very narrow pulses will be outputted, and there is the
possibility that some cycles may be skipped completely.
5. When the difference between VIN and VOUT is small, and the load current is heavy, very wide pulses will be outputted and
there is the possibility that some cycles may be skipped completely.
6. With the IC, the peak current of the coil is controlled by the current limit circuit. Since the peak current increases when
dropout voltage or load current is high, current limit starts operation, and this can lead to instability. When peak current
becomes high, please adjust the coil inductance value and fully check the circuit operation. In addition, please calculate
the peak current according to the following formula:
Ipk = (VIN - VOUT) x OnDuty / (2 x L x FOSC) + IOUT
L: Coil Inductance Value
FOSC: Oscillation Frequency
7. When the peak current which exceeds limit current flows within the specified time, the built-in P-ch driver transistor turns off.
During the time until it detects limit current and before the built-in transistor can be turned off, the current for limit current
flows; therefore, care must be taken when selecting the rating for the external components such as a coil.
8. When VIN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance.
9. Care must be taken when laying out the PC Board, in order to prevent misoperation of the current limit mode. Depending
on the state of the PC Board, latch time may become longer and latch operation may not work. In order to avoid the effect of
noise, the board should be laid out so that input capacitors are placed as close to the IC as possible.
10. Use of the IC at voltages below the recommended voltage range may lead to instability.
11. This IC should be used within the stated absolute maximum ratings in order to prevent damage to the device.
12. When the IC is used in high temperature, output voltage may increase up to input voltage level at no load because of the
leak current of the driver transistor.
13. The current limit is set to 1350mA (MAX.) at typical. However, the current of 1350mA or more may flow. In case that the
current limit functions while the VOUT pin is shorted to the GND pin, when P-ch MOSFET 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 MOSFET 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 MOSFET 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 MOSFET.
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.
④
②
①
③
Delay
LX
ILIM
ILX
14/28
Limit >
# ms
mS
⑤
XC9235/XC9236/XC9237
Series
■NOTE ON USE (Continued)
14. In order to stabilize VIN’s voltage level and oscillation frequency, we recommend that a by-pass capacitor (CIN) be
connected as close as possible to the VIN & VSS pins.
15. High step-down ratio and very light load may lead an intermittent oscillation.
16. During PWM / PFM automatic switching mode, operating may become unstable at transition to continuous mode.
Please verify with actual parts.
17. Please note the inductance value of the coil. The IC may enter unstable operation if the combination of ambient
temperature, setting voltage, oscillation frequency, and L value are not adequate.
In the operation range close to the maximum duty cycle, The IC may happen to enter unstable output voltage operation
even if using the L values listed below.
<External Components>
●The Range of L Value
FOSC
VOUT
L Value
3.0MHz
0.8V＜VOUT<4.0V
1.0μH～2.2μH
VOUT≦2.5V
3.3μH～6.8μH
2.5V＜VOUT
4.7μH～6.8μH
1.2MHz
*When a coil less value of 4.7μH is used at
FOSC=1.2MHz or when a coil less value of 1.5μH is
used at FOSC=3.0MHz, peak coil current more easily
reach the current limit ILMI. In this case, it may
happen that the IC can not provide 600mA output
current.
18. It may happen to enter unstable operation when the IC operation mode goes into continuous operation mode under the
condition of small input-output voltage difference. Care must be taken with the actual design unit.
<External Components>
15/28
XC9235/XC9236/XC9237 Series
■NOTE ON USE (Continued)
●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 driver transistors bring on heat because of the output current and ON resistance of driver transistors.
16/28
XC9235/XC9236/XC9237
Series
■TEST CIRCUITS
① >
< Circuit
Circuit No.1
Wave Form Measure Point
Circuit
②No.2 >
< Circuit
L
A
VIN
CE/
MODE
CIN
A
Lx
V
VOUT
VSS
CL
1μF
VIN
CE/
MODE
Lx
VOUT
VSS
※　External Components
L
: 1.5μH(NR3015) 3.0MHz
4.7μH(NR4018) 1.2MHz
CIN : 4.7μF(ceramic)
CL :10μF(ceramic)
Circuit
④No.4 >
< Circuit
CircuitNo.3
③>
< Circuit
Wave Form Measure Point
VIN
CE/
MODE
1μF
Lx
VIN
Rpulldown
200Ω
VOUT
VSS
1μF
CE/
MODE
Lx
V
VOUT
VSS
100mA
ON resistance = (VIN-VLx)/100mA
CircuitNo.5
⑤>
< Circuit
VIN
1μF
ICEH
A
Circuit
⑥No.6 >
< Circuit
ILeakH
CE/
MODE
Lx
Wave Form Measure Point
A
VIN
ILeakL
1μF
VOUT
VSS
CE/
MODE
Lx
V
VOUT
VSS
ILIM
ICEL
Circuit ⑦
Circuit ⑧
< Circuit No.7 >
< Circuit No.8 >
ILx
Wave Form Measure Point
VIN
1μF
CE/
MODE
Lx
VIN
Ilat
VOUT
1uF
VSS
CE/
MODE
Lx
A
VOUT
VSS
Rpulldown
1Ω
Circuit ⑨
< Circuit No.9 >
A
CIN
VIN
CE/
MODE
Lx
VOUT
VSS
17/28
XC9235/XC9236/XC9237 Series
■TYPICAL PERFORMANCE CHARACTERISTICS
(1) Efficiency vs. Output Current
XC9237A18C
L=4.7μH (NR4018), CIN=4.7μF, CL=10μF
PWM/PFM Automatic Sw itching Control
100
100
90
90
80
80
VIN= 4.2V
70
60
PWM Control
VIN= 4.2V
3.6V
2.4V
3.6V
50
Efficiency:
EFFI (%)
Efficency:EFFI(%)
Efficiency:
EFFI (%)
Efficency:EFFI(%)
XC9237A18D
L=1.5μH (NR3015), CIN=4.7μF, CL=10μF
PWM/PFM Automatic Sw itching Control
2.4V
40
30
70
VIN= 4.2V
60
3.6V
50
PWM Control
VIN= 4.2V
3.6V
2.4V
2.4V
40
30
20
20
10
10
0
0
0.1
1
10
100
0.1
1000
1
10
100
1000
Output
Current:IOUT(mA)
Output
Current:
IOUT (mA)
OutputCurrent:
Current:IOUT(mA)
Output
IOUT (mA)
(2) Output Voltage vs. Output Current
XC9237A18D
L=1.5μH (NR3015), CIN=4.7μF, CL=10μF
2.1
2.1
2.0
2.0
Output Voltage:Vout(V)
Output
Voltage:Vout(V)
Output Voltage:
VOUT (V)
XC9237A18C
L=4.7μH (NR4018), CIN=4.7μF, CL=10μF
PWM/PFM Automatic Sw itching Control
VIN＝4.2V,3.6V,2.4V
1.9
1.8
1.7
PWM Control
1.6
PWM/PFM Automatic Sw itching Control
VIN＝4.2V,3.6V,2.4V
1.9
1.8
1.7
PWM Control
1.6
1.5
1.5
0.1
1
10
100
1000
0.1
Output Current: IOUT (mA)
1
10
100
1000
Output Current: IOUT (mA)
Output Current:IOUT(mA)
Output Current:IOUT(mA)
(3) Ripple Voltage vs. Output Current
XC9237A18D
L=1.5μH (NR3015), CIN=4.7μF, CL=10μF
XC9237A18C
L=4.7μH (NR4018), CIN=4.7μF, CL=10μF
100
100
80
60
PWM/PFM Automatic
Sw itching Control
VIN＝4.2V
3.6V
2.4V
PWM Control
VIN＝4.2V,3.6V,2.4V
40
Ripple
Voltage:
Vr (mV)
Ripple
Voltage:Vr(mV)
Ripple
Voltage:
Vr (mV)
Ripple
Voltage:Vr(mV)
80
20
0
PWM/PFM Automatic
PWM Control
VIN＝4.2V,3.6V,2.4V Sw itching Control
VIN＝4.2V
3.6V
2.4V
40
20
0
0.1
1
10
100
Output
IOUT (mA)
OutputCurrent:
Current:IOUT(mA)
18/28
60
1000
0.1
1
10
100
Output
IOUT (mA)
OutputCurrent:
Current:IOUT(mA)
1000
XC9235/XC9236/XC9237
Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(4) Oscillation Frequency vs. Ambient Temperature
XC9237A18D
L=1.5μH (NR3015), CIN=4.7μF, CL=10μF
XC9237A18C
L=4.7μH (NR4018), CIN=4.7μF, CL=10μF
3.5
Oscillation Frequency
Frequency: FOSC
(MHz)
Oscillation
: FOSC(MHz)
Oscillation Frequency:
(MHz)
Oscillation
FrequencyFOSC
: FOSC(MHz)
1.5
1.4
1.3
VIN=3.6V
1.2
1.1
1.0
0.9
0.8
3.4
3.3
3.2
VIN=3.6V
3.1
3.0
2.9
2.8
2.7
2.6
2.5
-50
-25
0
25
50
75
100
-50
-25
Ambient
Ta(℃)
( ℃)
AmbientTemperature:
Temperature: Ta
0
25
50
75
100
Ambient
( ℃)
Ambient Temperature:
Temperature: TaTa
(℃)
(5) Supply Current vs. Ambient Temperature
XC9237A18D
40
40
35
35
30
VIN=6.0V
25
20
SupplyCurrent:
CurrentIDD
: IDD
(μA)
Supply
(μA)
Supply Current:
(μA)
Supply
CurrentIDD
: IDD
(μA)
XC9237A18C
VIN=4.0V
VIN=2.0V
15
10
5
0
-50
30
VIN=6.0V
VIN=4.0V
VIN=2.0V
25
20
15
10
5
-25
0
25
50
75
0
-50
100
-25
Ambient Temperature:
Temperature: TaTa
(℃)
Ambient
( ℃)
0
25
50
75
100
Ambient Temperature:
Temperature: TaTa
(℃)
Ambient
( ℃)
(6) Output Voltage vs. Ambient Temperature
(7) UVLO Voltage vs. Ambient Temperature
XC9237A18D
XC9237A18D
2.1
1.8
2.0
1.5
1.9
UVLOVoltage
Voltage:: UVLO
UVLO
UVLO(V)
(V)
Output
VOUT(V)(V)
OutputVoltage
Voltage::VOUT
CE=VIN
VIN=3.6V
1.8
1.7
1.6
1.5
1.2
0.9
0.6
0.3
0.0
-50
-25
0
25
50
Ambient
( ℃)
Ambient Temperature:
Temperature: TaTa
(℃)
75
100
-50
-25
0
25
50
75
100
Ambient
( ℃)
Ambient Temperature:
Temperature: TaTa
(℃)
19/28
XC9235/XC9236/XC9237 Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(8) CE "H" Voltage vs. Ambient Temperature
(9) CE "L" Voltage vs. Ambient Temperature
XC9237A18D
1.0
1.0
0.9
0.9
0.8
0.8
0.7
CE"L"
“L” Voltage
Voltage: VCEL
(V)(V)
CE
: VCEL
CE “H” Voltage: VCEH (V)
CE "H" Voltage : VCEH (V)
XC9237A18D
VIN=5.0V
0.6
0.5
0.4
0.3
VIN=2.4V
0.2
VIN=3.6V
0.1
VIN=5.0V
0.7
0.6
0.5
0.4
VIN=3.6V
0.3
VIN=2.4V
0.2
0.1
0.0
0.0
-50
-25
0
25
50
75
100
-50
-25
Ambient
Ta(℃)
( ℃)
AmbientTemperature:
Temperature: Ta
0
25
50
75
100
Ambient
Temperature:TaTa
( ℃)
Ambient Temperature:
(℃)
(10) Soft Start Time vs. Ambient Temperature
XC9237A18D
L=1.5μH (NR3015), CIN=4.7μF, CL=10μF
5
5
4
4
SoftStart
Start Time
Time: TSS
(ms)
Soft
: TSS
(ms)
Soft
TimeTSS
: TSS
(ms)
Soft Start
Start Time:
(ms)
XC9237A18C
L=4.7μH (NR4018), CIN=4.7μF, CL=10μF
3
2
VIN=3.6V
1
0
-50
-25
0
25
50
75
100
Ambient Temperature:
Temperature: TaTa
(℃)
Ambient
( ℃)
Lx
Resistance:
RLxH, RLxL (Ω) (Ω)
LxSW
SWON
ON
Resistance:RLxH,RLxL
XC9237A18D
1.0
0.9
0.8
Nch on Resistance
0.6
0.5
0.4
0.3
Pch on Resistance
0.2
0.1
0.0
0
1
2
3
4
Input
VIN(V)
(V)
InputVoltage
Voltage: :VIN
20/28
2
VIN=3.6V
1
0
-50
-25
0
25
50
Ambient Temperature:
(℃)
Ambient
Temperature:TaTa
( ℃)
(11) "Pch / Nch" Driver on Resistance vs. Input Voltage
0.7
3
5
6
75
100
XC9235/XC9236/XC9237
Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(12) XC9235B/36B/37B Rise Wave Form
XC9237B12C
L=4.7μH (NR4018), CIN=4.7μF, CL=10μF
XC9237B33D
L=1.5μH (NR3015), CIN=4.7μF, CL=10μF
VIN=5.0V
VIN=5.0V
IOUT=1.0mA
IOUT=1.0mA
VOUT：1.0V/div
VOUT：0.5V/div
CE：0.0V⇒1.0V
CE：0.0V⇒1.0V
100μs/div
(13) XC9235B/36B/37B
100μs/div
Soft-Start Time vs. Ambient Temperature
XC9237B12C
XC9237B33D
L=1.5μH(NR3015), CIN=4.7μF, CL=10μF
500
500
400
400
Soft Start Time :TSS (μs)
Soft Start Time :TSS (μs)
L=4.7μH(NR4018), CIN=4.7μF, CL=10μF
300
200
VIN=5.0V
IOUT=1.0mA
100
300
200
VIN=5.0V
IOUT=1.0mA
100
0
0
-50
-25
0
25
50
75
100
-50
0
25
50
75
100
Ambient Temperature: Ta(℃)
Ambient Temperature: Ta(℃)
(14) XC9235B/36B/37B
-25
CL Discharge Resistance vs. Ambient Temperature
XC9237B33D
600
CL Discharge Resistance: (Ω)
VIN=6.0V
500
VIN=4.0V
VIN=2.0V
400
300
200
100
-50
-25
0
25
50
75
100
Ambient Temperature: Ta (℃)
21/28
XC9235/XC9236/XC9237 Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(15) Load Transient Response
XC9237A18C
L=4.7μH (NR4018), CIN=4.7μF (ceramic), CL=10μF (ceramic), Topr=25℃
VIN=3.6V, VCE=VIN (PWM/PFM Automatic Switching Control)
IOUT=1mA → 100mA
IOUT=1mA → 300mA
1ch: IOUT
1ch: IOUT
2ch
2ch
VOUT: 50mV/div
VOUT: 50mV/div
50μs/div
50μs/div
IOUT=100mA → 1mA
IOUT=300mA → 1mA
1ch: IOUT
1ch: IOUT
2ch
2ch
VOUT: 50mV/div
VOUT: 50mV/div
200μs/div
22/28
200μs/div
XC9235/XC9236/XC9237
Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(15) Load Transient Response (Continued)
XC9237A18C
L=4.7μH (NR4018), CIN=4.7μF (ceramic), CL=10μF (ceramic), Topr=25℃
VIN=3.6V, VCE=1.8V (PWM Control)
IOUT=1mA → 100mA
IOUT=1mA → 300mA
1ch: IOUT
1ch: IOUT
2ch
2ch
VOUT: 50mV/div
VOUT: 50mV/div
50μs/div
50μs/div
IOUT=100mA → 1mA
IOUT=300mA → 1mA
1ch: IOUT
1ch: IOUT
2ch
2ch
VOUT: 50mV/div
VOUT: 50mV/div
200μs/div
200μs/div
23/28
XC9235/XC9236/XC9237 Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(15) Load Transient Response (Continued)
XC9237A18D
L=1.5μH (NR3015), CIN=4.7μF (ceramic), CL=10μF (ceramic), Topr=25℃
VIN=3.6V, VCE=VIN (PWM/PFM Automatic Switching Control)
IOUT=1mA → 100mA
IOUT=1mA → 300mA
1ch: IOUT
1ch: IOUT
2ch
2ch
VOUT: 50mV/div
VOUT: 50mV/div
50μs/div
50μs/div
IOUT=100mA → 1mA
IOUT=300mA → 1mA
1ch: IOUT
1ch: IOUT
2ch
2ch
VOUT: 50mV/div
VOUT: 50mV/div
200μs/div
24/28
200μs/div
XC9235/XC9236/XC9237
Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(15) Load Transient Response (Continued)
XC9237A18D
L=1.5μH (NR3015), CIN=4.7μF (ceramic), CL=10μF (ceramic), Topr=25℃
VIN=3.6V, VCE=1.8V (PWM Control)
IOUT=1mA → 100mA
IOUT=1mA → 300mA
1ch: IOUT
1ch: IOUT
2ch
2ch
VOUT: 50mV/div
VOUT: 50mV/div
50μs/div
50μs/div
IOUT=100mA → 1mA
IOUT=300mA → 1mA
1ch: IOUT
1ch: IOUT
2ch
2ch
VOUT: 50mV/div
VOUT: 50mV/div
200μs/div
200μs/div
25/28
XC9235/XC9236/XC9237 Series
■PACKAGING INFORMATION
●SOT-25
●USP-6C
●USP-6C Recommended Pattern Layout
●USP-6C Recommended Metal Mask Design
26/28
XC9235/XC9236/XC9237
Series
■MARKING RULE
●SOT-25 & USP-6C
①Represent product series
MARK
PRODUCT SERIES
4
5
6
C
D
E
K
L
M
XC9235A
XC9236A
XC9237A
XC9235B
XC9236B
XC9237B
XC9235C
XC9236C
XC9237C
SOT-25
(TOP VIEW)
②Represents integer number of output voltage and oscillation frequency
OUTPUT
MARK
VOLTAGE (V)
FOSC =1.2MHz
FOSC =3.0MHz
0.X
1.X
2.X
3.X
4.X
USP-6C
(TOP VIEW)
A
B
C
D
E
F
H
K
L
M
③Represents decimal point of output voltage
OUTPUT
OUTPUT
MARK
VOLTAGE (V)
VOLTAGE (V)
X.00
0
X.05
X.10
1
X.15
X.20
2
X.25
X.30
3
X.35
X.40
4
X.45
X.50
5
X.55
X.60
6
X.65
X.70
7
X.75
X.80
8
X.85
X.90
9
X.95
MARK
A
B
C
D
E
F
H
K
L
M
④⑤Represents production lot number
Order of 01, …09, 10, 11, …99, 0A, …0Z, 1A, …9Z, A0, …Z9, AA, …ZZ.
(G, I, J, O, Q, W excepted)
*No character inversion used.
27/28
XC9235/XC9236/XC9237 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 catalog 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 catalog.
3. Please ensure suitable shipping controls (including fail-safe designs and aging
protection) are in force for equipment employing products listed in this catalog.
4. The products in this catalog 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 catalog 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 catalog may be copied or reproduced without the
prior permission of Torex Semiconductor Ltd.
28/28