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XC9235/XC9236/XC9237 Series
600mA Driver Tr. Built-In, Synchronous Step-Down DC/DC Converters
ETR0514-007
The XC9235/XC9236/XC9237 series is a group of synchronous-rectification type DC/DC converters with a built-in 0.42 P-channel driver transistor and 0.52 N-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 1.0 A 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.
GENERAL DESCRIPTION
GreenOperation Compatible
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 0.42 : ON resistance 0.52 : 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
100 90 80
Efficiency: EFFI (%) Efficency:EFFI(%)
FOSC=1.2NHz, VOUT=1.8V
PWM/PFM Automatic Sw itching Control
70 60 50 40 30 20 10 0 0.1
2.4V
VIN= 4.2V 3.6V PWM Control VIN= 4.2V 3.6V 2.4V
1
10
100
1000
Output Current:IOUT(mA)
1/28
XC9235/XC9236/XC9237 Series
PIN CONFIGURATION
Lx VOUT
5
4
VIN VSS CE/MODE 6 5 4 1 2 3 Lx VSS VOUT * 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.
1
VIN
2
VSS
3
CE/MODE
SOT-25 (Top View)
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 VIN VSS CE / MODE VOUT Lx FUNCTION Power Input Ground Chip Enable Mode Switch Output Voltage Sense Switching Output
PRODUCT CLASSIFICATION
Ordering Information
XC9235 XC9236 XC9237 DESIGNATOR PWM fixed control PWM / PFM automatic switching control PWM fixed control PWM / PFM automatic switching, manual switching DESCRIPTION Transistor built-in, Output voltage internally set (VOUT product), Soft-start internally set Output Voltage SYMBOL A B C 0~4 DESCRIPTION : CE input logic High Active : CE input logic High Active, high speed soft start, CL discharge : CE input logic High Active, CL discharge : Integer number of output voltage e.g. VOUT=2.8V =2, VOUT=3.3V =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, =8 VOUT=2.85V =2, =L : 1.2MHz : 3.0MHz : SOT-25 (SOT-23-5) : USP-6C : Embossed tape, standard feed : Embossed tape, reverse feed
.
Output Voltage
0~9, A~M
Oscillation Frequency Packages
C D M E R L
Device Orientation
2/28
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 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 SYMBOL VIN VLx VOUT VCE ILx Pd Topr Tstg RATINGS - 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 UNIT V V V V mA mW
O O
C C
3/28
XC9235/XC9236/XC9237 Series
ELECTRICAL CHARACTERISTICS
XC9237A18Cxx, VOUT=1.8V, FOSC=1.2MHz, Ta=25 PARAMETER Output Voltage Operating Voltage Range Maximum Output Current U.V.L.O. Voltage Supply Current Stand-by Current Oscillation Frequency PFM Switching Current Maximum IPFM Limit Maximum Duty Cycle Minimum Duty Cycle Efficiency
(*2)
SYMBOL VOUT VIN IOUTMAX VUVLO IDD ISTB FOSC IPFM MAXIPFM MAXDTY MINDTY EFFI
CONDITIONS When connected to external components, VIN=VCE=5.0V, IOUT=30mA
MIN. 1.764
TYP.
MAX.
UNIT CIRCUIT V V mA V A A kHz mA % % % %
1.800 1.836 1.40 15 0 1200 160 200 92 0.35 0.42 0.45 0.52 0.01 0.01 1050 100 6.0 1.78 33 1.0 1380 200 0 0.55 0.67 0.66 0.77 1.0 1.0 1350 VIN 0.25 VIN 1.0 0.1 0.1 2.5 20.0
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 1 resistance Sweeping VOUT, VIN=VCE=5.0V, Short Lx at Short Protection VSHORT 1 resistance, VOUT voltage which Lx Threshold Voltage becomes "L" level within 1ms
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
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 0.65 VSS VIN - 0.25 - 0.1 - 0.1 0.5 1.0
A A mA ppm/ V V V
1.0 -
V A A ms ms V
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 ( )= (VIN - Lx pin measurement voltage) 100mA *4: R&D value *5: When temperature is high, a current of approximately 10 A (maximum) may leak. *6: 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 1 of 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.
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XC9235/XC9236/XC9237
Series
ELECTRICAL CHARACTERISTICS (Continued)
XC9237A18Dxx, VOUT=1.8V, FOSC=3.0MHz, Ta=25 PARAMETER Output Voltage Operating Voltage Range Maximum Output Current U.V.L.O. Voltage Supply Current Stand-by Current Oscillation Frequency PFM Switching Current Maximum IPFM Limit Maximum Duty Cycle Minimum Duty Cycle Efficiency 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 SYMBOL VOUT VIN IOUTMAX VUVLO IDD ISTB FOSC IPFM MAXIPFM MAXDTY MINDTY EFFI CONDITIONS When connected to external components, VIN=VCE=5.0V, IOUT=30mA MIN. 1.764 TYP. MAX. UNIT CIRCUIT V V mA V A A kHz mA % % % %
1.800 1.836 1.40 21 0 3000 220 200 86 0.35 0.42 0.45 0.52 0.01 0.01 1050 100 6.0 1.78 35 1.0 3450 270 300 0 0.55 0.67 0.66 0.77 1.0 1.0 1350 VIN 0.25 VIN 1.0 0.1 0.1 3.0 20
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 1 resistance (*7) Sweeping VOUT, VIN=VCE=5.0V, Short Lx at Short Protection 1 resistance, VOUT voltage which Lx VSHORT Threshold Voltage becomes "L" level within 1ms (*4)
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 0.65 VSS VIN - 0.25 - 0.1 - 0.1 0.5 1.0
A A mA ppm/ V V V
0.9 -
V A A ms ms V
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 ( )= (VIN - Lx pin measurement voltage) 100mA *4: R&D value *5: When temperature is high, a current of approximately 10 A (maximum) may leak. *6: 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 1 of 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 Output Voltage Operating Voltage Range Maximum Output Current U.V.L.O. Voltage Supply Current Stand-by Current Oscillation Frequency PFM Switching Current Maximum IPFM Limit Maximum Duty Cycle Minimum Duty Cycle Efficiency (*2) Lx SW "H" ON Resistance 1 Lx SW "H" ON Resistance 2 Lx SW "L" ON Resistance 1 Lx SW "L" ON Resistance 2 Lx SW "H" Leak Current (*5) Current Limit (*10) Output Voltage SYMBOL VOUT VIN IOUTMAX VUVLO IDD ISTB FOSC IPFM MAXIPFM MAXDTY MINDTY EFFI CONDITIONS When connected to external components, VIN=VCE=5.0V, IOUT=30mA MIN. 1.764 TYP. MAX. UNIT CIRCUIT V V mA V A A kHz mA % % % %
1.800 1.836 1.40 15 0 1200 160 200 92 0.35 0.42 0.45 0.52 0.01 1050 100 6.0 1.78 33 1.0 1380 200 0 0.55 0.67 0.66 0.77 1.0 1350 VIN 0.25 VIN 1.0 0.1 0.1 0.40 2.5 20.0
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 CE "H" Current CE "L" Current Soft Start Time (B Series) Soft Start Time (C Series) Latch Time Short Protection Threshold Voltage CL Discharge VPWML ICEH ICEL TSS TSS TLAT VSHORT Rdischg 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 1 resistance (*7) Sweeping VOUT, VIN=VCE=5.0V, Short Lx at 1 resistance, VOUT voltage which Lx becomes "L" level within 1ms VIN=5.0V, LX=5.0V, VCE=0V, VOUT=open
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 0.65 VSS VIN - 0.25 - 0.1 - 0.1 0.5 1.0
A mA ppm/ V V V
0.25 1.0 -
V A A ms ms ms V
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 ( )= (VIN - Lx pin measurement voltage) 100mA *4: R&D value *5: When temperature is high, a current of approximately 10 A (maximum) may leak. *6: 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 1 of 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 Output Voltage Operating Voltage Range Maximum Output Current U.V.L.O. Voltage Supply Current Stand-by Current Oscillation Frequency PFM Switching Current Maximum IPFM Limit Maximum Duty Cycle Minimum Duty Cycle Efficiency 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 SYMBOL VOUT VIN IOUTMAX VUVLO IDD ISTB FOSC IPFM MAXIPFM MAXDTY MINDTY EFFI CONDITIONS When connected to external components, VIN=VCE=5.0V, IOUT=30mA MIN. 1.764 TYP. MAX. UNIT CIRCUIT V V mA V A A kHz mA % % % %
1.800 1.836 1.40 21 0 3000 220 200 86 0.35 0.42 0.45 0.52 0.01 1050 100 6.0 1.78 35 1.0 3450 270 300 0 0.55 0.67 0.66 0.77 1.0 1350 VIN 0.25 VIN 1.0 0.1 0.1 0.50 2.5 20
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 1 resistance (*7) Sweeping VOUT, VIN=VCE=5.0V, Short Lx at Short Protection VSHORT 1 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
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 0.65 VSS VIN - 0.25 - 0.1 - 0.1 0.5 1.0
A mA ppm/ V V V
0.32 0.9 -
V A A ms ms ms V
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 ( )= (VIN - Lx pin measurement voltage) 100mA *4: R&D value *5: When temperature is high, a current of approximately 10 A (maximum) may leak. *6: 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 1 of 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 1.2VVOUT(E) 1.75V 1.8VVOUT(E) MIN. 140 130 120 1.2MHz TYP. 180 170 160 MAX. 240 220 200 MIN. 190 180 170 3.0MHz TYP. 260 240 220 MAX. 350 300 270
Input Voltage (VIN) for Measuring Maximum PFM Switching Current (MAXIPFM) Limit
FOSC C-1
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.
1.2MHz VOUT(E)+0.5V
3.0MHz VOUT(E)+1.0V
Soft-Start Time, Setting Voltage
SERIES FOSC 1200kHz XC9235B/XC9237B 1200kHz 1200kHz 1200kHz XC9236B XC9235B/ XC9236B/XC9237B 1200kHz 1200kHz 3000kHz 3000kHz
XC9235B/36B/37B Series only
SETTING VOLTAGE 0.8V OUT(E)<1.5 1.5V OUT(E)<1.8 1.8V OUT(E)<2.5 2.5V OUT(E)<4.0 0.8V OUT(E)<2.5 2.5V OUT(E)<4.0 0.8V OUT(E)<1.8 1.8V OUT(E)<4.0 MIN. TYP. 250 320 280 320 280 320 280 320 MAX. 400s 500s 400s 500s 400s 500s 400s 500s
TYPICAL APPLICATION CIRCUIT
FOSC=3.0MHz L: 1.5 H CIN: 4.7 F CL: 10 F FOSC=1.2MHz L: 4.7 H CIN: 4.7 F CL: 10 F
(NR3015, TAIYO YUDEN) (Ceramic) (Ceramic) (NR4018, TAIYO YUDEN) (Ceramic) (Ceramic)
8/28
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. The reference voltage source provides the reference voltage to ensure stable output voltage of the DC/DC converter. The ramp wave circuit determines switching frequency. The frequency is fixed internally 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. 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. 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. 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 driver transistor is turned off, the limiter circuit is then released from the current limit detection state. 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. 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 through . 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)

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. 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. 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) IPFM 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. IPFM
IPFM Ton
IPFM FOSC
M axum um IPFM Current
Lx
Lx
I Lx
IPFM 0mA
I Lx
IPFM 0mA
10/28
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 ( =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/ , or t=ln (VOUT(E) / V) V : Output voltage after discharge VOUT(E) : Output voltage t: Discharge time, :CxR C= Capacitance of Output capacitor (CL) R= CL auto-discharge resistance
Output Voltage Dischage Characteristics Rdischg = 300 TYP
100 90 80 70 60 50 40 30 20 10 0 0 10 20 30 40 50 60 70 80 90 100 CL=10uF CL=20uF CL=50uF
Discharge Time t (ms)
11/28
XC9235/XC9236/XC9237 Series
OPERATIONAL DESCRIPTION (Continued)
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 0A (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 0A (TYP.).
XC9235/XC9236 series - Examples of how to use CE/MODE pin
(A) SW CE STATUS Stand-by Operation
ON OFF (B) SW CE
STATUS Operation Stand-by (A) (B)
ON OFF
XC9237 series - Examples of how to use CE/MODE pin
(A) SW CE SW PWM/PFM * ON OFF STATUS PWM/PFM Automatic Switching Control PWM Control Stand-by
ON OFF OFF (B) SW CE
SW PWM/PFM * ON OFF
STATUS Stand-by PWM Control PWM/PFM Automatic Switching Control (A) (B)
ON OFF OFF
Intermediate voltage can be generated by RM1 and RM2. Please set the value of each R1, R2, RM1, RM2 from few hundreds k to few hundreds M. For switches, CPU open-drain I/O port and transistor can be used.
12/28
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 H Level (*1) M Level (*2) L Level (*3) Stand-by Stand-by OPERATIONAL STATES XC9235 Synchronous PWM Fixed Control XC9236 Synchronous PWM/PFM Automatic Switching 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. Current flows into P-ch MOSFET to reach the current limit (ILIM). The current of ILIM or more flows since the delay time of the circuit occurs during from the detection of the current limit to OFF of P-ch MOSFET. Because of no potential difference at both ends of the coil, the time rate of coil current becomes quite small. Lx oscillates very narrow pulses by the current limit for several ms. The circuit is latched, stopping its operation.
Delay LX ILIM ILX Limit >
mS ms
14/28
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.

The Range of L Value
FOSC 3.0MHz 1.2MHz VOUT 0.8VVOUT<4.0V VOUT2.5V 2.5VVOUT L Value 1.0H2.2H 3.3H6.8H 4.7H6.8H
*When a coil less value of 4.7H is used at FOSC=1.2MHz or when a coil less value of 1.5H 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.

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
< CircuitNo.1 > Circuit
L Wave Form Measure Point
Circuit No.2 > < Circuit
A
CIN
VIN CE/ MODE
Lx VOUT VSS
CL
A V
1F
VIN CE/ MODE
Lx VOUT VSS
External Components L : 1.5H(NR3015) 3.0MHz 4.7H(NR4018) 1.2MHz
CIN : 4.7F(ceramic) CL :10F(ceramic)
Circuit < Circuit No.3 >
Wave Form Measure Point
Circuit No.4 > < Circuit
VIN CE/ MODE Lx VOUT VSS
Rpulldown 200
VIN CE/ MODE
Lx VOUT VSS
1F
1F
V
100mA
ON resistance = (VIN-VLx)/100mA
Circuit < Circuit No.5 >
VIN
1F ICEH
ILeakH
Circuit < Circuit No.6 >
Wave Form Measure Point
Lx VOUT VSS
A
ILeakL 1F
VIN CE/ MODE
Lx VOUT VSS
A
ICEL
CE/ MODE
V
ILIM
< Circuit No.7 >
Wave Form Measure Point
Circuit
Circuit
VIN CE/ MODE Lx
Ilat
< Circuit No.8 >
VIN CE/ MODE Lx
ILx
A
1F
VOUT VSS
Rpulldown 1
1uF
VOUT VSS
< Circuit No.9 >
Circuit
A
CIN
VIN CE/ MODE
Lx
VOUT VSS
17/28
XC9235/XC9236/XC9237 Series
TYPICAL PERFORMANCE CHARACTERISTICS
(1) Efficiency vs. Output Current
100 90 80
Efficiency: EFFI (%) Efficency:EFFI(%) Efficiency: EFFI (%) Efficency:EFFI(%)
XC9237A18C L=4.7 H (NR4018), CIN=4.7 F, CL=10 PWM/PFM Automatic Sw itching Control
F
100 90 80
XC9237A18D L=1.5 H (NR3015), CIN=4.7 F, CL=10 PWM/PFM Automatic Sw itching Control
F
70 60 50 40 30 20 10 0 0.1
VIN= 4.2V 3.6V 2.4V PWM Control VIN= 4.2V 3.6V 2.4V
70 60 50 40 30 20 10 0 2.4V
VIN= 4.2V 3.6V PWM Control VIN= 4.2V 3.6V 2.4V
1
10
100
1000
0.1
1
10
100
1000
Output Current:IOUT(mA) Output Current: IOUT (mA)
Output Current:IOUT(mA) Output Current: IOUT (mA)
(2) Output Voltage vs. Output Current
XC9237A18C L=4.7 H (NR4018), CIN=4.7 F, CL=10 F
2.1 2.0 OutputVoltage: VOUT (V) Output Voltage:Vout(V) 1.9 1.8 1.7 PWM Control 1.6 1.5 0.1 1 10
Output Current: IOUT (mA)
XC9237A18D L=1.5 H (NR3015), CIN=4.7 F, CL=10 F
2.1 2.0
PWM/PFM Automatic Sw itching Control VIN4.2V,3.6V,2.4V
Output Voltage:Vout(V)
1.9 1.8 1.7 1.6 1.5
PWM/PFM Automatic Sw itching Control VIN4.2V,3.6V,2.4V
PWM Control
100
1000
0.1
1
10
Output Current: IOUT (mA)
100
1000
Output Current:IOUT(mA)
Output Current:IOUT(mA)
(3) Ripple Voltage vs. Output Current
XC9237A18C L=4.7 H (NR4018), CIN=4.7 F, CL=10 F XC9237A18D L=1.5 H (NR3015), CIN=4.7 F, CL=10 F
100
100
80
Ripple Voltage: Vr (mV) Ripple Voltage:Vr(mV) Ripple Voltage: Vr (mV) Ripple Voltage:Vr(mV)
80
60 PWM Control VIN4.2V,3.6V,2.4V
40
PWM/PFM Automatic Sw itching Control VIN4.2V 3.6V 2.4V
60
40
PWM/PFM Automatic PWM Control VIN4.2V,3.6V,2.4V Sw itching Control VIN4.2V 3.6V 2.4V
20
20
0 0.1 1 10 100 1000
Output Current: IOUT (mA) Output Current:IOUT(mA)
0 0.1 1 10 100 1000
Output Current: IOUT (mA) Output Current:IOUT(mA)
18/28
XC9235/XC9236/XC9237
Series
TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(4) Oscillation Frequency vs. Ambient Temperature
XC9237A18C L=4.7 H (NR4018), CIN=4.7 F, CL=10 F
1.5
Oscillation Frequency: : FOSC(MHz) Oscillation Frequency FOSC (MHz) Oscillation Frequency : FOSC(MHz) Oscillation Frequency: FOSC (MHz)
XC9237A18D L=1.5 H (NR3015), CIN=4.7 F, CL=10 F
3.5 3.4 3.3 3.2 3.1 3.0 2.9 2.8 2.7 2.6 2.5 -50 -25 0 25 50 75 100 VIN=3.6V
1.4 1.3 1.2 1.1 1.0 0.9 0.8 -50 -25 0 25 50 75 100 VIN=3.6V
Ambient Temperature:Ta ( () Ambient Temperature: Ta )
Ambient Temperature: Ta () ) Ambient Temperature: Ta (
(5) Supply Current vs. Ambient Temperature
XC9237A18C
40 35
Supply Current : IDD (A) Supply Current: IDD ( A)
XC9237A18D
40 35 Supply Current : IDD (A) Supply Current: IDD ( A) VIN=6.0V 30 25 20 15 10 5 0 -50 VIN=2.0V VIN=6.0V VIN=4.0V
30 25 20 15 10 5 0 -50 VIN=2.0V VIN=4.0V
-25
0
25
50
75
100
-25
0
25
50
75
100
Ambient Temperature: Ta ( ) Ambient Temperature: Ta ( )
Ambient Temperature: Ta ( Ambient Temperature: Ta () )
(6) Output Voltage vs. Ambient Temperature
XC9237A18D
2.1 2.0 Output Voltage :VOUT (V) Output Voltage: VOUT (V) 1.9 1.8 1.7 1.6 1.5 -50 -25 0 25 50 75 100 Ambient Temperature: Ta () ) Ambient Temperature: Ta (
UVLO Voltage: UVLO (V) UVLO Voltage : UVLO (V)
(7) UVLO Voltage vs. Ambient Temperature
XC9237A18D
1.8 CE=VIN 1.5 1.2 0.9 0.6 0.3 0.0 -50 -25 0 25 50 75 100 Ambient Temperature: Ta () Ambient Temperature: Ta ( )
VIN=3.6V
19/28
XC9235/XC9236/XC9237 Series
TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(8) CE "H" Voltage vs. Ambient Temperature
XC9237A18D
1.0 CE "H" Voltage : VCEH (V) 0.9
CE "L" Voltage: : VCEL (V) CE "L" Voltage VCEL (V)
(9) CE "L" Voltage vs. Ambient Temperature
XC9237A18D
1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 VIN=2.4V VIN=3.6V VIN=5.0V
0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 -50 -25 0 25 50 75 100 Ambient Temperature:Ta ( ( ) Ambient Temperature: Ta ) VIN=2.4V VIN=3.6V VIN=5.0V
CE "H" Voltage: VCEH (V)
-50
-25
0
25
50
75
100
Ambient Temperature: Ta ( ()) Ambient Temperature: Ta
(10) Soft Start Time vs. Ambient Temperature
XC9237A18C L=4.7 H (NR4018), CIN=4.7 F, CL=10 F
5 5
XC9237A18D L=1.5 H (NR3015), CIN=4.7 F, CL=10 F
Soft Start Time: TSS (ms) Soft Start Time : TSS (ms)
3
Soft Start Time: : TSS (ms) Soft Start Time TSS (ms)
4
4
3
2
VIN=3.6V
2
VIN=3.6V
1
1
0 -50
-25
0
25
50
75
100
0 -50
-25
0
25
50
75
100
Ambient Temperature: Ta ( Ambient Temperature: Ta () )
Ambient Temperature: ( Ambient Temperature: TaTa ())
(11) "Pch / Nch" Driver on Resistance vs. Input Voltage
XC9237A18D
Lx SW ON Resistance: RLxH, RLxL ( ) () Lx SW ON Resistance:RLxH,RLxL
1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0 1 2 3 4 5 6 Input Voltage :VIN (V) Input Voltage: VIN (V) Pch on Resistance Nch on Resistance
20/28
XC9235/XC9236/XC9237
Series
TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(12) XC9235B/36B/37B Rise Wave Form
XC9237B12C L=4.7 H (NR4018), CIN=4.7 F, CL=10 F VIN=5.0V IOUT=1.0mA XC9237B33D L=1.5 H (NR3015), CIN=4.7 F, CL=10 F VIN=5.0V IOUT=1.0mA
VOUT
0.5V/div
VOUT
1.0V/div
CE
0.0V 1.0V
CE
0.0V 1.0V
100 s/div
100 s/div
(13) XC9235B/36B/37B
Soft-Start Time vs. Ambient Temperature
XC9237B12C XC9237B33D F
500
L=4.7 H(NR4018), CIN=4.7 F, CL=10
500
L=1.5 H(NR3015), CIN=4.7 F, CL=10
F
Soft Start Time :TSS (s)
Soft Start Time :TSS (s)
400
400
300
300
200 VIN=5.0V IOUT=1.0mA
200 VIN=5.0V IOUT=1.0mA
100
100
0 -50 -25 0 25 50 75 100
0 -50 -25 0 25 50 75 100
Ambient Temperature: Ta()
Ambient Temperature: Ta()
(14) XC9235B/36B/37B
600
CL Discharge Resistance vs. Ambient Temperature
XC9237B33D
VIN=6.0V
CL Discharge Resistance: ( )
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=4.7 H (NR4018), CIN=4.7 F (ceramic), CL=10 F (ceramic), Topr=25
VIN=3.6V, VCE=VIN (PWM/PFM Automatic Switching Control)
IOUT=1mA
100mA
IOUT=1mA
300mA
1ch: IOUT
1ch: IOUT
2ch VOUT: 50mV/div
2ch VOUT: 50mV/div
50
s/div
50
s/div
IOUT=100mA
1mA
IOUT=300mA
1mA
1ch: IOUT
1ch: IOUT
2ch VOUT: 50mV/div 200 s/div
2ch VOUT: 50mV/div 200 s/div
22/28
XC9235/XC9236/XC9237
Series
TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(15) Load Transient Response (Continued) XC9237A18C L=4.7 H (NR4018), CIN=4.7 F (ceramic), CL=10 F (ceramic), Topr=25
VIN=3.6V, VCE=1.8V (PWM Control)
IOUT=1mA
100mA
IOUT=1mA
300mA
1ch: IOUT
1ch: IOUT
2ch VOUT: 50mV/div
2ch VOUT: 50mV/div
50
s/div
50
s/div
IOUT=100mA
1mA
IOUT=300mA
1mA
1ch: IOUT
1ch: IOUT
2ch VOUT: 50mV/div
2ch VOUT: 50mV/div
200
s/div
200
s/div
23/28
XC9235/XC9236/XC9237 Series
TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(15) Load Transient Response (Continued) XC9237A18D L=1.5 H (NR3015), CIN=4.7 F (ceramic), CL=10 F (ceramic), Topr=25
VIN=3.6V, VCE=VIN (PWM/PFM Automatic Switching Control)
IOUT=1mA
100mA
IOUT=1mA
300mA
1ch: IOUT
1ch: IOUT
2ch VOUT: 50mV/div
2ch VOUT: 50mV/div
50
s/div
50
s/div
IOUT=100mA
1mA
IOUT=300mA
1mA
1ch: IOUT
1ch: IOUT
2ch VOUT: 50mV/div
2ch VOUT: 50mV/div
200
s/div
200
s/div
24/28
XC9235/XC9236/XC9237
Series
TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(15) Load Transient Response (Continued) XC9237A18D L=1.5 H (NR3015), CIN=4.7 F (ceramic), CL=10 F (ceramic), Topr=25
VIN=3.6V, VCE=1.8V (PWM Control)
IOUT=1mA
100mA
IOUT=1mA
300mA
1ch: IOUT
1ch: IOUT
2ch VOUT: 50mV/div
2ch VOUT: 50mV/div
50
s/div
50
s/div
IOUT=100mA
1mA
IOUT=300mA
1mA
1ch: IOUT
1ch: IOUT
2ch VOUT: 50mV/div
2ch VOUT: 50mV/div
200
s/div
200
s/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
Represent product series MARK 4 5 6 C D E K L M SOT-25 (TOP VIEW) Represents 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 A B C D E F H K L M PRODUCT SERIES XC9235A XC9236A XC9237A XC9235B XC9236B XC9237B XC9235C XC9236C XC9237C
USP-6C (TOP VIEW)
Represents 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
Represents 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

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