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1/28 XC9235/xc9236/xc9237 series 600ma driver tr. built-in, sync hronous step-down dc/dc converters ? greenoperation compatible applications ? mobile phones ? bluetooth equipment ? pdas, portable communication modem ? portable games ? digital cameras, video cameras ? cordless phones ? notebook computers typical application circuit etr0514-007 general description the XC9235/xc9236/xc9237 series is a group of synchronous -rectification type dc/dc conv erters 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 config ured 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 fr om 0.8v to 4.0v in increments of 50mv (accuracy: ? 2.0%). with the built-in oscillator, et her 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 switch ed between the pwm control mode and the automatic pwm/pfm switching control m ode, 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 opti mized. 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 wh en 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 c l auto discharge function which enables the electric charge at the output capacitor c l to be discharged via the internal auto-discharge switch located between the l x and v ss pins. when the devices enter stand-by mode, output voltage quickly returns to the v ss level as a result of this function. two types of package sot-25 and usp-6c are available. features p-ch driver transistor built-in : on resistance 0.42
n-ch driver transistor built-in : on resistance 0.52
input voltage : 2.0v ~ 6.0v output voltage : 0.8v ~ 4.0v high efficiency : 92% (typ.) output current : 600ma oscillation frequency : 1.2mhz, 3.0mhz (+ 15%) maximum duty cycle : 100% control methods : 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 c l 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 performance characteristics ? efficiency vs. output current fosc=1.2nhz, v out =1.8v 0 10 20 30 40 50 60 70 80 90 100 0.1 1 10 100 1000 output current:iout(ma) efficency:effi(% ) pwm/pfm a utomatic sw itc hing contr ol pwm control vin= 4.2v 3.6v 2.4v vin= 4.2v 3.6v 2.4v efficiency: effi (%)
2/28 XC9235 / xc9236/xc9237 series pin number sot-25 usp-6c pin name function 1 6 v in power input 2 2, 5 v ss ground 3 4 ce / mode chip enable mode switch 4 3 v out output voltage sense 5 1 lx switching output designator description symbol description a : ce input logic high active b : ce input logic high active, high speed soft start, c l discharge ? . transistor built-in, output voltage internally set (v out product), soft-start internally set c : ce input logic high active, c l discharge ? output voltage 0~4 : integer number of output voltage e.g. v out =2.8v ? =2, v out =3.3v ? =3 ? output voltage 0~9, a~m : 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. v out =2.8v ? =2, ? =8 v out =2.85v ? =2, ? =l c : 1.2mhz ? oscillation frequency d : 3.0mhz m : sot-25 (sot-23-5) ? packages e : usp-6c r : embossed tape, standard feed ? device orientation l : embossed tape, reverse feed 1 3 2 5 4 sot-25 (top view) usp-6c (bottom view) v ss ce/mode v in lx v out ce/mode 4 2 v ss v in 6 1 lx 3 v out v ss 5 pin configuration * please short the v ss 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 v ss (no. 5) pin. pin assignment product classification ? ordering information XC9235 ?????? pwm fixed control xc9236 ?????? pwm / pfm automatic switching control xc9237 ?????? pwm fixed control q pwm / pfm automatic switching, manual switching
3/28 XC9235/xc9236/xc9237 series parameter symbol ratings unit v in pin voltage v in - 0.3 ~ 6.5 v lx pin voltage v lx - 0.3 ~ v in + 0.3 or 6.5v v v out pin voltage v out - 0.3 ~ 6.5 v ce / mode pin voltage v ce - 0.3 ~ 6.5 v lx pin current i lx 1500 ma sot-25 250 power dissipation (*ta=25 ) usp-6c pd 100 mw operating temperature range topr - 40 ~ + 85 o c storage temperature range tstg - 55 ~ + 125 o c block diagram 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/pf m automatic switching control. diodes inside the circuit are esd pr otection diodes and parasitic diodes. a bsolute maximum ratings ta = 2 5 ? ? XC9235a / xc9236a / xc9237a ? XC9235b ( c ) / xc9236b ( c ) / xc9237b ( c )
4/28 XC9235 / xc9236/xc9237 series xc9237a18cxx, v out =1.8v, fosc=1.2mhz, ta=25 parameter symbol conditions min. typ. max. unit circuit output voltage v out when connected to external components, v in =v ce =5.0v, i out =30ma 1.764 1.800 1.836 v ? operating voltage range v in 2.0 - 6.0 v ? maximum output current i outmax v in =v out(e) +2.0v, v ce =1.0v, when connected to external components (*9) 600 - - ma ? u.v.l.o. voltage v uvlo v ce =v in , v out =0v, voltage which lx pin holding ?l? level (*1, *11) 1.00 1.40 1.78 v ? supply current i dd v in =v ce =5.0v, v out =v out(e) 1.1v - 15 33 a ? stand-by current i stb v in =5.0v, v ce =0v, v out =v out(e) 1.1v - 0 1.0 a ? oscillation frequency fosc when connected to external components, v in =v out(e) +2.0v, v ce =1.0v, i out =100ma 1020 1200 1380 khz ? pfm switching current i pfm when connected to external components, v in =v out(e) +2.0v, v ce =v in , i out =1ma (*12) 120 160 200 ma ? maximum i pfm limit maxi pfm v ce =v in =(c-1), i out =1ma (*12) 200 % ? maximum duty cycle maxdty v in =v ce =5.0v, v out =v out(e) 0.9v 100 - - % ? minimum duty cycle mindty v in =v ce =5.0v, v out =v out(e) 1.1v - - 0 % ? efficiency (*2) effi when connected to external components, v ce =v in =v out(e) +1.2v, i out =100ma - 92 - % ? lx sw "h" on resistance 1 r lxh v in =v ce =5.0v, v out =0v, i lx =100ma (*3) - 0.35 0.55
? lx sw "h" on resistance 2 r lxh v in =v ce =3.6v, v out =0v, i lx =100ma (*3) - 0.42 0.67
? lx sw "l" on resistance 1 r lxl v in =v ce =5.0v (*4) - 0.45 0.66
? lx sw "l" on resistance 2 r lxl v in =v ce =3.6v (*4) - 0.52 0.77
- lx sw "h" leak current (*5) i leakh v in =v out =5.0v, v ce =0v, lx=0v - 0.01 1.0 a ? lx sw "l" leak current (*5) i leakl v in =v out =5.0v, v ce =0v, lx=5.0v - 0.01 1.0 a ? current limit (*10) i lim v in =v ce =5.0v, v out =v out(e) 0.9v (*8) 900 1050 1350 ma ? output voltage temperature characteristics v out v out ~ topr i out =30ma, -40 ?? topr ? 85 ? - ? 100 - ppm/ ? ? ce "h" voltage v ceh v out =0v, applied voltage to v ce , voltage changes lx to ?h? level (*11) 0.65 - v in v ? ce "l" voltage v cel v out =0v, applied voltage to v ce , voltage changes lx to ?l? level (*11) v ss - 0.25 v ? pwm "h" level voltage v pwmh when connected to external components, ? i out =1ma (*6) , voltage which oscillation frequency becomes 1020 khz ? fosc ? 1380khz (*13) - - v in - 1.0 v ? pwm "l" level voltage v pwml when connected to external components, ? i out =1ma (*6) , voltage which oscillation frequency becomes fosc ? 1020khz (*13) v in ? 0.25 - - v ? ce "h" current i ceh v in =v ce =5.0v, v out =0v - 0.1 - 0.1 a ? ce "l" current i cel v in =5.0v, v ce =0v, v out =0v - 0.1 - 0.1 a ? soft start time t ss when connected to external components, v ce =0v v in , i out =1ma 0.5 1.0 2.5 ms ? latch time t lat v in =v ce =5.0v, v out =0.8 v out(e) , short lx at 1
resistance (*7) 1.0 - 20.0 ms ? short protection threshold voltage v short sweeping v out , v in =v ce =5.0v, short lx at 1
resistance, v out voltage which lx becomes ?l? level within 1ms 0.675 0.900 1.150 v ? electrical characteristics test conditions: unless otherwise stated, v in =5.0v, v out(e) =setting voltage note: *1: including hysteresis operating voltage range. *2: effi = { ( output voltage output current ) ?? ( input voltage input current) } 100 *3: on resistance (
)= (v in - 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 v in minus 0.3v, and to the pwm mode when the ce/mode pin voltage is equal to or lower than v in minus 1.0v and equal to or greater than v ceh . *7: time until it short-circuits v out with gnd via 1
of resistor from an operational state and is set to lx=0v from current limit pulse generating. *8: when v in 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 maximiz es. 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?=v in ~v in -1.2v, ?l?=+0.1v~-0.1v *12: XC9235 series exclude i pfm and maxi pfm because those are only for the pfm control?s functions. *13: XC9235/9236 series exclude v pwmh and v pwml because those are onl y for the xc9237 series? functions.
5/28 XC9235/xc9236/xc9237 series xc9237a18dxx, v out =1.8v, fosc=3.0mhz, ta=25 parameter symbol conditions min. typ. max. unit circuit output voltage v out when connected to external components, v in =v ce =5.0v, i out =30ma 1.764 1.800 1.836 v ? operating voltage range v in 2.0 - 6.0 v ? maximum output current i outmax v in =v out(e) +2.0v, v ce =1.0v, when connected to external components (*9) 600 - - ma ? u.v.l.o. voltage v uvlo v ce =v in , v out =0v, voltage which lx pin holding ?l? level (*1,*11) 1.00 1.40 1.78 v ? supply current i dd v in =v ce =5.0v, v out =v out(e) 1.1v - 21 35 a ? stand-by current i stb v in =5.0v, v ce =0v, v out =v out(e) 1.1v - 0 1.0 a ? oscillation frequency fosc when connected to external components, v in =v out(e) +2.0v, v ce =1.0v, i out =100ma 2550 3000 3450 khz ? pfm switching current i pfm when connected to external components, v in =v out(e) +2.0v, v ce =v in , i out =1ma (*12) 170 220 270 ma ? maximum ipfm limit maxi pfm v ce =v in =(c-1), i out =1ma (*12) - 200 300 % ? maximum duty cycle maxdty v in =v ce =5.0v, v out =v out(e) 0.9v 100 - - % ? minimum duty cycle mindty v in =v ce =5.0v, v out =v out(e) 0.1v - - 0 % ? efficiency effi when connected to external components, v ce =v in 1 v out(e) +1.2v, i out =100ma - 86 - % ? lx sw "h" on resistance 1 r lxh v in =v ce =5.0v, v out =0v, i lx =100ma (*3) - 0.35 0.55
? lx sw "h" on resistance 2 r lxh v in =v ce =3.6v, v out =0v, i lx =100ma (*3) - 0.42 0.67
? lx sw "l" on resistance 1 r lxl v in =v ce =5.0v (*4) - 0.45 0.66
- lx sw "l" on resistance 2 r lxl v in =v ce =3.6v (*4) - 0.52 0.77
- lx sw "h" leak current (*5) i leakh v in =v out =5.0v, v ce =0v, lx=0v - 0.01 1.0 a ? lx sw "l" leak current (*5) i leakl v in =v out =5.0v, v ce =0v, lx=5.0v - 0.01 1.0 a ? current limit (*10) i lim v in =v ce =5.0v, v out =v out(e) 0.9v (*8) 900 1050 1350 ma ? output voltage temperature characteristics v out v out ~ topr i out =30ma, -40 ?? topr ? 85 ? - ? 100 - ppm/ ? ? ce "h" voltage v ceh v out =0v, applied voltage to v ce , voltage changes lx to ?h? level (*11) 0.65 - v in v ? ce "l" voltage v cel v out =0v, applied voltage to v ce , voltage changes lx to ?l? level (*11) v ss - 0.25 v ? pwm "h" level voltage v pwmh when connected to external components, ? i out =1ma (*6) , voltage which oscillation frequency becomes 2550khz ? fosc ? 3450khz (*13) - - v in - 1.0 v ? pwm "l" level voltage v pwml when connected to external components, ? i out =1ma (*6) , voltage which oscillation frequency becomes fosc ? 2550khz (*13) v in ? 0.25 - - v ? ce "h" current i ceh v in =v ce =5.0v, v out =0v - 0.1 - 0.1 a ? ce "l" current i cel v in =5.0v, v ce =0v, v out =0v - 0.1 - 0.1 a ? soft start time t ss when connected to external components, ? v ce =0v v in , i out =1ma 0.5 0.9 3.0 ms ? latch time t lat v in =v ce =5.0v, v out =0.8 v out(e) , short lx at 1
resistance (*7) 1.0 - 20 ms ? short protection threshold voltage v short sweeping v out , v in =v ce =5.0v, short lx at 1
resistance, v out voltage which lx becomes ?l? level within 1ms (*4) 0.675 0.900 1.150 v ? electrical characteristics (continued) test conditions: unless otherwise stated, v in =5.0v, v out(e) =setting voltage note: *1: including hysteresis operating voltage range. *2: effi = { ( output voltage output current ) ?? ( input voltage input current) } 100 *3: on resistance (
)= (v in - 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 v in minus 0.3v, and to the pwm mode when the ce/mode pin voltage is equal to or lower than v in minus 1.0v and equal to or greater than v ceh . *7: time until it short-circuits v out with gnd via 1
of resistor from an operational state and is set to lx=0v from current limit pulse generating. *8: when v in 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 maximiz es. 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?=v in ~v in -1.2v, ?l?=+0.1v~-0.1v *12: XC9235 series exclude i pfm and maxi pfm because those are only for the pfm control?s functions. *13: XC9235/9236 series exclude v pwmh and v pwml because those are onl y for the xc9237 series? functions.
6/28 XC9235 / xc9236/xc9237 series xc9237b(c)18cxx, v out =1.8v, fosc=1.2mhz, ta=25 parameter symbol conditions min. typ. max. unit circuit output voltage v out when connected to external components, v in =v ce =5.0v, i out =30ma 1.764 1.800 1.836 v ? operating voltage range v in 2.0 - 6.0 v ? maximum output current i outmax v in =v out(e) +2.0v, v ce =1.0v, when connected to external components (*9) 600 - - ma ? u.v.l.o. voltage v uvlo v ce =v in , v out =0v, voltage which lx pin holding ?l? level (*1, *11) 1.00 1.40 1.78 v ? supply current i dd v in =v ce =5.0v, v out =v out(e) 1.1v - 15 33 a ? stand-by current i stb v in =5.0v, v ce =0v, v out =v out(e) 1.1v - 0 1.0 a ? oscillation frequency fosc when connected to external components, v in =v out(e) +2.0v, v ce =1.0v, i out =100ma 1020 1200 1380 khz ? pfm switching current i pfm when connected to external components, v in =v out(e) +2.0v, v ce =v in , i out =1ma (*12) 120 160 200 ma ? maximum i pfm limit maxi pfm v ce =v in =(c-1), i out =1ma (*12) 200 % ? maximum duty cycle maxdty v in =v ce =5.0v, v out =v out(e) 0.9v 100 - - % ? minimum duty cycle mindty v in =v ce =5.0v, v out =v out(e) 1.1v - - 0 % ? efficiency (*2) effi when connected to external components, v ce =v in =v out(e) +1.2v, i out =100ma - 92 - % ? lx sw "h" on resistance 1 r lxh v in =v ce =5.0v, v out =0v, i lx =100ma (*3) - 0.35 0.55
? lx sw "h" on resistance 2 r lxh v in =v ce =3.6v, v out =0v, i lx =100ma (*3) - 0.42 0.67
? lx sw "l" on resistance 1 r lxl v in =v ce =5.0v (*4) - 0.45 0.66
? lx sw "l" on resistance 2 r lxl v in =v ce =3.6v (*4) - 0.52 0.77
- lx sw "h" leak current (*5) i leakh v in =v out =5.0v, v ce =0v, lx=0v - 0.01 1.0 a ? current limit (*10) i lim v in =v ce =5.0v, v out =v out(e) 0.9v (*8) 900 1050 1350 ma ? output voltage temperature characteristics v out v out ~ topr i out =30ma, -40 ?? topr ? 85 ? - ? 100 - ppm/ ? ? ce "h" voltage v ceh v out =0v, applied voltage to v ce , voltage changes lx to ?h? level (*11) 0.65 - v in v ? ce "l" voltage v cel v out =0v, applied voltage to v ce , voltage changes lx to ?l? level (*11) v ss - 0.25 v ? pwm "h" level voltage v pwmh when connected to external components, ? i out =1ma (*6) , voltage which oscillation frequency becomes 1020 khz ? fosc ? 1380khz (*13) - - v in - 1.0 v ? pwm "l" level voltage v pwml when connected to external components, ? i out =1ma (*6) , voltage which oscillation frequency becomes fosc ? 1020khz (*13) v in ? 0.25 - - v ? ce "h" current i ceh v in =v ce =5.0v, v out =0v - 0.1 - 0.1 a ? ce "l" current i cel v in =5.0v, v ce =0v, v out =0v - 0.1 - 0.1 a ? soft start time (b series) t ss when connected to external components, v ce =0v v in , i out =1ma - 0.25 0.40 ms ? soft start time (c series) t ss when connected to external components, v ce =0v v in , i out =1ma 0.5 1.0 2.5 ms ? latch time t lat v in =v ce =5.0v, v out =0.8 v out(e) , short lx at 1
resistance (*7) 1.0 - 20.0 ms ? short protection threshold voltage v short sweeping v out , v in =v ce =5.0v, short lx at 1
resistance, v out voltage which lx becomes ?l? level within 1ms 0.675 0.900 1.150 v ? cl discharge rdischg v in =5.0v, l x =5.0v, v ce =0v, v out =open 200 300 450
? electrical characteristics (continued) test conditions: unless otherwise stated, v in =5.0v, v out(e) =setting voltage note: *1: including hysteresis operating voltage range. *2: effi = { ( output voltage output current ) ?? ( input voltage input current) } 100 *3: on resistance (
)= (v in - 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 v in minus 0.3v, and to the pwm mode when the ce/mode pin voltage is equal to or lower than v in minus 1.0v and equal to or greater than v ceh . *7: time until it short-circuits v out with gnd via 1
of resistor from an operational state and is set to lx=0v from current limit pulse generating. *8: when v in 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 maximiz es. 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?=v in ~v in -1.2v, ?l?=+0.1v~-0.1v *12: XC9235 series exclude i pfm and maxi pfm because those are only for the pfm control?s functions. *13: XC9235/9236 series exclude v pwmh and v pwml because those are onl y for the xc9237 series? functions.
7/28 XC9235/xc9236/xc9237 series xc9237b(c)18dxx, v out =1.8v, fosc=3.0mhz, ta=25 parameter symbol conditions min. typ. max. unit circuit output voltage v out when connected to external components, v in =v ce =5.0v, i out =30ma 1.764 1.800 1.836 v ? operating voltage range v in 2.0 - 6.0 v ? maximum output current i outmax v in =v out(e) +2.0v, v ce =1.0v, when connected to external components (*9) 600 - - ma ? u.v.l.o. voltage v uvlo v ce =v in , v out =0v, voltage which lx pin holding ?l? level (*1,*11) 1.00 1.40 1.78 v ? supply current i dd v in =v ce =5.0v, v out =v out(e) 1.1v - 21 35 a ? stand-by current i stb v in =5.0v, v ce =0v, v out =v out(e) 1.1v - 0 1.0 a ? oscillation frequency fosc when connected to external components, v in =v out(e) +2.0v, v ce =1.0v, i out =100ma 2550 3000 3450 khz ? pfm switching current i pfm when connected to external components, v in =v out(e) +2.0v, v ce =v in , i out =1ma (*12) 170 220 270 ma ? maximum ipfm limit maxi pfm v ce =v in =(c-1), i out =1ma (*12) - 200 300 % ? maximum duty cycle maxdty v in =v ce =5.0v, v out =v out(e) 0.9v 100 - - % ? minimum duty cycle mindty v in =v ce =5.0v, v out =v out(e) 0.1v - - 0 % ? efficiency effi when connected to external components, v ce =v in 1 v out(e) +1.2v, i out =100ma - 86 - % ? lx sw "h" on resistance 1 r lxh v in =v ce =5.0v, v out =0v, i lx =100ma (*3) - 0.35 0.55
? lx sw "h" on resistance 2 r lxh v in =v ce =3.6v, v out =0v, i lx =100ma (*3) - 0.42 0.67
? lx sw "l" on resistance 1 r lxl v in =v ce =5.0v (*4) - 0.45 0.66
- lx sw "l" on resistance 2 r lxl v in =v ce =3.6v (*4) - 0.52 0.77
- lx sw "h" leak current (*5) i leakh v in =v out =5.0v, v ce =0v, lx=0v - 0.01 1.0 a ? current limit (*10) i lim v in =v ce =5.0v, v out =v out(e) 0.9v (*8) 900 1050 1350 ma ? output voltage temperature characteristics v out v out ~ topr i out =30ma, -40 ?? topr ? 85 ? - ? 100 - ppm/ ? ? ce "h" voltage v ceh v out =0v, applied voltage to v ce , voltage changes lx to ?h? level (*11) 0.65 - v in v ? ce "l" voltage v cel v out =0v, applied voltage to v ce , voltage changes lx to ?l? level (*11) v ss - 0.25 v ? pwm "h" level voltage v pwmh when connected to external components, ? i out =1ma (*6) , voltage which oscillation frequency becomes 2550khz ? fosc ? 3450khz (*13) - - v in - 1.0 v ? pwm "l" level voltage v pwml when connected to external components, ? i out =1ma (*6) , voltage which oscillation frequency becomes fosc ? 2550khz (*13) v in ? 0.25 - - v ? ce "h" current i ceh v in =v ce =5.0v, v out =0v - 0.1 - 0.1 a ? ce "l" current i cel v in =5.0v, v ce =0v, v out =0v - 0.1 - 0.1 a ? soft start time (b series) t ss when connected to external components, ? v ce =0v v in , i out =1ma - 0.32 0.50 ms ? soft start time (c series) t ss when connected to external components, ? v ce =0v v in , i out =1ma 0.5 0.9 2.5 ms ? latch time t lat v in =v ce =5.0v, v out =0.8 v out(e) , short lx at 1
resistance (*7) 1.0 - 20 ms ? short protection threshold voltage v short sweeping v out , v in =v ce =5.0v, short lx at 1
resistance, v out voltage which lx becomes ?l? level within 1ms 0.675 0.900 1.150 v ? cl discharge rdischg v in =5.0v, l x =5.0v, v ce =0v, v out =open 200 300 450
? electrical characteristics (continued) test conditions: unless otherwise stated, v in =5.0v, v out(e) =setting voltage note: *1: including hysteresis operating voltage range. *2: effi = { ( output voltage output current ) ?? ( input voltage input current) } 100 *3: on resistance (
)= (v in - 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 v in minus 0.3v, and to the pwm mode when the ce/mode pin voltage is equal to or lower than v in minus 1.0v and equal to or greater than v ceh . *7: time until it short-circuits v out with gnd via 1
of resistor from an operational state and is set to lx=0v from current limit pulse generating. *8: when v in 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 maximiz es. 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?=v in ~v in -1.2v, ?l?=+0.1v~-0.1v *12: XC9235 series exclude i pfm and maxi pfm because those are only for the pfm control?s functions. *13: XC9235/9236 series exclude v pwmh and v pwml because those are onl y for the xc9237 series? functions.
8/28 XC9235 / xc9236/xc9237 series series fosc setting voltage min. typ. max. 1200khz 0.8 Q v out(e) <1.5 - 250 400 s 1200khz 1.5 Q v out(e) <1.8 - 320 500 s 1200khz 1.8 Q v out(e) <2.5 - 280 400 s XC9235b/xc9237b 1200khz 2.5 Q v out(e) <4.0 - 320 500 s 1200khz 0.8 Q v out(e) <2.5 - 280 400 s xc9236b 1200khz 2.5 Q v out(e) <4.0 - 320 500 s 3000khz 0.8 Q v out(e) <1.8 - 280 400 s XC9235b/ xc9236b/xc9237b 3000khz 1.8 Q v out(e) <4.0 - 320 500 s electrical characteristics (continued) ? pfm switching current (i pfm ) by oscillation frequency and setting voltage ? input voltage (v in ) for measuring maximum pfm switching current (maxi pfm ) limit fosc 1.2mhz 3.0mhz c-1 v out(e) +0.5v v out(e) +1.0v minimum operating voltage is 2.0v. ex.) although when v out(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. typical application circuit ? fosc=3.0mhz l: 1.5 h (nr3015, taiyo yuden) c in : 4.7 f (ceramic) c l : 10 f (ceramic) ? fosc=1.2mhz l: 4.7 h (nr4018, taiyo yuden) c in : 4.7 f (ceramic) c l : 10 f (ceramic) (ma) 1.2mhz 3.0mhz setting voltage min. typ. max. min. typ. max. v out(e) Q 1.2v 140 180 240 190 260 350 1.2v v out(e) Q 1.75v 130 170 220 180 240 300 1.8v Q v out(e) 120 160 200 170 220 270 ? soft-start time, setting voltage XC9235b/36b/37b series only
9/28 XC9235/xc9236/xc9237 series operational description the XC9235/xc9236/xc9237 se r ies consists of a reference voltage source , ramp wave circuit, error amplifier, pwm comparator, phase compensation circuit, out put voltage adjustment resistors, p-channel mosfet driver transistor, n-channel mosfet switching transistor for the synchr onous 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 th e feedback voltage from the v out pin through split resistors, r1 and r2. p hase 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 cyc le. this process is continuously performed to ensure stable output voltage. the current feedback circuit monitors the p-channel mos driver transistor current for each swit ching operation, and modulates the error am plifier output signal to provide multiple feedback signals. this enables a stable feedback loop even w hen a low esr capacitor such as a ceramic capacitor is used ensuring stable output voltage. the reference voltage source provides t he reference voltage to ensure stable ou tput voltage of t he dc/dc converter. the ramp wave circuit determines switching frequency. the frequenc y 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. t he 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 increa ses. the gain and frequency characteristi cs of the error amplifier output are fixe d internally to deli ver an optimized signal to the mixer. the current limiter circuit of the xc92 35/xc9236/xc9237 series monitors the curr ent flowing through the p-channel mos driver transistor connected to the lx pin, and features a co mbination of the current limit mode and the operation suspension mode. when the driver current is greater than a s pecific level, the current limit function oper ates to turn off the pulses from the l x pin at any given timing. when the driver transistor is turned off, the limiter circuit is then released from the cu rrent limit det ection state. at the next pulse, the driver transistor is turned on. however, the transistor is imm ediately turned off in the case of an ove r 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 v in pin. the suspension mode does not mean a complete shutdown, but a state in which pulse output is suspended; theref ore, 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 miso peration of the current limit mode. depending on the state of the pc board, latch time may become lon ger and latch operation may not work. in order to avoid the effect of noise, the board should be laid out so that input capacitor s are placed as close to the ic as possible.
10/28 XC9235 / xc9236/xc9237 series operational description (continued) the short-circuit protection circuit monitors the internal r1 and r2 divider voltage from the v out 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 th an half of the reference voltage (vre f) and a current more than the i lim flows to the driver transistor, the short-circuit pr otection 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 v in pin. when sharp load transient happe ns, a voltage drop at the v out is propagated to the fb point through c fb , as a result, short circuit protection may operate in the voltage higher than 1/2 v out voltage. when the v in pin voltage becomes 1.4v or lower, the p-channel out put driver transistor is forced off to prevent false pulse output caused by unst able operation of the internal circuitry. when the v in pin voltage becomes 1.8v or higher, switching operation takes place. by releasing t he u.v.l.o. function, the ic performs t he soft start function to initiate output startup operation. the soft star t function operates even when the v in pin voltage falls momentarily below the u.v.l.o. operating voltage. t he u.v.l.o. circuit does not cause a complete s hutdown of the ic, but causes pulse output to be suspended; therefore, the inter nal circuitry remains in operation. in pfm control operation, until coil cu rrent reaches to a specified level (i pfm ), 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 i pfm (v in v out ) i pfm ? in pfm control operation, the maximum duty ratio (maxi pfm ) is set to 200% (typ.). ther efore, under the condition that the duty increases (e.g. the condition that t he step-down ratio is small), it?s possible for p-ch mosfet to be turned off even when coil current doesn?t reach to i pfm . ? i pfm ? ipfm ? ton lx i l x ipfm 0ma ipfm ? ipfm 0ma lx i l x fosc maxumum ipfm curren t
11/28 XC9235/xc9236/xc9237 series output voltage dischage characteristics rdischg = 300 typ discharge time t (ms) 0 10 20 30 40 50 60 70 80 90 100 0 102030405060708090100 cl=10uf cl=20uf cl=50uf operational description (continued) ? c l high speed discharge ? XC9235b(c)/ xc9236b(c)/ xc9237b(c) series can quickly di scharge the electric charge at the output capacitor (c l ) 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 l x pin and the v ss pin. when the ic is disabled, electr ic charge at the output capacitor (c l ) is quickly discharged so that it may avoid application malfunction. discharge time of the output capacitor (c l ) is set by the c l auto-discharge resistance (r ) and the output capacitor (c l ). by setting time constant of a c l auto-discharge resistance value [r] and an output capacitor value (c l ) as ( =c x r), discharge time of the output voltage after discharge via the n channel transistor is calculated by the following formulas. v = v out(e) x e ?t/ , or t= ln (v out(e) / v) v : output voltage after discharge v out(e) : output voltage t: discharge time, : c x r c= capacitance of output capacitor (c l ) r= c l auto-discharge resistance
12/28 XC9235 / xc9236/xc9237 series ? ? ? ? ? sw ? ce status on stand-by off operation sw ? ce status on operation off stand-by 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 on * stand-by off on pwm control off off pwm/pfm automatic switching control the operation of the XC9235/xc9236/xc9237 series will enter into t he shut down mode when a low level signal is input to the ce/mode pin. during the shutdown mode, t he current consumption of the ic becomes 0 a (typ.), with a state of high impedance at the lx pin and v out 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 0 a (typ.). XC9235/xc9236 series - exam p les of how to use ce/mode p in xc9237 series - exam p les of how to use ce/mode p in (a) (b) (a) (b) 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. (a) (b) (a) (b) operational description (continued)
13/28 XC9235/xc9236/xc9237 series ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?? operational states ce/mode voltage level XC9235 xc9236 xc9237 h level (*1) synchronous pwm fixed control synchronous pwm/pfm automatic switching synchronous pwm/pfm automatic switching m level (*2) 8 8 synchronous pwm fixed control l level (*3) stand-by stand-by stand-by function chart note on ce/mode pin voltage level range (*1) h level: 0.65v < h level < v in v (for XC9235/xc9236) h level: v in ? 0.25v < h level < v in (for xc9237) (*2) m level: 0.65v < m level < v in - 1.0v (for xc9237) (*3) l level: 0v < l level < 0.25v ? 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 turn ed on. operational description (continued) 90% of setting voltage
14/28 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 ca pacitor may fail to absorb the resulting high switching energy and oscillation could occur on the output. if the input-output potential di fference 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 di fferential, or load current, some pulses may be skipped, and the ripple voltage may increase. 4. when the difference between v in and v out 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 v in and v out is small, and the load current is heav y, 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 co il is controlled by the current limit circui t. since the peak current increases when dropout voltage or load current is high, current limit starts operation, and this c an lead to instability. when peak current becomes high, please adjust the coil inductance value and fu lly check the circuit operation. in addition, please calculate the peak current according to the following formula: ipk = (v in - v out ) x onduty / (2 x l x fosc) + i out l: coil inductance value fosc: oscillation frequency 7. when the peak current which ex ceeds limit current flows within the specified time, the built-in p-ch driver transistor turns off. during the time until it detects limit cu rrent and before the built-in transistor can be turned off, the current for limit curr ent flows; therefore, care must be tak en when selecting the rating for the external components such as a coil. 8. when v in 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 orde r to prevent misoperation of the current limit mode. depending on the state of the pc bo ard, latch time may become longer and latch operati on may not work. in order to avoid the effect of noise, the board should be laid out so that input c apacitors are placed as close to the ic as possible. 10. use of the ic at voltages below the reco mmended voltage range may lead to instability. 11. this ic should be used within the stated absolute ma ximum ratings in order to prevent damage to the device. 12. when the ic is used in high temperatur e, output voltage may increase up to inpu t 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 1350m a or more may flow. in case that the current limit functions while the v out 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 potentia l difference at both ends of the coil since the v out pin is shorted to the gnd pin. consequently, the time rate of coil current becomes quite small. according to t he repetition of this operation, and the delay time of the circuit, coil current will be converge d 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 with in the stated absolute maximum rating in order to prevent damage to the device. ?? current flows into p- ch mosfet to reach the current limit (i lim ). ? the current of i lim or more flows since the delay time of the circuit occu rs 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. lx il x il im limit > ms delay ms
15/28 XC9235/xc9236/xc9237 series the range of l value fosc v out l value 3.0mhz 0.8v v out <4.0v 1.0 h 2.2 h v out Q 2.5v 3.3 h 6.8 h 1.2mhz 2.5v v out 4.7 h 6.8 h *when a coil less value of 4.7 h is used at fosc=1.2mhz or when a coil less value of 1.5 h 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. note on use (continued) 14. in order to stabilize v in ?s voltage level and oscillation frequency, we recommend that a by-pass capacitor (c in ) be connected as close as possible to the v in & v ss pins. 15. high step-down ratio and very light l oad may lead an intermittent oscillation. 16. during pwm / pfm automatic switchin g 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, t he ic may happen to enter unstable output voltage operation even if using the l values listed below. 18. it may happen to enter unstable operation when the ic operat ion mode goes into continuo us operation mode under the condition of small input-output voltage difference. care must be taken with the actual design unit.
16/28 XC9235 / xc9236/xc9237 series ? instructions of pattern layouts 1. in order to stabilize v in voltage level, we recommend that a by-pass capacitor (c in ) be connected as close as possible to the v in & v ss 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 possi ble, as variations in ground potential caused by high ground currents at the time of switching ma y result in instability of the ic. 5. this series? internal driver transistors bring on heat bec ause of the output current and on resistance of driver transistors . note on use (continued)
17/28 XC9235/xc9236/xc9237 series < circuit no.1 > external components l : 1.5 h(nr3015) 3.0mhz 4.7 h(nr4018) 1.2mhz cin : 4.7 f(ceramic) cl :10 f(ceramic) < circuit no.2 > vin lx vss ce/ mode vout a v cl l cin wave form measure point < circuit no.3 > < circuit no.4 > vin lx vss ce/ mode vout a on resistance = (vin-vlx)/100ma vin lx vss ce/ mode vout v 100ma < circuit no.5 > vin lx vss ce/ mode vout a ileakh ileakl a iceh icel < circuit no.6 > < circuit no.7 > vin lx vss ce/ mode vout rpulldown 1 ilat wave form measure point vin lx vss ce/ mode vout v ilim wave form measure point vin lx vss ce/ mode vout 1 f rpulldown 200 wave form measure point 1 f 1 f 1 f 1 f 1 f ilx vin lx vss ce/ mode vout 1uf a test circuits circuit ? circuit ? circuit ? circuit ? circuit ? circuit ? circuit ? vin lx vss ce/ mode vout a cin circuit ? circuit ?
18/28 XC9235 / xc9236/xc9237 series (1) efficiency vs. output current (2) output voltage vs. output current (3) ripple voltage vs. output current 0 10 20 30 40 50 60 70 80 90 100 0.1 1 10 100 1000 output current:iout(ma) efficency:effi(% ) pwm/pfm a utomatic sw itc hing contr ol pwm control vin= 4.2v 3.6v 2.4v vin= 4.2v 3.6v 2.4v 0 10 20 30 40 50 60 70 80 90 100 0.1 1 10 100 1000 output current:iout(ma) efficency:effi(% ) pwm/pfm a utomatic sw itc hing contr ol pwm control vin= 4.2v 3.6v 2.4v vin= 4.2v 3.6v 2.4v 1.5 1.6 1.7 1.8 1.9 2.0 2.1 0.1 1 10 100 1000 output current:iout(ma) output voltage:vout(v) pwm/pfm a utomatic sw itc hing contr ol vin 4.2v,3.6v,2.4v pwm co n t r o l 1.5 1.6 1.7 1.8 1.9 2.0 2.1 0.1 1 10 100 1000 output current:iout(ma) output voltage:vout(v) pwm/pfm automatic sw itching control vin 4.2v,3.6v,2.4v pwm control 0 20 40 60 80 100 0.1 1 10 100 1000 output current:iout(ma) ripple voltage:vr(mv) pwm control vin 4.2v,3.6v,2.4v pwm/ pfm a u t o ma t ic sw itching control vin 4.2v 3.6v 2.4v 0 20 40 60 80 100 0.1 1 10 100 1000 output current:iout(ma) ripple voltage:vr(mv) pwm/pfm automatic sw itching control vin 4.2v 3.6v 2.4v pwm control vin 4.2v,3.6v,2.4v typical performance characteristics output current: iout (ma) output current: iout (ma) efficiency: effi (%) efficiency: effi (%) xc9237a18c l=4.7 h (nr4018), cin=4.7 f, c l = 1 0 f xc9237a18d l=1.5 h (nr3015), cin=4.7 f, c l = 1 0 f output current: iout (ma) output current: iout (ma) output voltage: vout (v) xc9237a18c l=4.7 h (nr4018), cin=4.7 f, c l = 1 0 f xc9237a18d l=1.5 h (nr3015), cin=4.7 f, c l = 1 0 f xc9237a18c l=4.7 h (nr4018), cin=4.7 f, c l = 1 0 f xc9237a18d l=1.5 h (nr3015), cin=4.7 f, c l = 1 0 f output current: iout (ma) ripple voltage: vr (mv) output current: iout (ma) ripple voltage: vr (mv)
19/28 XC9235/xc9236/xc9237 series (4) oscillation frequency vs. ambient temperature (5) supply current vs. ambient temperature (6) output voltage vs. ambient temperature ??????????? (7) uvlo voltage vs. ambient temperature 1.5 1.6 1.7 1.8 1.9 2.0 2.1 -50-250 255075100 ambient temperature: ta ( ) output voltage : vout (v) vin=3.6v 0.0 0.3 0.6 0.9 1.2 1.5 1.8 -50-250 255075100 ambient temperature: ta ( ) uvlo voltage : uvlo (v) ce=v in 0 5 10 15 20 25 30 35 40 -50 -25 0 25 50 75 100 ambient temperature: ta ( ) supply current : idd ( a ) vin=6.0v vin=4.0v vin=2.0v 0 5 10 15 20 25 30 35 40 -50-250 255075100 ambient temperature: ta ( ) supply current : idd ( a ) vin=6.0v vin=4.0v vin=2.0v 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 -50 -25 0 25 50 75 100 ambient temperature: ta ( ) vin=3.6v oscillation frequency : fosc(mhz) 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 -50 -25 0 25 50 75 100 ambient temperature: ta ( ) vin=3.6v oscillation frequency : fosc(mhz) typical performance chara cteristics (continued) ambient temperature: ta ( ? ) oscillation frequency: fosc (mhz) ambient temperature: ta ( ? ) oscillation frequency: fosc (mhz) supply current: idd ( a) supply current: idd ( a) ambient temperature: ta ( ? ) ambient temperature: ta ( ? ) ambient temperature: ta ( ? ) ambient temperature: ta ( ? ) uvlo voltage: uvlo (v) xc9237a18c l=4.7 h (nr4018), cin=4.7 f, c l = 1 0 f xc9237a18d l=1.5 h (nr3015), cin=4.7 f, c l = 1 0 f xc9237a18c xc9237a18d xc9237a18d xc9237a18d output voltage: vout (v)
20/28 XC9235 / xc9236/xc9237 series (8) ce "h" voltage vs. ambient temperature ????????? (9) ce "l" voltage vs. ambient temperature (10) soft start time vs. ambient temperature (11) "pch / nch" driver on resistance vs. input voltage 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0123456 input voltage : vin (v) pch on resistance nch on resistance lx sw on resistance:rlxh,rlxl ( ? ) 0 1 2 3 4 5 -50 -25 0 25 50 75 100 ambient temperature: ta ( ) soft start time : tss (ms ) vin=3.6v 0 1 2 3 4 5 -50-250 255075100 ambient temperature: ta ( ) soft start time : tss (ms ) vin=3.6v 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 -50 -25 0 25 50 75 100 ambient temperature: ta ( ) ce "h" voltage : vceh (v ) vin=5.0v vin=3.6v vin=2.4v 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 -50 -25 0 25 50 75 100 ambient temperature: ta ( ) ce "l" voltage : vcel (v) vin=5.0v vin=3.6v vin=2.4v typical perform a nce characteristics (continued) ambient temperature: ta ( ? ) ce ?h? voltage: vceh (v) ce ?l? voltage: vcel (v) input voltage: vin (v) lx sw on resistance: rlxh, rlxl (
) ambient temperature: ta ( ? ) soft start time: tss (ms) soft start time: tss (ms) xc9237a18c l=4.7 h (nr4018), cin=4.7 f, c l = 1 0 f xc9237a18d l=1.5 h (nr3015), cin=4.7 f, c l = 1 0 f ambient temperature: ta ( ? ) ambient temperature: ta ( ? ) xc9237a18d xc9237a18d xc9237a18d
21/28 XC9235/xc9236/xc9237 series (12) XC9235b/36b/37b rise wave form ???? (13) XC9235b/36b/37b soft-start time vs. ambient temperature xc9237b12c ???? xc9237b33d l=4.7 h(nr4018), cin=4.7 f, c l = 1 0 f l=1.5 h(nr3015), cin=4.7 f, c l = 1 0 f (14) XC9235b/36b/37b cl discharge resistance vs. ambient temperature xc9237b33d 100 200 300 400 500 600 -50 -25 0 25 50 75 100 ambient temperature: ta ( ) vin=6.0v vin=4.0v vin=2.0v 0 100 200 300 400 500 -50 -25 0 25 50 75 100 ambient temperature: ta() soft start time :tss (s) 0 100 200 300 400 500 -50 -25 0 25 50 75 100 ambient temperature: ta() soft start time :tss (s) vin=5.0v iout=1.0ma vin=5.0v iout=1.0ma typical performance chara cteristics (continued) xc9237b12c l=4.7 h (nr4018), cin=4.7 f, c l = 1 0 f xc9237b33d l=1.5 h (nr3015), cin=4.7 f, c l = 1 0 f 100 s/div 100 s/div cl discharge resistance: (
) vin=5.0v iout=1.0m a vin=5.0v iout=1.0m a vout 0.5v/div vout 1.0v/div ce 0.0v e 1.0v ce 0.0v e 1.0v
22/28 XC9235 / xc9236/xc9237 series (15) load transient response xc9237a18c l=4.7 h (nr4018), c in =4.7 f (ceramic), c l =10 f (ceramic), topr=25 ? v in =3.6v, v ce =v in (pwm/pfm automatic switching control) i out =1ma 100ma i out =1ma 300ma 1ch: i out 1ch: i out 2ch 2ch v out : 50mv/div v out : 50mv/div 50 s/div 50 s/div i out =100ma 1ma i out =300ma 1ma 1ch: i out 1ch: i out 2ch 2ch v out : 50mv/div v out : 50mv/div 200 s/div 200 s/div typical performance chara cteristics (continued)
23/28 XC9235/xc9236/xc9237 series (15) load transient response (continued) xc9237a18c l=4.7 h (nr4018), c in =4.7 f (ceramic), c l =10 f (ceramic), topr=25 ? v in =3.6v, v ce =1.8v (pwm control) i out =1ma 100ma i out =1ma 300ma 1ch: i out 1ch: i out 2ch 2ch v out : 50mv/div v out : 50mv/div 50 s/div 50 s/div i out =100ma 1ma i out =300ma 1ma 1ch: i out 1ch: i out 2ch 2ch v out : 50mv/div v out : 50mv/div 200 s/div 200 s/div typical performance chara cteristics (continued)
24/28 XC9235 / xc9236/xc9237 series (15) load transient response (continued) xc9237a18d l=1.5 h (nr3015), c in =4.7 f (ceramic), c l =10 f (ceramic), topr=25 ? v in =3.6v, v ce =v in (pwm/pfm automatic switching control) i out =1ma 100ma i out =1ma 300ma 1ch: i out 1ch: i out 2ch 2ch v out : 50mv/div v out : 50mv/div 50 s/div 50 s/div i out =100ma 1ma i out =300ma 1ma 1ch: i out 1ch: i out 2ch 2ch v out : 50mv/div v out : 50mv/div 200 s/div 200 s/div typical performance chara cteristics (continued)
25/28 XC9235/xc9236/xc9237 series (15) load transient response (continued) xc9237a18d l=1.5 h (nr3015), c in =4.7 f (ceramic), c l =10 f (ceramic), topr=25 ? v in =3.6v, v ce =1.8v (pwm control) i out =1ma 100ma i out =1ma 300ma 1ch: i out 1ch: i out 2ch 2ch v out : 50mv/div v out : 50mv/div 50 s/div 50 s/div i out =100ma 1ma i out =300ma 1ma 1ch: i out 1ch: i out 2ch 2ch v out : 50mv/div v out : 50mv/div 200 s/div 200 s/div typical performance chara cteristics (continued)
26/28 XC9235 / xc9236/xc9237 series packaging information ? sot-25 ? usp-6c ? usp-6c recommended pattern layout ? usp-6c recommended metal mask design
27/28 XC9235/xc9236/xc9237 series ?? ?? ??? ? represent product series mark product series 4 XC9235a 5 xc9236a 6 xc9237a c XC9235b d xc9236b e xc9237b k XC9235c l xc9236c m xc9237c ? represents integer number of output voltage and oscillation frequency mark output voltage (v) fosc =1.2mhz fosc =3.0mhz 0.x a f 1.x b h 2.x c k 3.x d l 4.x e m ? represents decimal point of output voltage output ? voltage (v) mark output voltage (v) mark x.00 0 x.05 a x.10 1 x.15 b x.20 2 x.25 c x.30 3 x.35 d x.40 4 x.45 e x.50 5 x.55 f x.60 6 x.65 h x.70 7 x.75 k x.80 8 x.85 l x.90 9 x.95 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. marking rule ? sot-25 & usp-6c sot-25 (top view) usp-6c (top view)
28/28 XC9235 / xc9236/xc9237 series 1. the products and product specifications cont ained herein are subject to change without notice to improve performance characteristic s. consult us, or our representatives before use, to confirm that the inform ation in this catalog is up to date. 2. we assume no responsibility for any infri ngement of patents, pat ent rights, or other rights arising from the use of any info rmation 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 ca n be reasonably expected to directly endanger the life of, or cause significant injury to, the user. (e.g. atomic energy; aerospace; transpor t; 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 ca talog may be copied or reproduced without the prior permission of torex semiconductor ltd.

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