XC9248B08-EVB-3.3V

XC9248 Series is Not Recommended for New Designs. XC9248 Series ETR05022-009 18V Driver Transistor Built-In Synchronous Step-Down DC/DC Converter ■GENERAL DESCRIPTION The XC9248 series is 18V bootstrap synchronous step-down DC/DC converter with built-in Nch-Nch driver transistors. With an input voltage range from 4.5V to 18V and a maximum output current of 2.2A, the series is suitable for digital home appliance power supplies and can be used with small ceramic capacitors. The series has a 0.8V reference voltage, and using externally connected resistors, the output voltage can be set freely from 1.0V to 12V. The control method is synchronous PWM (Source/ Sink). The soft start time is internally set to 2.8ms (TYP.), also can be adjusted using external capacitor. With UVLO (Under Voltage Lock Out) function, the internal driver transistors are forced OFF when input voltage falls down below 3.8V (TYP.). The series includes over current protection, VOUT short-circuit protection, Lx short-circuit protection, VOUT overvoltage protection and thermal shutdown. ■APPLICATIONS ■FEATURES ●Digital home appliance ●Office automation equipment Input Voltage ： 4.5V ~ 18V Output Voltage ： 1.0V ~ 12V (VFB=0.8V±1.5%) (*1) Output Current ： 2.2A ●Note PCs / Tablet PCs Efficiency ： 93.8% (*1) @VIN=12V,VOUT=5V, IOUT=700mA ●Car accessories power supplies Oscillation Frequency ： 500kHz Maximum Duty Cycle ： 79% Soft-Start Time ： Fixed 2.8ms, set by external capacitor Protection Circuit ： UVLO High side over current protection Low side over current protection VOUT Short-circuit Protection LX Short-circuit Protection VOUT Over voltage protection Thermal shutdown Package ： SOP-8FD Environmentally Friendly ： EU RoHS Compliant, Pb Free (*1) ■TYPICAL APPLICATION CIRCUIT Performance depends on external components and wiring on the PCB. ■TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs. Output Current L VIN EN CIN CSS EN GND SS BST FB VL 90 CBST CVL Ta=25°C 100 VOUT LX CFB CL RFB1 RFB2 80 Efficiency [%] VIN 70 VIN=12V , VOUT=5V 60 50 VIN=12V , VOUT=3.3V 40 30 20 10 0 0 500 1000 1500 Output Current : IOUT [mA] 2000 1/21 XC9248 Series is Not Recommended for New Designs. XC9248 Series ■BLOCK DIAGRAM EN EN VIN ENB SHORT to internal circuits ILIM Latch Delay Control Block VIN UVLO VL VL VL UVLO LX SHORT SS Thermal Shutdown Current Feedback Current Limit BST ILIM Nch DRV OVP + Soft Start VREF Output Buffer + ERR AMP - Phase Compensation PWM Comparator + IREF LX Nch DRV SHORT SHORT - FB ENB Ramp Wave Generator, OSC GND * Internal diodes include an ESD protection diode and a parasitic diode. ■PRODUCT CLASSIFICATION ●Ordering Information XC9248①②③④⑤⑥-⑦ DESIGNATOR ITEM ① TYPE ②③ FB Voltage 08 FB voltage is fixed in 0.8V Oscillation Frequency 5 500kHz Package QR-G ④ ⑤⑥-⑦ (*1) (*1) SYMBOL A DESCRIPTION Refer to Selection Guide B SOP-8FD (1,000pcs/Reel) The “-G” suffix denotes Halogen and Antimony free as well as being fully EU RoHS compliant. ●Selection Guide (*1) (*2) TYPE CURRENT LIMITER LATCH FOR CURRENT LIMITER LATCH FOR VOUT-SHORT LATCH FOR LX-SHORT (*2) A B YES YES YES (*1) NO YES NO YES YES TYPE ENABLE UVLO CL AUTO-DISCHARGE THERMAL SHUTDOWN A YES YES YES YES B YES YES YES YES The over-current protection latch is an integral latch type. To prevent an extremely large rush current from flowing in the event that Lx is short-circuited, both the A & B types have an Lx short protection latch function. 2/21 XC9248 Series is Not Recommended for New Designs. XC9248 Series ■PIN CONFIGURATION VIN 1 8 LX EN 2 7 GND SS 3 6 BST FB 4 5 VL SOP-8FD (TOP VIEW) * The dissipation pad for the SOP-8FD package should be solder-plated in recommended mount pattern and metal masking so as to enhance mounting strength and heat release. If the pad needs to be connected to other pins, it should be connected to the GND (No.7) pin. ■PIN ASSIGNMENT PIN NAME FUNCTIONS 1 VIN Power Input 2 EN Enable 3 SS External Soft-start 4 FB FB Voltage Monitor 5 VL Internal Regulator Output 6 7 BST Pre Driver Supply GND Ground 8 LX Switching Output PIN NUMBER ■FUNCTION PIN NAME EN (*1) SIGNAL STATUS L Stand-by H Active OPEN Undefined State (*1) On the XC9248 series, causes unspecified behavior and thus is prohibited. 3/21 XC9248 Series is Not Recommended for New Designs. XC9248 Series ■ABSOLUTE MAXIMUM RATINGS PARAMETER SYMBOL RATINGS UNITS VIN Pin Voltage VIN -0.3 ~ 20 V EN Pin Voltage VEN -0.3 ~ 20 V LX Pin Voltage VLX -0.3 ~ VIN + 0.3 or 20 (*1) V BST Pin Voltage VBST VL - 0.3 ~ VL + 20 VLX - 0.3 ~ VLX + 5.5 V VL Pin Voltage VVL -0.3 ~ VIN + 0.3 or 5.5 (*2) V FB Pin Voltage VFB -0.3 ~ 5.5 V SS Pin Voltage VSS -0.3 ~ 5.5 V LX Pin Current ILX ±5 A VL Pin Current IVL 85 mA Pd 300 1500 (40mm x 40mm Standard board) (*3) 2500 (JESD51-7 board)(*3) mW Operating Ambient Temperature Topr -40 ~ 105 °C Storage Temperature Tstg -50 ~ 125 °C Power Dissipation (Ta=25℃) SOP-8FD All voltages are described based on the ground voltage. (*1) The maximum value should be either VIN+0.3V or 20V in the lowest. (*2) The maximum value should be either VIN+0.3V or 5.5V in the lowest. (*3) The power dissipation figure shown is PCB mounted and is for reference only. Please refer to PACKAGING INFORMATION for the mounting condition. 4/21 XC9248 XC9248 Series is Not Recommended for New Designs. Series ■ELECTRICAL CHARACTERISTICS XC9248 Series PARAMETER Ta=25℃ SYMBOL CONDITIONS MIN. TYP. MAX. UNITS CIRCUIT 4.5 - 18 V ① 0.788 0.800 0.812 V ② ppm/℃ ② When connected to external components Operating Voltage Range VIN VIN ≦7V: Setup VOUT=3.3V FB Voltage VFB VFB=Sweep (0.812V→0.788V), VSS=OPEN FB Voltage VFB/ Temperature Characteristics (VFB・ΔTopr) Maximum Output Current IOUTMAX Supply Current Iq Stand-by Current VIN >7V: Setup VOUT=5V ±40 -40℃≦Topr≦105℃ When connected to external components 2.2(*1) - - A ① VIN=VEN=18V, VFB=0.9V - 0.76 1.10 mA ③ ISTB VIN=18V, VEN=0V, VFB=OPEN - 38 51 μA ③ Oscillation Frequency fOSC VFB=0.7V, VSS=OPEN 450 500 550 kHz ② Maximum Duty Cycle Dmax VFB=0.7V, VSS=OPEN 74 79 - % ② 3.50 3.80 4.45 V ④ 3.55 3.90 4.50 V ④ 2.1 - - A ⑦ 0.4 1.1 1.8 ms ⑤ - 2.8 - ms ② 2 4 6 μA ⑥ 1.2 1.8 2.4 V ② - 0.9 1.2 V ② - 93.8 - % ⑧ VIN=Sweep (4.5V→3.5V) , VEN=2V, VFB=0.9V UVLO Detection Voltage VUVLOD Voltage when VL pin changes from “H” level to “L” level (*2) VIN=Sweep (3.5V→4.5V), VEN=2V, VFB=0.9V UVLO Release Voltage VUVLOR Voltage when VL pin changes from “L” level to “H” level (*2) Low side Current Limit Integral Latch Time (Type A) ILIMLS VOUT=4.5V (Forced), Bottom point of LX pin current VFB=0.9V, ILX = ILIMLS tLAT Time until SS pin changes from “H” level to “L” level Internal Soft-start Time tSS SS Terminal Current ISS SS Threshold Voltage VSSTH OVP Detection Voltage VOVPD (*2) VIN=12V, VEN=2V, VFB=0.72V, VSS=OPEN Time until LX pin oscillates VSS=0V, VLX=VFB=OPEN VFB=0.72V, VSS=OPEN Voltage when LX pin oscillates VFB=Sweep (0.788V→1.2V), VSS=OPEN Setup VOUT=5V, IOUT=0.7A Efficiency EFFI (*3) Lx SW ”H” ON Resistance RLXH - 0.12(*4) - Ω - Lx SW ”L” ON Resistance RLXL - 0.12(*4) - Ω - 1.4 - 18 V ④ GND - 0.2 V ④ -1 0 - μA ⑥ ⑥ When connected to external components VIN=12V, VFB=0.9V, VEN=Sweep (0.2V→1.4V) EN ”H” Voltage VENH Voltage when VL pin changes from “L” level to “H” level (*2) VIN=12V, VFB=0.9V, VEN=Sweep (1.4V→0.2V) EN ”L” Voltage VENL Voltage when VL pin changes from “H” level to “L” level (*2) LX ”L” Current ILXL VIN=18V , VEN=VLX=0V , VFB=VSS=OPEN EN ”H” Current IENH VIN=VEN=18V , VLX=VFB=VSS=OPEN - 16 21 μA EN ”L” Current IENL VIN=18V , VEN=0V , VLX=VFB=VSS=OPEN -0.1 - 0.1 μA ⑥ FB ”H” Current IFBH VIN=18V , VEN=0V , VFB=5V , VLX=VSS=OPEN -0.1 - 0.1 μA ⑥ FB ”L” Current IFBL VIN=18V , VEN=VFB=0V , VLX=VSS=OPEN -0.1 - 0.1 μA ⑥ - Thermal Shutdown Temperature TTSD - 150 - °C Hysteresis Width THYS - 25 - °C - CL Discharge Resistance RDCHG VIN=12V , VEN=0V , VLX=2V , VFB=VSS=OPEN - 300 - Ω ⑥ CL Discharge Current IDCHG VIN=12V , VEN=0V , VLX=12V , VFB=VSS=OPEN - 9 - mA ⑥ Unless otherwise stated, VIN=VEN=12V (*1) Mount conditions affect heat dissipation. Maximum output current is not guaranteed when Thermal Shutdown starts to operate earlier. (*2) “H”=4.3V~5V, “L”=-0.1V~0.1V (*3) EFFI = {[(output voltage)×(output current)]÷[(input voltage)×(input current)]}×100 (*4) Design value 5/21 XC9248 Series is Not Recommended for New Designs. XC9248 Series ■TEST CIRCUITS CIRCUIT① L VIN VIN VOUT LX CBST EN CIN : 10μF 2parallel(ceramic) CVL : 0.1μF(ceramic) CBST : 0.1μF(ceramic) CL : 22μF 2parallel(ceramic) CFB RFB1 BST FB CIN Setup VOUT = 3.3V L : 6.8μH RFB1 : 47kΩ RFB2 : 15kΩ CFB : 470pF CL RFB2 VL SS Setup VOUT = 5V L : 6.8μH RFB1 : 43kΩ RFB2 : 8.2kΩ CFB : 470pF CVL GND CIRCUIT② CIRCUIT③ Wave Form Measurement Point LX VIN VIN CBST EN BST BST A FB CIN LX EN RL FB CIN VL VL SS V V GND SS CVL CVL GND CIN : 10μF 2parallel(ceramic) CVL : 0.1μF(ceramic) CBST : 0.1μF(ceramic) RL : 300Ω CIN : 1μF(ceramic) CVL : 0.1μF(ceramic) CIRCUIT④ CIRCUIT⑤ LX VIN VIN EN A BST Wave Form Measurement Point BST FB CIN V V LX EN Wave Form Measurement Point FB CIN VL VL SS SS CVL CVL GND GND CIN : 10μF 2parallel(ceramic) CVL : 0.1μF(ceramic) CIN : 10μF 2parallel(ceramic) CVL : 0.1μF(ceramic) CIRCUIT⑥ CIRCUIT⑦ Wave Form Measurement Point (Current Probe) VIN L LX VIN VOUT LX EN CBST EN RFB1 CFB BST A BST FB CIN VL A FB CIN A CL RFB2 VL SS SS CVL GND CVL A GND CIN : 10μF 2parallel(ceramic) CVL : 0.1μF(ceramic) CIRCUIT⑧ VIN IIN L VIN CBST EN RFB1 CFB A A BST FB CIN CL RFB2 VL V SS CVL GND 6/21 VOUT LX V IOUT CIN : 10μF 2parallel(ceramic) CVL : 0.1μF(ceramic) CBST : 0.1μF(ceramic) CL : 22μF 2parallel(ceramic) L : 6.8μH RFB1 : 43kΩ RFB2 : 8.2kΩ CFB : 470pF CIN : 10μF 2parallel(ceramic) CVL : 0.1μF(ceramic) CBST : 0.1μF(ceramic) CL : 22μF 2parallel(ceramic) L : 6.8μH RFB1 : 43kΩ RFB2 : 8.2kΩ CFB : 470pF XC9248 XC9248 Series is Not Recommended for New Designs. Series ■TYPICAL APPLICATION CIRCUIT L VIN VIN LX EN EN GND SS BST FB VL CIN CSS VOUT CBST CVL CFB CL RFB1 RFB2 【Typical Examples】 L CIN (*1) CL (*1) MANUFACTURER PART NUMBER VALUE TDK CLF10040T100N 10μH TDK CLF7045T6R8N 6.8μH TAIYO YUDEN NR6045T4R5M 4.5μH TAIYO YUDEN NR6028T2R2N 2.2μH C2012X5R1E106K 10μF/25V 2parallel C3216X7R1E106K 10μF/25V 2parallel C2012X5R1A226M 22μF/10V 2parallel C3216X5R1E226M 22μF/25V 2parallel TDK TDK C3225X7R1C226M 22μF/16V 2parallel C4532X7R1E226M 22μF/25V 2parallel CSS 0.1μF (*2)/10V CBST 0.1μF/10V CVL 0.1μF/10V (*1) Select components appropriate to the usage conditions (ambient temperature, input & output voltage). (*2) For the capacitance value, please refer to P.8 < External soft-start setting >. For stable operation by current feedback control, the XC9248 series is optimum when the peak-to-peak current (Ipk) in the coil is set approximately between 0.5A to 1A. The Ipk value can be calculated by using the following equation: Ipk [A] = (VIN－VOUT ) × VOUT / VIN / 0.5 / L [μH] L : Coil Inductance 【Examples】 VIN [V] VOUT [V] L [μH] Ipk [A] 5.0 1.0 2.2 0.73 5.0 2.5 3.3 0.76 12.0 3.3 6.8 0.70 12.0 5.0 6.8 0.86 18.0 5.0 10.0 0.72 18.0 12.0 10.0 0.80 7/21 XC9248 Series is Not Recommended for New Designs. XC9248 Series ■TYPICAL APPLICATION CIRCUIT (Continued) The output voltage can be set by connecting external dividing resistors. The output voltage is determined by the values of RFB1 and RFB2 as given in the equation below. The total of RFB1 and RFB2 should be less than 150kΩ. Output voltage range can be set freely from 1.0V to 12V with a 0.8V reference voltage. VOUT=0.8×(RFB1+RFB2)/RFB2 Adjust the value of the phase compensation speed-up capacitor CFB so that fzfp=1 / (2 × π× CFB x RFB1) is about 7kHz. Adjustments are required from 5kHz to 50kHz depending on the application, value of inductance (L), and value of load capacitance (CL). 【Examples】 RFB1=47kΩ, RFB2=15kΩ, VOUT=0.8V×(47kΩ+15kΩ) /15kΩ =3.3V CFB=470pF, fzfb=1/(2×π×470pF×47kΩ)=7.2kHz < Minimum VOUT > The Minimum VOUT is set by MINDUTY. The MINDUTY changes by the external inductance(L). For the L value, please choose the optimal value – see P.7 . The Minimum VOUT can be calculated by using the following equation: VOUT= VIN × MINDUTY / 100 【L vs. MINDUTY】 L [μH] MINDUTY [%] 2.2 18 3.3 20 4.7 21 6.8 21 10 22 A capacitor can be connected to the SS pin to set a time longer than the internal soft-start time voluntarily. By setting the EN pin to the VENH voltage or higher, a current ISS=4μA (TYP.) flows to the SS pin and charges the capacitor. When the SS pin voltage attains the SS threshold voltage VSSTH=1.8V (TYP.), the output voltage reaches about 90% of the set voltage. External soft-start can be calculated by using the following equation: External soft-start time=VSSTH × CSS / ISS 【Examples】 CSS=0.1μF, External soft-start time=1.8V × 0.1μF / 4μA × 1000=45ms 8/21 XC9248 XC9248 Series is Not Recommended for New Designs. Series ■OPERATIONAL EXPLANATION The XC9248 series consists of a reference voltage source, an internal reference voltage source, ramp wave circuit, error amplifier, PWM comparator, phase compensation circuit, Nch MOS driver transistor, current limiter circuit, UVLO, short protection circuit, thermal shutdown circuit, over voltage protection and others. (See the block diagram below.) By using the error amplifier, the FB pin voltage is compared with the internal reference voltage. The signal is input into the PWM comparator to determine the on time of switching. The signal from the error amplifier is compared with the ramp wave from the ramp wave circuit, and the resulting output is delivered to the output buffer circuit to provide on-time of the duty cycle at the LX pin. This process is continuously performed to ensure stable output voltage. The current feedback circuit monitors the Nch MOS driver transistor current for each switching operation, and modulates the error amplifier output signal to provide multiple feedback signals. This enables a stable feedback loop even when using a low ESR capacitor such as ceramic, which results in ensuring stable output voltage. XC9248 Series EN EN VIN ENB SHORT to internal circuits ILIM Latch Delay Control Block VIN UVLO VL VL VL UVLO LX SHORT SS Thermal Shutdown Current Feedback Current Limit BST ILIM Nch DRV OVP + VREF Soft Start ERR AMP - IREF SHORT PWM Comparator SHORT Ramp Wave Generator, OSC LX Nch DRV Phase Compensation + - FB Output Buffer + ENB GND 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 500kHz internally. Clock pulses generated in this circuit are used to produce ramp waveforms needed for PWM operation, and to synchronize all the internal circuits. The error amplifier is designed to monitor output voltage. The amplifier compares the reference voltage with the feedback voltage. When a voltage lower than the reference voltage is fed back, the output voltage of the error amplifier increases. The gain and frequency characteristics of the error amplifier output are fixed internally to deliver an optimized signal to the mixer. The error amplifier output signal optimized in the mixer is modulated with the current feedback signal. This signal is delivered to the PWM comparator. 9/21 XC9248 Series is Not Recommended for New Designs. XC9248 Series ■OPERATIONAL EXPLANATION (Continued) The current limiting circuit of the XC9248 series monitors the current that flows through the Low side and High side Nch MOS driver Tr, and when over-current is detected, the current limiting function activates. ① Low side driver current limiting The current in the Low side driver Tr. is detected to equivalently monitor the bottom value of the coil current. The Low side driver current limiting function prohibits the High side driver Tr. from turning on in an over-current state where the bottom value of the coil current is higher than the Low side driver current limit value ILIMLS. Control to lower the switching frequency fOSC is also performed. When the over-current state is released, normal operation resumes. ② High side driver current limiting + Low side driver current limiting The current in the High side driver Tr. is detected to equivalently monitor the peak value of the coil current. The High side driver current limiting function forcibly turns off the High side driver Tr. when the peak value of the coil current reaches the High side driver current limit value ILIMHS. ILIMLS < ILIMHS is set inside the IC, and therefore the Low side driver current limiting function of ① above also detects the over-current state at this time. When the over-current state is released, normal operation resumes. ③ Over-current latch (Type A) Type A turns off the High side and Low side driver transistors when state ① or ② continues for 1.1 ms (TYP.). The LX pin is in the CL discharged state, and is latch-stopped at the GND level (0V). The latch-stopped state only stops the pulse output from the Lx pin; the internal circuitry of the IC continues to operate. To restart after latch-stopping, L level and then H level must be input into the EN pin, or VIN pin re-input must be performed (after lowering the voltage below the UVLO detection voltage) to resume operation by soft start. The over-current latch function may occasionally be released from the current limit detection state by the effects of ambient noise, and it may also happen that the latch time becomes longer or latching does not take place due to board conditions. For this reason, place the input capacitor as close as possible to the IC. Type B is an automatic recovery type that performs the operation of ① or ② until the over-current state is released. Low side driver current limit value ILIMLS=2.1A (MIN.) High side driver current limit value ILIMHS=4.1A (TYP.) 1.1ms(TYP.) ① ② ③ （Type A） ILIMHS=4.1A(TYP.) ILX ILIMLS=2.1A(MIN.) 0A VLX VOUT 0V VEN 0V 10/21 XC9248 Series is Not Recommended for New Designs. XC9248 Series ■OPERATIONAL EXPLANATION (Continued) For protection against heat damage of the ICs, thermal shutdown function monitors chip temperature. The thermal shutdown circuit starts operating and the Nch MOS driver transistor will be turned off when the chip’s temperature reaches 150℃. The LX pin enters the CL discharged state and stops functioning at GND level (0V). When the temperature drops to 125℃ or less after shutting of the current flow, the IC performs the soft-start function to initiate output startup operation. When the VIN voltage becomes 3.8V (TYP.) or lower, the Nch MOS driver transistor is forced OFF. The LX pin enters the CL discharged state and stops functioning at GND level (0V). When the VIN voltage becomes 3.9V (TYP.) or higher, switching operation takes place. By releasing the UVLO function, the IC performs the soft-start function to initiate output startup operation. The soft-start function operates even when the VIN voltage falls momentarily below the UVLO detect voltage. The UVLO circuit does not cause a complete shutdown of the IC, but causes pulse output to be suspended; therefore, the internal circuitry remains in operation. An Nch MOS driver Tr. is used for the High side driver, and a voltage higher than the VIN voltage is needed to turn the driver on. For that purpose, the bootstrap method is used to generate a voltage higher than the VIN voltage. The CBST capacitance is connected between BST and LX, and because the VLX voltage is lower than the 4.6V (TYP.) VL voltage that is the internal power supply, CBST is charged from VL. With the A type, when the output voltage VOUT is shorted to GND or is near a shorted state (the FB voltage is 1/2 or lower), and a current over the current limit flows to the High side or Low side driver Tr., a VOUT short circuit is detected and the High side and Low side driver Trs. are immediately turned off and latched. The LX pin enters the CL discharged state and stops functioning at GND level (0V). Once in the latched state, operation is resumed by either turning the IC off and restarting with the EN pin, or by re-input into the VIN pin (the voltage is lowered below the under-voltage lockout detection voltage once). If the event that the LX pin shorts to GND, LX short-circuit protection activates for protection from over-current due to rush current and to protect the IC. If the LX pin shorts to GND, High side current limiting will activate due to rush current when the High side driver Tr. turns on. The High side driver Tr. turn offs, and the Low side driver Tr. turns on at the same time. At this time, if Low side current limiting did not activate, an LX short-circuit is detected, and the Low side driver is turned off and latched at the same time as the High side driver Tr. Once in the latched state, operation is resumed by either turning the IC off and restarting with the EN pin, or by re-input into the VIN pin (the voltage is lowered below the under-voltage lockout detection voltage once). To minimize output voltage overshoot, VOUT over-voltage protection activates when VOUT overshoot occurs due to the output resistance changing from a heavy load to a light load or otherwise. When VOUT overshoot occurs and the FB voltage that senses VOUT rises to 0.9V (TYP.) or more, the High side driver Tr. is immediately turned off and the Low side driver Tr. is turned on to prevent VOUT overshoot. When the FB voltage falls to 0.8V (TYP.) or less due to hysteresis, the High side driver Tr. turns on at the next clock cycle. 11/21 XC9248 Series XC9248 Series is Not Recommended for New Designs. ■OPERATIONAL EXPLANATION (Continued) When L level is input into the EN pin and the IC enters the standby state, the charge on the output capacitor CL can be discharged at high speed with the Nch MOS switch Tr. incorporated between LX and GND. This enables the prevention of application malfunctioning due to CL charge remaining when the IC stops. The CL discharge time can be calculated from the equation below. Note that the equation varies depending on the set voltage VOUT(E). (1) Equation when the set voltage VOUT(E) is 1V to 4V. The CL discharge time is determined by CL and RDCHG. If the time constant of CL and RDCHG is τ (τ = CL×RDCHG), the output voltage discharge time can be calculated by using the following equation: V = VOUT(E) × e -t / τor t = τ ln ( VOUT(E) / V ) V : Output voltage after discharge VOUT(E) : Output voltage t : Discharge time τ : CL×RDCHG (2) Equation when the set voltage VOUT(E) is 4.1V to 12V. The CL discharge time is determined by constant current until VOUT(E) is 4 V. When 4V or less, it is determined by CL and RDCHG as in (1). If τ (τ = CL×RDCHG) is the time constant of CL and RDCHG and the CL discharge current is IDCHG, the discharge time of the output voltage can be calculated by using the following equation: t=τ ln ( 4 / V ) + CL × (VOUT(E) - 4) / IDCHG V : Output voltage after discharge VOUT(E) : Output voltage, t: Discharge time τ : CL×RDCHG IDCHG : CL : Discharge time 12/21 XC9248 Series is Not Recommended for New Designs. XC9248 Series ■NOTE ON USE 1. For temporary, transitional voltage drop or voltage rising phenomenon, the IC is liable to malfunction should the ratings be exceeded. 2. The DC/DC converter characteristics depend greatly on the externally connected components as well as on the characteristics of this IC, so refer to the specifications and typical standard circuit examples of each component when carefully considering which components to select. Be especially careful of the capacitor characteristics and use B characteristics (JIS standard) or X7R, X5R (EIA standard) ceramic capacitors. 3. Where wiring impedance is high, operations may become unstable due to noise and/or phase lag depending on output current. Please wire the input capacitor (CIN) and the output capacitor (CL) as close to the IC as possible. 4. This IC monitors Peak to Peak current in the coil by means of a Low side driver current limiting circuit and a High side driver current limiting circuit. The Peak to Peak current varies depending on the difference between the input voltage and the output voltage as well as the L value of the coil and thus, in some cases, current limiting may activate too frequently and cause operation to become unstable or the current may not reach the maximum output current. 5. With the A type, when a sharp load fluctuation occurs, the VOUT voltage drop is conveyed directly to the FB pin through CFB, and short-circuit protection may activate at a voltage higher than 1/2 the VOUT voltage. 6. The VL pin is the output of the internal regulator for operation of the DC/DC control block. For stable operation, always connect an external capacitor CVL to the VL pin. Do not use the VL pin for external power supply, as it has been optimized as a local power supply. 7. With this IC, operation may become unstable at the minimum operating voltage or less. 8. Make sure that the absolute maximum ratings of the external components and of this IC are not exceeded. 9. Torex places an importance on improving our products and their reliability. We request that users incorporate fail-safe designs and post-aging protection treatment when using Torex products in their systems. 13/21 XC9248 Series is Not Recommended for New Designs. XC9248 Series ■NOTE ON USE (Continued) 10. Instructions for pattern layouts (1) In order to stabilize VIN voltage level, we recommend that a by-pass capacitor (CIN) be connected as close as possible to the VIN and GND pins. (2) Please mount each external component as close to the IC as possible. (3) Wire external components as close to the IC as possible and use thick, short connecting traces to reduce the circuit impedance. (4) Make sure that the GND traces are as thick as possible, as variations in ground potential caused by high ground currents at the time of switching may result in instability of the IC. (5) Internal driver transistors bring on heat because of the output current (IOUT) and ON resistance of the Nch MOS driver transistors. 1st Layer PCB mounted 14/21 2nd Layer XC9248 XC9248 Series is Not Recommended for New Designs. Series ■TYPICAL PERFORMANCE CHARACTERISTICS (1) Efficiency vs. Output current XC9248(VIN=12V , VOUT=3.3V) XC9248(VIN=12V , VOUT=5V) L=6.8μF(CLF7045T6R8N) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) 100 100 90 90 80 80 Efficiency :EFFI[%] Efficiency :EFFI[%] L=6.8μF(CLF7045T6R8N) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) 70 60 50 40 30 20 10 60 50 40 30 20 10 0 0 1 10 100 1000 10000 1 10 100 1000 Output Current :IOUT[mA] Output Current :IOUT[mA] XC9248(VIN=9V , VOUT=4V) XC9248(VIN=5V , VOUT=1V) L=4.5μF(NR6045T4R5M) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) 100 100 90 90 80 80 70 60 50 40 30 20 10000 L=2.2μF(NR6028T2R2N) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) Efficiency :EFFI[%] Efficiency :EFFI[%] 70 10 70 60 50 40 30 20 10 0 0 1 10 100 1000 10000 1 Output Current :IOUT[mA] 10 100 1000 10000 Output Current :IOUT[mA] (2) Output Voltage vs. Output Currnt XC9248(VIN=12V , VOUT=3.3V) XC9248(VIN=12V , VOUT=5V) L=6.8μF(CLF7045T6R8N) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) 3.40 5.10 3.38 5.08 Output Voltage : VOUT[V] Output Voltage : VOUT[V] L=6.8μF(CLF7045T6R8N) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) 3.36 3.34 3.32 3.30 3.28 3.26 3.24 3.22 5.04 5.02 5.00 4.98 4.96 4.94 4.92 4.90 3.20 1 10 100 1000 1 10000 10 100 1000 Output Current :IOUT[mA] Output Current :IOUT[mA] XC9248(VIN=9V , VOUT=4V) XC9248(VIN=5V , VOUT=1V) L=4.5μF(NR6045T4R5M) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) 4.10 1.10 4.08 1.08 4.06 4.04 4.02 4.00 3.98 3.96 3.94 3.92 3.90 10000 L=2.2μF(NR6028T2R2N) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) Output Voltage : VOUT[V] Output Voltage : VOUT[V] 5.06 1.06 1.04 1.02 1.00 0.98 0.96 0.94 0.92 0.90 1 10 100 1000 Output Current :IOUT[mA] 10000 1 10 100 1000 10000 Output Current :IOUT[mA] 15/21 XC9248 Series is Not Recommended for New Designs. XC9248 Series ■TYPICAL PERFORMANCE CHARACTERISTICS (Continued) (3) Ripple Voltage vs. Output Current XC9248(VIN=12V , VOUT=3.3V) XC9248(VIN=12V , VOUT=5V) L=6.8μF(CLF7045T6R8N) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) L=6.8μF(CLF7045T6R8N) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) 10 Ripple Voltage :Vr[mV] Ripple Voltage :Vr[mV] 10 8 6 4 2 0 6 4 2 0 1 10 100 1000 10000 1 10 100 10000 Output Current :IOUT[mA] XC9248(VIN=9V , VOUT=4V) XC9248(VIN=5V , VOUT=1V) L=2.2μF(NR6028T2R2N) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) 10 Ripple Voltage :Vr[mV] 10 8 6 4 2 0 8 6 4 2 0 1 10 100 1000 10000 1 10 Output Current :IOUT[mA] 100 1000 10000 Output Current :IOUT[mA] (4) FB Voltage vs. Ambient Temperature (5) UVLO Voltage vs. Ambient Temperature XC9248 XC9248 4.5 0.812 0.810 0.808 0.806 0.804 0.802 0.800 0.798 0.796 0.794 0.792 0.790 0.788 VIN=4.5V VIN=12V VIN=18V -50 -25 0 25 50 75 100 125 UVLO Voltage :VUVLOD,VUVLOR[V] FB Voltage :VFB[V] 1000 Output Current :IOUT[mA] L=4.5μF(NR6045T4R5M) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) Ripple Voltage :Vr[mV] 8 4.4 4.3 4.2 4.1 4.0 3.9 3.8 Detection 3.7 Release 3.6 3.5 Ambient Temperature :Ta[℃] -50 -25 0 25 50 75 100 125 Ambient Temperature :Ta[℃] (6) Oscillation Frequency vs. Ambient Temperature (7) Supply Current vs. Ambient Temperature XC9248 550 0.80 540 0.75 530 520 510 500 490 VIN=4.5V 480 VIN=12V 470 VIN=18V 0.70 0.65 0.60 VIN=4.5V 0.55 VIN=12V 0.50 VIN=18V 0.45 460 0.40 450 -50 16/21 Supply Current :Iq[mA] Oscillation Frequency :fosc[kHz] XC9248 -25 0 25 50 75 100 Ambient Temperature :Ta[℃] 125 -50 -25 0 25 50 75 100 Ambient Temperature :Ta[℃] 125 XC9248 XC9248 Series is Not Recommended for New Designs. Series ■TYPICAL PERFORMANCE CHARACTERISTICS (Continued) (8) Stand-by Current vs. Ambient Temperature (9) Lx SW"L" ON Resistance vs. Ambient Temperature XC9248 XC9248 0.20 45 0.18 Lx SW"L" ON Resistance :RLXL[Ω] Stand-by Current :ISTB[μA] 40 35 30 25 20 VIN=4.5V 15 VIN=12V 10 VIN=18V 5 0.16 0.14 0.12 0.10 VIN=4.5V VIN=12V 0.08 VIN=18V 0.06 0 -50 -25 0 25 50 75 100 -50 125 Ambient Temperature :Ta[℃] -25 0 25 50 75 (10) Lx "L" Current vs. Ambient Temperature XC9248 XC9248 30 VIN=4.5V EN "H" Current :IENH[μA] Lx "L" Current :ILXL[μA] 0.8 0.6 0.4 0.2 0.0 -0.2 -0.4 VIN=4.5V -0.6 VIN=12V VIN=18V -0.8 VIN=12V 25 VIN=18V 20 15 10 5 0 -1.0 -50 -25 0 25 50 75 100 -50 125 -25 0 25 50 75 100 125 Ambient Temperature :Ta[℃] Ambient Temperature :Ta[℃] (12) EN "H" Voltage vs. Ambient Temperature (13) EN "L" Voltage vs. Ambient Temperature XC9248 XC9248 1.4 1.4 1.2 EN "L" Voltage :VENL[V] EN "H" Voltage :VENH[V] 125 (11) EN "H" Current vs. Ambient Temperature 1.0 1.0 0.8 0.6 VIN=4.5V 0.4 VIN=12V 0.2 VIN=18V 0.0 1.2 1.0 0.8 0.6 VIN=4.5V 0.4 VIN=12V VIN=18V 0.2 0.0 -50 -25 0 25 50 75 100 125 -50 Ambient Temperature :Ta[℃] -25 0 25 50 75 100 125 Ambient Temperature :Ta[℃] (14) Internal Soft-Start Time vs. Ambient Temperature (15) SS Terminal Current vs. Ambient Temperature XC9248 XC9248 4.0 6.0 SS Terminal Current :ISS[μA] Internal Soft-Start Time :tSS[ms] 100 Ambient Temperature :Ta[℃] 3.5 3.0 2.5 2.0 VIN=4.5V VIN=12V 1.5 VIN=18V 1.0 5.5 5.0 4.5 4.0 3.5 VIN=4.5V 3.0 VIN=12V 2.5 VIN=18V 2.0 -50 -25 0 25 50 75 100 Ambient Temperature :Ta[℃] 125 -50 -25 0 25 50 75 100 125 Ambient Temperature :Ta[℃] 17/21 XC9248 Series is Not Recommended for New Designs. XC9248 Series ■TYPICAL PERFORMANCE CHARACTERISTICS (Continued) (16) SS Threshold Voltage vs. Ambient Temperature SS Threshold Voltage :VSSTH[V] XC9248 2.4 2.2 2.0 1.8 1.6 VIN=4.5V VIN=12V 1.4 VIN=18V 1.2 -50 -25 0 25 50 75 100 125 Ambient Temperature :Ta[℃] (17) Load Transient Response XC9248 XC9248 VIN=12V, VOUT=3.3V, IOUT=No Load→1000mA VIN=12V, VOUT=3.3V, IOUT=1000mA→No Load L=6.8μF(CLF7045T6R8N) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) L=6.8μF(CLF7045T6R8N) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) 50μs/div 50μs/div VOUT: 500mV/div VOUT: 500mV/div IOUT=No Load→1000mA IOUT=1000mA→No Load XC9248 XC9248 VIN=9V, VOUT=4V, IOUT=No Load→1000mA VIN=9V, VOUT=4V, IOUT=1000mA→No Load L=4.5μF(NR6045T4R5M) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) L=4.5μF(NR6045T4R5M) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) 50μs/div 50μs/div VOUT: 500mV/div VOUT: 500mV/div IOUT=No Load→1000mA IOUT=1000mA→No Load XC9248 XC9248 VIN=5V, VOUT=1V, IOUT=No Load→1000mA VIN=5V, VOUT=1V, IOUT=1000mA→No Load L=2.2μF(NR6028T2R2N) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) L=2.2μF(NR6028T2R2N) CIN=10μF×2(C2012X5R1E106K), CL=22μF×2(C2012X5R1A226K) 50μs/div 18/21 50μs/div VOUT: 500mV/div VOUT: 500mV/div IOUT=No Load→1000mA IOUT=1000mA→No Load XC9248 XC9248 Series is Not Recommended for New Designs. Series ■PACKAGING INFORMATION For the latest package information go to, www.torexsemi.com/technical-support/packages PACKAGE OUTLINE / LAND PATTERN SOP-8FD SOP-8FD PKG THERMAL CHARACTERISTICS Standard Board JESD51-7 Board SOP-8FD Power Dissipation 19/21 XC9248 Series is Not Recommended for New Designs. XC9248 Series ■MARKING RULE SOP-8FD 8 7 6 5 ① ② ③ ① represents products series MARK PRODUCT SERIES B XC9248******-G ④ ⑤ ② represents products type 1 2 3 4 MARK PRODUCT SERIES A B XC9248A*****-G XC9248B*****-G ③ represents FB voltage and oscillation frequency MARK VOLTAGE (V) OSCILLATION FREQUENCY PRODUCT SERIES 5 0.8 500kHz XC9248*085**-G ④⑤ represents production lot number 01～09、0A～0Z、11～9Z、A1～A9、AA～AZ、B1～ZZ in order. (G, I, J, O, Q, W excluded) * No character inversion used. 20/21 XC9248 Series is Not Recommended for New Designs. XC9248 1. The product and product specifications contained herein are subject to change without notice to improve performance characteristics. Consult us, or our representatives before use, to confirm that the information in this datasheet is up to date. 2. The information in this datasheet is intended to illustrate the operation and characteristics of our products. We neither make warranties or representations with respect to the accuracy or completeness of the information contained in this datasheet nor grant any license to any intellectual property rights of ours or any third party concerning with the information in this datasheet. 3. Applicable export control laws and regulations should be complied and the procedures required by such laws and regulations should also be followed, when the product or any information contained in this datasheet is exported. 4. The product is neither intended nor warranted for use in equipment of systems which require extremely high levels of quality and/or reliability and/or a malfunction or failure which may cause loss of human life, bodily injury, serious property damage including but not limited to devices or equipment used in 1) nuclear facilities, 2) aerospace industry, 3) medical facilities, 4) automobile industry and other transportation industry and 5) safety devices and safety equipment to control combustions and explosions. Do not use the product for the above use unless agreed by us in writing in advance. 5. Although we make continuous efforts to improve the quality and reliability of our products; nevertheless Semiconductors are likely to fail with a certain probability. So in order to prevent personal injury and/or property damage resulting from such failure, customers are required to incorporate adequate safety measures in their designs, such as system fail safes, redundancy and fire prevention features. 6. Our products are not designed to be Radiation-resistant. 7. Please use the product listed in this datasheet within the specified ranges. 8. We assume no responsibility for damage or loss due to abnormal use. 9. All rights reserved. No part of this datasheet may be copied or reproduced unless agreed by Torex Semiconductor Ltd in writing in advance. Series TOREX SEMICONDUCTOR LTD. 21/21