R1215D002F

R1215D SERIES STEP-UP DC/DC CONTOLLER NO.EA-134-0604 OUTLINE The R1215D Series are CMOS-based PWM step-up DC/DC converter controllers with low supply current. Each of the R1215D Series consists of an oscillator, a PWM comparator circuit, a reference voltage unit, an error amplifier, a reference current unit, a protection circuit, and an under voltage lockout (UVLO) circuit. A low ripple, high efficiency step-up DC/DC converter can be composed of this IC with some external components, or an inductor, a diode, a power MOSFET, resisters, and capacitors. Maximum duty cycle and the soft start time are easily adjustable with external resistors and capacitors. As for the protection circuit, after the soft-starting time, if the maximum duty cycle is continued for a certain period, the R1215D Series latch the external driver with its off state, or the latch-type protection circuit works. The delay time for latch the state can be set with an external capacitor. To release the protection circuit, restart with power-on (Voltage supplier is equal or less than UVLO detector threshold level). FEATURES • • • • • • • • Input Voltage Range ....................................................... 1.8V to 5.5V Two Options of Basic Oscillator Frequency .................... Typ.700kHz, 1.4MHz Built-in Latch-type Protection Function (Output Delay Time can be set with an external capacitor) Maximum Duty Cycle/Soft-start time ............................. Adjustable with external capacitors High Reference Voltage Accuracy .................................. ±1.5% UVLO Threshold level..................................................... Typ.1.6V/1.79V by mask option Small Temperature Coefficient of Reference Voltage ... Typ.±150ppm/°C Package .......................................................................... SON-8 ( t = Max. 0.9mm ) APPLICATIONS • Constant Voltage Power Source for portable equipment. • Constant Voltage Power Source for LCD and CCD. 1 R1215D BLOCK DIAGRAM Internal VR VIN VREFOUT UVLO VREFOUT Oscillator DTC PWM Comp Latch EXT VREF VFB Er.Amp AMPOUT GND DELAY SELECTION GUIDE In the R1215D Series, the oscillator frequency and UVLO detector threshold can be selected at the user's request. The selection can be made with designating the part number as shown below; R1215D002x-TR-x ←Part Number ↑ a Code ↑ b Contents Desiguation of Oscillator Frequency and Detector Threshold A: Oscillator Frequency Typ. 700kHz, UVLO Detector Threshold Typ. 1.79V B: Oscillator Frequency Typ. 1.4MHz, UVLO Detector Threshold Typ. 1.79V E: Oscillator Frequency Typ. 700kHz, UVLO Detector Threshold Typ. 1.60V F: Oscillator Frequency Typ. 1.4MHz, UVLO Detector Threshold Typ. 1.60V Desiguation of composition of pin plating -F: Lead free plating a b 2 R1215D PIN CONFIGURATION SON-8 Top View 8 7 65 Bottom View 5 6 7 8 ∗ ∗ ∗ 1 2 34 4 3 2 1 PIN DESCRIPTION Pin No 1 2 3 4 5 6 7 8 Symbol EXT GND DTC DELAY VFB VREFOUT AMPOUT VIN Description External FET Drive Pin (CMOS Output) Ground Pin Pin for Setting Maximum Duty Cycle and Soft start time Pin for External Capacitor (for Setting Output Delay of Protection) Feedback Pin for monitoring Output Voltage Reference Voltage Output Pin Amplifier Output Pin Power Supply Pin for the IC ∗ Tab in the parts have GND level. (They are connected to the reverse side of this IC.) Do not connect to other wires or land patterns. ABSOLUTE MAXIMUM RATINGS (GND=0V) Symbol VIN VEXT VDLY VREFOUT VAMP VDTC VFB IAMP IROUT IEXT PD Topt Tstg Item VIN Pin Voltage EXT Pin Output Voltage DELAY Pin Voltage VREFOUT Pin Voltage AMPOUT Pin Voltage DTC Pin Voltage VFB Pin Voltage AMPOUT Pin Current VREFOUT Pin Current EXT Pin Inductor Drive Output Current Power Dissipation Operating Temperature Range Storage Temperature Range Rating 6.5 −0.3 to VIN+0.3 −0.3 to VIN+0.3 −0.3 to VIN+0.3 −0.3 to VIN+0.3 −0.3 to VIN+0.3 −0.3 to VIN+0.3 ±10 30 ±80 480 −40 to +85 −55 to +125 Unit V V V V V V V mA mA mA mW °C °C ∗1 For Power Dissipation, please refer to PACKAGE INFORMATION to be described. 3 R1215D ELECTRICAL CHARACTERISTICS • R1215D002A Symbol VIN VFB ∆VFB/∆VIN ∆VFB/∆Topt IFB AV fT fosc ∆fosc/∆VIN ∆fosc/∆Topt IDD1 VREFOUT IOUT ∆VREFOUT/ ∆VIN ∆VREFOUT/ ∆IROUT ILIM ∆VREFOUT/ ∆Topt REXTH REXTL tr tf IDLY1 IDLY2 VDLY VUVLO1 VUVLO2 VHYS VDTC0 VDTC20 VDTC80 VDTC100 IAMPH IAMPL Item Operating Input Voltage VFB Voltage Tolerance VFB Voltage Line Regulation VFB Voltage Temperature Coefficient VFB Input Current Open Loop Voltage Gain Unity Gain Frequency Band Oscillator Frequency Oscillator Frequency Line Regulation Oscillator Frequency Temperature Coefficient Supply Current 1 VREFOUT Voltage VREFOUT Maximum Output Current VREFOUT Line Regulation VREFOUT Load Regulation VREFOUT Short Current Limit VREFOUT Voltage Temperature Coefficient EXT "H" ON Resistance EXT "L" ON Resistance EXT Rising Time EXT Falling Time DELAY Pin Charge Current DELAY Pin Discharge Current UVLO Detector Threshold UVLO Released Voltage UVLO Hysteresis Range Duty=0% DTC Pin Voltage Duty=20% DTC Pin Voltage Duty=80% DTC Pin Voltage Duty=100% DTC Pin Voltage AMP "H" Output Current AMP "L" Output Current VIN=2.5V VIN=2.5V VIN=2.5V VIN=2.5V VIN=2.5V, VAMP=1.0V, VFB=0.9V VIN=2.5V, VAMP=1.0V, VFB=1.1V 0.92 1.6 40 VIN=2.5V VIN: from 2.0V to 5.5V −40°C < = < = Topt=25°C Conditions Min. 2.0 Typ. Max. 5.5 Unit V V mV ppm/ °C 0.985 1.000 1.015 3 ±150 Topt 85 ° C −0.1 VIN=5.5V, VFB=0V or 5.5V VIN=2.5V VIN=2.5V, AV=0 VIN=2.5V, VDLY=VFB=0V VIN: from 2.0V to 5.5V −40°C < = 0 100 1.0 0.1 µA dB MHz 805 kHz kHz kHz/ °C 1000 µA 595 700 50 ±0.3 Topt < = 85°C VIN=5.5V, VDLY=VFB=0V VIN=2.5V,IROUT=1mA VIN=2.5V VIN: from 2.0V to 5.5V VIN=2.5V, IROUT: from 0.1mA to 5.0mA VIN=2.5V, VREFOUT=0V −40°C < = 600 1.280 1.300 1.320 10 5 6 15 ±150 V mA 10 20 mV mV mA ppm/ °C Topt < = 85°C VIN=2.5V, IEXT=−50mA VIN=2.5V, IEXT=50mA VIN=2.5V, CEXT=1000pF VIN=2.5V, CEXT=1000pF VIN=2.5V, VDLY=VFB=0V VIN=VFB=2.0V, VDLY=0.1V VIN=2.5V to 0V, VDLY=VFB=0V VIN=0V to 2.5V, VDLY=VFB=0V 3.0 0.08 0.95 1.70 1.78 0.04 0.28 2.8 1.8 12 8 6.0 0.20 1.00 1.79 1.88 0.09 0.38 0.48 0.92 1.02 3.2 85 6.0 4.0 Ω Ω ns ns 8.5 0.36 1.05 1.88 1.98 0.14 0.48 µA mA V V V V V V V DELAY Pin Detector Threshold VIN=2.5V, VFB=0V, VDLY=0V to 2V 1.12 5.8 130 V mA µA 4 R1215D • R1215D002B Symbol VIN VFB ∆VFB/∆VIN ∆VFB/∆Topt IFB AV fT fosc ∆fosc/∆VIN Item Operating Input Voltage VFB Voltage Tolerance VFB Voltage Line Regulation VFB Voltage Temperature Coefficient VFB Input Current Open Loop Voltage Gain Unity Gain Frequency Band Oscillator Frequency Oscillator Frequency Line Regulation Oscillator Frequency Temperature Coefficient Supply Current 1 VREFOUT Voltage VREFOUT Maximum Output Current VREFOUT Line Regulation VREFOUT Load Regulation VREFOUT Short Current Limit VREFOUT Voltage Temperature Coefficient EXT "H" ON Resistance EXT "L" ON Resistance EXT Rising Time EXT Falling Time DELAY Pin Charge Current DELAY Pin Discharge Current UVLO Detector Threshold UVLO Released Voltage UVLO Hysteresis Range Duty=0% DTC Pin Voltage Duty=20% DTC Pin Voltage Duty=80% DTC Pin Voltage Duty=100% DTC Pin Voltage AMP "H" Output Current AMP "L" Output Current VIN=2.5V VIN=2.5V VIN=2.5V VIN=2.5V VIN=2.5V, VAMP=1.0V, VFB=0.9V VIN=2.5V, VAMP=1.0V, VFB=1.1V 0.92 1.6 40 VIN=2.5V VIN: from 2.0V to 5.5V −40°C < = < = Topt=25°C Conditions Min. 2.0 Typ. Max. 5.5 Unit V V mV ppm/ °C 0.985 1.000 1.015 3 ±150 Topt 85 ° C −0.1 VIN=5.5V, VFB=0V or 5.5V VIN=2.5V VIN=2.5V, AV=0 VIN=2.5V, VDLY=VFB=0V VIN: from 2.0V to 5.5V −40°C < = 0 100 1.0 0.1 µA dB MHz 1.190 1.400 1.610 MHz 100 ±0.6 kHz kHz/ °C 1800 µA ∆fosc/∆Topt IDD1 VREFOUT IOUT ∆VREFOUT/ ∆VIN ∆VREFOUT/ ∆IROUT ILIM ∆VREFOUT/ ∆Topt REXTH REXTL tr tf IDLY1 IDLY2 VDLY VUVLO1 VUVLO2 VHYS VDTC0 VDTC20 VDTC80 VDTC100 IAMPH IAMPL Topt < = 85°C VIN=5.5V, VDLY=VFB=0V VIN=2.5V,IROUT=1mA VIN=2.5V VIN: from 2.0V to 5.5V VIN=2.5V, IROUT: from 0.1mA to 5.0mA VIN=2.5V, VREFOUT=0V −40°C < = 900 1.280 1.300 1.320 10 5 6 15 ±150 V mA 10 20 mV mV mA ppm/ °C Topt < = 85°C VIN=2.5V, IEXT=−50mA VIN=2.5V, IEXT=50mA VIN=2.5V, CEXT=1000pF VIN=2.5V, CEXT=1000pF VIN=2.5V, VDLY=VFB=0V VIN=VFB=2.0V, VDLY=0.1V VIN=2.5V to 0V, VDLY=VFB=0V VIN=0V to 2.5V, VDLY=VFB=0V 3.0 0.08 0.95 1.70 1.78 0.04 0.28 2.8 1.8 12 8 6.0 0.20 1.00 1.79 1.88 0.09 0.38 0.47 0.93 1.02 3.2 85 6.0 4.0 Ω Ω ns ns 8.5 0.36 1.05 1.88 1.98 0.14 0.48 µA mA V V V V V V V DELAY Pin Detector Threshold VIN=2.5V, VFB=0V, VDLY=0V to 2V 1.12 5.8 130 V mA µA 5 R1215D • R1215D002E Symbol VIN VFB ∆VFB/∆VIN ∆VFB/∆Topt IFB AV fT fosc ∆fosc/∆VIN Item Operating Input Voltage VFB Voltage Tolerance VFB Voltage Line Regulation VFB Voltage Temperature Coefficient VFB Input Current Open Loop Voltage Gain Unity Gain Frequency Band Oscillator Frequency Oscillator Frequency Line Regulation Oscillator Frequency Temperature Coefficient Supply Current 1 VREFOUT Voltage VREFOUT Maximum Output Current VREFOUT Line Regulation VREFOUT Load Regulation VREFOUT Short Current Limit VREFOUT Voltage Temperature Coefficient EXT "H" ON Resistance EXT "L" ON Resistance EXT Rising Time EXT Falling Time DELAY Pin Charge Current DELAY Pin Discharge Current UVLO Detector Threshold UVLO Released Voltage UVLO Hysteresis Range Duty=0% DTC Pin Voltage Duty=20% DTC Pin Voltage Duty=80% DTC Pin Voltage Duty=100% DTC Pin Voltage AMP "H" Output Current AMP "L" Output Current VIN=2.5V VIN=2.5V VIN=2.5V VIN=2.5V VIN=2.5V, VAMP=1.0V, VFB=0.9V VIN=2.5V, VAMP=1.0V, VFB=1.1V 0.92 1.6 40 VIN=2.5V VIN: from 1.8 V to 5.5V −40°C < = < = Topt=25°C Conditions Min. 1.8 Typ. Max. 5.5 Unit V V mV ppm/ °C 0.985 1.000 1.015 3 ±150 Topt 85 ° C −0.1 VIN=5.5V, VFB=0V or 5.5V VIN=2.5V VIN=2.5V, AV=0 VIN=2.5V, VDLY=VFB=0V VIN: from 1.8V to 5.5V −40°C < = 0 100 1.0 0.1 µA dB MHz 805 kHz kHz kHz/ °C 1000 µA 595 700 50 ±0.3 ∆fosc/∆Topt IDD1 VREFOUT IOUT ∆VREFOUT/ ∆VIN ∆VREFOUT/ ∆IROUT ILIM ∆VREFOUT/ ∆Topt REXTH REXTL tr tf IDLY1 IDLY2 VDLY VUVLO1 VUVLO2 VHYS VDTC0 VDTC20 VDTC80 VDTC100 IAMPH IAMPL Topt < = 85°C VIN=5.5V, VDLY=VFB=0V VIN=2.5V,IROUT=1mA VIN=2.5V VIN: from 1.8V to 5.5V VIN=2.5V, IROUT: from 0.1mA to 5.0mA VIN=2.5V, VREFOUT=0V −40°C < = 600 1.280 1.300 1.320 10 5 6 15 ±150 V mA 10 20 mV mV mA ppm/ °C Topt < = 85°C VIN=2.5V, IEXT=−50mA VIN=2.5V, IEXT=50mA VIN=2.5V, CEXT=1000pF VIN=2.5V, CEXT=1000pF VIN=2.5V, VDLY=VFB=0V VIN=VFB=1.8V, VDLY=0.1V VIN=2.5V to 0V, VDLY=VFB=0V VIN=0V to 2.5V, VDLY=VFB=0V 3.0 0.08 0.95 1.50 1.56 0.03 0.28 2.8 1.8 12 8 6.0 0.18 1.00 1.60 1.67 0.07 0.38 0.48 0.92 1.02 3.2 85 6.0 4.0 Ω Ω ns ns 8.5 0.36 1.05 1.70 1.78 0.11 0.48 µA mA V V V V V V V DELAY Pin Detector Threshold VIN=2.5V, VFB=0V, VDLY=0V to 2V 1.12 5.8 130 V mA µA 6 R1215D • R1215D002F Symbol VIN VFB ∆VFB/∆VIN ∆VFB/∆Topt IFB AV fT fosc ∆fosc/∆VIN Item Operating Input Voltage VFB Voltage Tolerance VFB Voltage Line Regulation VFB Voltage Temperature Coefficient VFB Input Current Open Loop Voltage Gain Unity Gain Frequency Band Oscillator Frequency Oscillator Frequency Line Regulation Oscillator Frequency Temperature Coefficient Supply Current 1 VREFOUT Voltage VREFOUT Maximum Output Current VREFOUT Line Regulation VREFOUT Load Regulation VREFOUT Short Current Limit VREFOUT Voltage Temperature Coefficient EXT "H" ON Resistance EXT "L" ON Resistance EXT Rising Time EXT Falling Time DELAY Pin Charge Current DELAY Pin Discharge Current UVLO Detector Threshold UVLO Released Voltage UVLO Hysteresis Range Duty=0% DTC Pin Voltage Duty=20% DTC Pin Voltage Duty=80% DTC Pin Voltage Duty=100% DTC Pin Voltage AMP "H" Output Current AMP "L" Output Current VIN=2.5V VIN=2.5V VIN=2.5V VIN=2.5V VIN=2.5V, VAMP=1.0V, VFB=0.9V VIN=2.5V, VAMP=1.0V, VFB=1.1V 0.92 1.6 40 VIN=2.5V VIN: from 1.8V to 5.5V −40°C < = < = Topt=25°C Conditions Min. 1.8 Typ. Max. 5.5 Unit V V mV ppm/ °C 0.985 1.000 1.015 3 ±150 Topt 85 ° C −0.1 VIN=5.5V, VFB=0V or 5.5V VIN=2.5V VIN=2.5V, AV=0 VIN=2.5V, VDLY=VFB=0V VIN: from 1.8V to 5.5V −40°C < = 0 100 1.0 0.1 µA dB MHz 1.190 1.400 1.610 MHz 100 ±0.6 KHz KHz/ °C 1800 µA ∆fosc/∆Topt IDD1 VREFOUT IOUT ∆VREFOUT/ ∆VIN ∆VREFOUT/ ∆IROUT ILIM ∆VREFOUT/ ∆Topt REXTH REXTL tr tf IDLY1 IDLY2 VDLY VUVLO1 VUVLO2 VHYS VDTC0 VDTC20 VDTC80 VDTC100 IAMPH IAMPL Topt < = 85°C VIN=5.5V, VDLY=VFB=0V VIN=2.5V,IROUT=1mA VIN=2.5V VIN: from 1.8V to 5.5V VIN=2.5V, IROUT: from 0.1mA to 5.0mA VIN=2.5V, VREFOUT=0V −40°C < = 900 1.280 1.300 1.320 10 5 6 15 ±150 V mA 10 20 mV mV mA ppm/ °C Topt < = 85°C VIN=2.5V, IEXT=−50mA VIN=2.5V, IEXT=50mA VIN=2.5V, CEXT=1000pF VIN=2.5V, CEXT=1000pF VIN=2.5V, VDLY=VFB=0V VIN=VFB=1.8V, VDLY=0.1V VIN=2.5V to 0V, VDLY=VFB=0V VIN=0V to 2.5V, VDLY=VFB=0V 3.0 0.08 0.95 1.50 1.56 0.03 0.28 2.8 1.8 12 8 6.0 0.18 1.00 1.60 1.67 0.07 0.38 0.47 0.93 1.02 3.2 85 6.0 4.0 Ω Ω ns ns 8.5 0.36 1.05 1.70 1.78 0.11 0.48 µA mA V V V V V V V DELAY Pin Detector Threshold VIN=2.5V, VFB=0V, VDLY=0V to 2V 1.12 5.8 130 V mA µA 7 R1215D TYPICAL APPLICATIONS AND TECHNICAL NOTES Inductor Diode R3 VIN C1 C2 GND AMPOUT C6 VREFOUT R5 DTC R6 C7 C5 R4 DELAY EXT VFB R2 NMOS C4 VOUT R1 C3 Inductor NMOS Diode C1 C2 C3 C4 C5 C6 C7 LDR655312T-100 (TDK) CPH6415 (Sanyo) CRS02 (Toshiba) 1.0µF 1.0µF 15µF 1000pF 2200pF 1.0µF 1.0µF R1 R2 R3 R4 R5 R6 160kΩ 20k Ω 1k Ω 4.7k Ω 68k Ω 240k Ω Use a 1µF or more capacitance value of bypass capacitor between VIN pin and GND, C1 as shown in the typical application above. Connect the capacitor as short as possible to the IC. • In terms of the capacitor for setting delay time of the latch protection, C2 is shown in typical application above. Latch delay time depends on this C2 value. Refer to the Latch Protection Operation Timing Chart. Set the C2 GND as close as possible to the IC GND. • Connect a 1µF or more value of capacitor between VOUT and GND, C3 as shown in typical application above. (10µF to 22µF is the capacitance recommendation range.) If the operation of the composed DC/DC converter may be unstable, use a tantalum type capacitor instead of ceramic type • Connect a capacitor between VREFOUT and GND, C6 as shown in typical application of the previous page. The capacitance value of C6 is between 0.1µF and 1.0µF. 8 R1215D • Output Voltage Setting Method and Phase Compensation Making Method • The feedback voltage is controlled into 1.0V. The output voltage can be set with divider resistors for voltage setting, R1 and R2 as shown in typical application of the previous page. Refer to the next formula. Output Voltage = VFB× (R1+R2)/R2 Output Voltage is adjustable with setting various resistor values combination. R1+R2 should be equal or less than 500kΩ As for the DC/DC converter, depending on the load current and external components such as L and C, phase may loss around 180°. In such case, phase margin becomes less and may be unstable. To avoid this situation, make the phase margin more. The pole is made with external components L and C. Fpole∼1/{2×π× (L × C3 ) } C4, C5, R3, and R4 shown in the diagram are for making phase compensation. The gain of the system can be set with using these resistors and capacitors. Each value in the diagram is just an example. R4 and C5 make zero (the backward phase). Fzero∼1/(2×π×R4×C5) Choose the R4 and C5 value so as to make the cutoff frequency of this zero point close to the cutoff frequency of the pole by external components, L and C. For example, supposed that L=10µH and COUT (C3) =15µF, the cutoff frequency of the pole is approximately 13kHz. Therefore make the cutoff frequency of the zero point close to 13kHz. Then R4=4.7kΩ and C5=2200pF are appropriate values. As for setting the gain, the ratio of the composite resistor (RT: RT=R1×R2/(R1+R2)) to R4 is the key. If the R4 against the composite resistor, RT, is large, the gain becomes also large. If the gain is large, the response characteristic is improved, however, too large gain makes the system be unstable. If the spike noise of VOUT may be large, the spike noise may be picked into VFB pin, and the unstable operation may result. In this case, a resistor R3, shown in typical application of the previous page. The recommended resistance value of R3 is in the range from 1kΩ to 5kΩ. Then, noise level will be decreased. Further, R1 and C4 makes another zero point (the backward phase). Fzero∼1/(2×π×R1×C4) Make the cutoff frequency of this zero point be lower than the cutoff frequency of the pole by external components, or, L and C. Herein, R1=160kΩ and C4=1000pF are appropriate values. • Select the Power MOSFET, the diode, capacitors and the inductor within ratings (Voltage, Current, Power) of this IC. Choose the power MOSFET with low threshold voltage depending on the input voltage to be able to turn on the FET completely. Choose the diode with low VF such as Shottky type with low reverse current IR, and with fast switching speed. When an external transistor is switching, spike voltage may be generated caused by an inductor, therefore recommended voltage tolerance of capacitor connected to VOUT is twice as much as the setting voltage or more. • The soft-start time and the maximum duty cycle setting method The soft-start time and the maximum duty cycle can be set with R5, R6, and C7 values connected to the VREFOUT pin and the DTC pin. (Refer to the timing chart: Soft-start operation.) 9 R1215D Output Current and Selection of External Components i2 Inductor VIN i1 Lx Tr CL Diode VOUT IOUT GND Discontinuous Mode IL ILxmax IL Continuous Mode ILxmax ILxmin ILxmin tf t ton t=1/fosc 1/ton toff Iconst t toff ton t=1/fosc 1/ton There are two modes, or discontinuous mode and continuous mode for the PWM step-up switching regulator depending on the continuous characteristic of inductor current. During on time of the transistor, when the voltage added on to the inductor is described as VIN, the current is VIN × t/L. Therefore, the electric power, PON, which is supplied with input side, can be described as in next formula. PON = ∫ ton 0 VIN 2 × t / L dt ...................................................................................................Formula 1 With the step-up circuit, electric power is supplied from power source also during off time. In this case, input current is described as (VOUT − VIN) ×t/L, therefore electric power, POFF is described as in next formula. POFF = ∫ tf 0 VIN × ( VOUT − VIN) × t / L dt .............................................................................Formula 2 In this formula, Tf means the time of which the energy saved in the inductance is being emitted. Thus average electric power, or PAV is described as in the next formula. PAV = 1 /( tON + tOFF ) × { ∫ ton 0 VIN2 × t / L dt + ∫ tf 0 VIN × ( VOUT − VIN) × t / L dt } ............................Formula 3 In PWM control, when tf = toff is true, the inductor current becomes continuos, then the operation of switching regulator becomes continuous mode. 10 R1215D In the continuous mode, the deviation of the current is equal between on time and off time. VIN = tON / L = ( VOUT − VIN) × toff / L ................................................................................ Formula 4 Further, the electric power, PAV is equal to output electric power, VOUT × IOUT, thus, IOUT = fOSC × VIN 2 × tON 2 /{2 × L × ( VOUT − VIN)} = VIN 2 × tON /( 2 × L × VOUT ) ....................... Formula 5 When IOUT becomes more than formula 5, the current flows through the inductor, then the mode becomes continuous. The continuous current through the inductor is described as Iconst, then, IOUT = fOSC × VIN 2 × tON 2 /{2 × L × ( VOUT − VIN)} + VIN × Iconst / VOUT ................................. Formula 6 In this moment, the peak current, ILxmax flowing through the inductor and the driver Tr. is described as follows: ILx max = Iconst + VIN × tON / L ...................................................................................... Formula 7 With the formula 4,6, and ILxmax is, ILx max = VOUT / VIN × IOUT + VIN × tON /(2 × L ) ................................................................. Formula 8 Therefore, peak current is more than IOUT. Considering the value of ILxmax, the condition of input and output, and external components should be selected. In the formula 7, peak current ILxmax at discontinuous mode can be calculated. Put Iconst=0 in the formula. The explanation above is based on the ideal calculation, and the loss caused by LX switch and external components is not included. The actual maximum output current is between 50% and 80% of the calculation. Especially, when the ILX is large, or VIN is low, the loss of VIN is generated with the on resistance of the switch. As for VOUT, Vf (as much as 0.3V) of the diode should be considered. 11 R1215D TIMING CHART The timing chart below describes the state of each pin from the power-on until the IC entering the stable operation. By raising the voltage of the DTC pin slowly, the switching duty cycle is limited, and prevent the drastic voltage rising (over-shoot) and inrush current. When the VIN voltage becomes equal or more than the UVLO released voltage (VUVLO+VHYS), VREFOUT operation starts. Following with the increase of the voltage level of VREFOUT, the internal oscillator begins to operate, then the DTC voltage is also rising, then, soft-start operation starts. When the DTC voltage crosses the chopping wave level inside the IC, EXT pin starts switching, then, step-up operation begins. During this term, the output voltage does not reach the set output voltage. Therefore the output of the amplifier is "H". Besides, the protection circuit may work and the IC charges the DELAY pin. Because of this, the soft-start time should be set shorter than the latch protection delay time. After the initial stage, when the output voltage reaches the set output voltage, the level of AMPOUT becomes the normal state. In other words, the level is determined with the input voltage, the output voltage, and the output current. When the level of AMPOUT becomes falling, charging the DELAY pin stops and discharges to the GND. The soft-start time (the time for the DTC pin voltage becoming to VDTC level) can be estimated with the next formula. t ≅1/α×ln(VDTC×α/β+1), herein, α=−1/C7×(1/R5+1/R6), and β=VREFOUT/(C7×R5). VIN (VUVLO+VHYS) VREFOUT OSC DTC AMPOUT DELAY Soft-start Time EXT VREFOUT R5 DTC R6 C7 12 R1215D The operation of Latch protection circuit is as follows: When AMPOUT becomes "H" and the IC detects maximum duty cycle, charge to an external capacitor, C2 of DELAY pin starts. The maximum duty cycle continues and the voltage of DELAY pin reaches delay voltage detector threshold, VDLY, outputs "L" to EXT pin and turns off the external power MOSFET. To release the latch protection operation, make the supply voltage down to UVLO detector threshold or lower, and make it rise up to the normal input voltage. Once after becoming the maximum duty cycle, if the duty cycle decreases before latch operation works, the charging the capacitor stops immediately, and the DELAY pin voltage is fixed at GND level with IDLY2. The delay time of latch protection can be calculated with C2, VDLY, and the delay pin charge current, IDLY1, as in the next formula. t=C2 × VDLY/IDLY1 Output Short DELAY AMPOUT VDLY DTC Normal Maxduty Operation Latched EXT IDLY1 DELAY VDLY C2 13 R1215D TEST CIRCUITS VIN EXT VREFOUT AMPOUT DTC VFB GND DELAY GND VIN EXT VREFOUT AMPOUT DTC VFB DELAY A Fig.1 Consumption Current Test Circuit Fig.2 Oscillator Frequency, VFB Voltage, Duty Cycle, EXT rising time/falling time Test Circuit VIN EXT VREFOUT AMPOUT DTC VFB VIN EXT VREFOUT A AMPOUT DTC VFB GND DELAY GND DELAY A Fig.3 AMP "L" Output Current/ "H" Output Current Test Circuit V VIN EXT VREFOUT AMPOUT DTC VFB GND DELAY Fig.4 DELAY Pin Charge Current/ Discharge Current Test Circuit VIN EXT VREFOUT AMPOUT DTC VFB V GND DELAY Fig.5 EXT "H" ON Resistance Test Circuit Fig.6 EXT "L" ON Resistance Test Circuit 14 R1215D VIN EXT VREFOUT AMPOUT DTC VFB VIN EXT VREFOUT AMPOUT DTC VFB GND DELAY GND DELAY Fig.7 DELAY Pin Detector Threshold Test Circuit Fig.8 UVLO Detector Threshold/Released Voltage Test Circuit VIN EXT VREFOUT AMPOUT DTC VFB 100kΩ 10kΩ VIN EXT VREFOUT AMPOUT DTC VFB A V GND DELAY GND DELAY Fig.9 Error AMP Gain/Phase Test Circuit Fig.10 VREFOUT Voltage Test Current VIN EXT VREFOUT AMPOUT DTC VFB GND DELAY A Fig.11 VFB Leakage Current Test Circuit 15 R1215D TYPICAL CHARACTERISTICS 1) Output Voltage vs. Output Current (Topt=25°C) R1215D002E 9.2 VOUT=9V,Frequency=700kHz R1215D002F 9.2 VOUT=9V,Frequency=1.4MHz 1.8V 2.5V 5.5V Output Voltage VIN(V) Output Voltage VIN(V) 9.1 9.0 8.9 8.8 1.8V 2.5V 5.5V 9.1 9.0 8.9 8.8 0 100 200 Output Current IOUT(mA) 300 0 100 200 Output Current IOUT(mA) 300 2) Efficiency vs. Output Current (Topt=25°C) R1215D002E 100 VOUT=9V,Frequency=700kHz 100 R1215D002F VOUT=9V,Frequency=1.4MHz Effciency η(%) 80 Effciency η(%) 80 60 1.8V 2.5V 5.5V 60 1.8V 2.5V 5.5V 40 0 50 100 150 200 250 Output Current IOUT(mA) 300 40 0 50 100 150 200 250 Output Current IOUT(mA) 300 3) Supply Current vs. Temperature R1215D002A/E 650 VIN=5.5V,Frequency=700kHz 900 R1215D002B/F VIN=5.5V,Frequency=1.4MHz Supply Current IDD(µA) 550 500 450 400 350 -40 -25 0 25 50 Temperature Topt(°C) 75 85 Supply Current IDD(µA) 600 850 800 750 700 650 600 -40 -25 0 25 50 Temperature Topt(°C) 75 85 16 R1215D 4) VFB Voltage vs. Temperature R1215D002x 1010 VIN=2.5V 1.32 5) VREFOUT Voltage vs. Temperature R1215D002x VIN=2.5V VFB Voltage VFB(mV) 1005 1000 995 990 985 980 -40 -25 0 25 50 Temperature Topt(°C) 75 85 VREFOUT Voltage VREFOUT(V) 1.31 1.30 1.29 1.28 -40 -25 0 25 50 Temperature Topt(°C) 75 85 6) Oscillator Frequency vs. Temperature R1215D002A/E Oscillator Frequency fosc(kHz) R1215D002B/F VIN=2.5V 750 700 650 600 -40 -25 Oscillator Frequency fosc(kHz) 800 1600 1500 1400 1300 1200 -40 -25 VIN=2.5V 0 25 50 Temperature Topt(°C) 75 85 0 25 50 Temperature Topt(°C) 75 85 7) UVLO Detector Threshold / Released Voltage vs. Temperature R1215D002A/B 1.90 1.69 R1215D002E/F UVLO Detector Threshold/ Released Voltage(V) UVLO Detector Threshold/ Released Voltage(V) 1.88 1.86 1.84 1.82 1.80 1.78 -40 -25 0 25 50 Temperature Topt(°C) 75 85 Detector Threshold Released Voltage 1.67 1.65 1.63 1.61 1.59 1.57 -40 -25 0 25 50 Temperature Topt(°C) 75 85 Detector Threshold Released Voltage 17 R1215D 8) DELAY Pin Charge Current vs. Temperature R1215D002x DELAY Pin Charge Current IDLY1(µA) 6.5 6.0 5.5 5.0 4.5 -40 -25 VIN=2.5V 9) DELAY Pin Discharge Current vs. Temperature R1215D002x DELAY Pin Discharge Current IDLY2(µA) 400 350 300 250 200 150 100 50 0 -40 -25 0 25 50 Temperature Topt(°C) 75 85 VIN=1.8V 0 25 50 Temperature Topt(°C) 75 85 10) DELAY Pin Detector Threshold vs. Temperature R1215D002x DELAY Pin Detector Threshold VDLY(V) 1.02 1.01 VIN=2.5V 11) VREFOUT Voltage vs. VREFOUT Current R1215D002x 1.6 1.4 VIN=2.5V VREFOUT Voltage(V) 1.2 1.0 0.8 0.6 0.4 0.2 0 1.00 0.99 0.98 0.97 0.96 -40 -25 0 25 50 Temperature Topt(°C) 75 85 0 10 20 30 40 VREFOUT Current(mA) 50 12) Maximum Duty Cycle vs. DTC Pin Voltage (Topt=25°C) R1215D002A/E 100 VIN=2.5V,Frequency=700kHz 100 R1215D002B/F VIN=2.5V,Frequency=1.4MHz Maxduty Cycle(%) 60 40 20 0 300 400 500 600 700 800 900 1000 1100 DTC Pin Voltage VDTC(mV) Maxduty Cycle(%) 80 80 60 40 20 0 300 400 500 600 700 800 900 1000 1100 DTC Pin Voltage VDTC(mV) 18 R1215D 13) Error Amplifier Frequency Characteristics (Topt=25°C) R1215D002X 200 VIN=2.5V Error Amplifier Gain(dB) / Phase(deg) 150 Phase 100 50 0 -50 Gain 100kΩ 1kΩ 1 10 100 1000 Freguency f(kHz) 10000 14) Load Transient Response (VIN=2.5V,Topt=25°C) R1215D002A/E 9.2 Frequency=700kHz 280 9.2 R1215D002B/F Frequency=1.4MHz 280 200 Output Current IOUT(mA) 9.0 8.9 8.8 8.7 8.6 8.5 8.4 0 4 8 Time t (ms) 12 200 9.0 8.9 8.8 8.7 8.6 8.5 8.4 0 4 8 Time t (ms) 12 VOUT 160 120 80 40 0 -40 VOUT 160 120 80 40 0 -40 IOUT IOUT 15) Power On Response (VIN=2.5V,Topt=25°C,ROUT=150Ω) R1215D002A/E 10 10 R1215D002B/F Output Voltage VOUT(V) 8 6 4 2 0 0 5 15 Time t (ms) 25 Output Voltage VOUT(V) 8 6 4 2 0 0 5 15 Time t (ms) 25 Output Current IOUT(mA) Output Voltage VOUT(V) Output Voltage VOUT(V) 9.1 240 9.1 240 19 PACKAGE INFORMATION PE-SON-8-0510 • SON-8 Unit: mm PACKAGE DIMENSIONS 2.9±0.2 0.475TYP 8 5 0.23±0.1 0.2±0.1 Bottom View 0.13±0.05 0.15 +0.1 −0.15 0.15 +0.1 −0.15 2.8±0.2 3.0±0.2 1 4 Attention : Tab suspension leads in the parts have VDD or GND level. (They are connected to the reverse side of this IC.) Refer to PIN DISCRIPTION. Do not connect to other wires or land patterns. 0.13±0.05 0.65 0.3±0.1 0.1 0.1 M TAPING SPECIFICATION 0.2±0.1 +0.1 φ1.5 0 4.0±0.1 2.0±0.05 0.9MAX. 3.5±0.05 ∅1.1±0.1 0 ∅ 180 −1.5 ∅ 60 +1 0 1.75±0.1 3.3 2.0MAX. 4.0±0.1 TR User Direction of Feed TAPING REEL DIMENSIONS (1reel=3000pcs) 11.4±1.0 9.0±0.3 ∅13±0.2 21±0.8 2±0.5 8.0±0.3 3.2 0.2±0.1 PACKAGE INFORMATION PE-SON-8-0510 POWER DISSIPATION (SON-8) This specification is at mounted on board. Power Dissipation (PD) depends on conditions of mounting on board. This specification is based on the measurement at the condition below: Measurement Conditions Standard Land Pattern Environment Board Material Board Dimensions Copper Ratio Through-hole Measurement Result (Topt=25°C,Tjmax=125°C) Mounting on Board (Wind velocity=0m/s) Glass cloth epoxy plactic (Double sided) 40mm × 40mm × 1.6mm Top side : Approx. 50% , Back side : Approx. 50% φ0.5mm × 44pcs Standard Land Pattern Power Dissipation Thermal Resistance 600 Free Air 300mW 333°C/W 480mW θja=(125−25°C)/0.48W=208°C/W Power Dissipation PD(mW) 500 400 300 480 On Board 40 Free Air 100 0 0 25 50 75 85 100 Ambient Temperature (°C) 125 150 Power Dissipation 40 200 Measurement Board Pattern IC Mount Area (Unit : mm) RECOMMENDED LAND PATTERN 0.35 0.65 1.15 0.65 (Unit: mm) MARK INFORMATION ME-R1215D-0603 R1215D SERIES MARK SPECIFICATION • SON-8 1 5 to , 6 4 : Product Code (refer to Part Number vs. Product Code) : Lot Number 1 2 3 5 4 6 • Part Number vs. Product Code Product Code 1 2 3 4 Part Number R1215D002A R1215D002B R1215D002E R1215D002F G0 G0 G0 G0 1 2 3 4 A B E F