NJU7678

NJU7678 Internal 60V, 3A MOSFET Step-Up / Flyback Switching Regulator IC GENERAL DESCRIPTION NJU7678 is Step-up/Fly back type switching regulator IC with PWM control. Internal soft-start function, dead time control and timer latch function are included, requiring no external components. All parameters can be optimized by additional external components for design flexibility. NJU7678MLK FEATURES Drain to Source Voltage 60V max. Drain to Source Current 3A max. PWM switching control Operating Voltage Range 2.5V to 7.0V Oscillating Frequency Range 300kHz to 1MHz Maximum Duty Cycle 90% typ. Soft-Start Function Internal fixed value: 4ms typ. or adjustable by external part Dead Time Control Timer Latch for Short Circuit Protection Package Outline NJU7678MLK: EQFN24 ■ PACKAGE OUTLINE Bottom View ■PIN CONFIGURATION 18 17 16 15 14 13 13 14 15 16 17 18 19 20 21 22 23 24 12 11 10 9 8 7 12 11 10 PAD (*1) 9 8 7 19 20 21 22 23 24 1 2 3 4 5 6 6 5 4 3 2 1 PIN FUNCTION 1. FB 2. IN3. N.C. 4. SCP 5. N.C. 6. DTC 7. N.C. 8. RT 9. N.C. 10. GND 11. N.C. 12. N.C. 13. N.C. 14. SOURCE 15. SOURCE 16. SOURCE 17. SOURCE 18. N.C. 19. DRAIN 20. DRAIN 21. DRAIN 22. N.C. 23. V+ 24. N.C. (Top View) NJU7678MLK (*1): Exposed Pad connected to Internal FET Drain (Bottom View) Ver.2010-10-26 -1- NJU7678 ■BLOCK DIAGRAM V FB + ER⋅AMP 0.65V IN1V Vref 0.15V Soft Start UVLO Latch PWM DRAIN DRAIN DRAIN SCP 2µA Buffer SCP OSC 2kΩ 0.5 A RT 0.5V 0.6V SOURCE SOURCE SOURCE SOURCE 1V 1V DTC RT RT GND The initial soft start time is 4msec. The soft start time can be adjusted by connecting the capacitor with the DTC pin. The charging current is calculated by 0.5/RT. The MaxDuty is 90%@700kHz. MaxDuty can be adjusted by connecting resistance with the DTC pin. MaxDuty is calculated by (RDTC / RT) × 86 - 24. The short-circuit protection circuit is a timer latch type. The protection Delay time can be adjusted with the capacitor connected with the SCP pin. To release the latch mode, it should do reclosing the power supply (below the UVLO detection voltage) or the SCP pin down to GND level. -2- Ver.2010-10-26 NJU7678 ABSOLUTE MAXIMUM RATINGS (Ta=25°C) PARAMETER SYMBOL Supply Voltage V+ Drain to Source Voltage VDS Drain to Source Current IDS Power Dissipation Operating Temperature Range Storage Temperature Range PD TOPR TSTG MAXIMUM RATINGS +8 66 3 660 (*2) 1,400 (*3) -40 ~ +85 -40 ~ +125 UNIT V V A mW °C °C (*2): Mounted on glass epoxy board based on EIA/JEDEC. (101.5 × 114.5 × 1.6mm: 2 Layers FR-4) (*3): Mounted on glass epoxy board. (101.5 × 114.5 × 1.6mm: 4 Layers FR-4, copper area 99.5 × 99.5mm) RECOMMENDED OPERATING CONDITIONS PARAMETER SYMBOL MIN. + Operating Voltage V 2.5 Drain to Source Voltage VDS – Oscillator Timing Resistor RT 30 Oscillation Frequency fOSC 300 PACKAGE THERMAL RESISTANCE PARAMETER SYMBOL Junction-toθja Ambient Temperature Junction-to-Case ψjt TYP. – – 47 700 MAX. 7 60 120 1,000 UNIT V V kΩ kHz THERMAL RESISTANCE 152 (*2) 71 (*3) 15.1 (*2) 9.7 (*3) UNIT °C/W °C/W (*2): Mounted on glass epoxy board based on EIA/JEDEC. (101.5 × 114.5 × 1.6mm: 2 Layers FR-4) (*3): Mounted on glass epoxy board. (101.5 × 114.5 × 1.6mm: 4 Layers FR-4, copper area 99.5 × 99.5mm) Ver.2010-10-26 -3- NJU7678 ELECTRICAL CHARACTERISTICS (V+=3.3V, RT=47kΩ, Ta=25°C) PARAMETER Under Voltage Lockout Block ON Threshold Voltage OFF Threshold Voltage Hysteresis Voltage Soft Start Block Soft Start Time Short Circuit Protection Block Input Threshold Voltage Charge Current Latch Mode ON Threshold Voltage Latch Mode OFF Threshold Voltage Oscillator Block RT Pin Voltage Oscillation Frequency Oscillate Supply Voltage Fluctuations Oscillate Temperature Fluctuations Error Amplifier Block Reference Voltage Input Bias Current Open Loop Gain Gain Bandwidth Product Output Source Current Output Sink Current PWM Comparator Block Input Threshold Voltage Maximum Duty Cycle Output Block Drain to Source ON Resistance Drain to Source Leak Current General Characteristic Quiescent Current RDS(ON) RDS(ON)_2.5 IDS_LEAK IO=3A IO=3A, V+=2.5V VDS=60V, VIN-=1.1V – – – 0.060 0.065 – 0.080 0.085 0.1 Ω Ω µA VT_0 VT_50 MAXDUTY_1 MAXDUTY_2 Duty=0% Duty=50% VFB=0.9V VFB=0.9V, RDTC=43kΩ 0.10 0.36 85 45 0.16 0.42 90 55 0.22 0.48 95 65 V V % % SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT VT_ON VT_OFF VHYS V+ = L → H V+ = H → L 1.6 1.5 60 1.7 1.6 100 1.8 1.7 – V V mV TSS VT_ON → Duty=80% 2 4 8 ms VT_PC ICHG VT_LA VT_LAOFF FB Pin VSCP=0V SCP Pin SCP Pin 0.95 1.5 0.90 0.35 1.00 2 1.00 0.6 1.05 2.5 1.10 0.85 V µA V V VRT fOSC fDV fDT V+=2.5V to 7V Ta=-40°C to +85°C -8% 630 – – 0.5 700 1 3 +8% 770 – – V kHz % % VB IB AV GB IOM+ IOM- VFB=1V, VIN-=0.9V VFB=1V, VIN-=1.1V -1.0% -0.1 – – 20 1.0 1.00 – 80 1 35 4.0 +1.0% 0.1 – – 50 12 V µA dB MHz µA mA IDD VIN-=1.1V, VFB=0.5V – 6.5 7.5 mA -4- Ver.2010-10-26 NJU7678 TYPICAL APPLICATIONS < Step-up Circuit > L V + SBD V CIN COUT R2 V C + DRAIN SOURCE R1 FB CNF RNF INSCP CSCP RDTC CDTC DTC NJU7678 GND RT RT < Fly Back Circuit > V + T CIN SBD VOUT R2 COUT R1 V C + DRAIN SOURCE FB CNF RNF INSCP CSCP RDTC CDTC DTC NJU7678 GND RT RT Ver.2010-10-26 -5- NJU7678 ■TYPICAL CHARACTERISTICS Oscillation Frequency vs. Timing Resistance (kHz) 1000 (V =3.3V, Ta=25 C) + o Maximum Duty Cycle vs. Oscillator Frequency 100 Maximum Duty Cycle MD (%) 95 (V =3.3V, Ta=25 C) + o Oscillation Frequency f OSC UTY_1 AX 90 85 100 10 100 Timing Resistance R (kΩ) T 80 100 Oscillator Frequency f OSC 1000 (kHz) Oscillation Frequency vs. Operating Voltage Oscillation Frequency fosc (kHz) 740 720 (R =47kΩ, Ta=25 C) T o Duty Cycle vs. RDTC 100 (%) 80 60 40 20 0 (V+=3.3V, RT=47kΩ, Ta=25 C) o 700 680 660 Duty Cycle M D AX UTY 0 2 4 6 Operating Voltage V+ (V) 8 0 20 40 60 80 Dead Time Control Resistance R DTC 100 (kΩ) Reference Voltage vs. Operating Voltage Quiescent Current vs. Operating Voltage (mA) 16 14 12 10 8 6 4 2 0 0 2 4 6 Operating Voltage V+ (V) 8 (R =47kΩ, V =1.1V, V =0.5V, Ta=25 C) T INFB o 1.01 Reference Voltage V (V) B (Ta=25 C) o 1 0.995 0.99 0 2 4 6 Operating Voltage V+ (V) 8 Quiescent Current I 1.005 DD -6- Ver.2010-10-26 NJU7678 ■TYPICAL CHARACTERISTICS Error Amplifier Block Voltage Gain, Phase vs. Frequency (V+=3.3V, Gain=40dB, Ta=25 oC) 60 Voltage Gain Av (dB) 45 180 135 90 45 Gain 30 15 0 0.1 1 10 100 1000 Frequency f (kHz) 0 10000 Drain - Source ON Resistance RDS(ON) (Ω) Drain - Source ON Resistance vs. Temperature (Io=3A) 0.12 0.1 0.08 0.06 0.04 0.02 0 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) V+=2.5V V+=3.3V V =7V + Drain - Source Leak Current vs. Temperature (V =60V, V =1.1V) DS IN1 Drain - Source Leak Current IDS_LEAK (µA) 0.8 0.6 0.4 0.2 0 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) Ver.2010-10-26 Phase Φ (deg) Phase -7- NJU7678 ■TYPICAL CHARACTERISTICS Soft Start Time vs. Temperature 8 Soft Start Time Tss (ms) 7 6 5 4 3 2 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) (V =3.3V) Reference Voltage V (V) + Reference Voltage vs. Temperature 1.01 1.005 (V =3.3V) + B 1 0.995 0.99 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) Oscillator Frequency vs. Temperature Oscillator Frequency fOSC (kHz) 760 740 720 700 680 660 640 -50 (V =3.3V, R =47kΩ) T + Muximum Duty Cycle vs. Temperature 100 Muximum Duty Cycle (%) MD 90 80 70 60 50 40 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) MAXDUTY_2 MAXDUTY_1 (V =3.3V) + -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) AX UTY (mA) 1.8 Threshold Voltage (V) 1.75 1.7 1.65 1.6 1.55 1.5 -50 Under Voltage Lockout Block vs. Temperature Quiescent Current vs. Temperature 8 7.5 7 6.5 6 5.5 5 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) (V =3.3V, RT=47kΩ, VIN-=1.1V, VFB=0.5V) + VT_OFF -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) Quiescent Current I T_ON DD V -8- Ver.2010-10-26 NJU7678 MEMO [CAUTION] The specifications on this databook are only given for information , without any guarantee as regards either mistakes or omissions. The application circuits in this databook are described only to show representative usages of the product and not intended for the guarantee or permission of any right including the industrial rights. Ver.2010-10-26 -9-