NJU7678 Internal 60V, 3A MOSFET Step-Up / Flyback Switching Regulator IC GENERAL DESCRIPTION ■ PACKAGE OUTLINE 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. Bottom View 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 ■PIN CONFIGURATION 18 17 16 15 14 13 13 14 15 16 17 18 19 12 12 19 20 11 11 20 21 10 10 21 PAD (*1) 22 9 9 22 23 8 8 23 24 7 7 24 1 2 3 4 5 6 6 (Top View) 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. (Bottom View) NJU7678MLK (*1): Exposed Pad connected to Internal FET Drain Ver.2010-10-26 -1- NJU7678 ■BLOCK DIAGRAM V + FB 0.65V ER⋅AMP IN1V 0.15V Vref DRAIN Soft Start DRAIN UVLO DRAIN Latch PWM 2µA SCP Buffer SCP OSC 2kΩ 0.5V 1V SOURCE 0.6V SOURCE 0.5 A RT SOURCE SOURCE 1V DTC RT GND RT 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 THERMAL RESISTANCE 152 (*2) 71 (*3) 15.1 (*2) 9.7 (*3) MAX. 7 60 120 1,000 UNIT V V kΩ kHz 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 SYMBOL VT_ON VT_OFF VHYS TSS TEST CONDITION V+ = L → H V+ = H → L VT_ON → Duty=80% MIN. TYP. MAX. UNIT 1.6 1.5 60 1.7 1.6 100 1.8 1.7 – V V mV 2 4 8 ms VT_PC ICHG FB Pin VSCP=0V 0.95 1.5 1.00 2 1.05 2.5 V µA VT_LA SCP Pin 0.90 1.00 1.10 V VT_LAOFF SCP Pin 0.35 0.6 0.85 V -8% 630 0.5 700 +8% 770 V kHz VRT fOSC fDV V+=2.5V to 7V – 1 – % fDT Ta=-40°C to +85°C – 3 – % 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 0.10 0.36 85 45 0.16 0.42 90 55 0.22 0.48 95 65 V V % % VB IB AV GB IOM+ IOM- PWM Comparator Block Input Threshold Voltage Maximum Duty Cycle VT_0 VT_50 MAXDUTY_1 MAXDUTY_2 Duty=0% Duty=50% VFB=0.9V VFB=0.9V, RDTC=43kΩ 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 IDD VIN-=1.1V, VFB=0.5V – 6.5 7.5 mA Output Block Drain to Source ON Resistance Drain to Source Leak Current General Characteristic Quiescent Current -4- Ver.2010-10-26 NJU7678 TYPICAL APPLICATIONS < Step-up Circuit > SBD L + V V CIN R2 COUT + R1 DRAIN V C SOURCE FB CNF NJU7678 IN- RNF GND RT DTC SCP RT CSCP CDTC RDTC < Fly Back Circuit > T + V SBD VOUT CIN R2 COUT R1 + DRAIN V C SOURCE FB CNF RNF NJU7678 IN- GND RT SCP DTC RT CSCP RDTC Ver.2010-10-26 CDTC -5- NJU7678 ■TYPICAL CHARACTERISTICS Oscillation Frequency vs. Timing Resistance + (V =3.3V, Ta=25 C) 90 AX UTY_1 95 100 10 85 80 100 100 Timing Resistance R (kΩ) 1000 Oscillator Frequency f T OSC o (%) UTY 720 80 60 AX 700 680 660 (V+=3.3V, RT=47kΩ, Ta=25 C) 100 T Duty Cycle M D Oscillation Frequency fosc (kHz) o (R =47kΩ, Ta=25 C) 740 0 2 4 6 Operating Voltage V+ (V) 40 20 0 8 0 20 40 60 80 Dead Time Control Resistance R DTC o o (Ta=25 C) (mA) DD 1.005 Quiescent Current I B Reference Voltage V (V) 1.01 1 0.995 0 2 4 6 Operating Voltage V+ (V) 100 (kΩ) Quiescent Current vs. Operating Voltage Reference Voltage vs. Operating Voltage 0.99 (kHz) Duty Cycle vs. RDTC Oscillation Frequency vs. Operating Voltage -6- o (V =3.3V, Ta=25 C) 100 Maximum Duty Cycle M D (%) 1000 Oscillation Frequency f Maximum Duty Cycle vs. Oscillator Frequency o OSC (kHz) + 8 16 (R =47kΩ, V =1.1V, V =0.5V, Ta=25 C) T IN- FB 14 12 10 8 6 4 2 0 0 2 4 6 Operating Voltage V+ (V) 8 Ver.2010-10-26 NJU7678 ■TYPICAL CHARACTERISTICS Error Amplifier Block Voltage Gain, Phase vs. Frequency (V+=3.3V, Gain=40dB, Ta=25 oC) 45 Gain 30 90 15 45 10 100 1000 Frequency f (kHz) V+=2.5V V+=3.3V + V =7V 0.06 0.04 0.02 0 -50 Ver.2010-10-26 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) 0 10000 Drain - Source Leak Current vs. Temperature (V =60V, V =1.1V) DS IN1 Drain - Source Leak Current IDS_LEAK (µA) Drain - Source ON Resistance RDS(ON) (Ω) 1 Drain - Source ON Resistance vs. Temperature (Io=3A) 0.12 0.08 135 Phase 0 0.1 0.1 180 Phase Φ (deg) Voltage Gain Av (dB) 60 0.8 0.6 0.4 0.2 0 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) -7- NJU7678 ■TYPICAL CHARACTERISTICS Soft Start Time vs. Temperature Reference Voltage vs. Temperature + 1.005 B 7 (V =3.3V) 1.01 Reference Voltage V (V) 8 Soft Start Time Tss (ms) + (V =3.3V) 6 5 4 3 2 -50 1 0.995 0.99 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) Muximum Duty Cycle vs. Temperature Oscillator Frequency vs. Temperature + 660 1.75 1.7 V T_ON VT_OFF -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) MAXDUTY_2 60 50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) Quiescent Current vs. Temperature Under Voltage Lockout Block vs. Temperature 1.6 1.5 -50 70 40 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) 1.65 1.55 MAXDUTY_1 80 UTY 680 640 -50 90 AX 700 + (mA) Threshold Voltage (V) Muximum Duty Cycle (%) M D 720 (V =3.3V) 100 T 740 1.8 -8- (V =3.3V, R =47kΩ) 8 (V =3.3V, RT=47kΩ, VIN-=1.1V, VFB=0.5V) 7.5 DD 760 Quiescent Current I Oscillator Frequency fOSC (kHz) + 7 6.5 6 5.5 5 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) 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-