NJU7631 Step-Down Switching Regulator IC with Power Saving PWM/PFM control ■ GENERAL DESCRIPTION ■ PACKAGE OUTLINE The NJU7631 is a low voltage operation high-speed switching regulator control IC for step-down converter, with PWM/PFM switching control. It can improve a switching efficiency on light load with automatically changing between PWM and PFM controls. It incorporates a totem pole output, which can drive an external MOS-FET easily. The NJU7631 also has a soft-start function, dead time control and timer latch for short circuit protection and their times are all adjustable with external parts. It is available in a small and thin 8-lead MSOP (TVSP) package. ■ FEATURES ● Automatic PWM/PFM Control ● Operating Voltage 2.2V to 8V ● Wide Oscillator Range 300kHz to 1MHz ● Maximum Duty Cycle 100% ● Quiescent Current 800µA typ. ● Soft-Start Function Internal : 16ms typ. or adjustable ● Dead Time Control ● Timer Latch for Short Circuit Protection ● C-MOS Technology ● Package Outline NJU7631RB1 : MSOP8 (TVSP8)* NJU7631RB1 (MSOP8 (TVSP8)) ■ PRODUCT VARIATION NJU763x** Standby Function PWM/PFM NJU7631 PWM/PFM Light Load to Efficiency NJU7630 PWM Control ** Planning *MEET JEDEC MO-187-DA / THIN TYPE ■ PIN CONFIGURATION 1 8 2 7 3 6 4 5 NJU7631RB1 Ver.2012-08-03 PIN FUNCTION 1. OUT 2. V+ 3. FB 4. IN5. SCP 6. DTC 7. RT 8. GND -1- NJU7631 ■ BLOCK DIAGRAM + V FB 0.8V ER⋅AMP IN- 0.2V 1V Vref PWM/PFM Control Soft Start UVLO Latch PWM 2µA SCP Buffer OUT SCP OSC 2kΩ 0.5V 1V 0.5 A RT 1V DTC RT GND RT -2- Ver.2012-08-03 NJU7631 ■ ABSOLUTE MAXIMUM RATINGS PARAMETER SYMBOL Supply Voltage V+ Output Pin Current IO Power Dissipation PD Operating Temperature Range TOPR Storage Temperature Range TSTG MAXIMUM RATINGS +9 ±50 MSOP8 (TVSP8) :320 -40 to +85 -40 to +125 ■ RECOMMENDED OPERATING CONDITIONS PARAMETER SYMBOL MIN. Operating Voltage V+ 2.2 Oscillator Timing Resistor RT 30 Oscillation Frequency fOSC 300 TYP. – 47 700 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 Ver.2012-08-03 MAX. 8 120 1,000 (Ta=25°C) UNIT V kΩ kHz (V+=3.3V, RT=47kΩ, Ta=25°C) ■ ELECTRICAL CHARACTERISTICS PARAMETER (Ta=25°C) UNIT V mA mW °C °C SYMBOL VT_ON VT_OFF VHYS TSS TEST CONDITION V+= L → H V+= H → L VT_ON → Duty=80% MIN. TYP. MAX. UNIT 1.9 1.8 60 2.0 1.9 100 2.1 2.0 – V V mV 8 16 24 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 0.95 1.00 1.05 V VT_LAOFF SCP Pin 0.2 0.45 0.7 V -5% 630 0.5 700 +5% 770 V kHz VRT fOSC fDV V+=2.2V to 8V – 1 – % fDT Ta=-40°C to +85°C – 3 – % -3- NJU7631 (V+=3.3V, RT=47kΩ, Ta=25°C) ■ ELECTRICAL CHARACTERISTICS PARAMETER Error Amplifier Block Reference Voltage Input Bias Current Open Loop Gain Gain Bandwidth Product Output Source Current Output Sink Current SYMBOL TEST CONDITION VB IB AV GB IOM+_1 IOM+_2 IOM- VFB=1V, VIN-=0.9V VFB=1V, VIN-=0.9V, V+=2.2V VFB=1V, VIN-=1.1V MIN. TYP. MAX. UNIT -1.0% -0.1 – – 25 4 0.10 1.00 – 80 1 55 9 0.16 +1.0% 0.1 – – 95 16 0.22 V µA dB MHz mA mA mA 0.29 0.44 100 40 17 0.35 0.5 – 50 25 0.41 0.56 – 60 33 V V % % % PWM Comparate Block Input Threshold Voltage Maximum Duty Cycle PWM/PFM Change Duty Cycle Output Block Output High Level ON Resistance Output Low Level ON Resistance General Characteristics Quiescent Current -4- VT_25 VT_50 MAXDUTY_1 MAXDUTY_2 PFMDUTY Duty= PFMDUTY Duty=50% VFB=0.9V VFB=0.9V, RDTC=47kΩ ROH IO=-20mA – 10 20 Ω ROL IO=+20mA – 5 10 Ω RL=Non Load – 800 1200 µA IDD Ver.2012-08-03 NJU7631 ■ TYPICAL APPLICATIONS Step-Down Converter FET L VIN VOUT CIN SBD COUT NJU7631 GND RT 7 FB DTC 6 IN- SCP 5 OUT 2 V 3 C R1 8 1 + Ver.2012-08-03 4 RT RDTC CS CNF RNF R2 CSCP -5- NJU7631 ■ TYPICAL CHARACTERISTICS Oscillation Frequency vs. Timing Resistance Oscillation Frequency fosc (kHz) Oscillation Frequency fOSC (kHz) 1000 100 10 Oscillation Frequency vs. Operating Voltage (V+=3.3V, Ta=25oC) 720 700 680 660 100 Timing Resistance RT (kΩ) Duty Cycle vs. R DTC T 10 (Ta=25oC) Reference Voltage V (V) 1.004 B 80 60 40 20 0 2 4 6 8 + Operating Voltage V (V) (V =3.3V, R =47kΩ, Ta=25 C) AX Duty Cycle M D UTY (%) 100 0 Reference Voltage vs. Operating Voltage o + (RT=47kΩ, Ta=25oC) 740 1.002 1 0.998 0.996 0 20 40 60 80 100 Dead Time Control Resistance RDTC (kΩ) 0 2 4 6 8 Operating Voltage V+ (V) 10 Quiescent Current vs. Operating Voltage (R =47kΩ, R =Non Load, Ta=25oC) T Quiescent Current IDD (µA) 1400 1200 1000 800 600 400 200 0 -6- L 0 2 4 6 8 Operating Voltage V+ (V) 10 Ver.2012-08-03 NJU7631 ■ TYPICAL CHARACTERISTICS Error Amplifier Block Voltage Gain, Phase vs. Frequency + o (V =3.3V, Gain=40dB, Ta=25 C) Gain 30 90 15 45 10 100 1000 Frequency f (kHz) + V =1.95V 8 Output Source Current IOM+ (mA) V+=3.3V 6 4 V+=8V 2 0 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) Error Amplifier Block Output Source Current vs. Temperature (VFB=1V, VIN-=0.9V) V+=8V 100 V+=3.3V 10 V+=1.95V 1 -50 Ver.2012-08-03 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) 0 10000 Output Block Output Low Level ON Resistance vs. Temperature (Io=+20mA) 12 10 10 1000 14 Output Sink Current IOM- (mA) Output High Level ON Resistance ROH (Ω) 1 Output Block Output High Level ON Resistance vs. Temperature (Io=-20mA) 12 135 Phase 0 0.1 14 180 Phase Φ (deg) 45 Output Low Level ON Resistance ROL (Ω) Voltage Gain Av (dB) 60 V+=1.95V 8 6 V+=3.3V 4 2 0 -50 0.2 0.15 V+=8V -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) Error Amplifier Block Output Sink Current vs. Temperature (VFB=1V, VIN- =1.1V) V+=1.95V, 3.3V, 8V 0.1 0.05 0 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) -7- NJU7631 ■ TYPICAL CHARACTERISTICS Soft Start Time vs. Temperature Reference Voltage vs. Temperature + (V =3.3V) 22 20 1.005 18 16 14 12 1 0.995 10 8 -50 0.99 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) (V+=3.3V, RT=47kΩ) 2.06 740 Threshold Voltage (V) Oscillator Frequency fOSC (kHz) Oscillator Frequency vs. Temperature 760 720 700 680 660 640 -50 (V+=3.3V) 1.01 Reference Voltage VB (V) Soft Start Time Tss (ms) 24 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) Under Voltage Lockout Block vs. Temperature 2.02 VT_ON 1.98 1.94 VT_OFF 1.9 1.86 -50 -25 0 25 50 75 100 125 Ambient Temperature Ta (oC) Quiescent Current vs. Temperature Quiescent Current IDD (µA) 1000 800 600 400 200 0 -50 -8- (V+=3.3V, RT=47kΩ) -25 0 25 50 75 100 125 o Ambient Temperature Ta ( C) Ver.2012-08-03 NJU7631 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.2012-08-03 -9-