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| NJM2374A PWM DC/DC CONVERTER IC GENERAL DESCRIPTION The NJM2374A is a PWM DC/DC converter IC. It features fixed frequency type PWM control for better noise handling and to avoid intermittent oscillation observed in a simplified controller. It is suitable for Step-Up, Step-Down and Inverting applications for EMI sensitive application. PACKAGE OUTLINE NJM2374AD NJM2374AM FEATURES Operating Voltage (2.5V to 40V) NJM2374AE Operating Voltage (2.5V to 48V) Wide Oscillator Frequency (100Hz to 100kHz) Internal High Power Transistor 1.5A (max.) Internal Over Current Limit Circuit PWM form Switching Power Supply Control Bipolar Technology Package Outline DIP8, DMP8, EMP8, SSOP14 NJM2374AE NJM2374AV PIN CONFIGURATION PIN FUNCTION 1.CS 5.IN+ 2.ES 6.V+ 3.CT 7.SI 4.GND 8.CD 1 8 2 7 3 6 4 5 NJM2374AD NJM2374AM NJM2374AE 1 2 3 4 5 6 7 14 13 12 11 10 9 8 PIN FUNCTION 1.CS 8.IN+ 2.NC 9.NC 3.ES 10.V+ 4.NC 11.NC 5.CT 12.SI 6.NC 13.NC 7.GND 14.CD NJM2374AV Ver 3.0 - 1 - NJM2374A BLOCK DIAGRAM CS 1 Q 1.5A 160 PWM Logic R S 8 CD ES 2 Vth=300mV Maximum ON duty 9:1 OSC BLOCK Ipk Sense 7 SI CT 3 PWM COMP 6 V+ GND 4 Vref 1.25V 2% ERR.AMP 5 IN+ (DIP8, DMP8, EMP8: PACKAGE) CS 1 Q 1.5A 160 PWM Logic R S 14 CD NC 2 13 NC ES 3 Vth=300mV 12 SI NC 4 Maximum ON duty 9:1 OSC BLOCK Ipk Sense 11 NC CT 5 PWM COMP 10 V+ NC 6 Vref 1.25V 2% ERR.AMP 9 NC GND 7 8 IN+ (SSOP14: PACKAGE) -2- NJM2374A ABSOLUTE MAXIMUM RATINGS (Ta=25C ) PARAMETER SYMBOL Maximum Supply Voltage V+ Output Switch Current Output Switch Voltage Comparator Input Voltage Power Dissipation PD ISW VSW VIR Operating Temperature Range Topr Storage Temperature Range Tstg (note1) At on PC board. In the case of Step-Down Conversion with the internal power transistor, the Output Voltage must be set lower than 6V. RATINGS 40 (NJM2374AE: 48V) 1.5 40 (NJM2374AE: 48V) -0.3 ~ 40 (NJM2374AE: 48V) (DIP8) 875 (DMP8) 750 (note1) (EMP8) 1,000 (note1) (SSOP14) 375 -40 ~ +85 -50 ~ +150 UNIT V A V V mW C C POWER DISSIPATION vs. AMBIENT TEMPERATURE (Topr=-40 to +85C,Tj= to +150C) 1200 1000 800 600 400 200 0 25 50 NJM2374AV NJM2374AE At on PC board Power Dissipation PD (mW) NJM2374AD NJM2374AM At on PC board 75 100 Ambient Temperature Ta (C) In the case of SSOP packaging, the power dissipation should carefully be considered when designing this parts. -3- NJM2374A ELECTRICAL CHARACTERISTICS DC Characteristics (V+=5V, Ta=25C) PARAMETER SYMBOL Operating Current 1 Operating Current 2 (NJM2374AE Only) Charge Current Discharge Current Voltage Swing Discharge to Charge Current Ratio Peak Current Sense Voltage Saturation Voltage 1 Saturation Voltage 2 Output Transistor Bias Resistance DC Voltage Gain Collector Off-State Current Threshold Voltage Input Bias Current ICC1 ICC2 Ichg Idis VOSC Iratio Vipk Vsat1 Vsat2 Rbias hFE IC(Off) Vth IIB ISW=0.7A, VCE=5.0V VCE=40V (NJM2374AE: VCE=48V) IN+=0V TEST CONDITIONS + + MIN. - - 12 110 - - 250 - - - 35 - 1.225 - TYP. 2.8 3.4 20 180 0.5 9 300 1.0 0.5 160 120 10 1.250 40 MAX. 4.0 4.5 30 300 - - 350 1.3 0.7 - - - 1.275 400 UNIT mA mA A A VP-P - mV V V - nA V nA CT=1nF, SI=V , IN > Vth, ES=GND V+=48V, CT=1nF, SI=V+, IN+> Vth, ES=GND SI=V+ Ichg=Idis Darlington Connection (CS=CD), ISW=0.7A ISW=0.7A, Ic(driver)=50mA (Forced 14) (note) Output switch tests are performed under pulsed conditions to minimize power dissipation. TIMING CHART High Voltage Detect Reference Voltage Output Voltage Oscillator Waveform HIGH LOW Collector-Emitter Voltage OFF ON Current-Limit Active Point OSC Block to FF Reset -4- NJM2374A TIPICAL CHARACTERISTICS Oscillator Frequency vs. Timing Capacitor (V+=5V,SI=V+,Pin5=GND,Ta=25C) 1000 Switch ON/OFF Time vs. Timing Capacitor (V+=5V,SI=V+,Pin5=GND,Ta=25C) 1000 Switch ON/OFF Time tON / t OFF (S) Oscillator Frequency f OSC (kHz) 100 100 tON 10 10 tOFF 1 100 1000 Timing Capacitor CT (pF) 10000 1 100 1000 Timing Capacitor CT (pF) 10000 Saturation Voltage 1 Vsat1 (V) 1.5 1 0.5 0 0 0.5 1 1.5 Collector Current IC (A) 2 Saturation Voltage 2 Vsat2 (V) 2 Saturation Voltage 1 vs. Collector Current (V+=5V,CS=CD,Ta=25C) 2 1.5 1 0.5 0 Saturation Voltage 2 vs. Collector Current (V+=5V,Ic(driver)=50mA,=14,Ta=25C) 0 0.5 1 1.5 Collector Current IC (A) 2 Operating Current I CC (mA) 4 3 2 1 0 Operating Current vs. Operating Voltage (CT=1nF,SI=V+,IN+>Vth,ES=GND,Ta=25C) 0 5 10 15 20 25 30 35 40 Operating Voltage V+ (V) -5- NJM2374A TIPICAL CHARACTERISTICS Threshold Voltage vs. Temperature (V+=5V) Discharge to Charge Current Ratio vs. Temperature (V+=5V,SI=V+) 1.28 1.26 1.24 1.22 -50 -25 0 25 50 75 100 125 150 Ambient Temperature Ta (C) Saturation Voltage 1 vs. Temperature (V+=5V,CS=CD,ISW =0.7A) Discharge to Charge Current Ratio I ratio Saturation Voltage 2 Vsat2 (V) 1.3 Threshold Voltage Vth (V) 10 9 8 7 6 -50 -25 0 25 50 75 100 125 150 Ambient Temperature Ta (C) Saturation Voltage 2 vs. Temperature (V+=5V,ISW =0.7A,Ic(driver)=50mA,=14) Saturation Voltage 1 Vsat1 (V) 1.2 1.1 1 0.9 0.8 0.7 0.6 0.8 0.6 0.4 0.2 0 -50 -25 0 25 50 75 100 125 150 -50 -25 0 25 50 75 100 125 150 Ambient Temperature Ta (C) Ambient Temperature Ta (C) 5 Operating Current ICC (mA) 4 3 2 1 0 Operating Current vs. Temperature (V =5V,CT=1nF,SI=V+,IN+>Vth,ES=GND) + -50 -25 0 25 50 75 100 125 150 Ambient Temperature Ta (C) -6- NJM2374A TYPICAL APPLICATIONS Step-Down Converter VIN=25V RSC 0.22 L1 220H 8 7 1 2 VOUT=5.0V NJM2374A 6 4 CIN 100F CT 470pF 3 D1 5 R2 3.6k R1 1.2k COUT 470F In the case of Step-Down Conversion with the internal power transistor, the Output Voltage must be set lower than 6V. Step-Up Converter VIN=14V RSC 0.22 L1 180H D1 VOUT=30V RC 180 R2 46k 1 2 COUT 150F 8 7 NJM2374A 6 4 CIN 100F 3 CT 1500pF R1 2k 5 Inverting Converter VIN=5V RSC 0.22 D1 7 6 4 CIN 100F CT 1300pF 3 L1 90H R1 8.2k 8 1 2 R2 953 5 VOUT=-12V NJM2374A COUT 1000F D1 use to schottky diode. In the case of SSOP packaging, the power dissipation should carefully be considered when designing this parts. -7- NJM2374A Step-Down Converter (High Current) VIN=20V RSC 0.05 RBE 75 RBC 300 2SA1010 L1 33F 8 7 1 2 VOUT=10V NJM2374A 6 4 CIN 300F CT 330pF 3 D1 5 R2 70k R1 10k COUT 300F Step-Up Converter (High Current) VIN=5V RSC 0.075 L1 22H D1 VOUT=7V RC2 680 RC1 100 R2 46k 1 2 2SC3255 COUT 940F 8 7 NJM2374A 6 4 CIN 940F CT 330pF 3 RBE 220 R1 10k 5 D1 use to schottky diode. [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. -8- |
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