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 NJM2374AV FEATURES Operating Voltage (2.5V to 40V) 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, SSOP14 PIN CONFIGURATION 1 8 2 7 3 6 4 5 PIN FUNCTION 1.CS 5.IN+ 2.ES 6.V+ 3.CT 7.SI 4.GND 8.CD NJM2374AD NJM2374AM 1 14 2 13 3 12 4 11 5 10 6 9 7 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 2.0 - 1 - NJM2374A BLOCK DIAGRAM CS 1 Q 8 CD 7 SI 6 V+ 5 IN+ S PWM Logic 1.5A R 160 ES 2 Vth=300mV Maximum ON duty 9:1 OSC BLOCK Ipk Sense CT 3 PWM COMP GND Vref 1.25V 2% 4 ERR.AMP (DIP8, DMP8: PACKAGE) CS 1 NC 2 Q PWM Logic 1.5A 14 CD 13 NC 12 SI 11 NC 10 V+ 9 NC 8 IN+ S R 160 ES 3 Vth=300mV NC 4 CT 5 Maximum ON duty 9:1 OSC BLOCK Ipk Sense PWM COMP NC GND 6 7 Vref 1.25V 2% ERR.AMP (SSOP14: PACKAGE) -2- NJM2374A ABSOLUTE MAXIMUM RATINGS (Ta=25C ) PARAMETER SYMBOL RATINGS + Maximum Supply Voltage V 40 Output Switch Current ISW 1.5 Output Switch Voltage VSW 40 Comparator Input Voltage VIR -0.3 ~ 40 (DIP8) 875 Power Dissipation PD (DMP8) 750 (note1) (SSOP14) 375 Operating Temperature Range Topr -40 ~ +85 Storage Temperature Range Tstg -50 ~ +150 (note1) At on PC board. UNIT V A V V mW C C POWER DISSIPATION vs. AMBIENT TEMPERATURE (Topr=-40 to +85C,Tj= to +150C) 1000 Power Dissipation P D (mW) NJM2374AD 800 600 NJM2374AM At on PC board 400 NJM2374AV 200 0 25 50 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 TEST CONDITIONS + + TYP. MAX. UNIT 2.8 20 180 0.5 9 4.0 30 300 - - mA A A VP-P - Operating Current Charge Current Discharge Current Voltage Swing Discharge to Charge Current Ratio Peak Current Sense Voltage Saturation Voltage 1 ICC Ichg Idis VOSC Iratio SI=V+ - 12 110 - - Vipk Ichg=Idis 250 300 350 mV Vsat1 - 1.0 1.3 V Saturation Voltage 2 Vsat2 Darlington Connection (CS=CD), ISW=0.7A ISW=0.7A, Ic(driver)=50mA (Forced 14) - 0.5 0.7 V Output Transistor Bias Resistance DC Voltage Gain Collector Off-State Current Threshold Voltage Input Bias Current Rbias - 160 - 35 - 120 10 - - - nA 1.225 - 1.250 40 1.275 400 V nA hFE IC(Off) Vth IIB CT=1nF, SI=V , IN > Vth, ES=GND MIN. ISW=0.7A, VCE=5.0V VCE=40V IN+=0V (note) Output switch tests are performed under pulsed conditions to minimize power dissipation. TIMING CHART High Voltage Detect Reference Voltage Output Voltage Oscillator Waveform OSC Block to FF Reset HIGH LOW Collector-Emitter Voltage OFF ON -4- Current-Limit Active Point NJM2374A TIPICAL CHARACTERISTICS Switch ON/OFF Time tON / t OFF (S) Oscillator Frequency f OSC (kHz) 1000 Switch ON/OFF Time vs. Timing Capacitor (V+=5V,SI=V+,Pin5=GND,Ta=25C) 1000 Oscillator Frequency vs. Timing Capacitor (V+=5V,SI=V+,Pin5=GND,Ta=25C) 100 10 tON 10 tOFF 1 100 1 100 10000 Saturation Voltage 1 vs. Collector Current (V+=5V,CS=CD,Ta=25C) 1.5 1 0.5 0 0 0.5 1 1.5 Collector Current IC (A) 4 1000 10000 Timing Capacitor CT (pF) Saturation Voltage 2 Vsat2 (V) 2 1000 Timing Capacitor CT (pF) Operating Current I CC (mA) Saturation Voltage 1 Vsat1 (V) 100 2 Saturation Voltage 2 vs. Collector Current (V+=5V,Ic(driver)=50mA,=14,Ta=25C) 1.5 1 0.5 0 2 0 0.5 1 1.5 Collector Current IC (A) 2 Operating Current vs. Operating Voltage (CT=1nF,SI=V+,IN+>Vth,ES=GND,Ta=25C) 3 2 1 0 0 5 10 15 20 25 30 35 40 Operating Voltage V+ (V) -5- NJM2374A TIPICAL CHARACTERISTICS Threshold Voltage vs. Temperature (V+=5V) 10 Discharge to Charge Current Ratio I ratio Threshold Voltage Vth (V) 1.3 1.28 1.26 1.24 1.22 -50 -25 0 25 50 9 8 7 6 75 100 125 150 -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) Saturation Voltage 2 Vsat2 (V) Saturation Voltage 1 Vsat1 (V) Ambient Temperature Ta (C) 1.2 1.1 1 0.9 0.8 0.7 0.6 -50 -25 0 25 50 Discharge to Charge Current Ratio vs. Temperature (V+=5V,SI=V+) 75 100 125 150 0.8 Saturation Voltage 2 vs. Temperature (V+=5V,ISW =0.7A,Ic(driver)=50mA,=14) 0.6 0.4 0.2 0 -50 -25 Ambient Temperature Ta (C) 0 Operating Current vs Temperature (V =5V,CT=1nF,SI=V+,IN+>Vth,ES=GND) Operating Current ICC (mA) 4 3 2 1 0 -50 -25 0 25 50 75 100 125 150 Ambient Temperature Ta (C) -6- 50 75 100 125 150 Ambient Temperature Ta (C) + 5 25 NJM2374A TYPICAL APPLICATIONS Step-Down Converter VIN=25V RSC 0.22 VOUT=5.0V L1 220H 8 1 7 2 NJM2374A R2 3.6k 5 6 4 3 CIN 100F R1 1.2k D1 CT 470pF 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 D1 L1 180H VOUT=30V RC 180 COUT 150F R2 46k 8 1 2 7 NJM2374A 5 6 4 3 CIN 100F R1 2k CT 1500pF Inverting Converter VIN=5V RSC 0.22 D1 7 1 8 NJM2374A R2 953 6 5 4 CIN 100F VOUT=-12V 2 3 CT 1300pF L1 90H R1 8.2k 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 VOUT=10V L1 33F 8 1 7 2 NJM2374A R2 70k 6 5 4 3 CIN 300F CT 330pF D1 R1 10k COUT 300F Step-Up Converter (High Current) VIN=5V RSC 0.075 D1 L1 22H VOUT=7V RC1 100 RC2 680 COUT 940F R2 46k 8 1 2SC3255 2 7 NJM2374A 5 6 4 CIN 940F 3 CT 330pF RBE 220 R1 10k 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-