NJM2378 PWM SWITCHING REGULATOR CONTROL IC FOR SLAVE TYPE GENERAL DESCRIPTION The NJM2378 is a high speed switching regulator control IC, and directly drive an external Bipolar Transistor to use internal totempole output circuit. The NJM2378 operate slave mode which synchronous external oscillation frequency, and the slave mode reduce the total noise. The NJM2378 is suitable for flyback type switching regulation up to 10W and several output power supply for LCD panel. PACKAGE OUTLINE NJM2378D (DIP8) NJM2378M (DMP8) NJM2378E FEATURES (SOP8) Operating Voltage (3.6 to 32V) Reference Voltage (2.5V2%) Input Outside Oscillator Frequency (5 to 350 kHz) Output Switch Current (8mA min.) Under Voltage Lockouts Circuit Bipolar Technology Package Outline DIP8, DMP8, SOP8 JEDEC 150mil, SSOP8 NJM2378V (SSOP8) BLOCK DIAGRAM REF 8 CT CS V+ 7 6 5 30uA VREF L.O U.V.LO 500 S.C.P ERAMP 0.52V PWM 1 2 - F.B IN Ver.2012-02-20 PIN FUNCTION 1.IN2.F.B 3.GND 4.OUT 5.V+ 6.CS 7.CT 8.REF 3 GND 4 OUT -1- NJM2378 ABSOLUTE MAXIMUM RATINGS (Ta=25C) PARAMETER SYMBOL RATINGS UNIT Supply Voltage + V 36 V Reference Output Current IOR 10 mA Output Current IO 50 mA CT Pin Voltage VCT 1.5 V Power Dissipation PD (DIP8) 700 (DMP8) 300 (SOP8) 300 (SSOP8) 250 mW Operating Temperature Range TOPR -40 to +85 C Storage Temperature Range TSTG -50 to +125 C RECOMMENDED OPERATING CONDITIONS (V+=6V, Ta=25C) PARAMETER SYMBOL + MIN. MAX. UNIT Operating Voltage V 3.6 32 V Feed Back Resistor RNF 100 - k Oscillate fOSC 5 350 kHz INPUT WAVEFORME PARAMETER Triangle Waveform Offset Voltage -2- SYMBOL RECOMMENDED UNIT VP-P 0.5 V VOFFSET 0.5 V Ver.2012-02-20 NJM2378 ELECTRICAL CHARACTERISTICS (V+=6V, RT=33k, CT=1000pF, Ta=25C OSC:Triangle Waveform, VP-P=0.5V, Offset=0.5V, fOSC=100kHz) REFERENCE VOLTAGE BLOCK PARAMETER SYMBOL Output Voltage VREF TEST CONDITION IOR=1mA + MIN. TYP. MAX. UNIT 2.45 2.50 2.55 V Line Regulation LINE V =3.6 to 32V, IOR=1mA - 6.8 20.7 mV Load Regulation LOAD IOR=0.1 to 5.0mA - 5 30 mV MIN. TYP. MAX. UNIT OSCILLATOR BLOCK PARAMETER SYMBOL TEST CONDITION Reference Voltage VB 0.51 0.52 0.53 V Input Bias Current IB - 5 100 nA Open Loop Gain AV - 90 - dB Gain Band width Product GB - 0.6 - MHz Maximum Output Voltage VOM+ RNF=100k VREF-0.2 - - V VOM- RNF=100k - - 200 mV IOM+ VOM=1V 40 85 200 A MIN. TYP. MAX. UNIT (F.B Pin) Output Source Current PWM COMPARATOR BLOCK PARAMETER SYMBOL TEST CONDITION Triangle Waveform Input Minimum Voltage (CT Pin) OSCLO CT Pin Triangle Waveform Input 0 - 0.4 V Triangle Waveform Input Maximum Voltage (CT Pin) OSCHI CT Pin Triangle Waveform Input 0.7 - 1.3 V Input Threshold Voltage (F.B Pin) VTH0 dutycycle=0% - 0.55 0.65 V Input Threshold Voltage (F.B Pin) VTH50 dutycycle=50% - 0.87 - V 55 64 85 % MIN. TYP. MAX. UNIT - 250 650 nA Maximum Duty Cycle M F.B Pin=1.2V SOFT START CIRCUIT BLOCK PARAMETER Input Bias Current (CS Pin) SYMBOL TEST CONDITION IBCS Input Threshold Voltage (CS Pin) VTHCS0 dutycycle=0% - 0.25 0.35 V Input Threshold Voltage (CS Pin) VTHCS50 dutycycle=50% - 0.52 - V Ver.2012-02-20 -3- NJM2378 ELECTRICAL CHARACTERISTICS (V+=6V, RT=33k, CT=1000pF, Ta=25C OSC:Triangle Waveform, VP-P=0.5V, OFFSET=0.5V, fOSC=100kHz) SHORT CIRCUIT PROTECTION PARAMETER Input Threshold Voltage (F.B Pin) SYMBOL TEST CONDITION VTHPC Charge Current (CS Pin) ICHG Latch mode Threshold Voltage (CS Pin) VTHLA CS Pin=0V,F.B Pin=2V MIN. TYP. MAX. UNIT 1.20 1.50 1.80 V 10 30 50 A 1.20 1.50 1.80 V MIN. TYP. MAX. UNIT UNDER VOLTAGE LOCKOUT PARAMETER SYMBOL TEST CONDITION ON Threshold Voltage VTHON - 2.70 - V OFF Threshold Voltage VTHOFF - 2.52 - V VHYS 60 180 - mV MIN. TYP. MAX. UNIT 3.50 4.00 - V Hysteresis Voltage OUTPUT PARAMETER SYMBOL TEST CONDITION H-Output Voltage (OUT Pin) VOH RL=10k L-Output Voltage (OUT Pin) VOL Output Sink Current=20mA - 0.25 0.65 V OUT Pin=0V 8 11 - mA MIN. TYP. MAX. UNIT Output Source Current (OUT Pin) ISOURCE GENERAL CHARACTERISTICS PARAMETER SYMBOL TEST CONDITION Quiescent Current ICCLA Latch Mode - 1.6 2.2 mA Average Quiescent Current ICCAV RL=, dutycycle=50% - 3.5 4.8 mA -4- Ver.2012-02-20 NJM2378 TYPICAL APPLICATIONS Synchronous mode with NJM2368 8 7 6 5 8 7 6 5 1 2 3 4 1 2 3 4 NJM2368 VOUT1 VOUT2 NJM2378 External pulse mode + V Rsf Rsr Cs Duty 50% Input Pulse 8 7 0.5V 6 D1 5 VOUT 30uA 0.5V VREF GND L.O U.V.LO 500 CIN N1 S.C.P R1 N2 ERAMP 0.52V PWM L COUT 1 2 3 4 R2 CLP Q1 Rf GND *100k GND When Short Circuit Protection (SCP) is activated, Output terminal (Pin 4) becomes high impedance and the external switching transistor (Q1) is turned off. However, small leak current from Output terminal at high ambient temperature may turn on the external switching transistor causing malfunction of the SCP particularly when FET is used as a switching device. To avoid this issue, insert a 100k resistor between the Gate and the Source of the external transistor. Ver.2012-02-20 -5- NJM2378 TYPICAL CHARACTERISTICS H Output Voltage(OUT Pin) vs. Source Current L Output Voltage(OUT Pin) vs. Sink Current (V+ =6V,OSC:Triangle Waveform VP-P =0.5V,Offset=0.5V,fosc=100kHz,Ta=25 1 7 Output Voltage V H Output Voltage VOH (V+ =6V,OUT Pin=0V,OSC:Triangle Waveform VP-P =0.5V,Offset=0.5V,fosc=100kHz,Ta=25 8 6 5 4 3 2 1 0.8 0.6 0.4 0.2 0 0 0 2 4 6 8 10 Source Current (mA 12 0 Reference Voltage vs. Operating Voltage Operating Current ICC (mA) Reference Voltage 2.5 2.49 2.48 4 ICCAV 3 ICCLA 2 1 0 0 10 20 30 + Operating Voltage -6- (Ta=25) 5 2.51 60 Operating Current vs. Operating Voltage (Ta=25) 2.52 10 20 30 40 50 Sink Current (mA) 40 0 10 20 30 40 + Operating Voltage V (V) Ver.2012-02-20 NJM2378 TYPICAL CHARACTERISTICS Reference Voltage vs. Temperature 2.6 12 2.55 Output Source Current ISOURCE mA Reference Voltage Output Source Current (OUT Pin) vs. Temperature (V+ =6V,IOR=1mA) 2.5 2.45 (V+ =6V,OSC:Triangle Waveform VP-P =0.5V,Offset=0.5V,fosc=100kHz) 11 10 9 2.4 -50 -25 0 25 50 75 8 100 125 -50 -25 Ambient Temperature 0 25 50 75 100 125 Ambient Temperature H Output Voltage (OUT Pin) vs. Temperature 5 4 3 2 1 (V+ =6V,ISINK=20mA,OSC:Triangle Waveform VP-P =0.5V,Offset=0.5V,fosc=100kHz) 0.3 L Output Voltage 6 H Output Voltage L Output Voltage (OUT Pin) vs. Temperature (V+ =6V,RL=10k,OSC:Triangle Waveform VP-P =0.5V,Offset=0.5V,fosc=100kHz) 0.25 0.2 0.15 0.1 0.05 0 0 -50 -25 0 25 50 75 -50 -25 100 125 0 25 50 75 100 125 Ambient Temperature Ambient Temperature Quiescent Current(Latch Mode) vs. Temperature Average Quiescent Current vs. Temperature (V+ =6V,RL=,OSC:Triangle Waveform VP-P =0.5V,Offset=0.5V,fosc=100kHz) + (V =6V,OSC:Triangle Waveform VP-P =0.5V,Offset=0.5V,fosc=100kHz) 5 Average Quiescent Current Quiescent Current (Latch Mode) 2 1.5 1 0.5 0 4 3 2 1 0 -50 -25 0 25 50 75 100 125 Ambient Temperature Ver.2012-02-20 -50 -25 0 25 50 75 100 125 Ambient Temperature -7- NJM2378 [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- Ver.2012-02-20