TIGER ELECTRONIC CO.,LTD DC-to-DC Converter Control Circuits MC34063A Outline Drawing GENERAL DESCRIPTION The MC34063A is a monolithic control circuit co ntaining th e primary functions required for DC-to-D C converters. These devices consist of an internal temperature co mpensated reference, comparator, controlled duty cycle oscillator with an active current li mit circuit, driver and high DIP8 current output switch. This series was specifically designed to be incorporated in Step-Down and Step-Up and voltage- Inver ting applications with a mini mu m nu mb er of external co mponents. FEATURES z Operation fro m 3.0V to 40V Input z Low Standby Current z Current Limiting z Output Switch Current to 1.2A z Output Voltage Adjustable z Frequency Operation to 100kHz z Precision 2% Reference SOP8 1/9 MC34063A BLOCK DIAGRAM PIN CONNECTION Switch ollector Switch Emitter 1 2 MC34063A 8 Drive Collector 7 Ipk Timing apacitor 3 6 Vcc Ground 4 5 Comparator Inverting Input MAXIMUM RATINGS (Ta=25°C) Rating Symbol Value Unit Power Supply Vo ltage Vcc 40 V Co mparator Input Voltage Range VIR 0.3~40 V Switch Collector Vo ltage Vc(switch) 40 V Switch Emitter Voltage (V P in 1 =40V) V E (switch) 40 V Switch Collector to Emitter Vo ltage V C E (switch) 40 V Driver Collector Vo ltage Vc(drive) 40 V Driver Collector Cu rrent (Note 1) Ic(drive) 100 mA ISW 1.2 A 1.25 W 625 mW Ta 0~70 °C Tstg -65~150 °C Switch Current Power Diss ipation DIP8 SOP8 Operating Ambient Temp erature Range Storage Temperature Range PD Notes: 1.Maximum package power dissipation limits must be observed 2.ESD data available upon request 2/9 MC34063A ELECTRICAL CHARACTERISTICS (Unless otherwise specified: Vcc=5.0V, Ta=0~70°C) CHARACT ERISTICS SYMBOL MIN TYP MAX UNIT Frequency (Vpin5=0V, Vcc=5.0V) fosc 24 33 42 kHz Charge current (Vcc=5.0~40V, Vpin3=L) Ichg 24 31 42 µA 199 260 µA 6.2 7.5 300 350 mV 0.9 1.3 V 0.45 0.7 V 100 µA 1.23 1.25 4.0 1.27 5.0 V mV IIB -40 -400 nA Icc 2.36 4.0 mA OSCILLATOR Discharge current (Vcc=5.0~40V, Vpin3=H) Idischg 140 Discharg e to charge current ratio Idischg/Ichg 5.2 (V P I N 7 =V C C , Ta=25°C) Current li mit sense voltage Vipk(sense) 250 (Ichg=Idischg, Ta=25°C) OUTPUT S WITCH (N ote 3) Saturation voltage, Darlington connection(Note 4) V C E (sat) (I S W =0.8A, pins 1,8 connected) Saturation voltage, Darlington connection V C E (sat) (I S W =0.8A, Rpin 8=82Ω to Vcc) DC current gain (I S W =0.8A,V C E =5.0V, Ta=25°C) hFE 50 Collector off-state current (V C E = 40V) Ic(off) COMPAR ATOR Threshold voltage (Ta=25°C, Vcc=5.0V) Threshold voltage line regulation (Vcc=5.0~40V) Vth Regline Input bias cu rrent(Vin=0V) 120 2 TOTAL DEVICE S u p p l y c u r r e n t ( V c c = 5 . 0 ~ 4 0 V, V p i n 5 = H ) Notes: 3. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as possible. 4. If the output switch is driven into hard saturation (non-Darlington configuration) at low switch currents (≤ 300 mA) and high driver currents (≥ 30 mA), it may take up to 2.0 µs for it to come out of saturation. This condition will shorten the off time at frequencies≥ 30 kHz, and is magnified at high temperatures. This condition does not occur with a Darlington configuration, since the output switch cannot saturate. If a non-Darlington configuration is used, the following output drive condition is recommended: Forced βof output switch : Ic output/ (Ic drive –7.0mA)* ≥10 *The 100Ω resistor in the emitter of the driver device requires about 7.0 mA before the output switch conducts. 3/9 MC34063A APPLICATION CIRCUITS 1.Step-Up Converter test conditions Results Line Regulation Vin=8.0~16V, Io=175mA 30mV=±0.05% Load Regu lation Vin=12V,Io=75~175 mA 10mV=±0.017% Output Ripp le Vin=12V, Io=175 mA 400mVpp Efficiency Vin=12V, Io=175mA 87.7% Output Ripple With Optional Filter Vin=12V, Io=175mA 40mVpp 2.External Current Boost Connections for Ic Peak Greater than 1.5A (1).External NPN Switch (2 ) External NPN Saturated Switch (Note 4) 4/9 MC34063A 3.Step-Down Converter test conditions Results Line Regulation Vin=15~25V, Io=500mA 12mV=±0.12% Load Regulation Vin=25V,Io=50~500 mA 3.0mV=±0.03% Vin=25V, Io=500 mA 120mVpp Vin=25V,RL=0.1Ω 1.1A Efficiency Vin=25V, Io=500mA 83.7% Output Ripple With Optional Filter Vin=25V, Io=500mA 40mVpp Output Ripp le Short Circuit Current 4.External Current Boost Connections for Ic Peak Greater than 1.5A (1).External NPN Switch (2) External NPN Saturated Switch 5/9 MC34063A 5. Voltage inverting converter test conditions Results Line Regulation Vin=4.5~6.0V, Io=100mA 3.0mV=±0.012% Load Regulation Vin=5.0V,Io=10~100mA 3.0mV=±0.09% Vin=5.0V, Io=100 mA 500mVpp Vin=5.0V,RL=0.1Ω 910mA Efficiency Vin=5.0V, Io=100mA 62.2% Output Ripple With Optional Filter Vin=5.0V, Io=100mA 70mVpp Output Ripp le Short Circuit Current 6.External Current Boost Connections for Ic Peak Greater than 1.5A (1).External NPN Switch (2) External NPN Saturated Switch 6/9 MC34063A CHARACTERISTICS CURVES Output switch on-off time versus Timing capacitor waveform oscillator ti ming capacitor Emitter fo llower configuration output common emitter co nfiguration output Saturation voltage versus emitter switch saturation voltage versus current co llector current current limit sense voltage versus standby supply current versus temperature supply voltage 7/9 MC34063A MARKING INFORMATION： OUTLINE DRAWING DIP8： Unit:mm 8/9 MC34063A SOP8： Unit:mm 9/9