MC34063A DC-DC CONVERTER CONTROL CIRCUITS ■ ■ ■ ■ ■ ■ OUTPUT SWITCH CURRENT IN EXCESS OF 1.5A 2% REFERENCE ACCURACY LOW QUIESCENT CURRENT: 2.5mA (TYP.) OPERATING FROM 3V TO 40V FREQUENCY OPERATION TO 100KHz ACTIVE CURRENT LIMITING DESCRIPTION The MC34063A series is a monolithic control circuit delivering the main functions for DC-DC voltage converting. The device contains an internal temperature compensated reference, comparator, duty cycle controlled oscillator with an active current limit circuit, driver and high current output switch. Output voltage is adjustable through two external resistors with a 2% reference accuracy. Employing a minimum number of external components the MC34063A devices series is designed for Step-Down, Step-Up and Voltage-Inverting applications. DIP-8 SO-8 BLOCK DIAGRAM April 2000 1/15 MC34063A ABSOLUTE MAXIMUM RATINGS Symbol V CC Parameter Value Unit 50 V Power Supply Voltage -0.3 to 40 V V SWC Switch Collector Voltage 40 V V SWE V ir Comparator Input Voltage Range Switch Emitter Voltage (VSWC = 40V) 40 V V CE Switch Emitter to Collector Voltage 40 V Vd c Driver Collector Voltage 40 V I dc Driver Collector Current 100 mA I SW Switch Current 1.5 A P tot Power Dissipation at Tamb = 25 oC (for Plastic Package) (for SOIC Package) 1.25 0.625 W T op Operating Ambient Temperature Range (for AC SERIES) (for AB SERIES) 0 to 70 - 40 to 85 o o C C T st g Storage Temperature Range - 40 to 150 o C Absolute Maximum Rating are those values beyond which damage to the device may occur. Functional operation under these condition is not implied. THERMAL DATA Symbol Parameter DIP-8 R thj- amb Thermal Resistance Junction-ambient (*) Max SO-8 100 160 Unit o C/W (*) This value depends from thermal design of PCB on which the device is mounted. CONNECTION DIAGRAM (top view) PIN CONNECTIONS Pin No Symbol Name and Function 1 SWC Switch Collector 2 SW E Switch Emitter 3 TC 4 GND 5 CII Comparator Inverting Input 6 V CC Voltage Supply 7 I pk 8 DRC Timing Capacitor Ground Ipk Sense Voltage Driver Collector ORDERING NUMBERS Type DIP-8 SO-8 SO-8 (tape & reel) MC34063AB MC34063ABN MC34063ABD MC34063ABD-TR MC34063AC MC34063ACN MC34063ACD MC34063ACD-TR 2/15 MC34063A ELECTRICAL CHARACTERISTICS (Refer to the test circuits, VCC = 5V, T a = TLOW to THIGH, unless otherwise specified, see note 2) OSCILLATOR Symbol Parameter Test Conditions Ta = 25 oC Min. Typ. Max. Unit 24 33 42 KHz 33 42 µA 200 260 µA f OSC Frequency Vpin5 = 0 V I ch g Charge Currernt VCC = 5 to 40 V Ta = 25 oC 24 Discharge Current VCC = 5 to 40 V Ta = 25 oC 140 I dischg I d is ch g/I chg Discharge to Charge Current Ratio CT = 1 nF o Pin 7 = VCC Ta = 25 C 5.2 6.2 7.5 V i pk( sense) Current Limit Sense Voltage Ichg = Idischg Ta = 25 oC 250 300 350 mV Test Conditions Min. Typ. Max. Unit 1 1.3 V 0.45 0.7 V 0.01 100 µA Min. Typ. Max. Unit 1.225 1.21 1.25 1.275 1.29 V V OUTPUT SWITCH Symbol Parameter V CE(sat) Saturation Voltage, Darlington Connection ISW = 1 A V CE(sat) Saturation Voltage ISW = 1 A Rpin8 = 82 Ω to VCC, Forced β ~ 20 DC Current Gain ISW = 1 A Collector Off-State Current VCE = 40 V hF E I C( off) Pins 1, 8 connected VCE = 5 V o Ta = 25 C 50 120 COMPARATOR Symbol Vt h Reg li ne II B Parameter Test Conditions o Threshold Voltage Ta = 25 C Ta = TLOW to THIGH Threshold Voltage Line Regulation VCC = 3 to 40 V 1 5 mV Input Bias Current VIN = 0 V -5 -400 nA Typ. Max. Unit 2.5 4 mA TOTAL DEVICE Symbol I CC Parameter Supply Current Test Conditions VCC = 5 to 40 V CT = 1 nF Pin 7 = VCC Vpin5 > Vth Pin 2 = GND Remaining pins open Min. NOTES: 1) Maximum package power dissipation limit must be observed. 2) TLOW = 0 oC, THIGH = 70 oC (AC series); TLOW = -40 oC, THIGH = 85 oC (AB series). 3) If Darlington configuration is not used, care must be taken to avoid deep saturation of output switch. The resulting switch-off time may be adversely affected. In a Darlington configuration the following output driver condition is suggested: Forced β of output current switch = I COUTPUT/(ICDRIVER - 1mA*) ≥ 10 * Current less due to a built in 1KΩ antileakage resistor. 3/15 MC34063A TYPICAL ELECTRICAL CHARACTERISTICS Emitter Follower Configuration Output Saturation Voltage vs Emitter Current Output Switch ON-OFF Time vs Oscillator Timing Capacitor Common Emitter Configuration Output Switch Saturation Voltage vs Collector Current Darlington Configuration Collector Emitter Saturation Voltage (VCE(sat)) vs Temperature Power Collector Emitter Saturation Voltage (VCE(sat)) vs Temperature Current Limit Sense Voltage Voltage (Vipk) vs Temperature 4/15 MC34063A TYPICAL ELECTRICAL CHARACTERISTICS (Continued) Reference Voltage vs Temperature Bias Current vs Temperature Supply Current vs Temperature Supply Current vs Input Voltage 5/15 MC34063A TYPICAL APPLICATION CIRCUIT Step-Up Converter Printed Demoboard Symbol Pin Vout 1 GND 2 GND 3 Vin 4 Test Condition (VOUT = 28V) Test Conditions Value (Typ.) Unit 30 mV IO = 75 to 175 mA 10 mV VIN = 12V, IO = 175 mA 300 mV VIN = 12V, IO = 175 mA 89 % Line Regulation VIN = 8 to 16V, Load Regulation VIN = 12V, Output Ripple Efficency 6/15 IO = 175 mA MC34063A Step-Down Converter Printed Demoboard Symbol Pin Vout 1 GND 2 GND 3 Vin 4 Test Condition (VOUT = 5V) Test Value (Typ.) Unit IO = 500 mA Conditions 5 mV VIN = 25V, IO = 50 to 500 mA 30 mV Output Ripple VIN = 25V, IO = 500 mA 100 mV Efficency VIN = 25V, IO = 500 mA 80 % ISC VIN = 25V, RLOAD = 0.1Ω 1.2 A Line Regulation VIN = 15 to 25V, Load Regulation 7/15 MC34063A Voltage Inverting Converter Printed Demoboard Symbol Pin Vout 1 GND 2 GND 3 Vin 4 Test Condition (VOUT = -12V) Test Value (Typ.) Unit IO = 100 mA Conditions 15 mV VIN = 5V, IO = 10 to 100 mA 20 mV Output Ripple VIN = 5V, IO = 100 mA 230 mV Efficency VIN = 5V, IO = 100 mA 58 % ISC VIN = 5V, RlLOAD = 0.1Ω 0.9 A Line Regulation VIN = 4.5 to 6V, Load Regulation 8/15 MC34063A Calculation Parameter ton/toff Step-Up (Discontinuos mode) Step-Down (Continuos mode) Voltage Inverting (Discontinuos mode) Vout + VF − Vin(min) Vi n(min) − Vsa t Vout + VF Vi n(min) − Vsat − Vout | Vo ut | + VF Vin − Vs at (ton + toff)max 1/f min 1/fmin 1/f mi n 4.5x10 - 5t on 4.5x10 -5 t on 4.5x10 -5t o n 2I ou t(max)[(to n/t off)+1] 2I out( max) 2I out(max)[(t on/t off )+1] RSC 0.3/IPK(switc h) 0.3/I PK(switc h) 0.3/I PK(switch ) CO ≅ CT IPK(switch) L(min) Iout ton Vri pple (p−p) Vin(mi n) − Vs at to n (max) IPK (swit ch) IPK (s witc h) (ton + toff ) 8Vri pple (p−p) Vin(min) − Vsa t − Vo ut ton (max) IPK (swit ch) ≅ Iout to n Vripp le (p−p) Vin(mi n) − Vsat ton (ma x) IPK (s wi tch) NOTES: Vsat = Saturation voltage of the output switch VF = Foward voltage drop of the output rectifier THE FOLLOWING POWER SUPPLY CHARACTERISTICS MUST BE CHOSEN: Vin = Nominal input voltage Vout = Desired output voltage, |V out| = 1.25(1+R2/R1) Iout = Desired output current fmin = Minimum desired output switching frequency at the selected values of Vin and Io Vripple = Desired peak to peak output ripple voltage. In practice, the calculaed capacitor value will and to be increased due to its equivalent series resistance and board layout. The ripple voltage should be kept to a low value since it will directly affect the line and load regulation. Step-up With External NPN Switch 9/15 MC34063A Step-down With External NPN Switch Step-down With External PNP Switch 10/15 MC34063A Voltage Inverting With External NPN Switch Voltage Inverting With External PNP Saturated Switch 11/15 MC34063A Dual Output Voltage Higher Output Power, Higher Input Voltage 12/15 MC34063A Plastic DIP-8 MECHANICAL DATA mm DIM. MIN. A TYP. inch MAX. MIN. 3.3 TYP. MAX. 0.130 a1 0.7 B 1.39 1.65 0.055 0.065 B1 0.91 1.04 0.036 0.041 b b1 0.028 0.5 0.38 0.020 0.5 D 0.015 0.020 9.8 0.386 E 8.8 0.346 e 2.54 0.100 e3 7.62 0.300 e4 7.62 0.300 F 7.1 0.280 I 4.8 0.189 L Z 3.3 0.44 0.130 1.6 0.017 0.063 P001F 13/15 MC34063A SO-8 MECHANICAL DATA mm DIM. MIN. TYP. A a1 inch MAX. MIN. TYP. 1.75 0.1 0.068 0.25 a2 MAX. 0.003 0.009 1.65 0.064 a3 0.65 0.85 0.025 0.033 b 0.35 0.48 0.013 0.018 b1 0.19 0.25 0.007 0.010 C 0.25 0.5 0.010 0.019 c1 45 (typ.) D 4.8 5.0 0.188 0.196 E 5.8 6.2 0.228 0.244 e 1.27 0.050 e3 3.81 0.150 F 3.8 4.0 0.14 0.157 L 0.4 1.27 0.015 0.050 M S 0.6 0.023 8 (max.) 0016023 14/15 MC34063A Information furnished is believed to be accurate and reliable. However, STMicroelectronic s assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems withoutexpress written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics 2000 STMicroelectronics – Printed in Italy – All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A. http://www.st.com . 15/15