MC34063A

® MC34063A DC-DC CONVERTER CONTROL CIRCUITS s s s s s s 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 DIP-8 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. SO-8 BLOCK DIAGRAM April 2000 1/15 MC34063A ABSOLUTE MAXIMUM RATINGS Symbol V CC V ir V SWC V SWE V CE Vd c I dc I SW P tot T op T st g Power Supply Voltage Comparator Input Voltage Range Switch Collector Voltage Switch Emitter Voltage (VSWC = 40V) Switch Emitter to Collector Voltage Driver Collector Voltage Driver Collector Current Switch Current Power Dissipation at Tamb = 25 oC (for Plastic Package) (for SOIC Package) Operating Ambient Temperature Range (for AC SERIES) (for AB SERIES) Storage Temperature Range Parameter Value 50 -0.3 to 40 40 40 40 40 100 1.5 1.25 0.625 0 to 70 - 40 to 85 - 40 to 150 Unit V V V V V V mA A W o o o C C 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 Max DIP-8 100 SO-8 160 Unit o R thj- amb Thermal Resistance Junction-ambient (*) C/W (*) This value depends from thermal design of PCB on which the device is mounted. CONNECTION DIAGRAM (top view) PIN CONNECTIONS Pin No 1 2 3 4 5 6 7 8 Symbol SWC SW E TC GND CII V CC I pk DRC Name and Function Switch Collector Switch Emitter Timing Capacitor Ground Comparator Inverting Input Voltage Supply Ipk Sense Voltage Driver Collector ORDERING NUMBERS Type MC34063AB MC34063AC DIP-8 MC34063ABN MC34063ACN SO-8 MC34063ABD MC34063ACD SO-8 (tape & reel) MC34063ABD-TR 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 f OSC I ch g I dischg Parameter Frequency Charge Currernt Discharge Current Vpin5 = 0 V Test Conditions CT = 1 nF Ta = 25 oC VCC = 5 to 40 V VCC = 5 to 40 V Pin 7 = VCC Ta = 25 oC Ta = 25 oC o Min. 24 24 140 5.2 250 Typ. 33 33 200 6.2 300 Max. 42 42 260 7.5 350 Unit KHz µA µA I d is ch g/I chg Discharge to Charge Current Ratio Ta = 25 C Ta = 25 oC V i pk( sense) Current Limit Sense Voltage Ichg = Idischg mV OUTPUT SWITCH Symbol V CE(sat) V CE(sat) hF E I C( off) Parameter Saturation Voltage, Darlington Connection Saturation Voltage DC Current Gain Collector Off-State Current ISW = 1 A Test Conditions Pins 1, 8 connected Min. Typ. 1 0.45 o Max. 1.3 0.7 Unit V V ISW = 1 A Rpin8 = 82 Ω to VCC, Forced β ~ 20 ISW = 1 A VCE = 40 V VCE = 5 V Ta = 25 C 50 120 0.01 100 µA COMPARATOR Symbol Vt h Reg li ne II B Parameter Threshold Voltage Threshold Voltage Line Regulation Input Bias Current o Test Conditions Ta = 25 C Ta = TLOW to THIGH VCC = 3 to 40 V VIN = 0 V Min. 1.225 1.21 Typ. 1.25 1 -5 Max. 1.275 1.29 5 -400 Unit V V mV nA 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. Typ. 2.5 Max. 4 Unit mA 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 Vout GND GND Vin Pin 1 2 3 4 Test Condition (VOUT = 28V) Test Line Regulation Load Regulation Output Ripple Efficency VIN = 8 to 16V, VIN = 12V, VIN = 12V, VIN = 12V, Conditions IO = 175 mA Value (Typ.) 30 10 300 89 Unit mV mV mV % IO = 75 to 175 mA IO = 175 mA IO = 175 mA 6/15 MC34063A Step-Down Converter Printed Demoboard Symbol Vout GND GND Vin Pin 1 2 3 4 Test Condition (VOUT = 5V) Test Line Regulation Load Regulation Output Ripple Efficency ISC VIN = 15 to 25V, VIN = 25V, VIN = 25V, VIN = 25V, VIN = 25V, Conditions IO = 500 mA Value (Typ.) 5 30 100 80 1.2 Unit mV mV mV % A IO = 50 to 500 mA IO = 500 mA IO = 500 mA RLOAD = 0.1Ω 7/15 MC34063A Voltage Inverting Converter Printed Demoboard Symbol Vout GND GND Vin Pin 1 2 3 4 Test Condition (VOUT = -12V) Test Line Regulation Load Regulation Output Ripple Efficency ISC VIN = 4.5 to 6V, VIN = 5V, VIN = 5V, VIN = 5V, VIN = 5V, Conditions IO = 100 mA Value (Typ.) 15 20 230 58 0.9 Unit mV mV mV % A IO = 10 to 100 mA IO = 100 mA IO = 100 mA RlLOAD = 0.1Ω 8/15 MC34063A Calculation Parameter ton/toff (ton + toff)max CT IPK(switch) RSC CO L(min) Step-Up (Discontinuos mode) Vout + VF − Vin(min) Vi n(min) − Vsa t 1/f min 4.5x10 - 5t on 2I ou t(max)[(to n/t off)+1] 0.3/IPK(switc h) ≅ Iout ton Vri pple (p−p) Step-Down (Continuos mode) Vout + VF Vi n(min) − Vsat − Vout 1/fmin 4.5x10 -5 t on 2I out( max) 0.3/I PK(switc h) IPK (s witc h) (ton + toff ) 8Vri pple (p−p) Vin(min) − Vsa t − Vo ut ton (max) IPK (swit ch) Voltage Inverting (Discontinuos mode) | Vo ut | + VF Vin − Vs at 1/f mi n 4.5x10 -5t o n 2I out(max)[(t on/t off )+1] 0.3/I PK(switch ) ≅ Iout to n Vripp le (p−p) Vin(mi n) − Vs at to n (max) IPK (swit ch) 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 DIM. MIN. A a1 B B1 b b1 D E e e3 e4 F I L Z 0.44 3.3 1.6 0.017 8.8 2.54 7.62 7.62 7.1 4.8 0.130 0.063 0.38 0.7 1.39 0.91 0.5 0.5 9.8 0.346 0.100 0.300 0.300 0.280 0.189 0.015 1.65 1.04 mm TYP. 3.3 0.028 0.055 0.036 0.020 0.020 0.386 0.065 0.041 MAX. MIN. inch TYP. 0.130 MAX. P001F 13/15 MC34063A SO-8 MECHANICAL DATA DIM. MIN. A a1 a2 a3 b b1 C c1 D E e e3 F L M S 3.8 0.4 4.8 5.8 1.27 3.81 4.0 1.27 0.6 8 (max.) 0.14 0.015 5.0 6.2 0.65 0.35 0.19 0.25 0.1 mm TYP. MAX. 1.75 0.25 1.65 0.85 0.48 0.25 0.5 45 (typ.) 0.188 0.228 0.050 0.150 0.157 0.050 0.023 0.196 0.244 0.025 0.013 0.007 0.010 0.003 MIN. inch TYP. MAX. 0.068 0.009 0.064 0.033 0.018 0.010 0.019 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