MC34063

DC-DC CONVERTER CONTROL CIRCUITS

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OUTPUT SWITCH CURRENT IN EXCESS OF1.5A

2% REFERENCE ACCURACY

LOW QUIESCENT CURRENT: 2.5mA (TYP.)OPERATING FROM 3V TO 40V

FREQUENCY OPERATION TO 100KHzACTIVE CURRENT LIMITING

DIP-8DESCRIPTION The MC34063A/E series is a monolithic controlcircuit delivering the main functions for DC-DCvoltage converting.

The device contains an internal temperaturecompensated reference, comparator, duty cyclecontrolled oscillator with an active current limitcircuit, driver and high current output switch.

Output voltage is adjustable through two externalresistors with a 2% reference accuracy.

Employing a minimum number of externalcomponents the MC34063A/E devices series isdesigned for Step-Down, Step-Up andVoltage-Inverting applications.

SO-8BLOCK DIAGRAM

March 2001 1/15

MC34063A/E

ABSOLUTE MAXIMUM RATINGS

SymbolVCCVirVSWCVSWEVCEVdcIdcISWPtotTopPower Supply VoltageComparator Input Voltage RangeSwitch Collector VoltageSwitch Emitter Voltage (VSWC = 40V)Switch Collector toEmitter VoltageDriver Collector VoltageDriver Collector CurrentSwitch CurrentPower Dissipation at Tamb = 25 oC (for Plastic Package) (for SOIC Package)Operating Ambient Temperature Range (for AC and EC SERIES) (for AB SERIES) (for EB SERIES)Storage Temperature RangeParameterValue50-0.3 to 40404040401001.51.250.6250 to 70- 40 to 85- 40 to 125- 40 to 150UnitVVVVVVmAAWooCCoCoTstgCAbsolute Maximum Rating are those values beyond which damage to the device may occur. Functional operation under these condition is not implied.

THERMAL DATA

SymbolParameterDIP-8100SO-8160UnitoRthj-ambThermal Resistance Junction-ambient (*) Max(*) This value depends from thermal design of PCB on which the device is mounted.C/WCONNECTION DIAGRAM (top view)PIN CONNECTIONS

Pin No12345678SymbolSWCSWETCGNDCIIVCCIpkDRCName and FunctionSwitch CollectorSwitch EmitterTiming CapacitorGroundComparator Inverting InputVoltage SupplyIpk SenseVoltage Driver CollectorORDERING NUMBERS

TypeMC34063AB (*)MC34063AC (*)MC34063EBMC34063ECDIP-8MC34063ABNMC34063ACNMC34063EBNMC34063ECNSO-8MC34063ABDMC34063ACDMC34063EBDMC34063ECDSO-8 (tape & reel)MC34063ABD-TRMC34063ACD-TRMC34063EBD-TRMC34063ECD-TR(*) The \"A\" version is not recommended for new designs.2/15MC34063A/E

ELECTRICAL CHARACTERISTICS (Refer to the test circuits, VCC = 5V, Ta = TLOW to THIGH, unlessotherwise specified, see note 2)OSCILLATOR

SymbolfOSCIchgIdischgParameterFrequencyCharge CurrerntDischarge CurrentTest ConditionsVpin5 = 0 V CT = 1 nF Ta = 25 oCVCC = 5 to 40 V Ta = 25 oCPin 7 = VCC Ta = 25 oCIchg = Idischg Ta = 25 oCMin.241405.2250Typ.33332006.2300Max.42422607.5350mVUnitKHzµAµAVCC = 5 to 40 V Ta = 25 oC 24Idischg/IchgDischarge to ChargeCurrent RatioVipk(sense)Current Limit Sense VoltageOUTPUT SWITCH

SymbolVCE(sat)VCE(sat)hFEIC(off)ParameterSaturation Voltage,Darlington ConnectionSaturation VoltageDC Current GainCollector Off-State CurrentTest ConditionsISW = 1 A Pins 1, 8 connectedISW = 1 A Rpin8 = 82 Ω to VCC, Forced β ~ 20ISW = 1 A VCE = 5 V Ta = 25 oCVCE = 40 V50Min.Typ.10.451200.01100µAMax.1.30.7UnitVVCOMPARATOR

SymbolVthReglineIIBParameterThreshold VoltageThreshold Voltage LineRegulationInput Bias CurrentTest ConditionsTa = 25 oCTa = TLOW to THIGH VCC = 3 to 40 VVIN = 0 VMin.1.2251.21Typ.1.251-5Max.1.2751.295-400UnitVVmVnATOTAL DEVICE

SymbolICCParameterSupply CurrentTest ConditionsVCC = 5 to 40 V CT = 1 nFPin 7 = VCC Vpin5 > Vth Pin 2 = GNDRemaining pins openfor MC34063Afor MC34063ETa = 25 oC CT = 1 µF Pin 5 = 0 Vfor MC34063Afor MC34063EMin.Typ.Max.Unit2.51.52.11.4mAmAVVVSTART-UPStart-up Voltage (note 4)NOTES:1) Maximum package power dissipation limit must be observed.

2) TLOW = 0 oC, THIGH = 70 oC (AC and EC series); TLOW = -40 oC, THIGH = 85 oC (AB series); TLOW = -40 oC, THIGH = 125 oC (EB 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 beadversely affected. In a Darlington configuration the following output driver condition is suggested:Forced β of output current switch = ICOUTPUT/(ICDRIVER - 1mA*) ≥ 10* Current less due to a built in 1KΩ antileakage resistor.

4) Start-up Voltage is the minimum Power Supply Voltage at which the internal oscillator begins to work.

3/15MC34063A/E

TYPICAL ELECTRICAL CHARACTERISTICSEmitter Follower Configuration Output SaturationVoltage vs Emitter Current

Output Switch ON-OFF Time vs OscillatorTiming Capacitor

Common Emitter Configuration Output SwitchSaturation Voltage vs Collector CurrentDarlington Configuration Collector EmitterSaturation Voltage (VCE(sat)) vs Temperature

Power Collector Emitter Saturation Voltage(VCE(sat)) vs TemperatureCurrent Limit Sense Voltage Voltage (Vipk) vsTemperature

4/15MC34063A/E

TYPICAL ELECTRICAL CHARACTERISTICS (Continued)Reference Voltage vs Temperature

Bias Current vs Temperature

Supply Current vs TemperatureSupply Current vs Input Voltage

5/15MC34063A/E

TYPICAL APPLICATION CIRCUITStep-Up Converter

Printed Demoboard

SymbolVoutGNDGNDVinPin1234Test Condition (VOUT = 28V)

Test ConditionsLine RegulationLoad RegulationOutput RippleEfficencyVIN = 8 to 16V, IO = 175 mAVIN = 12V, IO = 75 to 175 mAVIN = 12V, IO = 175 mAVIN = 12V, IO = 175 mAValue (Typ.)Unit3010300mVmVmV%6/15MC34063A/E

Step-Down Converter

Printed Demoboard

SymbolVoutGNDGNDVinPin1234Test Condition (VOUT = 5V)

Test ConditionsLine RegulationLoad RegulationOutput RippleEfficencyISCVIN = 15 to 25V, IO = 500 mAVIN = 25V, IO = 50 to 500 mAVIN = 25V, IO = 500 mAVIN = 25V, IO = 500 mAVIN = 25V, RLOAD = 0.1ΩValue (Typ.)Unit530100801.2mVmVmV%A7/15MC34063A/E

Voltage Inverting Converter

Printed Demoboard

SymbolVoutGNDGNDVinPin1234Test Condition (VOUT = -12V)

Test ConditionsLine RegulationLoad RegulationOutput RippleEfficencyISCVIN = 4.5 to 6V, IO = 100 mAVIN = 5V, IO = 10 to 100 mAVIN = 5V, IO = 100 mAVIN = 5V, IO = 100 mAVIN = 5V, RlLOAD = 0.1ΩValue (Typ.)Unit1520230580.9mVmVmV%A8/15MC34063A/E

Calculation

Parameterton/toff(ton + toff)maxCTIPK(switch)RSCCOL(min)Step-Up(Discontinuos mode)Vout + VF − Vin(min)Vin(min) − Vsat1/fmin4.5x10-5ton2Iout(max)[(ton/toff)+1]0.3/IPK(switch)≅ Iout tonVripple (p−p)Step-Down(Continuos mode)Vout + VFVin(min) − Vsat − Vout1/fmin4.5x10-5ton2Iout(max)0.3/IPK(switch)IPK (switch ) (ton + toff )8Vripple (p−p)Vin(min) − Vsat − Vout ton (max)IPK (switch )Voltage Inverting(Discontinuos mode)| Vout | + VFVin − Vsat1/fmin4.5x10-5ton2Iout(max)[(ton/toff)+1]0.3/IPK(switch)≅ Iout tonVripple (p−p)Vin(min) − Vsat ton (max)IPK (switch )Vin(min) − Vsat ton (max )IPK (switch )NOTES:Vsat = Saturation voltage of the output switchVF = Foward voltage drop of the output rectifier

THE FOLLOWING POWER SUPPLY CHARACTERISTICS MUST BE CHOSEN:Vin = Nominal input voltage

Vout = Desired output voltage, |Vout| = 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 equivalentseries 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

9/15MC34063A/E

Step-down With External NPN Switch

Step-down With External PNP Switch

10/15MC34063A/E

Voltage Inverting With External NPN Switch

Voltage Inverting With External PNP Saturated Switch

11/15MC34063A/E

Dual Output Voltage

Higher Output Power, Higher Input Voltage

12/15MC34063A/E

Plastic DIP-8 MECHANICAL DATADIM.MIN.Aa1BB1bb1DEee3e4FILZ0.443.31.60.0178.82.7.627.627.14.80.1300.0630.380.71.390.910.50.59.80.3460.1000.3000.3000.2800.10.0151.651.04mmTYP.3.30.0280.0550.0360.0200.0200.3860.0650.041MAX.MIN.inchTYP.0.130MAX.P001F13/15MC34063A/E

SO-8 MECHANICAL DATADIM.MIN.Aa1a2a3bb1Cc1DEee3FLMS3.80.44.85.81.273.814.01.270.68 (max.)0.140.0155.06.20.650.350.190.250.1mmTYP.MAX.1.750.251.650.850.480.250.5 (typ.)0.1880.2280.0500.1500.1570.0500.0230.1960.2440.0250.0130.0070.0100.003MIN.inchTYP.MAX.0.0680.0090.00.0330.0180.0100.019001602314/15MC34063A/EInformation furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequencesof use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license isgranted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication aresubject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics productsare not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.The ST logo is a registered trademark of STMicroelectronics© 2001 STMicroelectronics – Printed in Italy – All Rights ReservedSTMicroelectronics GROUP OF COMPANIESAustralia - Brazil - China - Finland - France - Germany - - India - Italy - Japan - Malaysia - Malta - Morocco Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A.http://www.st.com. 15/15