MC34063A

34063 Description The MC34063A Series is a monolithic control circuit containing the primary functions required for DC-to-DC converters. These devices consist of an internal temperature compensated reference, comparator, controlled duty cycle oscillator with an active current limit circuit, driver and high current output switch. This series was specifically designed to be incorporated in Step-Down and Step-Up and Voltage-Inverting applications with a minimum number of external components. Features • • • • • • • Operation from 3.0 V to 40 V Input Low Standby Current Current Limiting Output Switch Current to 1.5 A Output Voltage Adjustable Frequency Operation to 100 kHz Precision 2% Reference Plastic Package Pin Connections Internal Block Digram Driver Collector 1 S R Ipk Sense Ipk Oscillator Comparator 1.25 V Reference 4 Gnd CT 7 100 2 3 VCC Comparator Inverting Input 6 Switch Emitter Timing Capacitor Q Q2 Q1 8 Switch Collector 5 BEIJING ESTEK ELECTRONICS CO.,LTD 1 34063 Absolute Maximum Ratings Symbol VCC VIR VC(switch) VE(switch) VCE(switch) VC(driver) IC(driver) ISW TJ TA Tstg Power Supply Voltage Comparator Input Voltage Range Switch Collector Voltage Switch Emitter Voltage (V PIN1 = 40 V) Switch Collector to Emitter Voltage Driver Collector Voltage Driver Collector Current (Note 1) Switch Current Operating Junction Temperature Operating Ambient Temperature Range Storage Temperature Range Parameter Maximu m 40 -0.3 to +40 40 40 40 40 100 1.5 +150 0 to +70 -65 to +150 Units Vdc Vdc Vdc Vdc Vdc Vdc mA A ° C ° C ° C Electrical Characteristics (Vcc=5.0V, Ta=Tlow specified) to Thigh , unless otherwise Symbol fOSC Ichg Idischg Idischg / Ichg Vipk(sence) VCE(sat) VCE(sat) hFE IC(off) Vth 1.225 1.25 1.21 – – 1.4 – -20 1.275 1.29 5.0 -400 Min 24 24 140 5.2 250 – – 50 – Typ 33 35 220 6.5 300 1.0 0.45 75 40 Max 42 42 260 7.5 350 1.3 0.7 – 100 Units kHz µA µA – mV V V – µA V Characteristic s OSCILL ATOR Frequency (Vpin5 = 0V, CT = 1.0 nF, TA = 25° ) C Charge Current(VCC = 5.0V to 40V, TA = 25° ) C Discharge Current (V CC = 5.0V to 40V, TA = 25° ) C Discharge to Charge Current Ratio (Pin 7 to V CC, TA = 25° ) C Current Limit Sense Voltage (I chg = Idischg, TA = 25° ) C OUTPUT SWITCH (NOTE 2) Saturation Voltage, Darlington Connection (I SW = 1.0 A, Pins 1, 8 connected) Saturation Voltage, Darlington Connection (I SW = 1.0 A, Rpin 8 = 82Ω to VCC , Forced β ≅ 20) DC Current Gain (ISW = 1.0 A, VCE = 5.0 V, TA = 25° ) C Collector Off-State Current (V CE = 40 V) COMPARATOR Threshold Voltage (TA=25° C) (TA =Tlow to Thigh) Threshold Voltage Line Regulation (Vcc=3.0 V to 40 V) Input Bias Current (Vin=0 V) TOTAL DEVICE Supply Current (Vcc = 5.0 V to 40 V, CT = 1.0 nF, Pin 7 = V CC, Vpin 5 > Vth, Pin 2 = Gnd, remaining pins open) Regline IIB mV nA ICC – – 4.0 mA NOTES : 1.Maximum package power dissipation limits must be observed. 2.Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as possible BEIJING ESTEK ELECTRONICS CO.,LTD 2 34063 Typical Performance Characteristics Figure 1. Output Switch On-Off Time versus Oscillator Timing Capacitor Figure 2. Timing Capacitor Waveform A Figure 3. Emitter Follower Configuration Output Saturation Voltage versus Emi tter Current versus Figure 4. Common Emitter Configuration Output Switch Saturation Voltage Collector Current Figure 5. Current Limit Sense Voltage versus Temperature Figure 6. Standby Supply Current versus Supply Voltage BEIJING ESTEK ELECTRONICS CO.,LTD 3 34063 Typical Applications Circuit Figure 1. Step-Up Converte . r Note: R to 0 for constant Vin Figure 2a. External NPN Switch. Figure 2. External Current Boost Connections for I P Figure 2b. External NPN Saturated Switch. eak Greater than 1.5 A . BEIJING ESTEK ELECTRONICS CO.,LTD 4 34063 Figure 3. Step-Down Converte . r Figure 4a. External NPN Switch. Figure 4. External Current Boost Connections for I P Figure 4b. External PNP Suturated Switch. eak Greater than 1.5 A . BEIJING ESTEK ELECTRONICS CO.,LTD 5 34063 Figure 5. Voltage Inverting Converte . r Figure 6a. External NPN Switch. Figure 6. External Current Boost Connections for I P Figure 6b. External PNP Saturated Switch. eak Greater than 1.5 A . BEIJING ESTEK ELECTRONICS CO.,LTD 6 34063 Design Formula Table Calculation Step-Up Step-Down in Voltage-Inverting ton/toff + VV in − out − (min) sat V in (min) out + VF −Vsat − 1 V 1 V V + VF V +V in sat V 1 out min (ton+toff)max CT lpk(switch) RSC L(min)     f  + 1   −  t on (max)   f 4.0 x 10-5 t 2 I  (max) ton 4.0x1f -5 0 2I out (max) ton 4.0 x 10-5 2I   ot n 0.3/lpk(switch) V −sat  ×t on (max) V I pk ( switch )  in  on   + 1   0.3/lpk(switch) Vin (min) V sat V −  out    × on (max) I pk ( switch )   0.3/lpk(switch) Vin (min) V  sat I pk ( switch )  CO 9 I out ton Vripple ( pp ) I pk ( switch ) ( t 8V ripple ( pp ) + t ) 9 tI Vripple ( pp ) TERMS AND DEFINITIONS Vsat Saturation voltage of the output s witch. VF Forward voltage drop of the output rectifier. The following power supply characteristics must be chosen:  R Vout = .  5 1 12 + R 1  Vin Nominal input voltage. Vout Desired output voltage, Iout Desired output current. fmin Minimum desired output s witching frequenc y at the selected values of V in and IO. Vripple(p-p) –Desired peack -to-peack output ripple voltage. In practice, the calculated capacitor value will need to be increased due to its equivalent series resistance and board la yout. The ripple voltage should be kept to a low value since it will directly affect the line and load regulation. Ordering Information O R DER I NG NU M B E R 34063A P A C K AGE SOP-8 /DIP-8 6A06--6A07 Rm 6A07,Changyin Office Building ,No.88,Yong Ding Road,Hai Dian District ,Beijing Postalcode:100039 Tel: 86-010-58895780 / 81 / 82 / 83 / 84 Http://www.estek.com.cn Email:sales@estek.com.cn REV No:01-060810 BEIJING ESTEK ELECTRONICS CO.,LTD M A R K I NG MC34063A Address : Fax : 010-58895793 7