 |
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
| Datasheet File OCR Text: |
| * DATA SHEET LND34063A DC-to-DC Converter Control Circuits GENERAL DESCRIPTION The LND34063A is a monolithic control circuit containing the primary functions required for DC-to-DC converters This device 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 device 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 3.0V to 40V Input Low Standby Current Current Limiting Output Switch Current to 1.5A Frequency Operation to 100kHz Precision 2% Reference PIN CONNECTIONS Switch Collector Switch Emitter Timing Capacitor Ground Driver Collector LND34063A Ipk Sense V CC Comparator Inverting Input * Linear Dimensions, Inc. * 445 East Ohio Street, Chicago IL 60611 USA * tel 312.321.1810 * fax 312.321.1830 * www.lineardimensions.com * LND34063A ABSOLUTE MAXIMUM RATINGS Rating Power Supply Voltage Comparator Input Voltage Range Switch Collector Voltage Switch Emitter Voltage(Vpin=40V) Switch Collector to Emitter Voltage Driver Collector Voltage Driver Collector Current(Note 1) Switch Current Operating Junction Temperature Operating Ambient Temperature Storage Temperature Symbol Vcc VIR VC(Switch) VE(switch) VCE(switch) Vc(driver) Ic(driver) Isw TJ TA Tstg Value 40 -0.3 to +40 40 40 40 40 100 1.5 +150 0 to +70 -65 to +150 Unit Vdc Vdc Vdc Vdc Vdc Vdc mA A C C C SCHEMATIC DIAGRAM 8 Driver CollectorO 1 2 3 1 OSwitch Collector S Q Q2 CR I pk Sense O 7 I pk C 100 Q1 Oscillator T 1.25 V Reference V O6 CC + - 2 Switch O Emitter 3 O Timing Capacitor Comparator 5 Inverting O Input 4 O Ground * Linear Dimensions, Inc. * 445 East Ohio Street, Chicago IL 60611 USA * tel 312.321.1810 * fax 312.321.1830 * www.lineardimensions.com * LND34063A ELECTRICAL CHARACTERISTICS Vcc=5.0V,TA=Tlow to Thigh, unless otherwise specified.) Characteristics Oscillator Frequency (Vpin5=0V, CT=1.0nF, TA=25C) Charge Current (Vcc=5.0V to 40V, TA =25C) Discharge Current (Vcc=5.0V to 40V, TA=25C Discharge to charge Current ratio (Pin 7 to Vcc, TA =25C Current Limit Sense Voltage (Ichg=I dischg, T=25C Output Switch(Note 2) Saturation Voltage Darlington Connection (Isw=1.0 A, Pins 1,8 connected) Saturation Voltage, Darlington Connection (Isw=1.0A, Rpin8=82 to Vcc, forced=20) DC Current Gain (Isw=1.0A, Vce=5.0V TA = 25 C Collector Off-State Current (Vce=40V) Comparator Threshold Voltage (TA=25C) (TA=Tlow to Thigh) Threshold Voltage Line Regulation (Vcc=3.0V to 40V) Input Bias Current (Vin=0V) Total Device Supply Current (Vcc=5.0V to 40V, Ct=1.0nF, Pin 7=Vcc,Vpin 5>Vth, Pin 2=Gnd, remaining pins open) Symbol Min Typ Max Unit fOSC Ichg Idischg Idischg/Ichg Vipk(sense) 24 24 140 5.2 250 33 35 220 6.5 300 42 42 260 7.5 350 kHz A A mV Vce(sat) - 1.0 1.3 V Vce(sat) - 0.45 0.7 V hFE Ic(off) 50 - 75 40 100 A Vth Regline IIB 1.225 1.21 - 1.25 1.4 -20 1.275 1.29 5.0 -400 V 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. * Linear Dimensions, Inc. * 445 East Ohio Street, Chicago IL 60611 USA * tel 312.321.1810 * fax 312.321.1830 * www.lineardimensions.com * LND34063A SOME TYPICAL APPLICATIONS 170H L 180 8 1 2 1 3 S Q Q2 CR 7 100 Q1 Rsc 0.22 VO IN 12 V 6 + 100 I pk Oscillator T 1.25 V Reference C 2 3 CT 1500pf + - 5 R2 47k 4 V OUT O 28V/175mA + 330 Co 1.0 H O VOUT + 100 R1 2.2k Optional Filter Fig 1 : STEP UP CONVERTER 8 1 2 1 O VOUT 8 1 2 1 R O VOUT 3 S Q Q2 3 S Q Q2 R --> 0 for Constant V IN Q1 CR 7 100 Q1 CR 7 100 Rsc VO IN 6 I pk Oscillator C T 2 3 O 1.25 V Reference 4 O O 5 Rsc VO IN 6 I pk C 2 T Oscillator 3 O 1.25 V Reference 4 O + - + - 5 O 2a: External NPN Switch 2b: External NPN Saturated Switch Fig 2 : External Boost Connections for Ic Peak Greater than 1.5A * Linear Dimensions, Inc. * 445 East Ohio Street, Chicago IL 60611 USA * tel 312.321.1810 * fax 312.321.1830 * www.lineardimensions.com * LND34063A 8 1 2 3 1 S Q Q2 CR 7 100 Q1 Rsc 0.33 VO IN 25 V 6 + 100 I pk Oscillator T 3 + - C 2 1.25 V Reference CT 470pf L 220H 5 R2 3.6k 4 V OUT O 5.0V/500mA + 470 Co 1.0 H O VOUT + 100 R1 1.2k Optional Filter Fig 3 : STEP DOWN CONVERTER 8 1 3 2 8 1 1 3 2 1 S Q Q2 S Q Q2 O VOUT CR 7 100 I pk Q1 CR 7 100 Q1 Rsc VO IN 6 C 2 T Oscillator Rsc O O VOUT VO IN 6 I pk C 2 T Oscillator 3 1.25 V Reference 4 O 3 O 1.25 V Reference 4 O + - + - 5 O 5 O 4a: External NPN Switch 4b: External NPN Saturated Switch Fig4 : External Boost Connections for Ic Peak Greater than 1.5A * Linear Dimensions, Inc. * 445 East Ohio Street, Chicago IL 60611 USA * tel 312.321.1810 * fax 312.321.1830 * www.lineardimensions.com * LND34063A 8 1 2 1 3 S Q Q2 CR 7 100 Q1 Rsc 0.33 VO IN 25 V 6 + 100 I C Oscillator T pk 2 3 + - 1.25 V Reference CT 470pf L 220H 5 R2 3.6k 4 V OUT O 5.0V/500mA 470 + Co 1.0 H O VOUT + 100 R1 1.2k Optional Filter Fig 5 : VOLTAGE INVERTING CONVERTER 8 1 2 1 8 1 2 3 1 3 S Q Q2 S Q Q2 O VOUT CR 7 100 Q1 CR 7 100 Q1 Rsc VO IN 6 I pk Oscillator C T 2 3 O O VOUT 1.25 V Reference 4 O O 5 Rsc VO IN 6 I pk Oscillator C T 2 3 O 1.25 V Reference 4 O + - + - 5 O 6a: External NPN Switch 6b: External NPN Saturated Switch Fig6 : External Boost Connections for Ic Peak Greater than 1.5A * Linear Dimensions, Inc. * 445 East Ohio Street, Chicago IL 60611 USA * tel 312.321.1810 * fax 312.321.1830 * www.lineardimensions.com * LND34063A Figure 7: Design Formula Table Calculation tON/tOFF (tON/tOFF) max CT IPK(switch) RSC L(min) CO Step-Up (Vout+VF-VIN(min) ) / (VIN(min) -Vsat) 1/ f MIN 4.0 x 10 ton 2 Iout (max)(ton/toff + 1) 0.3 / Ipk(switch) (Vin(min) -Vsat )/(Ipk(switch))=tout(max) 9(Ioutt on) / (Vripple(pp)) -5 Step-down (Vout+VF ) / (Vin(min) -Vsat -Vout) 1/ f MIN 4.0 x 10 ton 2 Iout(max) 0.3 / Ipk(switch) (Vin(min) - Vsat -Vout ) / (Ipk(switch)) = tout(max) Ipk(switch) (ton + toff) / 8V ripple(pp) -5 Voltage-Inverting ( Vout|+VF ) / (Vin -Vsat ) 1/ f MIN 4.0 x 10 ton 2 Iout (max)(ton/toff + 1) 0.3 / Ipk(switch) (Vin(min) -Vsat ) / (Ipk(switch)) = tout(max) 9(Ioutt on) / (Vripple(pp)) -5 Terms and Definitions Vsat-Saturation voltage of the output switch VF -Forward 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-Minmum desired output switching frequency at the selected values of VIN and IO Vripple(p-p)- Desired peak-to-peak output ripple voltage. In pratice, the calculated capacitor value will need 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. * Linear Dimensions, Inc. * 445 East Ohio Street, Chicago IL 60611 USA * tel 312.321.1810 * fax 312.321.1830 * www.lineardimensions.com * |
Price & Availability of LND34063A
 |
|
|
|
|
All Rights Reserved © IC-ON-LINE 2003 - 2022 |
| [Add Bookmark] [Contact Us] [Link exchange] [Privacy policy] |
|
Mirror Sites : [www.datasheet.hk]
[www.maxim4u.com] [www.ic-on-line.cn]
[www.ic-on-line.com] [www.ic-on-line.net]
[www.alldatasheet.com.cn]
[www.gdcy.com]
[www.gdcy.net] |