LND34063A View Datasheet(PDF) - Linear Dimensions Semiconductor
Part Name
Description
Manufacturer
LND34063A Datasheet PDF : 7 Pages
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LND34063A
Figure 7: Design Formula Table
Calculation Step-Up
Step-down
Voltage-Inverting
tON/tOFF
(tON/tOFF)
max
CT
IPK(switch)
RSC
L(min)
CO
(Vout+VF-VIN(min) ) / (VIN(min) -Vsat) (Vout+VF ) / (Vin(min) -Vsat -Vout) ( Vout|+VF ) / (Vin -Vsat )
1/ f MIN
4.0 x 10-5 ton
2 Iout (max)(ton/toff + 1)
0.3 / Ipk(switch)
(Vin(min) –Vsat )/(Ipk(switch))=tout(max)
9(Ioutt on) / (Vripple(pp))
1/ f MIN
1/ f MIN
4.0 x 10-5 ton
4.0 x 10-5 ton
2 Iout(max)
2 Iout (max)(ton/toff + 1)
0.3 / Ipk(switch)
(Vin(min) – Vsat -Vout ) /
(Ipk(switch)) = tout(max)
Ipk(switch) (ton + toff) / 8V ripple(pp)
0.3 / Ipk(switch)
(Vin(min) –Vsat ) / (Ipk(switch)) =
tout(max)
9(Ioutt on) / (Vripple(pp))
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 •
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