SNVA103B October   2005  – February 2022 LM2743

 

  1.   Trademarks
  2. 1Introduction
  3. 2Additional Footprints
  4. 3Guidelines for Additional Options
  5. 4Typical Application Circuit
  6. 5Performance Characteristics
    1. 5.1 Load Transient Response
    2. 5.2 Switch Node Voltage and Output Ripple Voltage
  7. 6PCB Layout Diagrams
  8. 7Revision History

5.2 Switch Node Voltage and Output Ripple Voltage

GUID-3E396D07-45D0-4E82-8CB2-8C60D11A7A40-low.pngFigure 5-3 VIN = VCC = 3.3 V, VOUT = 1.2 V, ILOAD = 0 A, fSW = 1 MHz, 20-MHz Bandwidth Limit
GUID-B43F3A6D-4C22-4BFC-93E5-14C9892480E2-low.pngFigure 5-5 VIN = 14 V, VCC = 5 V, VOUT = 1.2 V, ILOAD = 0 A, fSW = 1 MHz, 20-MHz Bandwidth Limit
GUID-2AC5EC57-A0FF-4AB2-AB8D-718ABD483083-low.pngFigure 5-4 VIN = VCC = 3.3 V, VOUT = 1.2 V, ILOAD = 3.5 A, fSW = 1 MHz, 20-MHz Bandwidth Limit
GUID-07C09090-8616-4CE4-9267-8759140698AF-low.pngFigure 5-6 VIN = 14 V, VCC = 5 V, VOUT = 1.2 V, ILOAD = 3.5 A, fSW = 1 MHz, 20-MHz Bandwidth Limit
Table 5-1 Bill of Materials
Designator Function Part Description Part Number
U1 Controller IC LM2744 TSSOP14 Texas Instruments
U2 Low Dropout Reg IC LM4140BCM-1.0 SOIC-8 Texas Instruments
C5 VCC Decoupling Ceramic Capacitor, 1 µF, 25 V, 10%, 0805 Murata GRM216R61E105KA12B
C7 Soft Start Cap Ceramic Capacitor, 12 nF, 25 V, 10%, 0805 Vishay VJ0805Y123KXX
C8 Comp Cap Ceramic Capacitor, 1.2 nF, 25 V, 10%, 0805 Vishay VJ0805Y122KXX
C9 Comp Cap Ceramic Capacitor, 15 pF, 50 V, 10%, 0805 Vishay VJ0805A150KAA
C10 Cboot Ceramic Capacitor, 0.1 µF, 25 V, 10%, 0805 Vishay VJ0805Y104KXX
C11 Comp Cap Ceramic Capacitor, 1.8 nF, 25 V, 10%, 0805 Vishay VJ0805Y182KXX
C12 Input Filter Cap Ceramic Capacitor, 10 μF, 25 V, 10%, 1210 AVX 12103D106MAT
C14 Input Filter Cap Ceramic Capacitor, 10 μF, 25 V, 10%, 1210 AVX 12103D106MAT
C16 Output Filter Cap 470 μF, 6.3 V, 10-mΩ ESR POScap Sanyo 6TPD470
C21 Reference Output Cap Niobium Oxide Capacitor, 4.7 µF, 6 V AVX NOJA475M0006R
C22 Reference Input Cap Ceramic Capacitor, 0.47 µF, 25 V, 10%, 1206 Vishay VJ1206Y474KXX
R1 VCC Filter Resistor Resistor 10 Ω, .25 W, 0805 Vishay CRCW08051000F
R2 Frequency Adjust Resistor Resistor, 24.9 kΩ, .25 W, 0805 Vishay CRCW08052492F
R3 Comp Resistor Resistor, 21 kΩ, .25 W, 0805 Vishay CRCW08052102F
R4 Current Limit Resistor Resistor, 3.16 kΩ, .25 W, 0805 Vishay CRCW08053161F
R5 Comp Resistor Resistor, 2.94 kΩ, .25 W, 0805 Vishay CRCW08052941F
R6 Resistor Divider, upper Resistor, 10.0 kΩ, .25 W, 0805 Vishay CRCW08051002F
R7 Resistor Divider, lower Resistor, 59 kΩ, .25 W, 0805 Vishay CRCW08055902F
R8 PWGD Pull-Up Resistor, 100 kΩ, .25 W, 0805 Vishay CRCW08051003F
R10 Zero Ohm Resistor, 0 Ω, 0805 Vishay CRCW08050000
R11 Shut Down Pull-Up Resistor, 100 kΩ, .25 W, 0805 Vishay CRCW12061003F
D2 Bootstrap Diode Schottky Diode, SOD-123 MBR0530LTI
L1 Output Filter Inductor Inductor 1 µH, 5.3 Arms, 10.2 mΩ Cooper DR73-1R0
Q1-Q2 Top and Bottom FETs Dual N-MOSFET, VDS = 20 V, 24 mΩ at 2.5 V Vishay 9926BDY
GUID-7C51067E-01B7-4DDD-844D-85AD9653E344-low.gif Figure 5-7 Complete Demo Board Schematic