SNVA113B April 2006 – February 2022 LM2745 , LM2748
4 Performance Characteristics (Output Ripple Voltage and Switch Node Voltage)
Figure 4-1 VIN = VCC = 3.3 V,
VOUT = 1.2 V, ILOAD = 0 A, fSW = 1 MHz, 20-MHz
Bandwidth Limit
Figure 4-3 VIN = 14 V, VCC = 5 V,
VOUT = 1.2 V, ILOAD = 0 A, fSW = 1 MHz, 20-MHz
Bandwidth Limit
Figure 4-2 VIN = VCC = 3.3 V,
VOUT = 1.2 V, ILOAD = 3.5 A, fSW = 1 MHz, 20-MHz
Bandwidth Limit
Figure 4-4 VIN = 14 V, VCC = 5 V,
VOUT = 1.2 V, ILOAD = 3.5 A, fSW = 1 MHz, 20-MHz
Bandwidth Limit
Figure 4-5 Complete Demo Board SchematicTable 4-1 Bill of Materials (BOM)
| Designator | Function | Part Description | Part Number |
|---|---|---|---|
| U1 | Controller | LM2745/LM2748 TSSOP14 | Texas Instruments |
| C5 | VCC Decoupling | Cer Cap 1 µF 25 V 10% 0805 | Murata GRM216R61E105KA12B |
| C7 | Soft Start Cap | Cer Cap 12 nF 25 V 10% 0805 | Vishay VJ0805Y123KXX |
| C8 | Comp Cap | Cer Cap 1.5 nF 25 V 10% 0805 | Vishay VJ0805Y152KXX |
| C9 | Comp Cap | Cer Cap 18 pF 25 V 10% 0805 | Vishay VJ0805A180KAA |
| C10 | Cboot | Cer Cap 0.1 µF 25 V 10% 0805 | Vishay VJ0805Y104KXX |
| C11 | Comp Cap | Cer Cap 1.8 nF 25 V 10% 0805 | Vishay VJ0805Y182KXX |
| C12 | Input Filter Cap | Cer Cap 10 µF 25 V 10% 1210 | AVX 12103D106MAT |
| C14 | Input Filter Cap | Cer Cap 10 µF 25 V 10% 1210 | AVX 12103D106MAT |
| C15 | Output Filter Cap | 470µF, 6.3 V, 10 mΩ ESR POScap | Sanyo 6TPD470 |
| R1 | Filter Resistor | Res 10 Ω .25W 0805 | Vishay CRCW08051000F |
| R2 | Frequency Adjust Res | Res18.7 kΩ .25W 0805 | Vishay CRCW08052187F |
| R3 | Comp Res | Res 17.4 kΩ .25W 0805 | Vishay CRCW08051742F |
| R4 | Current Limit Res | Res 3.16 kΩ .25W 0805 | Vishay CRCW08053161F |
| R5 | Comp Res | Res 2.94 kΩ .25W 0805 | Vishay CRCW08052941F |
| R6 | Res Divider, upper | Res 10.0 kΩ .25W 0805 | Vishay CRCW08051002F |
| R7 | Res Divider, lower | Res 10.0 kΩ .25W 0805 | Vishay CRCW08051002F |
| R8 | PWGD Pullup | Res 100 kΩ .25W 0805 | Vishay CRCW08051003F |
| R11 | Shutdown Pullup | Res 100 kΩ .25W 0805 | Vishay CRCW080561003F |
| D2 | Bootstrap Diode | Schottky Diode, SOD-123 | MBR0530LTI |
| L1 | Output Filter Inductor | Inductor 1 µH, 5.3Arms, 10.2 mΩ | Cooper DR73-1R0 |
| Q1-Q2 | Top and Bottom FETs | Dual N-MOSFET, VDS = 20 V, 24 mΩ @ 2.5 V | Vishay 9926BDY |
| CCLK | Sync AC Coupling Cap | Cer Cap 56 pF 25 V 10% 0805 | Vishay VJ0805A560KXAA |