Fairchild RC5050 specifications RC5051

Page 6

AN50

 

 

 

 

 

 

 

 

 

 

 

APPLICATION NOTE

+12V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

L2

 

 

 

 

 

 

 

 

 

 

 

 

 

+5V

μH

 

 

 

 

 

 

 

 

 

 

 

 

 

2.5

 

 

 

C5

 

 

 

 

 

 

 

 

 

C4

C1

C2

 

C3

 

 

 

 

 

 

 

 

 

0.1 μF

1000 μ F

1000 μF

1000 μ F

0.1 μ F

R5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

47

D1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C8

C9

 

 

 

 

 

 

 

 

 

 

 

 

1N4691

 

 

 

 

 

 

 

 

 

 

 

 

0.1 μ F

0.1 μF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

M1

 

M2

 

 

 

 

 

 

 

11

 

 

10

C12

 

 

IRF7413

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

12

 

 

9

1μF

IRF7413

 

 

R SENSE

 

 

 

 

 

 

13

 

 

8

 

 

L1

 

 

 

 

 

 

14

 

 

7

C6

 

 

 

 

μF

 

 

VO

 

 

 

 

 

 

 

1.3μ H

6m Ω

μF

μ F

μF

 

 

15

RC5051

6

4.7 μF

 

 

 

 

 

 

 

 

1500

1500

1500

1500

VREF

 

16

 

 

5

 

 

 

DS1

 

 

17

 

 

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C7

 

 

 

 

 

 

1N5817

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C13

C14

 

C16

 

18

 

 

3

 

 

 

 

 

C15

 

 

 

 

 

M3

 

 

 

0.1 μF

 

19

 

 

2

 

 

M4

 

 

 

 

 

 

 

 

 

IRF7413

 

 

 

 

 

 

 

20

 

 

1

 

IRF7413

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

GND

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CEXT

 

 

 

 

 

 

 

 

 

 

 

 

 

100pF

 

 

 

 

 

 

 

 

 

 

VID4

 

 

 

 

 

 

VCC

 

 

 

 

 

 

 

VID3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VID2

 

 

 

 

 

10K

PWRGD

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VID1

 

 

 

 

 

C11

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VID0

 

 

 

C10

ENABLE

0.1 μ F

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0.1 μ F

 

 

 

 

 

 

 

 

 

Figure 4. Synchronous DC-DC Converter Application Schematic Using the RC5051

6

Image 6
Contents Intel Pentium Pro Processor Power Requirements IntroductionProcessor Voltage Identification Output Ripple and NoiseEfficiency Output Voltage Programming Codes RC5050 and RC5051 Description Upgrade Present UP# Power Good PwrgdOutput Enable Outen Internal Voltage ReferenceDesign Considerations and Component Selection Short Circuit ProtectionOscillator RC5051 Mosfet Selection Cosiderations Mosfet Selection TableLess heat sink required Converter Efficiency Calculation of Converter Efficiency Under Heavy LoadsRC5050 Short Circuit Comparator Threshold Voltage Selecting the InductorImplementing Short Circuit Protection Short Circuit ComparatorComparison of Sense Resistors Rsense for Various Load CurrentsSummary PC Trace Resistor Tolerance 16%Total Tolerance for PC Trace Resistor RC5050 and RC5051 Short Circuit Current Characteristics For each MosfetOutput Filter Capacitors Schottky Diode SelectionSchottky Diode Selection Table ManufacturerInput Filter Bill of MaterialBill of Materials for a 13A Pentium Pro Klamath Application ERJ-6GEY050Y PCB Layout Guidelines and ConsiderationsPCB Layout Guidelines ERJ-6ENF10.0KYExample of a PC Motherboard Layout and Gerber File Debugging Your First Design Implementation ProceduresGuidelines for Debugging and Performance Evaluations Performance Evaluation488 11010 505 504 501 496 493 492 491 490989 486Iload = 13.9A Case TemperatureEvaluation Summary Device DescriptionApplication Note Summary RC5050 Evaluation BoardAppendix a Directory of Component SuppliersLife Support Policy