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User Manual 

Please read the Important Notice and Warnings at the end of this document

 

V 1.0 

www.infineon.com/optimos-ipol

 

page 1 of 17 

2022-07-28 

UM_2111_PL12_2112_224717 
 

User manual for IR3447A evaluation board 

25 A single-phase buck regulator with 1.2 V output 

About this document

 

Scope and purpose 

The IR3447A is a synchronous buck converter, providing a compact, high-performance and flexible solution in a 
small 5 mm x 6 mm power QFN package. 

Key features offered by the IR3447A include internal digital soft-start, precision 0.6 V reference voltage, power 
good (P

good

), thermal protection, enable input, input undervoltage lockout (UVLO) for proper start-up, latched-

off overvoltage protection (OVP) and pre-bias start-up. 

Output overcurrent protection (OCP) function is implemented by sensing the voltage developed across the on-
resistance of the synchronous MOSFET for optimum cost and performance, and the current limit is thermally 
compensated.  

This user manual contains the schematic and bill of materials for the EVAL_3447A_1.2Vout engineering 
evaluation board. The manual describes operation and use of the evaluation board itself. Detailed application 
information for IR3447A is available in the IR3447A datasheet. 

Intended audience 

This document is intended as a guide for design engineers evaluating IR3447A performance with the 
EVAL_3447A_1.2Vout demo board.  

 

Table of contents

 

About this document ....................................................................................................................... 1

 

Table of contents ............................................................................................................................ 1

 

1.

 

Board information .................................................................................................................. 2

 

1.1

 

Board features ......................................................................................................................................... 2

 

1.2

 

Connections and operating instructions ................................................................................................ 2

 

1.3

 

Layout ...................................................................................................................................................... 3

 

1.4

 

PCB layout ............................................................................................................................................... 5

 

1.5

 

Bill of materials ........................................................................................................................................ 9

 

2.

 

Typical operating waveforms ................................................................................................. 11

 

Revision history ............................................................................................................................. 16

 

 

 

Summary of Contents for IR3447A

Page 1: ...start up Output overcurrent protection OCP function is implemented by sensing the voltage developed across the on resistance of the synchronous MOSFET for optimum cost and performance and the current...

Page 2: ...F 25 V ceramic 0805 2 x 100 F 25 V polymer optional Cout 6 x 47 F 6 3 V ceramic 0805 1 x 4 7 F 6 3 V ceramic 0603 1 x 0 1 F 50 V ceramic 0402 1 x 470 F 2 5 V 3 m SP cap 1 2 Connections and operating...

Page 3: ...easurement OCP limit ILIM Use a jumper to make one of two OCP limit selections Short 22 A open 32 5 A Pgood PGOOD1 Connect a scope probe to this pin to monitor power good signal GND GND VCC VCC 1 Conn...

Page 4: ...nual 4 of 17 V 1 0 2022 07 28 User manual for IR3447A evaluation board 25 A single phase buck regulator with 1 2 V output Board information Top Bottom Figure 2 Top and bottom view of IR3447A evaluatio...

Page 5: ...ser Manual 5 of 17 V 1 0 2022 07 28 User manual for IR3447A evaluation board 25 A single phase buck regulator with 1 2 V output Board information 1 4 PCB layout Figure 3 Top layer Figure 4 Bottom laye...

Page 6: ...User Manual 6 of 17 V 1 0 2022 07 28 User manual for IR3447A evaluation board 25 A single phase buck regulator with 1 2 V output Board information Figure 5 Mid layer 1 Figure 6 Mid layer 2...

Page 7: ...User Manual 7 of 17 V 1 0 2022 07 28 User manual for IR3447A evaluation board 25 A single phase buck regulator with 1 2 V output Board information Figure 7 Mid layer 3 Figure 8 Mid layer 4...

Page 8: ...t for Transient Testing TB7 PVIN_GND 1 2 3 4 5 6 TP26 GND PVin1 TP19 GND Vout1 J24 BODE1 1 2 BOOT1 R16 0 TP24 GND TP20 GND C42 22uF C49 100uF RS 1 Use seperate SW and GND trace on layout R15 7 5K Vout...

Page 9: ...E226ME44L 22 F 0805 25 V X5R 20 6 C53 C54 C55 C56 C57 C58 47 F Murata GRM21BR60J476ME11L 47 F 0805 6 3 V X5R 20 1 C66 470 F Panasonic EEF GX0E471R Capacitor aluminum polymer 470 F 20 2 5 V SMD 2 TP27...

Page 10: ...on 1 R24 20 Yageo RC0603FR 0720RL Resistor 0603 1 10 W 1 3 J15 J18 J23 VIN_Select Harwin M20 9990346 Header 1x3 TH 0 025 sq 0 1 inch space 1 D2 SMAT70A Diodes Inc SMAT70A 13 F SMA 3 5 V 40 A 4 TB5 TB6...

Page 11: ...gulator with 1 2 V output Typical operating waveforms 2 Typical operating waveforms Vin 12 0 V Vout 1 2 V Iout 0 to 25 A room temperature with no airflow Figure 10 Start up at 25 A load Ch1 Pgood Ch2...

Page 12: ...2 07 28 User manual for IR3447A evaluation board 25 A single phase buck regulator with 1 2 V output Typical operating waveforms Figure 12 Vout ripple at 25 A load fsw 600 kHz Ch6 Vout Figure 13 SW nod...

Page 13: ...h1 Pgood Ch6 Vout Figure 15 Transient response at 8 A step load current at 2 5 A s Iout 16 A to 24 A Ch6 Vout Ch5 Iout_MS pk pk 63 76 mV fsw 600 kHz Note The load transient test is performed using an...

Page 14: ...wer loss vs load current natural convection 12 Vin 1 2 Vout 600 kHz Ta 25 C FCCM 60 65 70 75 80 85 90 95 100 0 0 2 5 5 0 7 5 10 0 12 5 15 0 17 5 20 0 22 5 25 0 Efficiency Output current A PVin Vin 12...

Page 15: ...t regulation 12 Vin 1 2 Vout 600 kHz Ta 25 C FCCM Figure 19 Thermal image of the board at 25 A load IR3447A 55 5 C Fsw 600 kHz Ta room temperature natural convection 1 192 1 194 1 196 1 198 1 200 1 20...

Page 16: ...V 1 0 2022 07 28 User manual for IR3447A evaluation board 25 A single phase buck regulator with 1 2 V output Revision history Revision history Document version Date Description of changes V 1 0 2022 0...

Page 17: ...t is exclusively intended for technically trained staff It is the responsibility of customer s technical departments to evaluate the suitability of the product for the intended application and the com...

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