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SupIRBuck
USER GUIDE FOR IR3898 EVALUATION BOARD
DESCRIPTION
The
IR3898
is
a
converter,
providing
performance and flexible solution in a small
4mm X 5 mm Power QFN package.
Key features offered by the IR3898 include
internal Digital Soft Start/Soft Stop, precision
0.5Vreference
voltage,
thermal protection, programmable switching
frequency, Enable input, input under-voltage
lockout for proper start-up, enhanced line/
load regulation with feed forward, external
frequency
synchronization
clocking, internal LDO
up.
BOARD FEATURES
•
V
= +12V (+ 13.2V Max)
in
• V
= +3.3V @ 0-6A
out
•
F
= 1MHz
s
•
L = 1.0uH
•
C
= 3x10uF (ceramic 1206) + 1X330uF (electrolytic)
in
•
C
= 3x22uF (ceramic 0805)
out
8/15/2013
This evaluation board is a preliminary version meant for the engineering evaluation of the IR3898.
Based on the results of the continuing evaluation, this board can evolve and change without notice
TM
3.3Vout
synchronous
buck
a
compact,
high
,
Power
Good
with
smooth
and pre-bias start-
Pulse by pulse current limit and output over-
current protection function is implemented by
sensing the voltage developed across the on-
resistance
of
MOSFET for optimum cost and performance
and the current limit is thermally compensated.
This user guide contains the schematic and bill
of materials for the IR3898 evaluation board.
The guide describes operation and use of the
evaluation board itself. Detailed
information for IR3898 is available in the
IR3898 data sheet.
Confidential
IRDC3898-P3V3
the
synchronous
application
rectifier
1
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Table of Contents
Related Manuals for International Rectifier SupIRBuck IR3898
Summary of Contents for International Rectifier SupIRBuck IR3898
-
Page 1: Board Features
IRDC3898-P3V3 SupIRBuck USER GUIDE FOR IR3898 EVALUATION BOARD 3.3Vout DESCRIPTION Pulse by pulse current limit and output over- IR3898 synchronous buck current protection function is implemented by converter, providing compact, high sensing the voltage developed across the on- performance and flexible solution in a small resistance synchronous rectifier... - Page 2 IRDC3898-P3V3 CONNECTIONS and OPERATING INSTRUCTIONS A well regulated +12V input supply should be connected to VIN+ and VIN-. A maximum of 6A load should be connected to VOUT+ and VOUT-. The inputs and output connections of the board are listed in Table I. IR3898 has only one input supply and internal LDO generates Vcc from Vin.
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Page 3: Top View
IRDC3898-P3V3 Connection Diagram Vout Enable VDDQ Top View Vref Sync S-Ctrl AGnd PGood Vsns Vcc+ Vcc- Bottom View Fig. 1: Connection Diagram of IR3899/98/97 Evaluation Boards 8/15/2013 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3898. Based on the results of the continuing evaluation, this board can evolve and change without notice... - Page 4 IRDC3898-P3V3 Fig. 2: Board Layout-Top Layer Single point connection between AGnd and PGnd Fig. 3: Board Layout-Bottom Layer 8/15/2013 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3898. Based on the results of the continuing evaluation, this board can evolve and change without notice...
- Page 5 IRDC3898-P3V3 Fig. 4: Board Layout-Mid Layer 1 Fig. 5: Board Layout-Mid Layer 2 8/15/2013 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3898. Based on the results of the continuing evaluation, this board can evolve and change without notice...
- Page 6 IRDC3898-P3V3 8/15/2013 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3898. Based on the results of the continuing evaluation, this board can evolve and change without notice...
-
Page 7: Bill Of Materials
IRDC3898-P3V3 Bill of Materials BOM IRDC3898 Vin-12V Vout-3.3V/6.0A Freq-1MHz Item Qty Part Reference Value Description Manufacturer Part Number SMD Electrolytic F size 25V 20% Panasonic 330uF EEV-FK1E331P 1206, 16V, X5R, 20% C3 C4 C5 10uF C3216X5R1C106M C7 C12 C14 C24 0.1uF 0603, 25V, X7R, 10% Murata... - Page 8 IRDC3898-P3V3 TYPICAL OPERATING WAVEFORMS Vin=12.0V, Vo=3.3V, Io=0-6A, Room Temperature, no airflow Fig. 8: Start up at 6A Load, Fig. 7: Start up at 6A Load , Ch , Ch , Ch :PGood , Ch :Enable, Ch , Ch :PGood Fig. 9: Start up with 1.0V Pre Bias , 0A Fig.
- Page 9 IRDC3898-P3V3 TYPICAL OPERATING WAVEFORMS Vin=12.0V, Vo=3.3V, Io=0-6A, Room Temperature, no air flow Fig. 13: Transient Response, 3A to 6A step 8/15/2013 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3898. Based on the results of the continuing evaluation, this board can evolve and change without notice...
- Page 10 IRDC3898-P3V3 TYPICAL OPERATING WAVEFORMS Vin=12.0V, Vo=3.3V, Io=0-6A, Room Temperature Fig. 14: Bode Plot at 6A load shows a bandwidth of 156.1KHz and phase margin of 49.1 degrees 8/15/2013 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3898. Based on the results of the continuing evaluation, this board can evolve and change without notice...
- Page 11 IRDC3898-P3V3 TYPICAL OPERATING WAVEFORMS Vin=12.0V, Vo=3.3V, Io=0-6A, Room Temperature, no air flow Fig. 15: Soft start and soft stop using S_Ctrl pin Fig. 16: Feed Forward for Vin change from 7 to 16V and back to 7V 8/15/2013 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3898. Based on the results of the continuing evaluation, this board can evolve and change without notice...
- Page 12 IRDC3898-P3V3 TYPICAL OPERATING WAVEFORMS Vin=12.0V, Vo=3.3V, Io=0-6A, Room Temperature, no air flow Load Current (A) Fig. 17: Efficiency versus load current Load Current (A) Fig. 18: Power loss versus load current 8/15/2013 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3898. Based on the results of the continuing evaluation, this board can evolve and change without notice...
- Page 13 IRDC3898-P3V3 THERMAL IMAGES Vin=12.0V, Vo=3.3V, Io=0-6A, Room Temperature, No Air flow Fig. 19: Thermal Image of the board at 6A load Test point 1 is IR3898: 60.02 Test point 2 is inductor: 47.49 8/15/2013 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3898. Based on the results of the continuing evaluation, this board can evolve and change without notice...
- Page 14 IRDC3898-P3V3 PCB METAL AND COMPONENT PLACEMENT Evaluations have shown that the best overall performance is achieved using the substrate/PCB layout as shown in following figures. PQFN devices should be placed to an accuracy of 0.050mm on both X and Y axes. Self-centering behavior is highly dependent on solders and processes, and experiments should be run to confirm the limits of self-centering on specific processes.
- Page 15 IRDC3898-P3V3 SOLDER RESIST IR recommends that the larger Power or Land Area pads are Solder Mask Defined (SMD.) This allows the underlying Copper traces to be as large as possible, which helps in terms of current carrying capability and device cooling capability. When using SMD pads, the underlying copper traces should be at least 0.05mm larger (on each edge) than the Solder Mask window, in order to accommodate any layer to layer misalignment.
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Page 16: Stencil Design
IRDC3898-P3V3 STENCIL DESIGN Stencils for PQFN can be used with thicknesses of 0.100-0.250mm (0.004-0.010"). Stencils thinner than 0.100mm are unsuitable because they deposit insufficient solder paste to make good solder joints with the ground pad; high reductions sometimes create similar problems. Stencils in the range of 0.125mm-0.200mm (0.005-0.008"), with suitable reductions, give the best results. -
Page 17: Package Information
IRDC3898-P3V3 PACKAGE INFORMATION Figure 23: Package Dimensions IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: (310) 252-7105 TAC Fax: (310) 252-7903 This product has been designed and qualified for the Consumer market Visit us at www.irf.com for sales contact information Data and specifications subject to change without notice.04/11 8/15/2013 Confidential...
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