IRDC3448-P0V9
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This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the resultsof the continuing evaluation, this board can evolve and change without notice
AL
9/18/2013 1
USER GUIDE FOR IR3448 EVALUATION BOARD
DESCRIPTION
The IR3448 is a synchronous buckconverter, providing a compact, highperformance and flexible solution in a small5mmx6mm QFN package.
Key features offered by the IR3448 includeinternal Digital Soft Start, precision 0.6Vreference voltage, Power Good, thermalprotection, programmable switchingfrequency, Enable input, input under-voltagelockout for proper start-up, enhanced line/load regulation with feed forward, externalfrequency synchronization with smoothclocking, internal LDO, true differentialremote sensing and pre-bias start-up.
A thermally compensated output over-currentprotection function is implemented by sensingthe voltage developed across the on-resistanceof the synchronous rectifier MOSFET foroptimum cost and performance.
This user guide contains the schematic and billof materials for the IR3448 evaluation board.The guide describes operation and use of theevaluation board itself. Detailed applicationinformation for IR3448 is available in theIR3448 data sheet.
BOARD FEATURES
• Vin = +12V
• Vout = +0.9V @ 0-16A
• Fs = 1MHz
• L = 0.16uH
• Cin = 2x22uF (ceramic 1206) + 1x330uF* (electrolytic)
• Cout = 6x47uF (ceramic 0805)
* The 330uF input capacitor is placed for damping the parasitic inductance of bench power supply wires. It is not required for the POL applications where input is delivered with power planes.
SupIRBuckTM
IRDC3448-P0V9
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This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the resultsof the continuing evaluation, this board can evolve and change without notice
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9/18/2013 2
A well regulated +12V input supply should be connected to VIN+ and VIN-. A maximum of 16A load shouldbe connected to VOUT+ and VOUT-. The inputs and output connections of the board are listed in Table I.
IR3448 needs only one input supply and internal LDO generates Vcc from Vin. The board is configured forremote sensing.
External Enable signal can be applied to the board via exposed Enable pad and R18 should be removed forthis purpose.
CONNECTIONS and OPERATING INSTRUCTIONS
LAYOUTThe PCB is a 6-layer board. All of layers are 2 Oz. copper. The IR3448 and most of the passivecomponents are mounted on the top side of the board.
Power supply decoupling capacitors and feedback components are located close to IR3448. Thefeedback resistors are connected to the output of the remote sense amplifier of the IR3448 and arelocated close to the IR3448. To improve efficiency, the circuit board is designed to minimize the length
of the on-board power ground current path. Separate power ground and analog ground are used andmay be connected together using a single point connection.
Table I. Connections
Connection Signal Name
VIN+ Vin (+12V)
VIN- Ground of Vin
Vout+ Vout(+0.9V)
Vout- Ground for Vout
Vcc+ Vcc Pin
Vcc- Ground for Vcc input
Enable Enable
PGood Power Good Signal
AGnd Analog ground
IRDC3448-P0V9
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This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the resultsof the continuing evaluation, this board can evolve and change without notice
AL
9/18/2013 3
CONNECTIONS and OPERATING INSTRUCTIONS
LAYOUTThe PCB is a 6-layer board. All of layers are 2 Oz. copper. The IR3448 and most of the passivecomponents are mounted on the top side of the board.
Power supply decoupling capacitors and feedback components are located close to IR3448. Thefeedback resistors are connected to the output of the remote sense amplifier of the IR3448 and arelocated close to the IR3448. To improve efficiency, the circuit board is designed to minimize the length of
the on-board power ground current path.
Vin
Vo
Gnd
Gnd
Top View
IRDC3448-P0V9
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This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the resultsof the continuing evaluation, this board can evolve and change without notice
AL
9/18/2013 4
Fig
.1:
Sch
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ico
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3448
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ion
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ard
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yp
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+
123456
Vin
-
123456
IRDC3448-P0V9
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This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the resultsof the continuing evaluation, this board can evolve and change without notice
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Bill of Materials
Item Qty Part Reference Value Description Manufacturer Part Number
1 1 C1 330uFSMD Elecrolytic, Fsize,
25V, 20%Panasonic EEE-FK1E331P
2 2 C2 C3 22uF 1206, 25V, X5R, 10% Murata GRM31CR61E226KE15L
3 1 C10 100pF 0402, 50V, NP0, 5% Murata GRM1555C1H101JZ01D4 3 C14 C25 C37 0.1uF 0402, 50V, X7R, 10% TDK C1005X7R1H104K050BB5 1 C8 2200pF 0402, 25V, NP0, 5% Kemet C0402C222J3GACTU6 1 C11 75pF 0402, 50V, NP0, 5% Murata GRM1555C1H750JA01D
7 6C15 C16 C17C18 C19 C20
47uF 0805, 6.3V, X5R, 20% TDK C2012X5R0J476M
8 1 C26 4.7nF 0402, 50V, X7R, 10% Murata GRM155R71H472KA01D9 1 C39 1uF 0402, 25V, X5R,10% TDK C1005X5R1E105K050BC
10 1 C66 10uF 0603, X5R, 10V, 20% TDK C1608X5R1A106M080AC11 1 L1 0.16uH 0.16uH, DCR=2.15mohm Coilcraft XAL5030-161ME_12 1 R1 1.8k 0402,1/10W,1% Panasonic ERJ-2RKF1801X13 1 R2 2.67k 0402,1/10W,1% Panasonic ERJ-2RKF2671X14 1 R3 5.36k 0402,1/10W,1% Panasonic ERJ-2RKF5361X15 1 R4 47.5 0402,1/10W,1% Panasonic ERJ-2RKF47R5X16 1 R6 20 0402,1/10W,1% Panasonic ERJ-2RKF20R0X17 1 R9 23.2k 0402,1/10W,1% Panasonic ERJ-2RKF2322X18 1 R17 10k 0402,1/10W,1% Panasonic ERJ-2RKF1002X19 1 R18 49.9k 0402,1/10W,1% Panasonic ERJ-2RKF4992X20 1 R19 7.5k 0402,1/10W,1% Panasonic ERJ-2RKF7501X
21 1 U1 IR3448 IR3448 5mm X6mmInternational
RectifierIR3448MPBF
IRDC3448-P0V9
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This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the resultsof the continuing evaluation, this board can evolve and change without notice
AL
9/18/2013 6
TYPICAL OPERATING WAVEFORMSVin=12.0V, Vout=0.9V, Iout=0A-16A, Fs=1MHz, Room Temperature, No air flow
Fig. 5: Output Voltage Ripple, 16A load Ch2: Vout
Fig. 6: Inductor node at 16A loadCh1:SW Node
Fig. 7: Short (Hiccup) RecoveryCh2:Vout, Ch3:PGood, Ch4:Iout
Fig. 3: Start up at 16A Load Ch1:Vin, Ch2:Vout, Ch3:PGood,Ch4:Vcc
Fig. 2: Start up at 16A LoadCh1:Vin, Ch2:Vout, Ch3:PGood, Ch4:Enable
Fig. 4: Start up with 0.81V Pre Bias , 0A Load Ch2:Vout , Ch3:PGood, Ch4:Enable
IRDC3448-P0V9
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This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the resultsof the continuing evaluation, this board can evolve and change without notice
AL
9/18/2013 7
TYPICAL OPERATING WAVEFORMSVin=12.0V, Vout=0.9V, Iout=8A-16A, Fs=1MHz, Room Temperature, No air flow
Fig. 8: Transient Response, 8A to 16A step with Electronic load setting = 2.5A/us
Ch2:Vout, Ch4:Iout
IRDC3448-P0V9
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This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the resultsof the continuing evaluation, this board can evolve and change without notice
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9/18/2013 8
TYPICAL OPERATING WAVEFORMSVin=12.0V, Vout=0.9V, Iout=0A-16A, Fs=1MHz, Room Temperature, No air flow
Fig. 9: Bode Plot at 16A load shows: Fc = 185.6kHz, Phase Margin = 52.3º
IRDC3448-P0V9
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This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the resultsof the continuing evaluation, this board can evolve and change without notice
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Fig.11: Power loss versus load current
Fig.10: Efficiency versus load current
TYPICAL OPERATING WAVEFORMSVin=12.0V, Vout=0.9V, Iout=0A-16A, Fs=1MHz, Room Temperature, No air flow
IRDC3448-P0V9
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This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the resultsof the continuing evaluation, this board can evolve and change without notice
AL
9/18/2013 10
THERMAL IMAGESVin=12.0V, Vout=0.9V, Iout=0A-16A, Fs=1MHz, Room Temperature, No air flow
Fig. 12: Thermal Image of the board top at 16A loadIR3448: 65.130C
Fig. 13: Thermal Image of the board bottom at 16A loadInductor: 69.290C