IRDC3448-P0V9 - International Rectifier

IRDC3448-P0V9
SupIRBuck
TM
USER GUIDE FOR IR3448 EVALUATION BOARD
DESCRIPTION
The IR3448 is a synchronous buck
converter, providing a compact, high
performance and flexible solution in a small
5mmx6mm QFN package.
Key features offered by the IR3448 include
internal Digital Soft Start, precision 0.6V
reference voltage, Power Good, 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 with smooth
clocking, internal LDO, true differential
remote sensing and pre-bias start-up.
A thermally compensated output over-current
protection function is implemented by sensing
the voltage developed across the on-resistance
of the synchronous rectifier MOSFET for
optimum cost and performance.
This user guide contains the schematic and bill
of materials for the IR3448 evaluation board.
The guide describes operation and use of the
evaluation board itself. Detailed application
information for IR3448 is available in the
IR3448 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.
9/18/2013
Confidential
1
This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results
of the continuing evaluation, this board can evolve and change without notice
AL
IRDC3448-P0V9
CONNECTIONS and OPERATING INSTRUCTIONS
A well regulated +12V input supply should be connected to VIN+ and VIN-. A maximum of 16A load should
be 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 for
remote sensing.
External Enable signal can be applied to the board via exposed Enable pad and R18 should be removed for
this purpose.
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
LAYOUT
The PCB is a 6-layer board. All of layers are 2 Oz. copper. The IR3448 and most of the passive
components are mounted on the top side of the board.
Power supply decoupling capacitors and feedback components are located close to IR3448. The
feedback resistors are connected to the output of the remote sense amplifier of the IR3448 and are
located 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 and
may be connected together using a single point connection.
9/18/2013
Confidential
2
This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results
of the continuing evaluation, this board can evolve and change without notice
AL
IRDC3448-P0V9
CONNECTIONS and OPERATING INSTRUCTIONS
LAYOUT
The PCB is a 6-layer board. All of layers are 2 Oz. copper. The IR3448 and most of the passive
components are mounted on the top side of the board.
Power supply decoupling capacitors and feedback components are located close to IR3448. The
feedback resistors are connected to the output of the remote sense amplifier of the IR3448 and are
located 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
Gnd
Top View
Vo
Gnd
9/18/2013
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This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results
of the continuing evaluation, this board can evolve and change without notice
AL
Fb
4.7nF
C66
10uF
10k
R17
C26
R1
1.8k
75pF
20
C11
R6
PGD
5
16
18
8
7
9
23.2k
R9
49.9k
IR3448
RS+
Vsns
SW
SW
SW
SW
SW
SW
SW
Boot
PGnd
13
6
20
21
22
23
24
25
32
2
26
C39
1uF
Vout
0.1uF
C37
C25
0.1uF
Vo_R_N
Vo_R_P
22uF
22uF
160nH
L1
C2
C3
+
47uF
PIN11
C19
Vin-
Vin+
47uF
6
5
4
3
2
1
6
5
4
3
2
1
C20
330uF
C1
PVin
Fig. 1: Schematic of the IR3448 evaluation board
Cby p
NC0
NC1
NC2
NC3
NC4
100pF
19
28
30
31
33
Rt/Sy nc
OCSelect
PGD
Vcc
Comp
FB
RSo
C10
U1
R19
7.5k
Rt/Sy nc 4
BODE
2.67k
2200pF
JUMPER 2
R2
R3
5.36k VCC
47.5
C8
15
NC5
3
Enable
R4
LGnd
11
Cbyp
14
17
Vin
1
PVin
PGnd
PGnd
PGnd
10
27
29
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RS-
9/18/2013
12
R18
47uF
C18
47uF
C16
PIN10
47uF
C17
47uF
C15
6
5
4
3
2
1
0.1uF
6
5
4
3
2
1
14
Vout
Vout-
Vout+
IRDC3448-P0V9
4
This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results
of the continuing evaluation, this board can evolve and change without notice
AL
IRDC3448-P0V9
Bill of Materials
Item Qty
Part Reference
Value
Description
SMD Elecrolytic, Fsize,
25V, 20%
Manufacturer
Part Number
Panasonic
EEE-FK1E331P
1
1
C1
330uF
2
2
C2 C3
22uF
1206, 25V, X5R, 10%
Murata
GRM31CR61E226KE15L
3
4
5
6
1
3
1
1
100pF
0.1uF
2200pF
75pF
0402, 50V, NP0, 5%
0402, 50V, X7R, 10%
0402, 25V, NP0, 5%
0402, 50V, NP0, 5%
Murata
TDK
Kemet
Murata
GRM1555C1H101JZ01D
C1005X7R1H104K050BB
C0402C222J3GACTU
GRM1555C1H750JA01D
7
6
47uF
0805, 6.3V, X5R, 20%
TDK
C2012X5R0J476M
8
9
10
11
12
13
14
15
16
17
18
19
20
1
1
1
1
1
1
1
1
1
1
1
1
1
C10
C14 C25 C37
C8
C11
C15 C16 C17
C18 C19 C20
C26
C39
C66
L1
R1
R2
R3
R4
R6
R9
R17
R18
R19
4.7nF
1uF
10uF
0.16uH
1.8k
2.67k
5.36k
47.5
20
23.2k
10k
49.9k
7.5k
0402, 50V, X7R, 10%
0402, 25V, X5R,10%
0603, X5R, 10V, 20%
0.16uH, DCR=2.15mohm
0402,1/10W,1%
0402,1/10W,1%
0402,1/10W,1%
0402,1/10W,1%
Murata
TDK
TDK
Coilcraft
Panasonic
Panasonic
Panasonic
Panasonic
GRM155R71H472KA01D
C1005X5R1E105K050BC
C1608X5R1A106M080AC
XAL5030-161ME_
ERJ-2RKF1801X
ERJ-2RKF2671X
ERJ-2RKF5361X
ERJ-2RKF47R5X
0402,1/10W,1%
0402,1/10W,1%
0402,1/10W,1%
0402,1/10W,1%
0402,1/10W,1%
ERJ-2RKF20R0X
ERJ-2RKF2322X
ERJ-2RKF1002X
ERJ-2RKF4992X
ERJ-2RKF7501X
21
1
U1
IR3448
IR3448 5mm X6mm
Panasonic
Panasonic
Panasonic
Panasonic
Panasonic
International
Rectifier
9/18/2013
Confidential
IR3448MPBF
5
This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results
of the continuing evaluation, this board can evolve and change without notice
AL
IRDC3448-P0V9
TYPICAL OPERATING WAVEFORMS
Vin=12.0V, Vout=0.9V, Iout=0A-16A, Fs=1MHz, Room Temperature, No air flow
Fig. 2: Start up at 16A Load
Ch1:Vin, Ch2:Vout, Ch3:PGood, Ch4:Enable
Fig. 3: Start up at 16A Load
Ch1:Vin, Ch2:Vout, Ch3:PGood,Ch4:Vcc
Fig. 4: Start up with 0.81V Pre Bias , 0A Load
Ch2:Vout , Ch3:PGood, Ch4:Enable
Fig. 5: Output Voltage Ripple, 16A load
Ch2: Vout
Fig. 7: Short (Hiccup) Recovery
Ch2:Vout, Ch3:PGood, Ch4:Iout
Fig. 6: Inductor node at 16A load
Ch1:SW Node
9/18/2013
Confidential
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This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results
of the continuing evaluation, this board can evolve and change without notice
AL
IRDC3448-P0V9
TYPICAL OPERATING WAVEFORMS
Vin=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
9/18/2013
Confidential
7
This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results
of the continuing evaluation, this board can evolve and change without notice
AL
IRDC3448-P0V9
TYPICAL OPERATING WAVEFORMS
Vin=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
9/18/2013
Confidential
8
This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results
of the continuing evaluation, this board can evolve and change without notice
AL
IRDC3448-P0V9
TYPICAL OPERATING WAVEFORMS
Vin=12.0V, Vout=0.9V, Iout=0A-16A, Fs=1MHz, Room Temperature, No air flow
Fig.10: Efficiency versus load current
Fig.11: Power loss versus load current
9/18/2013
Confidential
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This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results
of the continuing evaluation, this board can evolve and change without notice
AL
IRDC3448-P0V9
THERMAL IMAGES
Vin=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 load
IR3448: 65.130C
Fig. 13: Thermal Image of the board bottom at 16A load
Inductor: 69.290C
9/18/2013
Confidential
10
This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results
of the continuing evaluation, this board can evolve and change without notice
AL