IRF IRDCIP1203-A Irdcip1203-a: 400khz, 15a, synchronous buck converter using ip1203 Datasheet

International Rectifier • 233 Kansas Street, El Segundo, CA 90245 USA
IRDCiP1203-A: 400kHz, 15A, Synchronous
Buck Converter Using iP1203
Overview
This reference design is capable of delivering a continuous current of 15A (with
heatsink) or 12A (without heatsink) at an ambient temperature of 45ºC and airflow
of 300LFM. Figures 1–20 provide performance graphs, thermal images, and
waveforms. Figures 21–33 and Table 1 are provided to engineers as design
references for implementing an iP1203 solution.
The components installed on this demoboard were selected based on operating at
an input voltage of 12V (+/-10%) and a switching frequency of 400kHz (+/-15%).
Major changes from these set points may require optimizing the control loop
and/or adjusting the values of input/output filters in order to meet the user’s
specific application requirements. Refer to the iP1203 datasheet User Design
Guidelines section for more information.
Note: The 16-pin connector (CON1) is used only for production test purposes and
should not be used for evaluation of this demoboard.
(Photo shown without heatsink)
Demoboard Quick Start Guide
Initial Settings:
VOUT is set to 1.8V, but can be adjusted from 1.0V to 3.3V by changing the values of R3 and R7 according to the following
formula:
R3 = R7 = (15k * 0.8) / (VOUT - 0.8)
The switching frequency is set to 400kHz, but can be adjusted by changing the value of R10. The graph in Figure 22 shows the
relationship between R10 and the switching frequency.
Power Up Procedure:
1. Apply input voltage across VIN and PGND.
2. Apply load across VOUT pads and PGND pads.
3. Adjust load to desired level. See recommendations below.
IRDCiP1203-A Recommended Operating Conditions
(refer to the iP1203 datasheet for maximum operating conditions)
Input voltage:
5.5V – 13.2V
Output voltage:
1.0 – 3.3V
Switching Freq:
400kHz
Output current:
This reference design is capable of delivering a continuous current of 15A (with heatsink) or 12A
(without heatsink) at an ambient temperature of 45ºC and airflow of 300LFM.
11/30/04
5.5
5.0
Vo=1.0V
Vo=1.3V
Vo=1.8V
Vo=2.5V
Vo=3.3V
4.5
2.5
Power Loss (W)
3.0
Fig. 1: Power Loss vs.
Output Current for
Vin=5.5V
Power Loss (W)
3.5
Fig. 2: Power Loss vs.
Output Current for
Vin=8.0V
Power Loss (W)
4.0
Fig. 3: Power Loss vs.
Output Current for
Vin=12.0V
2.0
1.5
Conditions:
Vin=5.5V
Fsw=400kHz
Ta=25ºC
1.0
0.5
0.0
0
1
2
3
4
5
6
7
8
9
10
Total Output Current (A)
11
12
13
14
15
5.5
5.0
Vo=1.0V
Vo=1.3V
Vo=1.8V
Vo=2.5V
Vo=3.3V
4.5
4.0
3.5
3.0
2.5
2.0
1.5
Conditions:
Vin=8.0V
Fsw=400kHz
Ta=25ºC
1.0
0.5
0.0
0
1
2
3
4
5
6
7
8
9
10
Total Output Current (A)
11
12
13
14
15
5.5
5.0
Vo=1.0V
Vo=1.3V
Vo=1.8V
Vo=2.5V
Vo=3.3V
4.5
4.0
3.5
3.0
2.5
2.0
1.5
Conditions:
Vin=12V
Fsw=400kHz
Ta=25ºC
1.0
0.5
0.0
0
1
2
3
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4
5
6
7
8
9
10
Total Output Current (A)
11
12
13
2
14
15
Vo=1.8V
Vo=1.3V
Vo=1.0V
Conditions:
Vin=5.5V
Fsw=400kHz
Ta=25ºC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Efficiency (%)
Vo=2.5V
Fig. 4: Efficiency vs.
Output Current for
Vin=5.5V
Efficiency (%)
Vo=3.3V
Fig. 5: Efficiency vs.
Output Current for
Vin=8.0V
Efficiency (%)
96%
95%
94%
93%
92%
91%
90%
89%
88%
87%
86%
85%
84%
83%
82%
81%
80%
79%
78%
77%
76%
75%
Fig. 6: Efficiency vs.
Output Current for
Vin=12.0V
15
Total Output Current (A)
96%
95%
94%
93%
92%
91%
90%
89%
88%
87%
86%
85%
84%
83%
82%
81%
80%
79%
78%
77%
76%
75%
Vo=3.3V
Vo=2.5V
Vo=1.8V
Vo=1.3V
Vo=1.0V
Conditions:
Vin=8.0V
Fsw=400kHz
Ta=25ºC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Total Output Current (A)
Conditions:
Vin=12V
Fsw=400kHz
Ta=25ºC
96%
95%
94%
93%
92%
91%
90%
89%
88%
87%
86%
85%
84%
83%
82%
81%
80%
79%
78%
77%
76%
75%
Vo=3.3V
Vo=2.5V
Vo=1.8V
Vo=1.3V
Vo=1.0V
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Total Output Current (A)
3
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100.0%
99.9%
Conditions:
Vin=12V
Vout=1.8V
Fsw=400kHz
99.8%
99.7%
99.6%
99.5%
99.4%
99.3%
99.2%
99.1%
99.0%
0
1
2
3
4
5
6
7
8
9
10
11
12
Output Current (A)
Fig. 7: Output Voltage Regulation vs. Current
Phase-Margin = 59.3º
Fc = 56.6kHz
Conditions:
Vin=12V
Vout=1.8V
Iout=15A
Fsw=400kHz
Gain-Margin = -18.9dB
Fig. 8: Bode Plot
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4
13
14
15
Fig. 9: Thermograph (With Heatsink)
*>89.2°C
Conditions:
Vin = 12V
Vout = 1.8V
Iout = 15A
Fsw = 400kHz
Ambient Temp. = 45ºC
Airflow = 300LFM
Stabilizing Time = 15 min.
80.0
70.0
60.0
50.0
40.0
83.8
82.9
Max
83.2
30.0
Direction of Airflow
*<24.1°C
Fig. 10: Thermograph (No Heatsink)
*>97.4°C
Conditions:
Vin = 12V
Vout = 1.8V
Iout = 12A
Fsw = 400kHz
Ambient Temp. = 45ºC
Airflow = 300LFM
Stabilizing Time = 15 min.
90.0
80.0
70.0
60.0
50.0
40.0
74.9
77.9
Max
92.9
30.0
20.0
*<19.8°C
Direction of Airflow
5
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Fig. 11: Power Up Sequence
Conditions:
Vin=12V
Vout=1.8V
Iout=15A
Fsw=400kHz
Conditions:
Vin=12V
Vout=1.8V
Iout=15A
Fsw=400kHz
Fig. 12: Power Down Sequence
For Closeup, see
Fig. 13
Fig. 13: Power Down – Close Up
Conditions:
Vin=12V
Vout=1.8V
Iout=15A
Fsw=400kHz
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Fig. 14: Output Voltage Ripple
Conditions:
Vin=12V
Vout=1.8V
Iout=15A
Fsw=400kHz
Ripple = 11.6mVp-p
Conditions:
Vin=12V
Vout=1.8V
Fsw=400kHz
Hiccups until
short circuit
is removed
Fig. 15: Short Circuit Protection
Conditions:
Vin=12V
Vout=1.8V
Iout=15A
Fsw=400kHz
Fig. 16: Over-voltage Protection
7
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+ 41.0mV peak
- 42.0mV peak
Conditions:
Vin=12V
Vout=1.8V
Fsw=400kHz
Conditions:
Vin=12V
Vout=1.8V
Fsw=400kHz
Step-Up 50% to 75%
Fig. 17: Iout Transient Step-Up 50% - 75%
Step-Down 75% to 50%
Fig. 18: Iout Transient Step-Down 75% - 50%
+ 81.0mV peak
- 85.0mV peak
Conditions:
Vin=12V
Vout=1.8V
Fsw=400kHz
Conditions:
Vin=12V
Vout=1.8V
Fsw=400kHz
Step-Up 50% to 100%
Fig. 19: Iout Transient Step-Up 50% - 100%
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Step-Down 100% to 50%
Fig. 20: Iout Transient Step-Down 100% - 50%
Adjusting the Over-Current Limit
R9 is the resistor used to adjust the over-current trip point. The trip point corresponds to the peak inductor current indicated on the
x-axis of Fig. 21. (Note: Fig. 21 is based on iP1203 TBLK = 125°C. The trip point will be higher than expected if the reference
board is cool and is being used for short circuit testing.)
55
205
50
185
V o u t = 1.5V
F sw = 300kH z
L = 1u H
45
40
165
145
0
T BL K = 125 C
35
125
Vin=12 V
30
105
Vin=5.5V
25
85
20
65
15
45
10
25
5
5
6
8
10
12
14
16
18
20
22
24
O ver-Current T rip Point (Amps)
Fig. 21: ROCSET vs. Over-Current Trip Point
50
45
Ω
40
35
30
25
20
15
200
220
240
260
280
300
320
340
360
380
Switching Frequency (kHz)
Fig. 22: R10 vs. Frequency
9
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400
Fig. 23: Component Placement Top Layer
Fig. 24: Component Placement Bottom Layer
Fig. 25: Top Copper Layer
Fig. 26: 1 Mid Copper Layer
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st
10
nd
Fig. 27: 2
rd
Mid Copper Layer
Fig. 28: 3 Mid Copper Layer
th
Fig. 29: 4 Mid Copper Layer
Fig. 30: Bottom Copper Layer
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Fig. 31: Heatsink Photo
Tolerances are ±0.38 (±0.015)
Fig. 32: Mechanical Outline Drawing of Heatsink
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Fig. 33: Reference Design Schematic
J2
PGND
J1
VIN
TP2
PGND
C1
10uF
TP1
VIN
C2
10uF
C3
10uF
C4
10uF
R10
21.0k(400kHz)
TP6
SYNC
C6
0.1uF
C5
2.2uF
10K
R1
C7
100pF
SS
TP5
PGOOD
PGNDS
VINS
12
15
14
8
6
13
1
23
24
RT
SYNC
VREF
SS
Vcc_bypass
PGOOD
VIN
VIN
VINS
U1
iP1203
PGND
PGND
PGND
PGND
PGND
PGND
PGND
PGND
2
3
4
5
7
17
20
21
13
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FBs
CC
FB
Vsws
Vsw
Vsw
OCSET
11
9
10
19
22
18
16
C11
100pF
C8
33pF
L1
1.2uH
R7
12.1K
15K
R6
C10
8200pF
R4
10K
TP7
VSW
R9
37.4K VSW
15K
R2
C12
100uF
R3
12.1K
249
R5
C13
100uF
C15
22uF
C9
1000pF
C14
100uF
C16
22uF
C17
22uF
R8
0
TP3
VOUT
TP4
PGND
C18
0.1uF
VOUTS
J4
PGND
J3
VOUT
Quantity
4
1
2
3
3
2
1
1
1
1
1
2
1
2
2
1
1
1
7
1
Designator
C1, C2, C3, C4
C10
C11, C7
C12, C13, C14
C15, C16, C17
C18, C6
C5
C8
C9
H1
L1
R1, R4
R10
R2, R6
R3, R7
R5
R8
R9
PGND, PGND, PGOOD,
SYNC, VIN, VOUT, VSW
U1
Type 1
Type 2
capacitor
X7R
capacitor
X7R
capacitor
NPO
capacitor
X5R
capacitor
X5R
capacitor
X7R
capacitor
X5R
capacitor
NPO
capacitor
COG
hardware
heatsink
inductor metal composite
resistor
thick film
resistor
thick film
resistor
thick film
resistor
thick film
resistor
thick film
resistor
carbon film
resistor
thick film
Value 1
10.0uF
8200pF
100pF
100uF
22.0uF
0.100uF
2.20uF
33.0pF
1000pF
16 fins
1.20uH
10.0K
21.0K
15.0K
12.1K
249
0
37.4K
Value 2
16V
50V
50V
6.3V
6.3V
16V
6.3V
50V
100V
0.400"
22A
1/10W
1/10W
1/10W
1/10W
1/10W
1/16W
1/10W
hardware
test point
90 mils 112 x 150 mils
iP1203
LGA unit
-
-
Tolerance
Package
Manufacturer
Manufacturer P/N
10%
1206
TDK
C3216X7R1C106KT
10%
0603
KOA
X7R0603HTTD822K
5%
0603
Phycomp
0603CG101J9B20
20%
1210
TDK
C3225X5R0J107M
20%
1206
TDK
C3216X5R0J226M
10%
0603
MuRata
GRM188R71C104KA01D
10%
0603
Murata
GRM39X5R225K6.3
5%
0603
KOA
NPO0603HTTD330J
5%
0603
TDK
C1608COG2A102J
10.6mm x 10.6mm Aavid/ Thermalloy
NP974686 REV 1
20%
SMT
Delta Electronics
MPL104-1R2IR
1%
0603
KOA
RK73H1J1002F
1%
0603
KOA
RK73H1JLTD2102F
1%
0603
KOA
RK73H1J1502F
1%
0603
KOA
RK73H1JLTD1212F
1%
0603
KOA
RK73H1JLTD2490F
<50m
0603
ROHM
MCR03EZHJ000
1%
0603
KOA
RK73H1J3742F
-
SMT
Keystone
5016
-
9mm x 9mm
IRF
-
Table 1: Reference Design Bill of Materials
Refer to the following application notes for detailed guidelines and suggestions when
implementing iPOWIR Technology products:
AN-1028: Recommended Design, Integration and Rework Guidelines for International Rectifier’s
iPowIR Technology BGA and LGA and Packages
This paper discusses optimization of the layout design for mounting iPowIR BGA and LGA packages on
printed circuit boards, accounting for thermal and electrical performance and assembly considerations.
Topics discussed includes PCB layout placement, and via interconnect suggestions, as well as soldering,
pick and place, reflow, inspection, cleaning and reworking recommendations.
AN-1030: Applying iPOWIR Products in Your Thermal Environment
This paper explains how to use the Power Loss and SOA curves in the data sheet to validate if the
operating conditions and thermal environment are within the Safe Operating Area of the iPOWIR product.
AN-1047: Graphical solution for two branch heatsinking Safe Operating Area
Detailed explanation of the dual axis SOA graph and how it is derived.
Use of this design for any application should be fully verified by the customer. International Rectifier
cannot guarantee suitability for your applications, and is not liable for any result of usage for such
applications including, without limitation, personal or property damage or violation of third party
intellectual property rights.
IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: (310) 252-7105
TAC Fax: (310) 252-7903
www.irf.com
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