International Rectifier IRU3038 User manual

IRDC3038
1
Rev. 1.2
06/05/02 www.irf.com
SPECIFICATION DATAINTRODUCTION
IRU3038EVALUATIONBOARDUSERGUIDE
INPUT/OUTPUT CONNECTIONS
The IRU3038 controller IC is designed to provide a low
cost synchronous Buck regulator for voltage tracking
applications such DDR memory and general purpose
on-boardDCtoDCconverter.Modernmicroprocessors
combinedwithDDRmemory,needhigh-speedbandwidth
databuswhichrequires a particular busterminationvolt-
age. This voltage will be tightly regulated to track the
halfofchipsetvoltage for best performance.
Switcher:
VIN = 5V
VOUT = 2.5V
IOUT = 8A
DVOUT = 75mV
FS = 200KHz
Thefollowing is theinput/output connections:
Inputs:
J1:Input(+5V)
J2:Gnd
Outputs:
J5: VOUT (+2.5V)
J6:Gnd
OtherConnections:
J7: VDDQ (for tracking system)
J3:VREF (outputforreferencevoltage)
TheconnectionpointsisshowninFigure1.Connectthe
power supply cables according to this figure, minimize
wire lengths to reduce losses in the wire. Test point J8
and J9 provide easy connections for oscilloscope volt-
age probe to monitor the output inductor point and the
outputvoltages.

IRDC3038
2
Rev. 1.2
06/05/02 www.irf.com
Figure1-Connectiondiagramofevaluation-boardforIRU3038.
CONNECTION DIAGRAM
Power Supply
Gnd+5V
6A Supply
Load
0 - 8A

IRDC3038
3
Rev. 1.2
06/05/02 www.irf.com
Thetopside (component) layer forIRU3038Evalboard
isshowninFigure2.Theinputcapacitorsare all located
close to the MOSFETs. All the decoupling capacitors,
charge pump capacitor and feedback components are
located close to IC. The feedback resistors are tied to
theoutput voltage atthe point ofregulation.
The PCB is 4-layers board, one layer is dedicated to
PowerGNDandtheanalogGNDiskeptseparatedfrom
the PGND and it is connected at a single point.
LAYOUT
Figure2-Top layer of evaluation-board for IRU3038.

IRDC3038
4
Rev. 1.2
06/05/02 www.irf.com
SCHEMATIC
Figure3-Schematicofevaluation-boardforIRU3038.
{Doc} IRU3038EVAL
A
1Friday, May 24, 2002
Title Size Document Number Date: Sheet of
INPUT
V
O
+5V
GND
Vref GND VDDQ
G
N
Vc
Fb
Comp SS Rt
Vo
Vrin
+5V
Vgl
Vgh
Vp Vref
Vd
Vds
R3 0 Ohm R5 0 Ohm
D1
BAT54S 32
1L1
1uH
U1
IRU3038
Vc 10
Vcc 4
Vref
3
SS
13 Vp
2
Fb
1
Comp
12 Rt 11
HDrv 9
LDrv 6
PGnd 8
Gnd 7
C5
0.1uF
+
C10
C3 1uF
+
C1 33uF, ECS-T1CD336R
C17
OPEN
R10
OPEN
R8 1K
R9
26.1K
C15
1800pF
C13
OPEN
C14
OPEN C16
OPEN
R7
OPEN
R4 OPEN C8 0.1uF
R2
0 Ohm
R1
OPEN
C12 1uF
C4 1uF
L2
3.3uH, DO5022P-332HC
C9 470pF
J1 1 J2 1
J5
1
J6
1
J4 1
+
C11
2X150uF, 6TPC150M
R13 OPEN
J7 1
R12 OPEN
C7 OPEN
R11 1.00k
J3 1
+
C2 47uF
C6 1uF J9
TP14
3
2
1
J8 TP1
4
3
2
1
+
C18
47uF, 16TPB47M
Q1
IRF7460
8
7
5
6
1
2
3
4
Q2
IRF7460
8
7
5
6
1
2
3
4
R6 4.7Ohm
D2 NOT USED
1 2

IRDC3038
5
Rev. 1.2
06/05/02 www.irf.com
BILL OF MATERIAL
Ref Desig Description Value Qty Part# Manuf Web site (www.)
2
1
1
1
1
1
2
2
2
1
1
1
3
1
1
2
3
6
5
1
Q1,Q2
U1
D1
L1
L2
C1
C2,C18
C10,C11
C5,C8
C4
C15
C9
C3,C6,C12
R9
R6
R8,R11
R2,R3,R5
R1,4,7,
10,12,13
C7,12,13,
14,16
D2
MOSFET
Controller
Diode
Inductor
Inductor
Cap,Tantalum
Cap,Poscap
Cap,Poscap
Cap,Ceramic
Cap,Ceramic
Cap,Ceramic
Cap,Ceramic
Cap,Ceramic
Resistor
Resistor
Resistor
Resistor
Resistor
Capacitor
Diode
IRF7460
IRU3038
BAT54S
D03316P-102HC
D05022P-332HC
ECS-T1CD336R
16TPB47M
6TPC150M
ECJ-2VF1E104Z
ECJ-3YB1E105K
ECJ-2VB1H182K
ECJ-2VB2D471K
ECJ-2VF1C105Z
IR
IR
IR
Coilcraft
Coilcraft
Panasonic
Sanyo
Sanyo
Panasonic
Panasonic
Panasonic
Panasonic
Panasonic
20V,10mV, 12A
SynchronousPWM
Fast Switching,
Schottky
1mH, 10A
3.3mH,12A
33mF, 16V
47mF, 16V, 70mV
150mF, 6.3V, 40mV
0.1mF, Y5V, 25V
1mF, X7R, 25V
1800pF, X7R, 50V
470pF,X7R
1mF, Y5V, 16V
26.1K, 5%
4.7V,5%
1K, 1%
0V
NotUsed
NotUsed
NotUsed
irf.com
coilcraft.com
maco.panasonic.co.jp
sanyo.com/industrial
maco.panasonic.co.jp

IRDC3038
6
Rev. 1.2
06/05/02 www.irf.com
TEST DATA
Figure 16 - Start-up time @ IOUT=5A.
Figure17 - Shutdoownthe outputby
pullingdown the soft-start. Figure18 - 3.3Voutput voltage ripple @ IOUT=5A.
Figure 19 - Transient response @ IOUT=0 to 2A. Figure 20 - Transient response @ IOUT=0 to 4A.
0A
2A
Vss
VOUT
IOUT
VIN
Vss
VOUT
4A
0A
Figure15-Efficiencyfor IRU3038 Evaluation Board.
VIN=5V, VOUT=2.5V
80
82
84
86
88
90
92
94
0123456789
OutputCurrent (A)
Efficiency (%)

IRDC3038
7
Rev. 1.2
06/05/02 www.irf.com
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Dataand specifications subjecttochange withoutnotice.7/25/2002