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IRDC3637EVAL
IR3637 EVALUATION BOARD USER GUIDE
DESCRIPTION
The IR3637 controller IC is designed to
provide a low cost synchronous Buck
regulator for on-board DC to DC
applications in a small 8-pin SOIC. The
output voltage can be precisely regulated
using the internal 0.8V reference voltage
for low voltage applications.
The IR3637 operates at a fixed internal
400KHz switching frequency to reduce the
component size.
The device features under-voltage lockout
for both input supplies, an external
programmable soft-start function as well as
output under-voltage detection that latches
off the device when an output short is
detected.
INPUT / OUTPUT CONNECTIONS
The following is the input / output connections:
Inputs:
JP1: Input (+5V) and GND
JU1: V
c
Outputs:
JP2: V
(+1.8V) and GND
out
Other Connections:
J1: Scope connection for V
J2: Scope connection for Inductor Point
out
The reference board is designed for
1.8V output using +5V and +12V
supplies. This will demonstrate the
main features of IC.
This user guide contains the schematic
and bill of materials, the design
guidelines are described in data sheet.
SPECIFICATION DATA
Vc= 12V
Vcc=Vin=5V
V
=1.8V
out
Iout =7A
Output Ripple = 50mV
Fs= 400KHz
The connection points are shown in
Figure1. Connect the power supply
cables according to this figure,
minimizing wire lengths to reduce
losses in the wire. Test points J1 and
J2 provide easy connection for
oscilloscope voltage probe to monitor
the inductor points and output voltage.
Rev1.0
4/29/2005
PACKAGE INFORMATION
1
Fb
2
Vcc
3
LDrv
4
Gnd HDrv
8
7
6
5
SS/SD
Comp
Vc
1
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CONNECTION DIAGRAM
IRDC3637EVAL
+12V
Supply
+5V
Supply
Figure 1 – Connection diagram of evaluation board for IR3637
7A
Load
Rev1.0
4/29/2005
2
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LAYOUT
The top side (component) layer for
IR3637 Eval board is shown in Figure
2. The input capacitors are all located
close to the MOSFETs. All the
decoupling capacitors, and feedback
components are located close to IC.
The feedback resistors are tied to the
output voltage at the point of
regulation.
IRDC3637EVAL
The PCB is 4-layers board, one
layer is dedicated to Power GND
and the analog GND is kept
separated from the PGND and it is
connected at a single point.
Figure 2 – Top layer of evaluation board for IR3637
Rev1.0
4/29/2005
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SCHEMATIC
IRDC3637EVAL
321
JP1
VIN
D
INPU T
GND
C
B
VC/VCC
VIN
R4
D1
VC
JU1
C1
C2
SS
8
COMP
7
1
R1
C3
R3
R2
FB
C4
SS
COMP
FB
R5
VCC
2
6
VC
VCC
HDRV
U1
IR3637
LDR V
GND
R9
5
3
4
HDRV
LDR V
D3
R7
BAT54SCT
C6C5
R6
VGL
R8
R10
N15
Q1
S1
VGH
G1
S2
G2
MOSFET N_DUAL
C7
N40
C8
+
C9
+
C10
D1
D1
N25
D2
D2
L1
LX
J2
C12
C13
+
+
4
D
J1
VO
C11
JP2
+
OUTP UT
C
VO
GND
B
A
Rev1.0
4/29/2005
Title
IR3637 - DUAL SO8 MOSFET
Number RevisionSize
Orcad A
Date: 10-Mar -2005 Shee t of
1 2 34
File: C:\PCB2\PCB_last6.dd b Drawn By:
JE3637S-V1R 0
A
Figure 3 – Schematic of the evaluation board
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IRDC3637EVAL
BILL OF MATERIAL
Ref Desig Description Value Qty Part# Manuf
Q1 Dual MOSFET 20V, 13.4mOhm 1 IRF8910 IR
U1 Controller Synchronous PWM 1 IR3637 IR
D3 Diode Fast Switching 1 BAT54A IR
L1 Inductor 1.5uH, 8A, 10 mOhm 1 DO3316P-152 Coilcraft
C8,9,12,13 Cap, Poscap 150uF, 6.3V, 40mOhm 4 6TPC150M Sanyo
C2,C5 Cap, Ceramic 0.1uF, X7R, 16V 2 ECJ-1VB1C104K Panasonic
C1,10,11 Cap, Ceramic 1uF, X5R, 6.3V 3 ECJ-1VB0J105K Panasonic
C3 Cap, Ceramic 22pF, NPO, 100V 1 ECJ- 1 VC2A22 0J Panasonic
C4 Cap, Ceramic 1800pF, X7R, 50V 1 ECJ-1VB1H182K Panasonic
R3 Resistor 16K, 1% 1 Any
R8 Resistor 1.24K, 1% 1 Any
R9 Resistor 1K, 1% 1 Any
R2,4,6,7 Resistor 0 Ohm 4 Any
R1,5,10 Resistor Not Used 3
C6,7 Ca pacitor Not Used 2
D1 Diode Not Used 1
J1,J2 Socket Scope probe 2 131-5031-00 Tektronix
JP1,JP2 Terminal Wire Connect 2 ED1973-ND Digi-Key
JU1 Terminal 2-Pin Header 1 S1012-02-ND Digi-Key
Rev1.0
4/29/2005
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IRDC3637EVAL
TYPICAL OPERATING WAVEFORMS
Test Conditions:
Vcc=Vin=5V, Vc=12V, Vout=1.8V, Iout=0-7A, Ta=Room Temp, No Air Flow.
Unless otherwise specified.
Figure 4 - Start up waveforms
Ch1: Vin=Vcc, Ch2: Vc, Ch3: Vss, Ch 4: Vout
Figure 6 - Gates waveforms
Ch1: Hdrv, Ch2Ldrv,, Ch4:Inductor Current
ILoad=5A
Figure 5 - Start up waveforms
Ch1: Vin=Vcc, Ch2: Vc, Ch3: Vss, Ch 4: Vout
Figure 7 - Gates waveforms
Ch1: Hdrv, Ch2Ldrv,, Ch3:Inductor Point
ILoad=5A
Rev1.0
4/29/2005
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IRDC3637EVAL
TYPICAL OPERATING WAVEFORMS
Test Conditions:
Vcc=Vin=5V, Vc=12V, Vout=1.8V, Iout=0-7A, Ta=Room Temp, No Air Flow.
Unless otherwise specified.
Figure 8 - Shutdown by shorting the SS pin
Ch1: Hdrv, Ch2Ldrv,, Ch3:SS
ILoad=5A
Figure 10 - Load Transient (0-5A)
Ch1: Vout, Ch4: Step Load Current
Figure 9 - Output Voltage Ripple
Ch1: Vout, Ch4: Inductor Current
ILoad=5A
Figure 11 - Load Transient (5-0A)
Ch1: Vout, Ch4: Step Load Current
Rev1.0
4/29/2005
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IRDC3637EVAL
TYPICAL PERFORMANMCE CURVES
Test Conditions:
Vcc=Vin=5V, Vc=12V, Vout=1.8V, Iout=0-7A, Ta=Room Temp, No Air Flow.
Unless otherwise specified.
Efficiency
Vc=12V, Vcc=Vbus=5V, I out= 0- 8A, Fs=400KHz
100
90
80
70
60
50
40
30
Effici en cy (%)
20
10
0
0123456789
Iout (A)
Figure 12 - Efficiency using IRF8910 Dual MOSFET
This product has been designed and qualified for the Industrial market.
IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: (310)252-7105
TAC FAX: (310) 252-7903
Visit us at www.irf.com
Data and specification subject to change without notice. 02/01
for sales contact information
Rev1.0
4/29/2005
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