Rev1.0
4/29/2005
IRDC3637EVAL
1
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- st art function as well as
output under-voltage detection that latches
off the device when an output short is
detected.
INPUT / OUTPUT CONNECTIO NS
The following is the input / output connections:
Inputs:
JP1: Input (+5V) and GND
JU1: Vc
Outputs:
JP2: Vout (+1.8V) and GND
Other Connections:
J1: Scope connection for Vout
J2: Scope connection for Inductor Point
SPECIFICATION DATA
Vc= 12V
Vcc=Vin=5V
Vout=1.8V
Iout =7A
Output Ripple = 50mV
Fs= 400KHz
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.
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.
PACKAGE INFORMATION
Fb
Vcc
LDrv
Gnd HDrv
Vc
Comp
SS/SD
4
3
2
1
5
6
7
8
Rev1.0
4/29/2005
IRDC3637EVAL
2
CONNECTION DIAGRAM
Figure 1 – Connection diagram of evaluation board for IR3637
+5V
Supply
+12V
Supply
7A
Load
Rev1.0
4/29/2005
IRDC3637EVAL
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.
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
3
Rev1.0
4/29/2005
IRDC3637EVAL
SCHEMATIC
Figure 3 – Schematic of the evaluation bo ard
4
1234
A
B
C
D
4
321
D
C
B
ATitle
Number RevisionSize
Orca d A
Date: 10-Mar-20 05 Sheet o f
File: C:\PCB2\PC B_last6.ddb Dr awn By:
VO
VIN
+
C12
L1
+
C13
+
C9
+
C8
INPUT
OUTPUT
+
VIN
GND
JP1
JP2
D3
D1
BAT54SCT
LDR V
SS
COMP
FB
N15
N40
HDRV VGH
VGL
J1
N25
VC
JU1
IR3 637 - DUAL SO8 MOSF ET
VCC
JE3637S-V1R0
SS
8
COMP
7
VC 6
HDRV 5
FB
1
VCC 2
LDR V 3
GND 4
U1
IR3637
GND
VO
S1
G1
S2
G2
D1
D1
D2
D2
Q1
MOSFET N_DUAL
C10
C6C5
C1
C2
C11
C3
C4 C7
R3
R1
R2
R9
R8
R10
R7
R6
R4
R5
J2
VC/VCC
LX
Rev1.0
4/29/2005
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 Diod e 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 Panasoni c
C1,10,11 Cap, Ceramic 1uF, X5R, 6.3V 3 ECJ-1VB0J105K Panasonic
C3 Cap, Cera mic 22pF , NPO, 100V 1 ECJ-1VC2A220J Panasonic
C4 Cap, Ceramic 1800pF, X7R, 50V 1 ECJ-1VB1H182K Panaso nic
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 Capacitor Not Used 2
D1 Diod e Not Used 1
J1,J2 Socket Scope probe 2 131-5031-00 Tektronix
JP1,JP2 Termina l Wire Connect 2 ED1973-ND Digi-Key
JU1 Termi nal 2-Pin Header 1 S1012-02-ND Digi-Key
5
Rev1.0
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IRDC3637EVAL
TYPICAL OPERATI NG WAVEFORMS
Test Conditions:
Vcc=Vin=5V, Vc=12V, Vout=1.8V, Iout=0-7A, Ta=Room Temp, No Air Flow.
Unless otherwise specified.
6
Figure 4 - Start up waveforms
Ch1: Vin=V cc, Ch2: Vc, Ch3: Vss, Ch4: Vout Figure 5 - Start up waveforms
Ch1: Vin=V cc, Ch2: Vc, Ch3: Vss, Ch4: Vout
Figure 6 - Gates waveforms
Ch1: Hdrv, Ch2Ldrv,, Ch4:Inductor Current
ILoad=5A
Figure 7 - Gates waveforms
Ch1: Hdrv, Ch2Ldrv,, Ch3:Inductor Point
ILoad=5A
Rev1.0
4/29/2005
IRDC3637EVAL
TYPICAL OPERATI NG 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 9 - Output Voltage Ripple
Ch1: Vout, Ch4: Inductor Current
ILoad=5A
Figure 10 - Load Transient (0-5A)
Ch1: Vout, Ch4: Step Load Current Figure 11 - Load Transient (5-0A)
Ch1: Vout, Ch4: Step Load Current
Rev1.0
4/29/2005
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
0
10
20
30
40
50
60
70
80
90
100
0123456789
Iout (A)
E fficiency (% )
Figure 12 - Efficiency using IRF8910 Dual MOSFET
IR WORLD HEADQUART ERS: 233 Kansas St., El Segundo, California 90245, USA Tel: (310)252-7105
TAC FAX: (310) 252-7903
Visit us at www.irf.com for sales contact information
Data and specification subject to change without notice. 02/01
This product has been designed and qualified for the Industrial market.
