International Rectifier IR3637 User Manual

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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
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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
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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
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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
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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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