an1372

ISL8500EVAL1Z 2A Regulator Standard
Buck PWM
®
Application Note
November 21, 2007
AN1372.0
Description
Recommended Equipment
The ISL8500EVAL1Z REV A kit is intended for use by
individuals with requirements for Point-of-Load applications
sourcing from 4.5V to 25V. The ISL8500EVAL1Z evaluation
board is used to demonstrate the performance of the
ISL8500 standard buck regulator.
The following materials are recommended to perform
testing:
The ISL8500 is offered in a 4mmx3mm 12 Ld DFN package
with 1mm maximum height. The complete converter
occupies less than 0.425in2 area.
• 0V to 25V power supply with at least 5A source current
capability, battery, notebook AC adapter
• One electronic load capable of sinking current up to 5A
• Digital Multimeters (DMMs)
• 100MHz quad-trace oscilloscope
Features
• Signal generator
• Standard Buck Controller with Integrated Switching Power
MOSFET
Quick Setup Guide
• Integrated Boot Diode
1. Ensure that the circuit is correctly connected to the supply
and loads prior to applying any power.
• Input Voltage Range
- Fixed 5V ±10%
- Variable 5.5V to 25V
2. Connect the bias supply to VIN, the plus terminal to TP1
(VIN) and the negative return to TP2 (GND).
• PWM Output Voltage Adjustable from 0.6V to 20V with
Continuous Output Current up to 2A
4. Turn on the power supply.
3. Verify that SW1 is on ENABLE.
• Voltage Mode Control with Voltage Feed Forward
5. Verify the PG is on and the output voltage is 2.5V for
VOUT(TP3).
Evaluating the Other Output Voltage
• Fixed 500kHz Switching Frequency
The ISL8500EVAL kit outputs are preset to 2.5V; however, it
can be programmed using resistor dividers using Equation 1:
• Externally Adjustable Soft-Start Time
• Output Undervoltage Protection
R 1 ⋅ 0.6V
R 2 = ---------------------------------V OUT – 0.6V
• PGOOD Output
(EQ. 1)
• Overcurrent Protection
The output voltage programming resistor R2 will depend on
on the feedback resistor R1, as referred to in Figure 1. The
value of R1 is typically between 1kΩ and 10kΩ. If the output
voltage desired is 0.6V, then R2 is left opened.
• Thermal Overload Protection
• Internal 5V LDO regulator
Applications
VOUT
• General Purpose
R1
• WLAN Cards-PCMCIA, Cardbus32, MiniPCI CardsCompact Flash Cards
+
EA
• Hand-Held Instruments
R2
0.6V
REFERENCE
What’s Inside
The Evaluation Board Kit contains the following materials:
FIGURE 1. EXTERNAL RESISTOR DIVIDER
• The ISL8500 EVAL REV D board
• The ISL8500 datasheet
TABLE 1. SWITCH 1 SETTINGS
• This EVAL KIT document
SW1
1
1
ENABLE
SW1
OPERATING MODE
Enable or disable the buck controller
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2007. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
Schematic
1
R2
2200PF
C2
10K
1
1
220UF
C20
2
1
2
0.1UF
7
4 SP2
2
TP13
1
R12
100K
VDD
ON
3
SW1
1
OFF
2
EN
1
2
4 SP1
1
ISL8500IRZ
R30
1
C9
BOOT
3
8
C8
13
TP3
9
C21
6
VOUT
1
OPEN
5
L1
10UH
PHASE
2
4
10
100UF
EN
PG
11
2 C13 1
3
TP2
2 C12 1
0.1UF
1
GND
12
3
2
C4
VIN
VIN
PHASE
PHASE
BOOT
VDD
1
VIN
OPEN
POPULATE R30 IF VIN <6V ONLY
TP4
Application Note 1326
2
FB
COMP
SS
EN
PG
GND
EP
1
1
2
TP1
1
1
U1
FB
COMP
3
PG
2N7002
2 C10 1
3.16K
TP16
VIN
2
D3
1
OPEN
2
1
C3
470PF
R4
1
Q4
2
301
D1
R3
10PF
10UF
C11
10K
C1
2
2
R21
R1
51.1K
1UF
2.43K
R20
VDD
AN1372.0
November 21, 2007
Application Note 1326
ISL8500EVAL1Z Bill of Materials
PART NUMBER
REFERENCE
QTY UNITS DESIGNATOR
ISL8500EVAL1ZREVAPCB
1
ea
H1044-00222-50V10-T
1
ea
H1065-00106-25V10-T
1
ea
DNP
0
ea
H1082-00107-6R3V20-T
1
ea
DESCRIPTION
MANUFACTURER
MANUFACTURER PART
PWB-PCB, ISL8500EVAL1Z, TITAN
REVA, ROHS
ISL8500EVAL1ZREVAPCB
C1
CAP, SMD, 0402, 2200pF,
50V, 10%, X7R, ROHS
PANASONIC
ECJ-0EB1H222K
C10
CAP, SMD, 1206, 10µF, 25V,
10%, X5R, ROHS
VENKEL
C1206X5R250-106KNE
TDK
C3225X5R0J107M
PANASONIC
ECJ-4YB0J107M
AVX
12106D107MAT
C11, C13, C20, DO NOT POPULATE OR
C21
PURCHASE
C12
CAP, SMD, 1210, 100µF,
6.3V, 20%, X5R, ROHS
H1044-00100-50V5-T
1
ea
C2
CAP, SMD ,0402, 10pF, 50V,
5%, NPO ,ROHS
VENKEL
C0402COG500-100JNE
H1044-00471-50V10-T
1
ea
C3
CAP, SMD, 0402, 470pF,
50V, 10%, X7R, ROHS
PANASONIC
ECJ-0EB1H471K
VENKEL
C0402X74500-471KNE
H1044-00104-16V10-T
1
ea
C4
CAP, SMD, 0402, 0.1µF, 16V, MURATA
10%, X7R, ROHS
VENKEL
GRM36X7R104K016AD
C0402X7R160-104KNE
H1045-00105-6R3V10-T
1
ea
C8
CAP, SMD, 0603, 1µF, 6.3V,
10%, X5R, ROHS
PANASONIC
ECJ1VB0J105K
C1608X7R1H104K-T
1
ea
C9
CAPACITOR, SMD, 0603,
0.10µF, 50V, 10%, X7R
TDK
C1608X7R1H104K
B340LB-13-F-T
1
ea
D1
DIODE-SCHOTTKY SMD,
SMB, 2P, 40V, 3A LOW VF,
ROHS
DIODES INC.
B340LB-13-F
LTST-C170CKT
1
ea
D3
LED-GaAs RED, SMD,
2x1.25mm, 100mW, 40mA,
10mcd, ROHS
LITEON/VISHAY
LTST-C170CKT
ROHM
SML-210LTT86
STANLEY ELECTRIC BR112H-TR
VISHAY
IHLP2525CZRZ100M01
IHLP2525CZRZ100M01
1
ea
L1
COIL-PWR INDUCTOR,
SMD, 6.9x6.5, 10µH, 20%,
3A, ROHS
2N7002-7-F-T
1
ea
Q4
TRANSISTOR,N-CHANNEL, DIODES, INC.
3LD, SOT-23, 60V, 115mA,
ON
ROHS
SEMICONDUCTOR
2N7002-7-F
RES, SMD, 0402, 51.1k,
1/16W, 1%, TF, ROHS
PANASONIC
ERJ-2RKF5112X
VENKEL
CR0402-16W-5112FT
H2510-05112-1/16W1-T
1
ea
R1
2N7002LT1G
H2510-01003-1/16W1-T
1
ea
R12
RES, SMD, 0402, 100k,
1/16W, 1%, TF,ROHS
PANASONIC
ERJ2RKF1003
H2510-01002-1/16W1-T
1
ea
R2
RES, SMD, 0402, 10k,
1/16W, 1%, TF,ROHS
PANASONIC
ERJ-2RKF1002
VENKEL
CR0402-16W-1002FT
RES, SMD, 0603, 2.43k,
1/10W, 1%, TF, ROHS
VENKEL
CR0603-10W-2431FT
YAGEO
RC0603FR-072K43L
RES, SMD, 0603, 10k,
1/10W, 1%, TF,ROHS
KOA
RK73H1JT1002F
VENKEL
CR0603-10W-1002FT
H2511-02431-1/10W1-T
H2511-01002-1/10W1-T
1
ea
1
ea
3
R20
R21
AN1372.0
November 21, 2007
Application Note 1326
ISL8500EVAL1Z Bill of Materials (Continued)
PART NUMBER
H2510-03010-1/16W1-T
REFERENCE
QTY UNITS DESIGNATOR
1
ea
R3
DESCRIPTION
RES, SMD, 0402, 301Ω,
1/16W, 1%, TF, ROHS
H2511-DNP
0
ea
R30
RES, SMD, 0603, DNPPLACE HOLDER, ROHS
H2510-03161-1/16W1-T
1
ea
R4
RES,SMD, 0402, 3.16k,
1/16W, 1%, TF, ROHS
MANUFACTURER
MANUFACTURER PART
PANASONIC
ERJ-2RKF3010X
VENKEL
CR0402-16W-3010-FT
VENKEL
CR0402-16W-3161FT
PANASONIC
ERJ-2RKF3161X
VISHAY/DALE
CRCW04023K16FKED
131-4353-00
131-4353-00
2
ea
SP1,SP2
CONN-SCOPE PROBE
TEST PT, COMPACT, PCB
MNT, ROHS
TEKTRONIX
GT11MSCBE-T
1
ea
SW1
SWITCH-TOGGLE, SMD,
ULTRAMINI, 1P, SPST MINI
C&K COMPONENTS GT11MSCKE
5002
2
ea
TP13,TP16
CONN-MINI TEST POINT,
VERTICAL, WHITE, ROHS
KEYSTONE
1514-2
4
ea
TP1-TP4
ISL8500IRZ
1
ea
U1
4
5002
CONN-TURRET, TERMINAL KEYSTONE
POST, TH, ROHS
1514-2
IC-2A BUCK REGULATOR,
12P, DFN, 4x3, ROHS
ISL8500IRZ
INTERSIL
AN1372.0
November 21, 2007
Application Note 1326
ISL8500EVAL1Z Board Layout
FIGURE 2. TOP COMPONENTS
FIGURE 3. TOP LAYER ETCH
5
AN1372.0
November 21, 2007
Application Note 1326
ISL8500EVAL1Z Board Layout
(Continued)
FIGURE 4. BOTTOM LAYER COMPONENTS (MIRRORED)
FIGURE 5. BOTTOM LAYER ETCH (MIRRORED)
Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to
verify that the Application Note or Technical Brief is current before proceeding.
For information regarding Intersil Corporation and its products, see www.intersil.com
6
AN1372.0
November 21, 2007
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