Intersil ISL8500EVAL1Z Application Note

®

ISL8500EVAL1Z 2A Regulator Standard

Buck PWM

November 21, 2007 AN1372.0Application Note

Description

The ISL8500EV AL1Z REV A kit is intended for use by
individuals with requirements for Point-of-Load applications
sourcing f ro m 4. 5 V t o 2 5V. The ISL8500EVAL1Z evaluation
board is used to demonstrate the performance of the
ISL8500 standard buck regulator.

The ISL8500 is offered in a 4mmx3mm 12 Ld DFN package
with 1mm maximum height. The complete converter
occupies less than 0.425in

2

area.

Features

• Standard Buck Controller with Integrated Switching Power
MOSFET

• Integrated Boot Diode

• Input Voltage Range

- Fixed 5V ±10%

- Variable 5.5V to 25V

• PWM Output Voltage Adjustable from 0.6V to 20V with
Continuous Output Current up to 2A

• Voltage Mode Control with Voltage Feed Forward

• Fixed 500kHz Switching Frequency

• Externally Adjustable Soft-Start Time

• Output Undervoltage Protection

• PGOOD Output

• Overcurrent Protection

• Thermal Overload Protection

• Internal 5V LDO regulator

Applications

• General Purpose

• WLAN Cards-PCMCIA, Cardbus32, MiniPCI Cards­Compact Flash Cards

• Hand-Held Instruments

Recommended Equipment

The following materials are recommended to perform
testing:

• 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

• Signal generator

Quick Setup Guide

1. Ensure that the circuit is correctly connected to the supply
and loads prior to applying any power.

2. Connect the bias supply to VIN, the plus terminal to TP1
(VIN) and the negative return to TP2 (GND).

3. Verify that SW1 is on ENABLE.

4. Turn on the power supply.

5. Verify the PG is on and the output voltage is 2.5V for
VOUT(TP3).

Evaluating the Other Output Voltage

The ISL8500EVAL kit outputs are preset to 2.5V; however, it
can be programmed using resistor dividers using Equation 1:

R10.6V⋅

----------------------------------

R

=

2

The output voltage programming resistor R
on the feedback resistor R

V

OUT

0.6V–

will depend on

, as referred to in Figure 1. The

1

2

value of R1 is typically between 1kΩ and 10kΩ. If the output
voltage desired is 0.6V, then R

­+

EA

is left opened.

2

R1

R2

V

OUT

(EQ. 1)

What’s Inside

The Evaluation Board Kit contains the following materials:

• The ISL8500 EVAL REV D board

• The ISL8500 datasheet

• This EVAL KIT document

1

0.6V

REFERENCE

FIGURE 1. EXTERNAL RESISTOR DIVIDER

TABLE 1. SWITCH 1 SETTINGS

SW1 ENABLE OPERATING MODE

1 SW1 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.

All other trademarks mentioned are the property of their respective owners.

Copyright Intersil Americas Inc. 2007. All Rights Reserved

2

AN1372.0

November 21, 2007

Schematic

POPULATE R30 IF VIN <6V ONLY

OFF

R1

2

C4

1

2

0.1UF

TP16

8

1UF

10K

PG

2

C8

13

9

7

6

5

4

2

12
11

1

U1

432

1

432

SP1

TP13

1

R12

R30

2

1

2

1

3

Q4

1

3

2

SW1

2

1

2

D3

1

TP2

1

TP1

1

TP3

L1

2

1

TP4

2.43K

VOUT

EN

2N7002

ON EN

100K

BOOT

VIN

GND

VIN

301

PG

COMP

VDD

VDD

C2

2

1

C1

1

D1

2

1

1

2

C12

1

PHASE

10

FB

C9

10UH

220UF

C20

OPEN

1

C13

1

C10

C11

100UF

OPEN

2

1

C21

R21

R20

SP2

10UF

C3

OPEN

1

0.1UF

470PF

ISL8500IRZ

1

R2

10K

R3

2200PF

3

3.16K

R4

10PF

51.1K

FB
COMP
SS

PG

EN

GND

VIN

VIN
PHASE
PHASE

BOOT

VDD

EP

Application Note 1326

Application Note 1326

ISL8500EVAL1Z Bill of Materials

REFERENCE

PART NUMBER QTY UNITS

ISL8500EVAL1ZREV APCB 1 ea PWB-PCB, ISL8500EVAL1Z,

H1044-00222-50V10-T 1 ea C1 CAP, SMD, 0402, 2200pF,

H1065-00106-25V10-T 1 ea C10 CAP, SMD, 1206, 10µF, 25V,

DNP 0 ea C11, C13, C20,

H1082-00107-6R3V20-T 1 ea C12 CAP, SMD, 1210, 100µF,

H1044-00100-50V5-T 1 ea C2 CAP, SMD ,0402, 10pF , 50V,

H1044-00471-50V10-T 1 ea C3 CAP, SMD, 0402, 470pF,

H1044-00104-16V10-T 1 ea C4 CAP , SMD, 0402, 0.1µF, 16V ,

H1045-00105-6R3V10-T 1 ea C8 CAP, SMD, 0603, 1µF, 6.3V,

C1608X7R1H104K-T 1 ea C9 CAPACITOR, SMD, 0603,

B340LB-13-F-T 1 ea D1 DIODE-SCHOTTKY SMD,

LTST-C170CKT 1 ea D3 LED-GaAs RED, SMD,

IHLP2525CZRZ100M01 1 ea L1 COIL-PWR INDUCTOR,

2N7002-7-F-T 1 ea Q4 TRANSISTOR,N-CHANNEL,

H2510-05112-1/16W1-T 1 ea R1 RES, SMD, 0402, 51.1k,

H2510-01003-1/16W1-T 1 ea R12 RES, SMD, 0402, 100k,

H2510-01002-1/16W1-T 1 ea R2 RES, SMD, 0402, 10k,

H2511-02431-1/10W1-T 1 ea R20 RES, SMD, 0603, 2.43k,

H2511-01002-1/10W1-T 1 ea R21 RES, SMD, 0603, 10k,

DESIGNATOR DESCRIPTION MANUFACTURER MANUFACTURER PART

REVA, ROHS

50V, 10%, X7R, ROHS

10%, X5R, ROHS

C21

DO NOT POPULATE OR
PURCHASE

6.3V, 20%, X5R, ROHS

5%, NPO ,ROHS

50V, 10%, X7R, ROHS

10%, X7R, ROHS

10%, X5R, ROHS

0.10µF, 50V, 10%, X7R

SMB, 2P, 40V, 3A LOW VF,
ROHS

2x1.25mm, 100mW, 40mA,
10mcd, ROHS

SMD, 6.9x6.5, 10µH, 20%,
3A, ROHS

3LD, SOT-23, 60V, 115mA,
ROHS

1/16W, 1%, TF, ROHS

1/16W, 1%, TF,ROHS

1/16W, 1%, TF,ROHS

1/10W, 1%, TF, ROHS

1/10W, 1%, TF,ROHS

TITAN ISL8500EVAL1ZREVAPCB

PANASONIC ECJ-0EB1H222K

VENKEL C1206X5R250-106KNE

TDK C3225X5R0J107M
PANASONIC ECJ-4YB0J107M
AVX 12106D107MAT
VENKEL C0402COG500-100JNE

PANASONIC ECJ-0EB1H471K
VENKEL C0402X74500-471KNE
MURATA GRM36X7R104K016AD
VENKEL C0402X7R160-104KNE
PANASONIC ECJ1VB0J105K

TDK C1608X7R1H104K

DIODES INC. B340LB-13-F

LITEON/VISHAY LTST-C170CKT
ROHM SML-210LTT86
STANLEY ELECTRIC BR112H-TR
VISHAY IHLP2525CZRZ100M01

DIODES, INC. 2N7002-7-F
ON

SEMICONDUCTOR
PANASONIC ERJ-2RKF5112X
VENKEL CR0402-16W-5112FT
PANASONIC ERJ2RKF1003

PANASONIC ERJ-2RKF1002
VENKEL CR0402-16W-1002FT
VENKEL CR0603-10W-2431FT
YAGEO RC0603FR-072K43L
KOA RK73H1JT1002F
VENKEL CR0603-10W-1002FT

2N7002LT1G

3

AN1372.0

November 21, 2007

Application Note 1326

ISL8500EVAL1Z Bill of Materials (Continued)

REFERENCE

PART NUMBER QTY UNITS

H2510-03010-1/16W1-T 1 ea R3 RES, SMD, 0402, 301Ω,

H2511-DNP 0 ea R30 RES, SMD, 0603, DNP-

H2510-03161-1/16W1-T 1 ea R4 RES,SMD, 0402, 3.16k,

131-4353-00 2 ea SP1,SP2 CONN-SCOPE PROBE

GT11MSCBE-T 1 ea SW1 SWITCH-TOGGLE, SMD,

5002 2 ea TP13,TP16 CONN-MINI TEST POINT,

1514-2 4 ea TP1-TP4 CONN-TURRET, TERMINAL

ISL8500IRZ 1 ea U1 IC-2A BUCK REGULATOR,

DESIGNATOR DESCRIPTION MANUFACTURER MANUFACTURER PART

1/16W, 1%, TF, ROHS

PLACE HOLDER, ROHS

1/16W, 1%, TF, ROHS

TEST PT, COMPACT, PCB
MNT, ROHS

ULTRAMINI, 1P, SPST MINI

VERTICAL, WHITE, ROHS

POST, TH, ROHS

12P, DFN, 4x3, ROHS

PANASONIC ERJ-2RKF3010X
VENKEL CR0402-16W-3010-FT

VENKEL CR0402-16W-3161FT
PANASONIC ERJ-2RKF3161X
VISHAY/DALE CRCW04023K16FKED
TEKTRONIX 131-4353-00

C&K COMPONENTS GT11MSCKE

KEYSTONE 5002

KEYSTONE 1514-2

INTERSIL ISL8500IRZ

4

AN1372.0

November 21, 2007

ISL8500EVAL1Z Board Layout

Application Note 1326

FIGURE 2. TOP COMPONENTS

5

FIGURE 3. TOP LAYER ETCH

AN1372.0

November 21, 2007

Application Note 1326

ISL8500EVAL1Z Board Layout (Continued)

FIGURE 4. BOTTOM LAYER COMPONENTS (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

FIGURE 5. BOTTOM LAYER ETCH (MIRRORED)

AN1372.0

November 21, 2007