an1935

Application Note 1935
ISL85003DEMO1Z, ISL85003ADEMO1Z Evaluation
Board User Guide
Description
Quick Setup Guide
The ISL85003 and ISL85003A Demo kits are intended for use
for point-of-load applications sourcing from 4.5V to 18V. The
kits are used to demonstrate the performance of the
ISL85003 and ISL85003A, high efficiency synchronous buck
regulators. The ISL85003 and ISL85003A are offered in a
4x3mm dual flat no lead (DFN) package.
1. Ensure that the circuit is correctly connected to the supply
and loads prior to applying any power.
Recommended Equipment
4. Verify the output voltage is 5V for VOUT.
The following materials are recommended to perform testing:
• 0V to 25V power supply with at least 10A source current
capability
• Electronic loads capable of sinking current up to 7A
• Digital Multimeters (DMMs)
• 100MHz quad-trace oscilloscope
3. Turn on the power supply.
Evaluating the Other Output Voltage
The ISL85003DEMO1Z kit output is preset to 5V; however,
output voltages are programmed using an external resistor
divider that scales the feedback relative to the internal
reference voltage. Please refer to the application note AN1930
and the ISL85003, ISL85003A datasheet for further information.
Disabling/Enabling Function
Key Features
The ISL85003DEMO1Z board has EN pin tied to VIN via R7.
This keeps the part enabled all the time. To disable the part,
remove R7.
• Input voltage range 4.5V to 18V
• Current mode control
-
2. Connect the bias supply to VIN, the plus terminal to VIN and
the negative return to PGND.
DCM/PWM
Internal or external compensation options
500kHz switching frequency option
External synchronization up to 2MHz on ISL85003
• Adjustable soft-start time on the ISL85003A
• Continuous output current up to 3A
• Minimal external components required
References
MODE/SS Control
The ISL85OO3 evaluation board has a MODE pin that allows
different mode operation. Default board configuration has
R6 = 200k to VCC, which defaults to PWM operation mode. If
this pin is tied to GND the IC will operate in CCM mode.
The ISL85OO3A evaluation board has an SS pin that provides a
programmable soft-start. When the chip is enabled, the
regulated 4μA pull-up current source charges a capacitor C10
connected from SS to ground. Default board configuration has
R6 = 200k to VCC, which defaults to internal SS.
ISL85003, ISL85003A Datasheet
Ordering Information
PART NUMBER
DESCRIPTION
ISL85003DEMO1Z
Small form factor Demo board for 3A,
4.5V to 18V Switching Regulator, external
synchronization.
ISL85003ADEMO1Z
Small form factor Demo board for 3A,
4.5V to 18V Switching Regulator,
adjustable soft-start time
TOP SIDE
BOTTOM SIDE
FIGURE 1. ISL85003ADEMO1Z PICTURES
May 16, 2014
AN1935.0
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Copyright Intersil Americas LLC 2014. All Rights Reserved.
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
Application Note 1935
ISL85003ADEMO1Z Board Layout
FIGURE 3. SILK SCREEN BOTTOM
FIGURE 2. SILK SCREEN TOP
ISL85003ADEMO1Z Schematic
D2
U1
BOOT
SS
PG
VO
EN
R1
C7
301K
DNP
R3
UNNAMED_1_SMCAP_I186_A
C4
C8
UNNAMED_1_SMCAP_I185_A
4.7PF
DNP
1
SS
BOOT
12
2
PG
VDD
11
3
EN/SS
VIN
10
4
FB
VIN
9
5
COMP
PHASE
8
6
AGND
PHASE
7
13
UNNAMED_1_SMCAP_I193_A
DNP
1
3
VO
2
VCC
VCC
P4
VIN
C9
C2
1UF
10UF
C1
10UF
P5
GND
C3
EP
0.1UF
A
R11
0
L1
ISL85003AFRZ
R2
P7
VO
UNNAMED_1_POWERIND_I179_A
VO
4.7UH
57.6K
C5
22UF
A
A
C6
C11
22UF
22UF
P9
GND
VCC
VCC
VIN
SS
R7
200K
R14
PG
200K
R6
200K
VCC
A
EN
NOTE: If the IC is used in an application where the input test leads have large parasitic
inductance, the input electrolytic capacitor C10 may be added to prevent transient
voltages on the input pin.
C10
OPEN
DRAWN BY:
A
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Application Note 1935
ISL85003DEMO1Z, ISL85003ADEMO1Z Bill of Materials
QTY
UNIT
S
REFERENCE
DESIGNATOR
ISL85003FRZ
1
ea.
U1
IC-3A BUCK REGULATOR, 12P, DFN,
4X3, ROHS
ISL85003AFRZ
1
ea.
U1
IC-3A BUCK REGULATOR PWM, 12P, INTERSIL
DFN, 4X3, ROHS
ISL85003AFRZ
H1044-00104-50V10-T
1
ea.
C3
CAP, SMD, 0402, 0.1µF, 50V, 10%,
X7R, ROHS
TDK
C1005X7R1H104K
H1044-004R7-50VR25-T
1
ea.
C4
CAP, SMD, 0402, 4.7PF, 50V, 0.25pF, AVX
NPO, ROHS
04025A4R7CAT2A
H1044-DNP
0
ea.
C7, C10
H1045-00105-16V10-T
1
ea.
C9
H1065-00106-25V10-T
2
ea.
H1065-00226-16V10-T
3
744311470
PART NUMBER
DESCRIPTION
MANUFACTURER
INTERSIL
MANUFACTURER PART
ISL85003FRZ
CAP, SMD, 0402, DNP-PLACE
HOLDER, ROHS
CAP, SMD, 0603, 1µF, 16V, 10%,
X5R, ROHS
MURATA
GRM188R61C105KA12D
C1, C2
CAP, SMD, 1206, 10µF, 25V, 10%,
X7R, ROHS
VENKEL
C1206X7R250-106KNE
ea.
C5, C6, C11
CAP, SMD, 1206, 22µF, 16V, 10%,
X5R, ROHS
VENKEL
C1206X5R160-226KNE
1
ea.
L1
COIL-PWR CHOKE, SMD, 7X6.9,
4.7µH, 20%, 6A, 19.5mΩ, ROHS
WURTH ELECTRONICS 744311470
MIDCOM INC.
BAT54C-T
1
ea.
D2
DIODE-RECTIFIER, SMD, SOT23, 3P,
30V, 200mA, ROHS
FAIRCHILD
H2510-00R00-1/16W-T
1
ea.
R11
RES, SMD, 0402, 0Ω, 1/16W, 5%, TF, VENKEL
ROHS
CR0402-16W-00T
H2510-02003-1/16W1-T
3
ea.
R6, R7, R14
RES, SMD, 0402, 200k, 1/16W, 1%, ROHM
TF, ROHS
MCR01MZPF2003
H2510-03013-1/16W1-T
1
ea.
R1
RES, SMD, 0402, 301k, 1/16W, 1%, YAGEO
TF, ROHS
RC0402FR-07301KL
H2510-05762-1/16W1-T
1
ea.
R2
RES, SMD, 0402, 57.6k, 1/16W, 1%, PANASONIC
TF, ROHS
ERJ-2RKF5762X
BAT54C
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
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