an1930

Application Note 1930
ISL85003EVAL2Z, ISL85003AEVAL2Z Evaluation Board
User Guide
Description
Key Board Features
The ISL85003 and ISL85003A 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, low quiescent current high efficiency
synchronous buck regulators.
• Small, compact design
• Switch selectable EN (enabled/disabled)
• Switch selectable MODE (auto-DCM/forced-PWM)
• Connectors and test points for easy probing
The ISL85003 and ISL85003A are offered in a 4x3mm dual flat
no lead (DFN) package.
References
Specifications
• ISL85003, ISL85003A datasheet
The boards are designed to operate at the following operating
conditions:
Ordering Information
• Input voltage range from 4.5V to 18V
PART NUMBER
• Resistor programmable output voltage from 0.8V, ±1%
• Up to 3A output current
• Current mode control
- DCM/CCM
- Internal or external compensation options
- 500kHz switching frequency option
- External synchronization up to 2MHz on ISL85003
ISL85003EVAL2Z
Evaluation Board for ISL85003FRZ and
ISL85003AFRZ
Evaluating the Other Output
Voltage
• Adjustable soft-start time on the ISL85003A
• Operating junction temperature range: -40°C to +125°C
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 VIN (P4)
and the negative return to PGND (P5).
3. Connect the output load to V0, the plus terminal to V0 (P8)
and the negative return to PGND (P9).
4. Verify that the position is PWM or PFM for SW2.
The ISL85003 and ISL85003A kit outputs are preset to 5V for
VOUT; however, the output voltages are programmed using an
external resistor divider that scales the feedback relative to the
internal reference voltage. The output voltage programming
resistor, R2, will depend on the value chosen for the feedback
resistor, R1, and the desired regulator output voltage, VOUT .
The value for the feedback resistor R1 is typically between
10kΩ and 400kΩ as shown in Equation 1.
R 1  0.8V
R 2 = ------------------------------V OUT – 0.8V
(EQ. 1)
If the output voltage desired is 0.8V, then R2 is left
unpopulated. R1 is still required to set the low frequency pole
of the modulator compensation.
Switch Control
5. Verify that the position is ON for SW1.
The ISL85003 and ISL85003A evaluation boards contain SW1
and SW2 for various controls of the ISL85003 and ISL85003A
circuitries. Table 1 details this function.
6. Turn on the power supply.
7. Verify the output voltage is 5V for VO.
TABLE 1. SWITCH SETTINGS
Recommended Equipment
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
DESCRIPTION
SW1
ENABLE
FUNCTION
1
OFF
Disable V0
3
ON
Enable V0
SW2
MODE
• Digital multimeters (DMMs)
FUNCTION
1
DCM
Force DCM
• 100MHz quad-trace oscilloscope
3
PWM
Fixed PWM frequency at light load
• Signal generator
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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2014. All Rights Reserved
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 1930
Components Selection
VOUT
0.8V
1V
1.2V
1.5V
1.8V
2.5V
3.3V
5V
C1, C2
10µF
10µF
10µF
10µF
10µF
10µF
10µF
10µF
C5
22µF
22µF
22µF
47µF
47µF
47µF
47µF
47µF
C6
22µF
22µF
22µF
22µF
22µF
22µF
22µF
22µF
C4
Open
Open
Open
4.7pF
4.7pF
4.7pF
4.7pF
4.7pF
L1
1.8µH
2.2µH
2.2µH
3.3µH
3.3µH
3.3µH
4.7µH
4.7µH
R1
301kΩ
301kΩ
301kΩ
301kΩ
301kΩ
301kΩ
301kΩ
301kΩ
R2
Open
1.2MΩ
604kΩ
344kΩ
241kΩ
142kΩ
96.3kΩ
57.6kΩ
NOTE: VIN = 12V, IOUT = 3A; The components selection table is a suggestion for typical application using internal compensation mode. For applications
that require high output capacitance greater than 200µF, R1 should be adjusted to maintain a loop response bandwidth about 40kHz.
ISL85003EVAL2Z Evaluation Board
FIGURE 1. TOP VIEW
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FIGURE 2. BOTTOM VIEW
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ISL85003EVAL2Z Rev B Schematic
D2
VOUT
U1
VOUT
SYNC
1
PG
2
EN
3
SYNC
BOOT
PG
VDD
12
DNP
11
VCC
P7
3
VCC
R4
20
EN
VIN
ISL85003
4
VIN
C3
0.1uF
9
DNP
5
DNP
C4
C8
R11
0
6
COMP
PHASE
AGND
PHASE
EPAD
301k
GND
P8
7
4.7uH
VOUT
C5
47uF
13
R2
57.1k
D1
LTST-C190KGKT
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Q1
2N7002
2
VIN
R6
200k
SYNC
SW2
PWM
SYNC
R9
DNP
DCM
R7
200k
P6
ENABLE
SW1
ON
EN
R8
DNP
P9
GND
1
J1
2
J2
VCC
P2
C6
22uF
VOUT
PHASE
R5
2k
VIN
P5
L1
DNP
VCC
PG
+ C10
150uF
C2
10uF
8
1
P1
C1
10uF
OFF
Application Note 1930
R3
R14
200k
C9
1uF
C7
R1
4.7p
FB
P4
10
Application Note 1930
Bill of Materials
PART NUMBER
QTY UNITS
REFERENCE
DESIGNATOR
DESCRIPTION
MFR
INTERSIL
MFR PART #
ISL85003FRZ
1
ea
U1
IC-3A BUCK REGULATOR, 12P, DFN, 4X3,
ROHS
ISL85003AFRZ
1
ea
U1
IC-3A BUCK REGULATOR PWM, 12P, DFN, 4X3, INTERSIL
ROHS
ISL85003AFRZ
EEE-FK1H151P-T
1
ea
C10
CAP, SMD, 10.3mm, 150µF, 50V, 20%, ROHS, PANASONIC
ALUM.ELEC.
EEE-FK1H151P
H1044-004R7-50VR25-T
1
ea
C4
CAP, SMD, 0402, 4.7pF, 50V, 0.25pF, NPO,
ROHS
GRM36COG4R7C050AQ
H1044-DNP
0
ea
C7, C8, CSS
H1045-00104-50V10-T
1
ea
C3
CAP, SMD, 0603, 0.1µF, 50V, 10%, X7R, ROHS AVX
06035C104KAT2A
H1045-00105-16V10-T
1
ea
C9
CAP, SMD, 0603, 1µF, 16V, 10%, X5R, ROHS
GRM188R61C105KA12D
H1065-00106-25V10-T
2
ea
C1, C2
CAP, SMD, 1206, 10µF, 25V, 10%, X7R, ROHS VENKEL
C1206X7R250-106KNE
H1065-00226-25V10-T
2
ea
C5, C6
CAP, SMD, 1206, 22µF, 25V, 10%, X5R, ROHS MURATA
GRM31CR61E226KE15L
RLF7030T-4R7M3R4
1
ea
L1
COIL-PWR INDUCTOR, SMD, 7.3X6.8mm,
4.7µH, 20%, 3.5A, ROHS
RLF7030T-4R7M3R4
131-4353-00
2
ea
J1, J2
1514-2
4
ea
P4, P5, P8, P9 CONN-TURRET, TERMINAL POST, TH, ROHS
KEYSTONE
1514-2
5002
4
ea
P1, P2, P6, P7 CONN-MINI TEST POINT, VERTICAL, WHITE,
ROHS
KEYSTONE
5002
BAT54C-T
1
ea
D2
DIODE-RECTIFIER, SMD, SOT23, 3P, 30V,
200mA, ROHS
FAIRCHILD
BAT54C
LTST-C190KGKT-T
1
ea
D1
LED, SMD, 0603, GREEN CLEAR, 2V, 20mA,
571nm, 35mcd, ROHS
LITEON/VISHAY
LTST-C190KGKT
2N7002LT1G-T
1
ea
Q1
TRANSISTOR-MOS, N-CHANNEL, SMD, SOT23, ON
60V, 115mA, ROHS
SEMICONDUCTOR
2N7002LT1G
H2510-00R00-1/16W-T
1
ea
R11
RES, SMD, 0402, 0Ω, 1/16W, 5%, TF, ROHS
CR0402-16W-00T
H2510-03013-1/16W1-T
1
ea
R1
RES, SMD, 0402, 301k, 1/16W, 1%, TF, ROHS YAGEO
RC0402FR-07301KL
H2510-05762-1/16W1-T
1
ea
R2
RES, SMD, 0402, 57.6k, 1/16W, 1%, TF, ROHS PANASONIC
ERJ-2RKF5762X
H2510-DNP
0
ea
R3
RES, SMD, 0402, DNP, DNP, DNP, TF, ROHS
H2511-00200-1/10W1-T
1
ea
R4
RES, SMD, 0603, 20Ω, 1/10W, 1%, TF, ROHS PANASONIC
ERJ-3EKF20R0V
H2511-02001-1/10W1-T
1
ea
R5
RES, SMD, 0603, 2k, 1/10W, 1%, TF, ROHS
RK73H1JTTD2001F
H2511-02003-1/10W1-T
3
ea
R6, R7, R14
H2511-DNP
0
ea
R8, R9
GT11MSCBE-T
2
ea
SW1, SW2
SWITCH-TOGGLE, SMD, 6PIN, SPDT, 2POS, ON- ITT INDUSTRIES/
ON, ROHS
C&K DIVISION
GT11MSCBE
SJ-5003-BLACK
4
ea
Bottom four
corners
BUMPONS, 0.44inW x 0.20inH, DOMETOP,
BLACK
SJ-5003SPBL
MURATA
ISL85003FRZ
CAP, SMD, 0402, DNP-PLACE HOLDER, ROHS
MURATA
TDK
CONN-SCOPE PROBE TEST PT, COMPACT, PCB TEKTRONIX
MNT, ROHS
VENKEL
KOA
RES, SMD, 0603, 200k, 1/10W, 1%, TF, ROHS VENKEL
131-4353-00
CR0603-10W-2003FT
RES, SMD, 0603, DNP-PLACE HOLDER, ROHS
3M
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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Application Note 1930
PCB Layout
FIGURE 3. TOP LAYER
FIGURE 4. INNER LAYER 1
FIGURE 5. INNER LAYER 2
FIGURE 6. BOTTOM LAYER
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