an1324

ISL8560EVAL2Z: 2A High Voltage Buck Regulator
with Integrated MOSFETs
®
Application Note
February 13, 2008
AN1324.3
The ISL8560 is a step down DC/DC power switching
regulator which accepts a 9V to 60V input, and provides up
to 2A of output current. The output voltage can be set
between 1.21V and 35V by means of an external resistor
divider. The device uses an internal power DMOS transistor
with a typical rDS(ON) of 0.19Ω to obtain very high efficiency
and high switching speed. A switching frequency in the
range of 100kHz to 600kHz can be realized (the maximum
power dissipation of the various packages must be
observed). Notable features of this next generation DC/DC
converter include pulse-by-pulse current limit for FET
protection, hiccup-mode short circuit protection, voltage
feedforward, frequency SYNC, soft-start, low standby
current of 60µA typical in the disabled state and thermal
shut-down. The device is available in a 20 Ld QFN package.
Features
Ordering Information
• Low standby current of 60µA typical
PART
NUMBER
(Note)
PART
MARKING
TEMP.
RANGE
(°C)
• Voltage feedforward
• Step down DC/DC supporting up to 2A
• Input voltage range of 9V to 60V
• Internal reference of 1.21V ±1%
• Adjustable output voltage range of 1.21V to 35V
• Adjustable switching frequency 100kHz to 600kHz
• Frequency SYNC pin
• Zero load current operation
• Pulse-by-pulse mode current limit
• Hiccup mode short-circuit protection
• Thermal shut-down
PACKAGE
(Pb-free)
PKG.
DWG. #
• Transient survival up at 100V for 400ms
ISL8560IRZ
ISL 8560IRZ -40 to +85 20 Ld 6x6 QFN L20.6x6B
• Pb-free (RoHS compliant)
ISL8560IRZ-T*
ISL 8560IRZ -40 to +85 20 Ld 6x6 QFN L20.6x6B
Applications
ISL8560EVAL2Z Evaluation Board
• Industrial and automotive power supplies
*Please refer to TB347 for details on reel specifications.
NOTE: These Intersil Pb-free plastic packaged products employ
special Pb-free material sets; molding compounds/die attach
materials and 100% matte tin plate PLUS ANNEAL - e3 termination
finish, which is RoHS compliant and compatible with both SnPb and
Pb-free soldering operations. Intersil Pb-free products are MSL
classified at Pb-free peak reflow temperatures that meet or exceed
the Pb-free requirements of IPC/JEDEC J STD-020.
• Portable computers
• Battery chargers
• Distributed power systems
Related Literature
• Technical Brief TB363 “Guidelines for Handling and
Processing Moisture Sensitive Surface Mount Devices
(SMDs)”
Pinouts
1
VIN
VIN
VIN
VIN
LX
ISL8560
(20 LD QFN)
TOP VIEW
20
19
18
17
16
14 SS
BOOT
3
13 PGND
EN
4
12 PGOOD
VCC5
5
11 REF
6
7
8
9
10
COMP
2
FB
LX
SGND
15 LX
RTCT
1
SYNC
LX
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, 2008. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
Application Note 1324
What’s Inside
Evaluating the Other Output Voltage
The Evaluation Board Kit contains the following materials:
The ISL8560EVAL2Z kit output is preset to 5V. The output
voltage can be adjusted from 1.21V to 55V by Equation 1:
• The ISL8560EVAL2Z REVB board.
R 1 = ( R 2 ) ⁄ ( ( V OUT ⁄ V FB1 ) – 1 )
• The ISL8560 datasheet.
• ISL8560 Evaluation Board Application Note.
Recommended Equipment
The following equipment is recommended to evaluate the
performance of the board:
• 0V to 100V power supply with at least 5A current sourcing
capability.
• Electronic Loads capable of sinking current up to 5A.
• Digital Multimeters (DMMs.)
• 100MHz quad-trace Oscilloscope.
• Signal generator (to test the SYNC feature only).
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, with the positive terminal
connected to P1(VIN), and the return to P2(GND).
3. Connect the load across the output terminals, between
pins P3 (positive) and P4 (return).
4. Verify that the jumper JP1 is connected.
5. Apply a voltage between 9V and 60V across the input.
with R2 = 51.1kΩ and VFB1 = 1.21V.
Note: The inductor, output capacitors and the compensation
network may need to be tweaked, along with the
corresponding compensation network, for optimal
performance with change in output voltage and/or load. Also,
additional heatsinking or airflow may required to insure that
the junction temperature does not exceed +125°C.
Frequency
The ISL8560EVAL2Z kit is preset at 500kHz. The
ISL8560EVAL2Z can be adjusted to operate at switching
frequencies from 100kHz to 600kHz. Use C16 to program
the switching frequency using Equation 2:
6.25
1000
C 16 [ nF ] = -------------------- ⎛ ------------------------------ – 0.3⎞
⎠
R 7 [ kΩ ] ⎝ f OSC [ kHz ]
(EQ. 2)
Synchronization
The ISL8560EVAL2Z circuit may be synchronized to a TTL
signal that is set at a higher switching frequency than the
pre-set frequency. The range of the external synchronizing
frequency is from 100kHz to 600kHz. It is recommended to
use and RTCT capacitor (C16) of 2700pF in this
configuration.
6. Verify that the output voltage is 5V.
TABLE 1. SWITCH 1 SETTINGS
JP1
2
(EQ. 1)
ENABLE
OPERATING MODE
1
OPEN
Unit Disabled
2
GND
Unit Enabled
AN1324.3
February 13, 2008
Schematic
3
Application Note 1324
AN1324.3
February 13, 2008
Application Note 1324
TABLE 2. COMPONENT LIST
REF DES QTY VALUE TOL. VOLTAGE
C5, C10, C11 3 0.10µF 10%
50V
PACKAGE
0603
PART NUMBER
C1608X7R1H104K-T
C12-C14
3
150µF 20%
25V
8mmx10mm
EEE-FK1E151P-T
C1-C3
3
47µF
20
100V
12.5mmx13.5mm
EEV-FK2A470Q-T
C7,C9
2
100pF
5%
50V
0603
H1045-00101-50V5-T
C15
1
0.01µF 10%
50V
0603
H1045-00103-50V10-T
C18
1
1µF
10%
16V
0603
H1045-00105-16V10-T
C19
1
390pF
5%
50V
0603
H1045-00391-50V5-T
C8, C17
0
OPEN
-
-
-
H1045-DNP
C6
1
1.0µF
10%
25V
0805
H1046-00105-25V10-T
C4
1
0.1µF
10%
100V
1206
H1065-00104-100V10-T
C16
1
47pF
5%
50V
1206
H1065-00471-100V5-T
L1
1
22µH
20%
-
18mmx15mm
DO5010H-223MLB
JP1
1
0Ω
-
-
Header
SPC02SYAN
D1
1
5A
100V
Power DI-5
PDS5100H
U1
1
2A
-
72V
6x6 QFN
ISL8560IRZ
R9
1
20Ω
1%
100V
0603
H2511-0200-1/10W1-T
R5, R6, R8
3
10k
1%
100V
0603
H2511-1002-1/16W1-T
R1
1
16.2k
1%
100V
0603
H2511-1622-1/16W1-T
R4
1
301k
1%
100V
0603
H2511-3013-1/10W1-T
R2
1
51.1k
1%
100V
0603
H2511-05112-1/16W1-T
R3
1
5.62k
1%
100V
0603
H2511-5621-1/16W1-T
R7
1
20k
1%
100V
0603
H2513-02002-1/4W1-T
R10
1
0Ω
1%
100V
0603
H2515-00R00-1W-T
4
MANUFACTURER
DESCRIPTION
TDK
CAPACITOR, SMD, 0603,
0.10µF, 50V, 10%, X7R
PANASONIC
CAPACITOR, SMD, 10.3mm,
150µF, 25V, 20%, ROHS,
ALUM. ELEC.
PANASONIC
CAPACITOR, SMD, H13, 47µF,
100V, 20%, ROHS, ALUM.
ELEC.
CAPACITOR, SMD, 0603,
AVX, Samsung,
100pF, 50V, 5%, NPO, ROHS
TDK, Murata,
Vishay
CAPACITOR, SMD, 0603,
AVX, Samsung,
0.01µF, 50V, 10%, X7R, ROHS
TDK, Murata,
Vishay
CAPACITOR, SMD, 0603, 1µF,
AVX, Samsung,
16V, 10%, X7R, ROHS
TDK, Murata,
Vishay
CAPACITOR, SMD, 0603,
AVX, Samsung,
390pF, 50V, 5%, NPO, ROHS
TDK, Murata,
Vishay
CAPACITOR, SMD, 0603,
AVX, Samsung,
DNP-PLACE HOLDER, ROHS
TDK, Murata,
Vishay
CAPACITOR, SMD, 0805,
AVX, Samsung,
1.0uF, 25V, 10%, X7R, ROHS
TDK, Murata,
Vishay
CAPACITOR, SMD, 1206,
AVX, Samsung,
0.1µF, 100V, 10%, X7R, ROHS
TDK, Murata,
Vishay
CAPACITOR, SMD, 1206, 47pF,
AVX, Samsung,
50V, 5%, NPO, ROHS
TDK, Murata,
Vishay
COILCRAFT
COIL-PWR INDUCTOR, SMD,
18x15, 22µH, 20%, 7A, ROHS,
47mΩ
SULLINS
CONN-JUMPER, 2 PIN,
SHUNT, ROHS
DIODES INC.
DIODE-RECTIFIER, SMD,
Power DI-5,100V, 5A, ROHS,
SCHOTTKY
INTERSIL
IC-STEP DOWN DC/DC
CONVERTER, 20P, QFN, 6x6,
ROHS
PANASONIC
RESISTOR, SMD, 0603, 20Ω,
1/10W, 1%, TF, ROHS
PANASONIC
RESISTOR, SMD, 0603, 10k,
1/16W, 1%, TF, ROHS
PANASONIC
RESISTOR, SMD, 0603, 16.2k,
1/16W, 1%, TF, ROHS
YAGEO
RESISTOR, SMD, 0603, 301k,
1/10W, 1%, TF, ROHS
PANASONIC
RESISTOR, SMD, 0603, 51.1k,
1/16W, 1%, TF, ROHS
PANASONIC
RESISTOR, SMD, 0603, 5.62k,
1/16W, 1%, TF, ROHS
PANASONIC
RESISTOR, SMD, 1206, 20k,
1/4W, 1%, TF, ROHS
VENKEL
RESISTOR, SMD, 2512, 0Ω,
1W, TF, ROHS
AN1324.3
February 13, 2008
Application Note 1324
ISL8560EVAL2Z Board Layout
FIGURE 1. TOP COMPONENTS
FIGURE 2. TOP LAYER ETCH
5
AN1324.3
February 13, 2008
Application Note 1324
ISL8560EVAL2Z Board Layout
(Continued)
FIGURE 3. 2ND LAYER ETCH
FIGURE 4. 3RD LAYER ETCH
6
AN1324.3
February 13, 2008
Application Note 1324
ISL8560EVAL2Z Board Layout
(Continued)
FIGURE 5. BOTTOM LAYER COMPONENTS (MIRRORED)
FIGURE 6. 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
7
AN1324.3
February 13, 2008
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