an1459

ISL8107EVAL2Z
®
Application Note
June 9, 2009
AN1459.0
Introduction
Circuit Setup
The ISL8107 is a single-phase PWM controller that operates
from 9V to 75V bias supply voltage. The PWM controller
drives an external high-side N-Channel MOSFET in a
non-synchronous buck converter topology. The ISL8107
features input voltage feed-forward compensation and
overcurrent protection, etc. For a more detailed description
of the ISL8107 functionality, refer to the ISL8107 Data Sheet
http://www.intersil.com/data/fn/fn6605.pdf.
The input supply of the power stage can be connected to the
terminals P5 (VIN) and P6 (PGND). For single supply
application, the ISL8107’s bias supply can be tied to VIN
through J1 with shunt between pins 2 and 3. When using
separate supplies, provide the ISL8107 bias voltage through
P1 (VBIAS) with J1’s shunt between pins 1 and 2. The load
can be connected to terminal P7 (VOUT) and P8 (PGND).
TP3 and TP4 can be used for DMM to measure the output
voltage. Enabling and disabling the controller can be done
through the toggle switch, SW1.
The ISL8107EVAL2Z Reference Design
The ISL8107EVAL2Z evaluation board is designed to meet
the output voltage and current specifications shown in
Table 1. Schematic, bill of materials, and layout plots are
included.
TABLE 1. ISL8107EVAL2Z DESIGN PARAMETERS
PARAMETER
Input Voltage (VIN)
MIN
TYP
MAX
18V
48V
75V
Output Voltage (VOUT)
12V
Output Voltage Ripple
30mV
Continuous Load Current
5A
Switching Frequency
200kHz
Quick Start Evaluation
Figure 1 shows a photograph of the ISL8107EVAL2Z board.
ISL8107EVAL2Z Performance
Start-Up
Figure 2 shows the start-up waveforms of the
ISL8107EVAL2Z. Upon the VCC and VFF exceeding their
rising POR thresholds, the ISL8107 provides initially 2µA to
charge the soft-start capacitor, CSS, connected to the ENSS
pin. If the voltage at this pin is allowed to rise (the toggle
switch, SW1, at ON position), the voltage on ENSS pin will
ramp-up with at a slope determined by the 2µA current and
the value of the soft-start capacitor. When the voltage at
ENSS reaches 0.77V, the oscillator circuit is active, and
generates sawtooth waveform. At the same time, the
soft-start current is increased to 33µA; the ENSS voltage
then ramps up at a faster rate. The UGATE starts switching
when the ENSS voltage reaches 1.4V (Typ).
PGOOD
VOUT
ENSS
PHASE
FIGURE 1. ISL8107EVAL2Z
1
FIGURE 2. START-UP WAVEFORMS
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. 2008. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
Application Note 1459
Output Voltage Ripple
Figure 3 shows the ripple voltage on the output of the
regulator at 5A load current.
VOUT
PHASE
VOUT
FIGURE 6. OUTPUT TRANSIENT
FIGURE 3. OUTPUT VOLTAGE RIPPLE @ IOUT = 5A
Figure 7 shows the response of the output when subjected
to transient loading from 0.1A to 5A at 1A/µs (transition
between continuous conduction mode and discontinuous
conduction mode).
Transient Responses
Figures 4, 5, and 6 show the response of the output when
subjected to transient loading from 1A to 5A at 1A/µs (within
continuous conduction mode).
VOUT
VOUT
FIGURE 7. OUTPUT TRANSIENT
Efficiency and Line Regulation
FIGURE 4. OUTPUT TRANSIENT
The efficiency and the line regulation of the evaluation board
with various input voltages are shown in Figures 8 and 9,
respectively.
100
VOUT
EFFIECIENCY (%)
95
PHASE
90
VIN = 24V
85
VIN = 36V
VIN = 48V
80
VIN = 60V
75
70
FIGURE 5. OUTPUT TRANSIENT
2
VIN = 18V
0
1
2
3
4
LOAD CURRENT (A)
5
6
FIGURE 8. CONVERTER EFFICIENCY (VOUT = 12V)
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Application Note 1459
12.100
OUTPUT VOLTAGE (V)
12.090
VIN = 24V
12.080
VIN = 18V
12.070
12.060
12.050
12.040
VIN = 60V
VIN = 48V
VIN = 36V
12.030
12.020
12.010
12.000
0
1
2
3
4
LOAD CURRENT (A)
5
6
FIGURE 9. LINE REGULATION FOR VOUT = 12V
3
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ISL8107EVAL2Z Schematic
J1
P1
1
3
2
1
VBias
R19
DNP
P2
R8
0
P5
VIN
1
1
1
P6
2
2
C17
100uF
100V
1
1
2
C15
1uF
1
4
C8
100pF
1
C7
1uF
SYNC
2
C14
1uF
C9
1uF
P4
1
C16
100uF
100V
2
2
R9
0
1
Vin
GND
GND
1
2
GND
R6
3.16k
1
R17
2
2
D3
MMBD1204/SOT
VFF
OCSET
VBIAS
SYNC
1k
1
2
1
1
1
1
2
1
R20
1k
2
1
C26
1uF
1
2
1
C24
1uF
C22
150uF
C20
DNP
Vout
C25
1uF
C23
1uF
1
PGND
ENSS
DNP
1
I aefgaeg
2
C21
150uF
2
2
P7
L1
22uH
VOUT
2
D2
D1
V10P10
C12
1uF
C13
0.01uF
2
1
C19
DNP
ENSS 12
C11
PGOOD
COMP
TP3
TP1
R7
10
2
COMP
Q2
DNP
2
8
ISL8107
C29
DNP
1
13 PHASE
FB
2
PHASE
7
C18
DNP
Q1
HAT2175H
1
14 TGATE
U1
1
TGATE
C10
0.1uF
1
15 BOOT
C30
DNP
2
BOOT
FB
C28
DNP
2
1
SGND
17
1
2
VFF
6
TP4
2
R12
DNP
P8
1
1
2
SGND
DNP
C6
DNP
OCSET
16 PVCC
2
C2
82pF
3
PVCC
EP
1
RTCT
PGND 11
2
5
PGOOD 10
1
R2
20k
RT/CT
VBG
C1
8.2nF
VBIAS
4
SYNC
2
C5
1000pF
VBG 9
1
R16
0
1
GND
TP2
R11
PVCC
D4
2
C3
6.8nF
R4
1.24k
1
1
SW1
1
Q3
BSS123LT1
R10
1
PGOOD
0
C27
1000pF
1
GND
PGND
0
PVCC
3
R15
0
C4
0.22uF
2
2
R1
11.3k
P3
R13
R18
10K
2
1
R3
442
2
Vreg
Vreg
10K
Application Note 1459
R14
0
R5
40.2k
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Application Note 1459
Bill of Materials
REFERENCE
QTY
PART NUMBER
DESCRIPTION
PACKAGE
VENDOR
U1
1
ISL8107IRZ
Single PWM Controller
16 Ld QFN
Q1
1
HAT2175
100V N-Channel MOSFET
LFPAK
Renesas
Q3
1
BSS123LT1G
N-Channel MOSFET, 0.17A
SOT-23
On Semi.
D1
1
V10P10
100V Schottky Diode Rectifier
TO-277A
Vishay
D3
1
MMBD1204
100V Ultrafast Diode
SOT-23
Fairchild
DIALIGHT
Intersil
D4
1
597-3311
LED Green
SMD1206
L1
1
HC9-220-R
22µH Power Inductor
SMD 12.9x13.2 Coiltronics
Q2, D2
0
DNP
CAPACITORS
C1
1
8200pF, 50V, X7R, 10%, Ceramic Capacitor
0603
Various
C2
1
82pF, 50V, COG, 10%, Ceramic Capacitor
0603
Various
C3
1
6800pF, 50V, X7R, 10%, Ceramic Capacitor
0603
Various
C4
1
0.22µF, 16V, X7R, 10%, Ceramic Capacitor
0603
Various
C5
1
0805
Murata
C7, C9, C14, C15
4
1µF, 100V, X7R, 10%, Ceramic Capacitor
1210
Various
C8
1
100pF, 50V, COG, 10%, Ceramic Capacitor
0603
Various
C10
1
0.1µF, 50V, X7R, 10%, Ceramic Capacitor
0603
Various
C12, C23, C24, C25, C26
5
1µF, 25V, X5R, 10%, Ceramic Capacitor
0805
Various
C13
1
0.01µF, 50V, X7R, 10%, Ceramic Capacitor
0603
Various
C16, C17
2
100ME100PX
100µF, 100V, Aluminum Electrolytic Capacitor
RAD 12.5x20
Sanyo
C21, C22
2
20SEQP150M
150µF, 20V, OSCON Capacitor
RAD 10x13
Sanyo
1000pF, 50V, X7R, 10%, Ceramic Capacitor
0603
Various
C27
1
C6, C11, C18, C19, C20,
C28, C29, C30
0
GRM2195C2A102JA01D 1000pF, 100V, COG, 5%, Ceramic Capacitor
DNP
RESISTORS
R1
1
Resistor, 11.3kΩ, 1%, 1/10W
0603
Various
R2
1
Resistor, 20kΩ, 1%, 1/10W
0603
Various
R3
1
Resistor, 442Ω, 1%, 1/10W
0603
Various
R4
1
Resistor, 1.24kΩ, 1%, 1/10W
0603
Various
R5
1
Resistor, 40.2kΩ, 1%, 1/10W
0603
Various
R6
1
Resistor, 3.16kΩ, 1%, 1/10W
0603
Various
R7
1
Resistor, 10Ω, 1%, 1/10W
0603
Various
R8, R9, R10, R11, R14,
R15, R16
7
0Ω Resistor, 1/10W
0603
Various
R13, R18
2
Resistor, 10kΩ, 5%, 1/10W
0603
Various
R17
1
Resistor, 1kΩ, 1%, 1/10W
0603
Various
R20
1
Resistor, 1kΩ, 1%, 1W
2512
Various
R12, R19
0
DNP
OTHERS
J1
1
68000-236-1X3
Connector Header
BERG/FCI
SW1
1
GT11MSCKE
SMD Toggle Switch
C&K
P1 through P8
8
1514-2
Turret Post
Keystone
5
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Application Note 1459
ISL8107EVAL2Z Layout
FIGURE 10. TOP SILK SCREEN
FIGURE 11. TOP ASSEMBLY
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Application Note 1459
ISL8107EVAL2Z Layout (Continued)
FIGURE 12. TOP LAYER
FIGURE 13. LAYER 2
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Application Note 1459
ISL8107EVAL2Z Layout (Continued)
FIGURE 14. LAYER 3
FIGURE 15. BOTTOM LAYER
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Application Note 1459
ISL8107EVAL2Z Layout (Continued)
FIGURE 16. BOTTOM SILK SCREEN
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
9
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