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®
ISL8107EVAL2Z
Application Note June 9, 2009
Introduction
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 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 MIN TYP MAX
Input Voltage (V
Output Voltage (V
Output Voltage Ripple 30mV
Continuous Load Current 5A
Switching Frequency 200kHz
) 18V 48V 75V
IN
) 12V
OUT
Quick Start Evaluation
Figure 1 shows a photograph of the ISL8107EVAL2Z board.
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Circuit Setup
The input supply of the power stage can be connected to the
terminals P5 (V
application, the ISL8107’s bias supply can be tied to V
) and P6 (PGND). For single supply
IN
IN
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.
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, C
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).
, connected to the ENSS
SS
FIGURE 1. ISL8107EVAL2Z
1
PGOOD
V
OUT
ENSS
PHASE
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.
All other trademarks mentioned are the property of their respective owners.
Copyright Intersil Americas Inc. 2008. All Rights Reserved
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Application Note 1459
Output Voltage Ripple
Figure 3 shows the ripple voltage on the output of the
regulator at 5A load current.
V
OUT
V
OUT
FIGURE 3. OUTPUT VOLT AGE RIPPLE @ I
OUT
= 5A
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).
V
OUT
PHASE
FIGURE 6. OUTPUT TRANSIENT
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).
V
OUT
FIGURE 4. OUTPUT TRANSIENT
V
OUT
PHASE
FIGURE 5. OUTPUT TRANSIENT
2
FIGURE 7. OUTPUT TRANSIENT
Efficiency and Line Regulation
The efficiency and the line regulation of the evaluation board
with various input voltages are shown in Figures 8 and 9,
respectively.
100
95
90
85
80
EFFIECIENCY (%)
75
70
0123456
VIN = 48V
VIN = 60V
LOAD CURRENT (A)
V
VIN = 36V
IN
FIGURE 8. CONVERTER EFFICIENCY (V
= 24V
VIN = 18V
OUT
= 12V)
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Application Note 1459
12.100
12.090
V
12.080
12.070
12.060
12.050
12.040
12.030
OUTPUT VOLTAGE (V)
12.020
12.010
12.000
0123456
VIN = 60V
LOAD CURRENT (A)
= 24V
IN
VIN = 48V
FIGURE 9. LINE REGULATION FOR V
OUT
VIN = 18V
VIN = 36V
= 12V
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Application Note 1459
ISL8107EVAL2Z Schematic
TGATE
BOOT
GND
PGND
SYNC
PGND
PVCC
SGND
FB
VBG
Vreg
ENSS
VIN
Vreg
RT/CT
PHASE
PGOOD
OCSET
VBIAS
VFF
COMP
VOUT
PVCC
PGOOD
PVCC
P6
GNDP6GND
1
R3
442R3442
C18
DNP
C18
DNP
1 2
R710R7
10
C13
0.01uF
C13
0.01uF
1 2
C1
8.2nFC18.2nF
1 2
C10
0.1uF
C10
0.1uF
1 2
SW1SW1
TP2TP2
R80R8
0
J1J1
123
R201kR20
1k
Q2
DNPQ2DNP
R13
10K
R13
10K
C14
1uF
C14
1uF
1 2
R12
DNP
R12
DNP
P4
SYNCP4SYNC
1
P3
GNDP3GND
1
D1
V10P10D1V10P10
R140R14
0
C24
1uF
C24
1uF
1 2
C29
DNP
C29
DNP
1 2
C27
1000pF
C27
1000pF
1 2
D3
MMBD1204/SOT
D3
MMBD1204/SOT
C7
1uFC71uF
1 2
C17
100uF
100V
C17
100uF
100V
12
C9
1uFC91uF
1 2
R171kR17
1k
R110R11
0
C20
DNP
C20
DNP
12
D4D4
2 1
C26
1uF
C26
1uF
1 2
C23
1uF
C23
1uF
1 2
R90R9
0
Q3
BSS123LT1Q3BSS123LT1
2
1
3
Q1
HAT2175HQ1HAT2175H
C12
1uF
C12
1uF
1 2
C11
DNP
C11
DNP
12
C15
1uF
C15
1uF
1 2
R150R15
0
P7
VoutP7Vout
1
C4
0.22uFC40.22uF
1 2
L1
22uHL122uH
1 2
P2
GNDP2GND
1
P5
VinP5Vin
1
R2
20kR220k
C22
150uF
C22
150uF
12
C3
6.8nFC36.8nF
1 2
R1
11.3kR111.3k
R5
40.2kR540.2k
R160R16
0
C25
1uF
C25
1uF
1 2
TP1TP1
C6
DNPC6DNP
1 2
C21
150uF
C21
150uF
12
TP3TP3
C2
82pFC282pF
1 2
D2
DNPD2DNP
C30
DNP
C30
DNP
1 2
P1
VBiasP1VBias
1
C19
DNP
C19
DNP
12
C8
100pFC8100pF
1 2
P8
GNDP8GND
1
TP4TP4
C28
DNP
C28
DNP
1 2
R19
DNP
R19
DNP
C5
1000pFC51000pF
1 2
C16
100uF
100V
C16
100uF
100V
12
R4
1.24kR41.24k
U1
ISL8107U1ISL8107
VFF
1
OCSET
2
SYNC
4
RTCT
5
TGATE
14
VBG9PGOOD
10
COMP
8
PGND
11
PHASE
13
BOOT
15
VBIAS
3
SGND
6
PVCC
16
FB
7
ENSS
12
EP
17
R100R10
0
R6
3.16kR63.16k
R18
10K
R18
10K
I
aefgaeg
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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 Intersil
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
D4 1 597-3311 LED Green SMD1206 DIALIGHT
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 GRM2195C2A102JA01D 1000pF, 100V, COG, 5%, Ceramic Capacitor 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
C27 1 1000pF, 50V, X7R, 10%, Ceramic Capacitor 0603 Various
C6, C11, C18, C19, C20,
C28, C29, C30
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
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
0DNP
70Ω Resistor, 1/10W 0603 Various
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ISL8107EVAL2Z Layout
Application Note 1459
FIGURE 10. TOP SILK SCREEN
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FIGURE 11. TOP ASSEMBLY
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ISL8107EVAL2Z Layout (Continued)
Application Note 1459
FIGURE 12. TOP LAYER
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FIGURE 13. LAYER 2
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ISL8107EVAL2Z Layout (Continued)
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FIGURE 14. LAYER 3
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FIGURE 15. BOTTOM LAYER
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ISL8107EVAL2Z Layout (Continued)
Application Note 1459
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
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