an1220

Using the ISL6443EVAL2Z Evaluation Board
®
Application Note
March 7, 2008
AN1220.1
Using the Evaluation Board
Power Good
The ISL6443 is a high performance triple-output controller
offering control and protection features for 2 synchronous
buck PWMs and 1 linear regulator.
When both PWMs are within ±10% of their set value and the
linear regulator output is within 75% of its set value, the
PGOOD signal will go high. The open drain PGOOD pin is
pulled HIGH to VCC_5V on the board. The PGOOD circuitry
monitors the FBx pin of each regulated output to determine if
the outputs are in regulation. PGOOD can be monitored at
post P8.
The ISL6443 evaluation board highlights the operation of the
IC in an embedded DC/DC converter application. Table 1
shows the available evaluation board.
TABLE 1. EVALUATION BOARDS
BOARD NAME
ISL6443EVAL2Z
IC
ISL6443IRZ
PACKAGE
The overcurrent thresholds can be adjusted on the ISL6443
evaluation board. The current sense resistors, ISENSE, are
set at 1.0kΩ. The overcurrent set resistor is 95.3kΩ. The
overcurrent trip point can be adjusted by modifying ROCSET,
R5 and R10:
28 Ld QFN
Recommended Test Equipment
•
•
•
•
Overcurrent Protection
A 12V, 5A capable power supply
An electronic load
Four channel oscilloscope with probes
Precision digital multimeters
7 ⋅ R CS
R OCSET = ------------------------------------I OC ⋅ r DS ( ON )
Power and Load Connections
Input Voltage
To connect a +12V power supply to the evaluation board,
connect the positive lead of the power supply to the VIN (P1)
post and the ground lead of the supply to the GND (P2) post.
(EQ. 3)
ROCSET is the overcurrent set resistor, RCS is the current
sense resistor, IOC is the desired overcurrent trip point, and
rDS(ON) is the ON-resistance of the respective PWM’s lower
MOSFET. Refer to the ISL6443 Data Sheet for more
information on how to select the current sense and
overcurrent select resistors.
The input voltage to the linear controller is already taken
from the 1.8V output of VOUT2.
Output Adjustment
Change the respective output voltage feedback resistors to
modify the output voltage using Equation 1:
R 1⎞
⎛
V OUT1 = 0.8 ⋅ ⎜ 1 + -------⎟
R 2⎠
⎝
R 3⎞
⎛
V OUT2 = 0.8 ⋅ ⎜ 1 + -------⎟
R 4⎠
⎝
R6 ⎞
⎛
V OUT3 = 0.8 ⋅ ⎜ 1 + ----------⎟
R
⎝
11⎠
(EQ. 1)
Soft-Start and Shutdown
The soft-start capacitors can be adjusted for sequencing of
the output voltages, PWM start-up tracking, and/or to adjust
the start-up current required to charge the output capacitors.
0.8V
t SS ( PWM1 ) = C 2 ⋅ -----------5μA
0.8V
t SS ( PWM2 ) = C 3 ⋅ -----------5μA
(EQ. 2)
To independently shutdown the PWMs, the SD1 or SD2 pin
can be pulled to GND using the on-board posts, P9 and P10
respectively.
1
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. 2006. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
ISL6443EVAL2Z Schematic
P1
+12V
+12V
P2
GND
C20
10uF
GND
C21
10uF
R12
5.11k
D1
BAT54HT1
C6
1uF
D2
BAT54HT1
C1
4.7uF
P11
PGOOD
PGOOD
Q2A
Q1A
24
3
11
17
10
4
27
+3.3V, 2A
6.8uH, 27mOhm
P4
GND
GND
R1
1K
C31
10TPB220M
220uF, 10V, 40mOhm
C5
0.1uF
BOOT1
PGOOD
SYNC
SGND
VIN
VCC_5V
BOOT2
L1
DO3316P-682ML
R7
1k
Q1B
FDS6912A
23
22
21
25
20
15
14
UGATE1
PHASE1
ISEN1
LGATE1
PGND
FB1
SGND
29
SGND
L2
DO3316P-682ML
28
1
2
26
8
9
5
P5
+1.8V
+1.8V, 2A
6.8uH, 27mOhm
C30
10TPB220M
220uF, 10V, 40mOhm
Q2B
R3
1k
P6
GND
GND
FDS6912A
R4
806
R2
324
P10
SD1
SD2
P9
SD1
SD1
C4
10uF
C2
0.01uF
R5
95.3k
R10
95.3k
C3
0.01uF
R8
100
Q3
IRLML6401
P7
+1.2V
+1.2V, 0.2A
R6
1k
C32
10uF
C33
DNP
C34
DNP
P8
GND
GND
R11
2k
Application Note 1220
U1
ISL6443IRZ
R9
1k
UGATE2
PHASE2
ISEN2
LGATE2
FB2
SGND
SD2
SD1
SS1
OCSET1
FB3
GATE3
OCSET2
SS2
P3
+3.3V
19
18
16
12
13
7
6
2
C7
0.1uF
AN1220.1
March 7, 2008
Application Note 1220
ISL6443EVAL2Z Bill of Materials
ITEM
REFERENCE
QTY
PART NUMBER
1
P1 to P12
12
1514-2
Test Point
Turret 0.281 Height
Keystone
2
D1, D2
2
BAT54HT1G
Diode, Schottky
30V, 200mA
On Semi
3
C4
1
C1608X5R0J106
Cap, Ceramic, X5R
10µF, 6.3V, 0603, X5R
TDK
4
C30, C31
2
10TPB220M
Cap, POSCAP
220µF, 10V
Panasonic
5
C20, C21
2
C3225X5R1C106KT
Cap, Ceramic, 1210
10µF, 16V, 1210, X5R
TDK
6
L1, L2
2
DO3316P-682ML
SMT Power Inductor
6.8µH, ±20%, 4.6A, 27mΩ
Coilcraft
7
C1
1
Capacitor, Ceramic, 0603
4.7µF, 20%, 6.3V, 0603
Generic
8
Q1, Q2
2
Dual NFET
6A, 30V, Dual NFET, SO8
Fairchild
9
C5, C7
2
Cap, Ceramic, 0603
0.1µF, 10%, 16V
Generic
C2, C3
2
Cap, Ceramic, 0603
0.01µF, 10%, 16V
Generic
10
C6
1
Cap, Ceramic, 0603
1.0µF, 10%, 16V
Generic
11
C32
1
Cap, Ceramic, 0805
10µF, 10%, 6.3V
Generic
12
C33, C34
2
NOT POPULATED
-
13
R8
1
Resistor, Film
100Ω, 0603, 1%, 1/16W
Any
14
R1, R3, R6, R7, R9
5
Resistor, Film
1kΩ, 0603, 1%, 1/16W
Any
15
R11
1
Resistor, Film
2kΩ, 0603, 1%, 1/16W
Any
16
R2
1
Resistor, Film
324Ω, 0603, 1%, 1/16W
Any
17
R5, R10
1
Resistor, Film
95.3kΩ, 0603, 1%, 1/16W
Any
18
R12
1
Resistor, Film
5.11kΩ, 0603, 1%, 1/16W
Any
19
R4
1
Resistor, Film
806Ω, 0603, 1%, 1/16W
Any
20
Q3
1
IRLML6401PBF
Single NFET
Power MOSFET
IR
21
U1
1
ISL6443IRZ
300kHz, Dual PWM
Controller
FDS6912A
PART TYPE
DESCRIPTION
VENDOR
Intersil
ISL6443EVAL2Z Layout
FIGURE 1. TOP SILK
3
FIGURE 2. TOP LAYER
AN1220.1
March 7, 2008
Application Note 1220
ISL6443EVAL2Z Layout
(Continued)
FIGURE 3. LAYER 2
FIGURE 4. LAYER 3
FIGURE 5. BOTTOM LAYER
FIGURE 6. BOTTOM SILK
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
4
AN1220.1
March 7, 2008
Similar pages