an1927

Application Note 1927
ISL78236DUALEVAL1Z Dual Output Evaluation Board
User Guide
Description
Quick Setup Guide
The ISL78236DUALEVAL1Z kit is intended for use by individuals
with requirements for Point-of-Load (POL) applications sourcing
from 2.85V to 6V. The ISL78236DUALEVAL1Z evaluation board
is used to demonstrate the performance of the ISL78236 low
quiescent current mode converter. The evaluation board is
configured to deliver up to 3A output current on each of the
two output channels. The ISL78236 can be configured in a
current share mode for a single 6A output current. For this
application, reference ISL78236CRSHEVAL1Z AN1928.
The ISL78236 is offered in a 4mmx4mm 24 Ld QFN package
with 1mm maximum height. The complete converter occupies
less than 5.46cm2 area.
1. Ensure that the evaluation board is correctly connected to
the supply and loads prior to applying any power.
2. Connect the bias supply to VIN: The positive terminal to
VIN1 and the negative return to PGND1.
3. Verify that switch position is on PWM for S1. Verify that
switch position is ON for S2 and S3.
4. Turn on the power supply.
5. Verify the output voltage is 1.8V for both channels.
Evaluating Other Output Voltages
• 180° out-of-phase channel switching
The ISL78236DUALEVAL1Z kit outputs are preset to 1.8V for
VOUT1 and 1.8V for VOUT2; however, output voltages can be
adjusted from 1.2V to 3.3V. The output voltage programming
resistor, RF12 (or RF22 in Channel 2), will depend on the
desired output voltage of the regulator. The value for the
feedback resistor (RF12 and RF22) is typically between 50kΩ
and 750kΩ as shown in Equations 1 and 2.
• 2% output accuracy over-temperature/load/line
Setting RF11 and RF21 = 100k, then RF12 and RF22 will be:
Key Features
• Dual 3A high efficiency synchronous buck regulator with up
to 95% efficiency
• Internal digital soft-start - 1.5ms
V OUT1
RF12 = RF11  ---------------- – 1
 0.8

(EQ. 1)
• Internal current mode compensation
V OUT2
RF22 = RF21  ---------------- – 1
 0.8

(EQ. 2)
• Peak current limiting, hiccup mode short circuit protection
and over-temperature protection
SYNC Mode Control
• Soft-stop output discharge during disable
• Typical 8µA shutdown current
• 100% maximum duty cycle for lowest dropout
• Negative current detection and protection
Recommended Equipment
The following equipment is recommended to perform
evaluation of this board:
• 5V or higher power supply with at least 6A source current
capability or 5V battery
• Electronic loads capable of sinking current up to 3A
The ISL78236 has a SYNC pin, which connects to logic high or
input voltage VIN for internal 2.5MHz switching frequency.
Connect the test point by the switch S1 to an external function
generator for external synchronization on the negative edge
trigger. A 100kΩ pull-up resistor to VIN normally pulls the SYNC
pin high. Each channel’s switching frequency will be 1/2 of the
synchronization frequency at 180° out-of-phase.
Synchronization frequency range is 6MHz to 8MHz. Do not
leave this pin floating. Do not tie this pin low (or to GND).
TABLE 1. SWITCH SETTINGS
• Digital Multimeters (DMMs)
• 100MHz quad-trace oscilloscope
• 10MHz signal generator
SWITCH
POSITION
S1
PFM
DO NOT LEAVE IN THIS POSITION
PWM
2.5MHz switching frequency if floating.
External synchronization switching 6MHz
to 8MHz range with generator.
Ordering Information
PART NUMBER
ISL78236DUALEVAL1Z
DESCRIPTION
Dual Output 3A/3A Synchronous Buck
Evaluation Board
S2
S3
June 17, 2014
AN1927.0
1
MODE
ON
Enable VOUT1
OFF
Disable VOUT1
ON
Enable VOUT2
OFF
Disable VOUT2
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Copyright Intersil Americas LLC. 2014. All Rights Reserved.
1-888-INTERSIL or 1-888-468-3774 | 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.
LX2_S
LX1_S
LX2
A
VIN2
VIN1
VIN2
0
CIN2
22UF
SYNC
R_PH SYNC
0
S1
PWM
PFM
C_PH
OPEN
RF22
124K
C5
C1
OPEN
R3
OPEN
A
C2
OPEN
A
12PF
R7
RF21
100K
A
A
A
A
R4
100K
SGND
SGND
ON/EX
OFF
S3
ON/EX
OFF
EN2
EN1
A
EN2
PG2
EN2
A
PG2
A
COMP
NC
FB1
SGND
PG1
SYNC
C11
22UF
VOUT1_S
A
A
RF12
124K
C10
12PF
PGND1
A
A
2N7002
Q1
A
PG1
PG1
0
R12
2K
C8
150PF
D1
R13
VIN_PG
R11
52.3K
R14
OPEN
D2
2N7002
Q2
A
VOUT1
VOUT1_S
C6
C7
OPEN OPEN
PGND
RF11
100K
R8
2K
R10
OPEN
C9
22UF
A
VIN_PG
A
R6
100K
EN1
A
A
COMP
A
EN1
VOUT1
VOUT1
SYNC
CD1
OPEN
COMP
VDD
S2
PG1
FB1
VDD
EN1
A
CDC
OPEN
OPEN
PGND
PGND2
A
R9
VOUT2_S
SS
SYNC
C3
C4
22UF 22UF
VOUT2_S
EN1
COMP
0
VDD
FB2
EP
SS
VOUT2
OPEN
VDD
SS
VDD
ISL8036AIRZ
PG2 ISL78236AIRZ
R_OUT
L1
VIN1
EN2
A
VIN1
Application Note 1927
SS
VOUT2
LX1
LX1
VIN1
U1
VIN2
EN2
PG2
FB2
FB
FB
VOUT2
VOUT2
CD2
R5
L2
OPEN
R2
LX2
VIN2
VIN1
0
R1
100K
LX2
PGND
PGND11
LX2
PGND2
PGND2
PGND1
PGND1
LX1
2
A
VIN1
CIN1
22UF
A
A
PGND
VDD
VIN1
VIN1
PGND22
VDD
A
VIN2
FB1
R_IN
VIN2
LX1
0
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ISL78236DUALEVAL1Z Schematic
AN1927.0
June 17, 2014
QTY
UNITS
ISL8033_36EVAL1ZREVAPCB
1
ea.
a) PUT “X” IN ISL8036 BOX ON
PCB
PWB-PCB, ISL8033_36EVAL1Z,
REVA, ROHS
IMAGINEERING INC.
ISL8033_36EVAL1ZREVAPCB
ISL8033_36EVAL1ZREVAPCB
0
ea.
b) SEE LABEL-RENAME BOARD
PWB-PCB, ISL8033_36EVAL1Z,
REVA, ROHS
IMAGINEERING INC.
ISL8033_36EVAL1ZREVAPCB
C2012X5R0J226M-T
6
ea.
C3, C4, C9, C11, CIN1, CIN2
CAP, SMD, 0805, 22µF, 6.3V, 20%,
X5R, ROHS
TDK
C2012X5R0J226M
3
H1045-00120-50V5-T
2
ea.
C5, C10
CAP, SMD, 0603, 12pF, 50V, 5%, COG, AVX
ROHS
06035A120JAT2A
H1045-00151-50V5-T
1
C8
CAP, SMD, 0603, 150pF, 50V, 5%,
NPO, ROHS
ECJ-1VC1H151J
H1045-DNP
0
ea.
C1, C2, C8, CD1, CD2, CDC, C_PH
CAP, SMD, 0603, DNP-PLACE
HOLDER, ROHS
H1046-DNP
0
ea.
C6, C7
CAP, SMD, 0805, DNP-PLACE
HOLDER, ROHS
FDV0630-R60M
2
ea.
L1, L2
COIL-PWR INDUCTOR, SMD, 7.4X6.7, TOKO
0.6µH, 20%, ROHS
FDV0630-R60M
131-4353-00
4
ea.
LX1, LX2, VOUT1_S, VOUT2_S
CONN-SCOPE PROBE TEST PT,
COMPACT, PCB MNT, ROHS
TEKTRONIX
131-4353-00
1514-2
8
ea.
a) PGND1, PGND2, PGND11,
PGND22, VIN1, VIN2
CONN-TURRET, TERMINAL POST, TH,
ROHS
KEYSTONE
1514-2
1514-2
0
ea.
b) VOUT1, VOUT2
CONN-TURRET, TERMINAL POST, TH,
ROHS
KEYSTONE
1514-2
5000
6
ea.
a) EN1, EN2, PG1, PG2, SS, SYNC CONN-MINI TEST PT, VERTICAL, RED, KEYSTONE
ROHS
5000
5000
0
ea.
b) SYNC located left of C_PH
CONN-MINI TEST PT, VERTICAL, RED, KEYSTONE
ROHS
5000
5001
1
ea.
SGND
CONN-MINI TEST PT, VERTICAL, BLK,
ROHS
KEYSTONE
5001
5002
2
ea.
COMP, FB
CONN-MINI TEST PT, VERTICAL,
WHITE, ROHS
KEYSTONE
5002
LTST-C170CKT
2
ea.
D1, D2
LED-GaAs RED, SMD, 2mmX1.25mm, LITEON/VISHAY
100mW, 40mA, 10mcd, ROHS
LTST-C170CKT
ISL78236IRZ
1
ea.
U1
IC-DUAL 3A BUCK REGULATOR,
2.5MHz, 24P, QFN, 4X4, ROHS
INTERSIL
ISL78236IRZ
2N7002-7-F-T
2
ea.
Q1, Q2
TRANSISTOR, N-CHANNEL, 3 LD,
SOT-23, 60V, 115mA, ROHS
DIODES, INC.
2N7002-7-F
H2509-DNP
1
ea.
R9
RES, SMD, 0201, 0Ω, 1/20W, 0%, TF PANASONIC
H2509-00R00-1/20W-T
H2511-00R00-1/10W-T
4
ea.
R2, R5, R13, R_PH
RES, SMD, 0603, 0Ω, 1/10W, TF,
ROHS
CR0603-10W-000T
PART
NUMBER
REFERENCE
DESIGNATOR
DESCRIPTION
MANUFACTURER
PART
MANUFACTURER
PANASONIC
VENKEL
Application Note 1927
AN1927.0
June 17, 2014
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Bill of Materials
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Bill of Materials (Continued)
QTY
UNITS
H2511-01003-1/10W1-T
5
ea.
R1, R4, R6, RF11, RF21
RES, SMD, 0603, 100k, 1/10W, 1%,
TF, ROHS
H2511-01243-1/10W1-T
2
ea.
RF12, RF22
RES, SMD, 0603, 124k, 1/10W, 1%, YAGEO
TF, ROHS
9C06031A1243FKHFT
H2511-02001-1/10W1-T
2
ea.
R8, R12
RES, SMD, 0603, 2k, 1/10W, 1%, TF, KOA
ROHS
RK73H1JTTD2001F
4
H2511-05232-1/10W1-T
1
ea.
R11
RES, SMD, 0603, 52.3k, 1/10W, 1%, VENKEL
TF, ROHS
CR0603-10W-5232FT
H2511-DNP
0
ea.
R3, R7, R10, R14
RES, SMD, 0603, DNP-PLACE
HOLDER, ROHS
PART
NUMBER
REFERENCE
DESIGNATOR
DESCRIPTION
MANUFACTURER
MANUFACTURER
PART
1
ea.
R_IN
RES, SMD, 1210, 0Ω, 1/4W, TF, ROHS VENKEL
H2514-DNP
0
ea.
R_OUT
RES, SMD, 1210, DNP, DNP, DNP, TF,
ROHS
GT11MSCBE-T
3
ea.
S1-S3
SWITCH-TOGGLE, SMD, 6 PIN, SPDT,
2POS, ON-ON, ROHS
ITT INDUSTRIES/C&K
DIVISION
GT11MSCBE
SJ-5003-BLACK
4
ea.
Bottom four corners
BUMPONS, 0.44”Wx0.20”H,
DOMETOP, BLACK
3M
SJ-5003SPBL
5X8-STATIC-BAG
1
ea.
Place assy in bag
BAG, STATIC, 5X8, ZIP LOC
INTERSIL
212403-013
LABEL-RENAME BOARD
1
ea.
RENAME PCB TO:
ISL78236DUALEVAL1Z
LABEL, TO RENAME BOARD
INTERSIL
LABEL-RENAME BOARD
LABEL-SERIAL NUMBER
1
ea.
LABEL, FOR SERIAL NUMBER AND
BOM REV #
CR1210-4W-000
Application Note 1927
H2514-00R00-1/4W-T
AN1927.0
June 17, 2014
Application Note 1927
ISL78236DUALEVAL1Z Board Layout
FIGURE 1. TOP COMPONENTS
FIGURE 2. TOP LAYER ETCH
FIGURE 3. 2ND LAYER ETCH
FIGURE 4. 3RD LAYER ETCH
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Application Note 1927
ISL78236DUALEVAL1Z Board Layout
FIGURE 5. BOTTOM LAYER ETCH
(Continued)
FIGURE 6. BOTTOM COMPONENTS (MIRROR)
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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