an1928

Application Note 1928
ISL78236CRSHEVAL1Z Current Share Evaluation Board
User Guide
Description
Quick Setup Guide
The ISL78236CRSHEVAL1Z kit is intended for use by individuals
with requirements for Point-of-Load (POL) applications sourcing
from 2.85V to 6V. The ISL78236CRSHEVAL1Z evaluation board
is used to demonstrate the performance of the ISL78236 low
quiescent current mode converter in current sharing
configuration. The evaluation board is configured to deliver up
to 6A output current with both outputs paralleled together. The
ISL78236 can also be used in dual output 3A/3A
configuration. For this application, reference
ISL78236DUALEVAL1Z AN1927.
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 VOUT1, VOUT2.
Evaluating Other Output Voltages
• Current sharing 6A high efficiency synchronous buck
regulator with up to 95% Efficiency
The ISL78236CRSHEVAL1Z kit output is preset to 1.8V
(VOUT1 = VOUT2); however, output voltage can be adjusted from
1.2V to 3.3V. The output voltage programming resistor, RF22, will
depend on the desired output voltage of the regulator. The value
for the feedback resistor is typically between 50kΩ and 750kΩ
as shown in Equation 1.
• 180° out-of-phase channel switching
Setting RF21 = 100k, then RF22 will be:
Key Features
• 2% output accuracy over-temperature/load/line
• Externally adjustable soft-start time
• Soft-stop output discharge during disabled
• External synchronization up to 6MHz
• Typical 8µA shutdown current
• 100% maximum duty cycle for lowest dropout
• External current mode compensation
• Peak current limiting, hiccup mode short circuit protection
and over-temperature protection
• Negative current detection and protection
Recommended Equipment
The following materials are recommended to perform testing:
• 5V or higher power supply with at least 6A source current
capability or 5V battery
• Electronic loads capable of sinking current up to 7A
• Digital Multimeters (DMMs)
V OUT
RF22 = RF21  ------------- – 1
 0.8

Mode Control
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)
Enable Control
EN1 and EN2 pins should be tied together for current sharing
operation.
TABLE 1. SWITCH SETTINGS
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.
• 100MHz quad-trace oscilloscope
• 10MHz signal generator
Ordering Information
PART NUMBER
ISL78236CRSHEVAL1Z
June 17, 2014
AN1928.0
DESCRIPTION
(EQ. 1)
S2/S3
MODE
ON
Enable VOUT. Both must be in ON state.
OFF
Disable VOUT.
Current Sharing 6A Synchronous Buck
Evaluation Board
1
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
LX1
LX2
R_IN
VIN2
A
VIN2
VIN1
0
CIN2
22UF
VIN2
0
VOUT2
VDD
VOUT2_S
SS
SYNC
SYNC
R_PH SYNC
0
S1
PWM
PFM
C_PH
OPEN
C3
C4
22UF 22UF
VOUT2_S
C1
R3
OPEN
A
C2
OPEN
0.01UF
A
C5
RF22
124K
22PF
A
R7
RF21
100K
A
A
A
A
SGND
A
ON/EX
OFF
A
EN2
R11
C9
22UF
C11
22UF
S3
ON/EX
OFF
PG2
PG2
A
R10
OPEN
VOUT1_S
A
A
PGND1
A
A
2N7002
Q1
A
PG1
PG1
R13
0
R12
2K
C8
150PF
D1
VOUT1
VOUT1_S
C6
C7
OPEN OPEN
SYNC
VIN_PG
30.1K
R8
2K
EN2
A
EN1
VOUT1
VOUT1
A
VIN_PG
A
EN2
EN1
VDD
SS
CD1
OPEN
A
A
R6
100K
EN1
PG1
FB1
VDD
S2
SS
EN1
A
CDC
OPEN
VDD
VOUT2
0
PGND
COMP
R4
100K
SGND
FB2
EP
ISL8036AIRZ
ISL78236AIRZ
R_OUT
L1
COMP
VDD
EN1
PG2
0
PGND
PGND2
EN2
A
R14
OPEN
D2
2N7002
Q2
A
VIN1
Application Note 1928
SS
VOUT2
EN2
PG2
FB2
FB
FB
VOUT2
VIN1
COMP
NC
FB1
SGND
PG1
SYNC
R5
LX1
LX1
VIN1
U1
VIN2
R9
R2
L2
COMP
VIN1
CD2
DNP
LX2
OPEN
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
VIN2
0
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ISL78236CRSHEVAL1Z Schematic
AN1928.0
June 17, 2014
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BILL OF MATERIALS
PART NUMBER
REFERENCE
DESIGNATOR
QTY
UNITS
ISL8033_36EVAL1ZREVAPCB
1
ea.
SEE LABEL-RENAME BOARD
PWB-PCB, ISL8033_36EVAL1Z, REVA, ROHS
DESCRIPTION
MANUFACTURER
C2012X5R0J226M-T
6
ea.
C3, C4, C9, C11, CIN1, CIN2
CAP, SMD, 0805, 22µF, 6.3V, 20%, X5R, ROHS TDK
C2012X5R0J226M
H1045-00103-50V5-T
1
ea.
C1
CAP, SMD, 0603, 0.01µF, 50V, 5%, X7R, ROHS VENKEL
C0603X7R500-103JNE
TBD
MANUFACTURER PART
ISL8033_36EVAL1ZREVAPCB
KEMET
C0603C103J5RACTU
AVX
06035C103JAT2A
C1608X7R1H103J
1
ea.
C8
CAP, SMD, 0603, 150pF, 50V, 5%, NPO, ROHS
PANASONIC
VENKEL
ECJ-1VC1H151J
C0603C0G500-151JNE
H1045-00220-50V5-T
1
ea.
C5
CAP, SMD, 0603, 22pF, 50V, 5%, C0G, ROHS
VENKEL
C0603C0G500-220JNE
3
TDK
H1045-00151-50V5-T
C0603C220J5GACTU
TDK
C1608C0G1H220J
MURATA
GRM1885C1H220JA01D
ROHM
MCH185A220JK
H1045-DNP
0
ea.
C2, C10, 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, 0.6µH,
20%, ROHS
TOKO
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, ROHS
KEYSTONE
5000
5000
0
ea.
b) SYNC located left of C_PH
CONN-MINI TEST PT, VERTICAL, RED, ROHS
KEYSTONE
5000
5001
1
ea.
SGND
CONN-MINI TEST PT, VERTICAL, BLK, ROHS
KEYSTONE
5001
5002
2
ea.
COMP, FB
CONN-MINI TEST POINT, VERTICAL, WHITE,
ROHS
KEYSTONE
5002
LTST-C170CKT
2
ea.
D1, D2
LED-GaAs RED, SMD, 2mmX1.25mm, 100mW, LITEON/VISHAY
40mA, 10mcd, ROHS
ROHM
LTST-C170CKT
SML-210LTT86
STANLEY ELECTRIC
BR112H-TR
ISL78236IRZ
AN1928.0
June 17, 2014
ISL78236IRZ
1
ea.
U1
IC-DUAL 3A CONTROLLER, 2.5MHz, 24P,
QFN,4X4, ROHS
INTERSIL
2N7002-7-F-T
2
ea.
Q1, Q2
TRANSISTOR,N-CHANNEL, 3 LD, SOT-23, 60V,
115mA, ROHS
DIODES, INC.
2N7002-7-F
ON SEMICONDUCTOR
2N7002LT1G
Application Note 1928
KEMET
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BILL OF MATERIALS (Continued)
PART NUMBER
REFERENCE
DESIGNATOR
UNITS
DESCRIPTION
H2509-00R00-1/20W-T
1
ea.
R9
RESISTOR, SMD, 0201, 0Ω, 1/20W, 0%, TF
PANASONIC
H2509-00R00-1/20W-T
H2511-00R00-1/10W-T
4
ea.
R7, R5, R13, R_PH
RES, SMD, 0603, 0Ω, 1/10W, TF, ROHS
VENKEL
CR0603-10W-000T
ROHM
MCR03EZPJ000
PANASONIC
ERJ-3GEY0R00V
YAGEO
RC0603JR-070RL
VISHAY/DALE
CRCW06030000Z0EA
VENKEL
CR0603-10W-1003FT
PANASONIC
ERJ-3EKF1003V
4
QTY
H2511-01003-1/10W1-T
H2511-01243-1/10W1-T
1
1
ea.
ea.
ea.
R1, R4, R6
RF21
RF22
RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS
RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS
RES, SMD, 0603, 124k, 1/10W, 1%, TF, ROHS
MANUFACTURER PART
ROHM
MCR03EZPFX1003
YAGEO
RC0603FR-07100KL
STACKPOLE
RMCF 1/16 100K 1% R
VISHAY/DALE
CRCW0603100KFKEA
VENKEL
CR0603-10W-1003FT
PANASONIC
ERJ-3EKF1003V
ROHM
MCR03EZPFX1003
YAGEO
RC0603FR-07100KL
STACKPOLE
RMCF 1/16 100K 1% R
VISHAY/DALE
CRCW0603100KFKEA
YAGEO
9C06031A1243FKHFT
PANASONIC
ERJ-3EK1243V
RK73H1JTTD2001F
CR0603-10W-2001FT
H2511-02001-1/10W1-T
2
ea.
R8, R12
RES, SMD, 0603, 2k, 1/10W, 1%, TF, ROHS
KOA
VENKEL
H2511-03012-1/10W1-T
1
ea.
R11
RESISTOR, SMD, 0603, 30.1k, 1/10W, 1%, TF,
ROHS
VENKEL
CR0603-10W-3012FT
YAGEO
RC0603FR-0730K1L
VENKEL
CR1210-4W-000
AN1928.0
June 17, 2014
H2511-DNP
0
ea.
R2, R3, R10,
R14, RF11, RF12
RES, SMD, 0603, DNP-PLACE HOLDER, ROHS
H2514-00R00-1/4W-T
2
ea.
R_IN, R_OUT
RES, SMD, 1210, 0Ω, 1/4W, TF, ROHS
GT11MSCBE-T
3
ea.
S1-S3
SWITCH-TOGGLE, SMD, 6 PIN, SPDT, 2POS, ON- ITT INDUSTRIES/
ON, ROHS
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, ZIPLOC, ROHS
INTERSIL
212403-013
LABEL-RENAME BOARD
1
ea.
RENAME PCB TO:
ISL78236CRSHEVAL1Z
LABEL, TO RENAME BOARD
INTERSIL
LABEL-RENAME BOARD
LABEL-SERIAL NUMBER
1
ea.
LABEL-FOR SERIAL NUMBER AND BOM REV #
INTERSIL
LABEL-SERIAL NUMBER
Application Note 1928
H2511-01003-1/10W1-T
3
MANUFACTURER
Application Note 1928
ISL78236CRSHEVAL1Z 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 1928
ISL78236CRSHEVAL1Z 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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