an1605

Application Note 1605
Author: Paul Orfanu
ISL85033CRSHEVAL1Z Wide VIN Current Sharing
Standard Buck Regulator With 6A Output Current
Description
Evaluating the Other Output Voltage
The ISL85033CRSHEVAL1Z kit is intended for use by individuals
with requirements for Point-of-Load applications sourcing from
4.5V to 28V. The ISL85033CRSHEVAL1Z evaluation board is
used to demonstrate the performance of the ISL85033 wide
VIN standard buck regulator with 6A output current.
The ISL85033CRSHEVAL1Z kit output is preset to 5V; however,
output voltages can be adjusted from 0.8V to 5V. The output
voltage programming resistor, R3, will depend on the desired
output voltage of the regulator. The value for the feedback
resistor is typically between 0Ω and 42.3kΩ as shown in
Equation 1.
The ISL85033 is offered in a 4mmx4mm 28 Ld TQFN package
with 1mm maximum height. The complete converter occupies
6.25cm2 area.
Key Features
• Wide Input Voltage Range from 4.5V to 28V
• Adjustable Output Voltage with Continuous Output Current
up to 6A
• Current Mode Control
• Adjustable Switching Frequency from 300kHz to 2MHz
• Power-Good Detection
• External Soft-start Time
• Overcurrent and Hiccup Mode Short Circuit Protection,
Thermal Overload Protection, UVLO
• Boot Undervoltage Detection
• Channels are Out-of-phase, Reducing Voltage Ripple and
Component Size
Recommended Equipment
The following materials are recommended to perform testing:
• 0V to 30V Power Supply with at least 7A source current
capability or 5V battery
VOUT
R3 = R2 ⎛ -------------- – 1⎞
⎝ VFB
⎠
If the output voltage desired is 0.8V, then R3 is shorted. The
value for R2 is typically between 1k and 10k. Please note that
if VOUT is less than 2.5V, the switching frequency and
compensation must be changed for 300kHz operation due to
minimum on-time limitation. Please refer to the data sheet for
further information (FN6676).
Frequency Control
ISL85033 has an FS pin that controls the frequency of operation.
Programmable frequency allows for optimization between efficiency
and external component size. Default switching frequency is 500kHz
when FS is tied to VCC (R9 = 0). By removing R9 and connecting R10
to GND, the switching frequency could be changed from 300kHz
(R10 = 383k) to 2MHz (R10 = 40.2k). Please refer to the data sheet
(FN6676) for calculating the value of R10. Do not leave this pin
floating.
Disabling/enabling Function
The ISL85033 evaluation board contains S1, S2 switches that
need to be tied together in current sharing in order to enable or
disable both of the channels, thus allowing low quiescent
current state. Table 1 details this function.
• Electronic Loads capable of sinking current up to 7A
TABLE 1. SWITCH SETTINGS
• Digital Multimeters (DMMs)
S1
S2
• 100MHz quad-trace oscilloscope
ON
ON
Enable VOUT
• Signal generator
OFF
OFF
Disable VOUT
Quick Setup Guide
1. Ensure that the circuit is correctly connected to the supply
and loads prior to applying any power.
2. Connect the bias supply to VIN1, the plus terminal to VIN1
and the negative return to GND2.
3. Verify that the position is ON for S1 and S2.
4. Turn on the power supply.
(EQ. 1)
ON/OFF CONTROL
SYNC Control
The ISL85033 evaluation board has an SI pin that allows
external synchronization frequency to be applied. Default
board configuration has R18 = 0 to GND, which defaults to the
internal selected switching frequency. Removing R18 allows
the synchronization to be external between 600kHz to 4MHz.
Do not leave this pin floating.
5. Verify the output voltage is 5V for VOUT.
January 3, 2011
AN1605.0
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Copyright Intersil Americas Inc. 2011. 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.
ISL85033CRSHEVAL1Z Schematic
C5
A
A
D1
47UF
B340B
A
A
C6
10UF
A
C7
A
A
SGND
EN1
PGOOD2
A
A
COMP2
PHASE2
A
15 0.01UF
A
VOUT2
VOUT=5V
VOUT2=3.3V
7UH
B340B
C17
47UF
C8
10UF
VIN2
C12
DNP
A
BOOT2
D3
DNP
EN2
GND3
D4
VCC
BOOT1
DNP
A
BOOT2
D5
D6
DNP
DNP
EXT_5V
VCC
100K
100K
AN1605.0
January 3, 2011
EN1
ON
S1 OPEN
OFF
A
EN2
R7
OPEN
ON
OPEN
OFF
S2
A
SS1
R8
OPEN
SS2
FS
R10
DNP
A
R26
R17
DNP
R9
SYNCIN
R18
0
R6
0
R4
A
DNP
VOUT1
VO2
VIN2
A
BOOT1
A
R22
JLX2
L2
D2
VIN1
0
VOUT2
0
VIN2
GND4
A
A
VIN1
R20
DNP
PGOOD1
PHASE1
EP
C9
16
A
C18
10UF
R19
DNP
A
PHASE2
EN1
VCC
EN2
7UH
C14
VCC
GND2
PHASE1
A
L1
A
DNP
VIN1
29
A
C2
6
A
R21
R16
OPEN
C11
OPEN
22nF
BOOT2
17
BOOT2
R15
OPEN
VOUT1
SS2
18
PGND2
ISL85033IRTZ
SS2
19
SS2
U1
BOOT1
0.01UF 7
JLX1
VOUT1
VOUT1=5V
SS1
A
C16
OPEN
FB2
20
FB2
PGND1
BOOT1 5
A
VO1
3
R14
OPEN
OPEN
C15
OPEN
OPEN
21
R11
C10
DNP
JVO2
R27
DNP
VOUT2
FB1
R23
COMP1
R24
SS1
0
0
R25
0
DNP
FB2
COMP2
SS2
Application Note 1605
GND1
R13
VOUT2
COMP2
FB1
4
C3
22nF
0.047UF
8.06K
COMP1
2
SS1
SS1
R2
1
R5
4.7UF
FB1
DNP
VIN1
VIN1
EN1
VCC
EN2
VIN2
VIN2
A
C4
SYNCIN
PGOOD1
FS
A
2
C13
1000PF 34K
R1
0
A
R12
NC1
PGOOD1
FS
NC
SGND
SYNCIN
SYNCOUT
PGOOD2
42.2K
R3
68PF
VCC
PG2
8
9
10
11
12
13
14
JVO1
22PF
COMP1
C1
SO
28
27
26
25
24
23
22
VOUT1
A
SI
PGOOD2
FS GND
PG1
Application Note 1605
TABLE 2. BILL OF MATERIALS
PART
NUMBER
UNITS
ISL85033EVAL1ZREVBPCB
1
ea
SEE LABEL-RENAME
BOARD
PWB-PCB,
ISL85033EVAL1Z,
REVB, ROHS
TBD
ISL85033EVAL1ZREVBPCB
EEE-FK1V101P-T
0
ea
DNP (C2,C12)
CAP, SMD, 8X10.2,
100µF, 35V, 20%,
AL.EL., ROHS
PANASONIC
EEE-FK1V101P
GMK325BJ106KN-T
2
ea
C6,C8
CAP, SMD, 1210,
10µF, 35V, 10%,
X5R, ROHS
TAIYO YUDEN
GMK325BJ106KN-T
H1044-00220-50V5-T
1
ea
C13
CAP, SMD, 0402,
22pF, 50V, 5%, NPO,
ROHS
MURATA
GRM36COG220J050AQ
PANASONIC
ECU-E1H220JCQ
SAMSUNG
CL05C220JBNC
H1044-00680-50V10-T
H1045-00102-50V5-T
H1045-00103-50V10-T
1
ea
1
ea
2
ea
REFERENCE DESIGNATOR
C1
C4
C5, C9
DESCRIPTION
MANUFACTURER
MANUFACTURER
PART
QTY
MURATA
CAP, SMD, 0402,
68pf, 50V, 10%, X7R,
PANASONIC
ROHS
CAP, SMD, 0603,
1000pF, 50V, 5%,
COG, ROHS
CAP, SMD, 0603,
0.01µF, 50V, 10%,
X7R, ROHS
C0402COG500-680KNE
MURATA
GRM1885C1H102JA01D
VENKEL
C0603COG500-102JNE
PANASONIC
ECJ-1VC1H102J
TDK
C1608C0G1H102J
AVX
06035A102JAT2A
KEMET
C0603C102J5GACTU
TAIYO YUDEN
UMK107CG102JZ-T
MURATA
GRM39X7R103K050
AVX
06035C103KAT2A
VENKEL
C0603X74500-103KNE
1
ea
C3, C11
PANASONIC
CAP, SMD, 0603,
22nF, 50V, 10%, X7R,
ROHS
H1045-00475-6R3V10-T
1
ea
C7
CAP, SMD, 0603,
4.7µF, 6.3V, 10%,
X5R, ROHS
0
ea
C10, C15, C16
CAP, SMD, 0603,
DNP-PLACE HOLDER,
ROHS
H1082-00106-50V10-T
1
ea
C18
CAP, SMD, 1210,
10µF, 50V, 10%,
X5R, ROHS
3
ECJ-0EC1H680J
VENKEL
H1045-00473-50V10-T
H1045-DNP
GRM36COG680K050AQ
ECJ-1VB1H473K
VENKEL
C0603X5R6R3-475KNE
TDK
C1608X5R0J475K
PANASONIC
ECJ-1VB0J475K
MURATA
GRM188R60J475KE19D
KEMET
C0603C475K9PACTU
TAIYO YUDEN
JMK107BJ475KA-T
TAIYO YUDEN
UMK325BJ106KM-T
AN1605.0
January 3, 2011
Application Note 1605
TABLE 2. BILL OF MATERIALS (Continued)
PART
NUMBER
H1082-00476-16V20-T
QTY
UNITS
2
ea
REFERENCE DESIGNATOR
C14, C17
DESCRIPTION
MANUFACTURER
PART
MANUFACTURER
TDK
CAP, SMD, 1210,
47µF, 16V, 20%, X5R,
PANASONIC
ROHS
C3225X5R1C476M
ECJ-4YB1C476M
MURATA
GRM32ER61C476ME15L
TAIYO YUDEN
EMK325BJ476MM-T
KEMET
C1210C476M4PACTU
VENKEL
C1210X5R160-476MNE
FALCO
SQL004
SQL004
2
ea
L1, L2
COIL-PWR
INDUCTOR, SMD,
10mm, 7µH, 25%,
4.8A, ROHS
131-4353-00
4
ea
JLX1, JLX2, JVO1, JVO2
CONN-SCOPE PROBE TEKTRONIX
TEST PT, COMPACT,
PCB MNT, ROHS
1514-2
8
ea
VO1, VO2, GND1-GND4,
VIN1, VIN2
CONN-TURRET,
TERMINAL POST, TH,
ROHS
KEYSTONE
1514-2
5002
11
ea
a) FS, SI, SO, EN1, EN2,
GND, PG1, PG2
CONN-MINI TEST
POINT, VERTICAL,
WHITE, ROHS
KEYSTONE
5002
5002
0
ea
b) SS1, SS2, EXT_5V
CONN-MINI TEST
POINT, VERTICAL,
WHITE, ROHS
KEYSTONE
5002
B340B-13-F-T
2
ea
D1, D2
DIODE-SCHOTTKY, DIODES INC.
SMD, SMB, 2P, 40V,
3A, ROHS
ISL85033IRTZ
1
ea
U1
IC-3A DUAL STD
REGULATOR, 28P,
TQFN, 4x4, ROHS
H2505-DNP
0
ea
R10, R17, R19, R20, R26, RESISTOR, SMD,
R27
0603, 0.1%, MF,
DNP-PLACE HOLDER
H2510-04222-1/16W1-T
1
ea
R3
H2510-08061-1/16W1-T
1
ea
R2
B340B-13-F
INTERSIL
ISL85033IRTZ
RES,SMD, 0402,
42.2k, 1/16W, 1%,
TF, ROHS
PANASONIC
ERJ-2RKF4222X
VENKEL
CR0402-16W-4222FT
RES, SMD, 0402,
8.06k, 1/16W, 1%,
TF, ROHS
VENKEL
CR0402-16W-8061FT
PANASONIC
ERJ-2RKF8061X
ROHM
MCR01MZPF8061
YAGEO
RC0402FR-078K06L
VISHAY/DALE
CRCW04028K06FKED
VENKEL
CR0603-10W-000T
ROHM
MCR03EZPJ000
H2510-DNP
0
ea
R7, R8, R14, R16
RES, SMD, 0402,
DNP, DNP, DNP, TF,
ROHS
H2511-00R00-1/10W-T
1
ea
R25
RES, SMD, 0603,
DNP
4
131-4353-00
AN1605.0
January 3, 2011
Application Note 1605
TABLE 2. BILL OF MATERIALS (Continued)
PART
NUMBER
H2511-00R00-1/10W-T
H2511-01004-1/10W1-T
H2511-03402-1/10W1-T
QTY
UNITS
6
ea
2
ea
1
ea
REFERENCE DESIGNATOR
R1, R9, R18, R23, R24
R4, R6
R5
DESCRIPTION
MANUFACTURER
RES, SMD, 0603, 0Ω, VENKEL
1/10W, TF, ROHS
ROHM
CR0603-10W-000T
MCR03EZPJ000
PANASONIC
ERJ-3GEY0R00V
YAGEO
RC0603JR-070RL
VISHAY/DALE
CRCW06030000Z0EA
RES, SMD, 0603, 1M, PANASONIC
1/10W, 1%, TF,
VENKEL
ROHS
RES, SMD, 0603,
34k, 1/10W, 1%, TF,
ROHS
MANUFACTURER
PART
ERJ-3EKF1004V
CR0603-10W-1004FT
YAGEO
RC0603FR-071ML
ROHM
MCR03EZPFX1004
KOA
RK73H1JTTD1004F
VISHAY/DALE
CRCW06031M00FKEA
VENKEL
CR0603-10W-3402FT
PANASONIC
ERJ-3EKF3402V
YAGEO
RC0603FR-0734KL
VISHAY/DALE
CRCW060334K0FKEA
ROHM
MCR03EZPFX3402
H2511-DNP
0
ea
R11, R12, R13, R15
RES, SMD, 0603,
DNP-PLACE HOLDER,
ROHS
H2514-00R00-1/4W-T
2
ea
R21, R22
RES, SMD, 1210, 0Ω, VENKEL
1/4W, TF, ROHS
GT13MCBE
2
ea
S1, S2
SWITCH-TOGGLE,
THRU-HOLE, 5PIN,
SPDT, 3POS,
ON-OFF-ON, ROHS
C&K COMPONENTS
GT13MCBE
SJ-5003-BLACK
4
ea
Bottom four corners
BUMPONS,
0.44” W x 0.20” H,
DOMETOP, BLACK
3M
SJ-5003SPBL
5X8-STATIC-BAG
1
ea
Place assy in bag
BAG, STATIC, 5X8,
ZIPLOC, ROHS
INTERSIL
212403-013
DNP
0
ea
D3-D6
DO NOT POPULATE
OR PURCHASE
LABEL-RENAME BOARD
1
ea
RENAME PCB TO:
ISL85033CRSHEVAL1Z
LABEL, TO RENAME
BOARD
INTERSIL
LABEL-RENAME BOARD
LABEL-SERIAL NUMBER
1
ea
5
CR1210-4W-000
LABEL, FOR SERIAL
NUMBER AND BOM
REV #
AN1605.0
January 3, 2011
Application Note 1605
ISL85033CRSHEVAL1Z Board Layout
FIGURE 1. TOP LAYER COMPONENTS
FIGURE 2. TOP LAYER ETCH
6
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Application Note 1605
ISL85033CRSHEVAL1Z Board Layout (Continued)
FIGURE 3. SECOND LAYER ETCH
FIGURE 4. THIRD LAYER ETCH
7
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Application Note 1605
ISL85033CRSHEVAL1Z Board Layout (Continued)
FIGURE 5. BOTTOM LAYER ETCH
FIGURE 6. BOTTOM LAYER COMPONENTS
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
8
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