an1574

Application Note 1574
Author: Paul Orfanu
ISL85033DUALEVAL1Z Wide VIN Dual Standard
Buck Regulator With 3A/3A Output Current
Quick Setup Guide
Description
The ISL85033DUALEVAL1Z kit is intended for use by
individuals with requirements for Point-of-Load
applications sourcing from 4.5V to 28V. The
ISL85033DUALEVAL1Z evaluation board is used to
demonstrate the performance of the ISL85033 wide VIN
dual standard buck regulator with 3A/3A output
current converter.
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 3A
• Current Mode Control
• Adjustable Switching Frequency from 300kHz to 2MHz
• Independent Power-Good Detection
• Selectable In-Phase or Out-of-Phase PWMs Switching
Operation
• Independent, Sequential, Ratiometric or Absolute
Tracking Between Outputs
• Internal 2ms 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
• Electronic Loads capable of sinking current up to 7A
• Digital Multimeters (DMMs)
• 100MHz quad-trace oscilloscope
• Signal generator
November 29, 2010
AN1574.2
1
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.
5. Verify the output voltage is 5V for VOUT1 and 3.3V
for VOUT2.
Evaluating the Other Output Voltage
The ISL85033DUALEVAL1Z kit outputs are preset to 5V
for VOUT1 and 3.3V for VOUT2; however, output voltages
can be adjusted from 0.8V to 5V. The output voltage
programming resistor, R3 (or R14 in Channel 2), will
depend on the desired output voltage of the regulator
and the value for the feedback resistor R2 (R16
respectively), as shown in Equation 1.
R3 = ( V OUT1 – V FB ) • R2 ⁄ V FB
(EQ. 1)
R14 = ( V OUT2 – V FB ) • R16 ⁄ V FB
If the output voltage desired is 0.8V, then R3 (R14
respectively) is shorted. The value for R2 (R16
respectively) 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 ground, 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.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Copyright Intersil Americas Inc. 2010. 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.
Application Note 1574
Disabling/enabling Function
TABLE 2.
The ISL85033 evaluation board contains S1, S2 switches
to enable or disable each of the channels, thus allowing
low quiescent current state. Table 1 details this function.
EN1
EN2
VOUT1
VOUT2
High
Floating
First
After
VOUT1 > 90%
TABLE 1. SWITCH SETTINGS
Floating
High
After
VOUT2 > 90%
First
High
High
Same time
as VOUT2
Same time
as VOUT1
Floating
Floating
S1
S2
ON/OFF CONTROL
ON
OFF
Enable VOUT1; Disable VOUT2
OFF
ON
Disable VOUT1; Enable VOUT2
ON
ON
Enable VOUT1; Enable VOUT2
OFF
OFF
Disable VOUT1; Disable VOUT2
If EN1 or EN2 are floating, then the outputs will start in
the sequencing described in the data sheet section on
output sequencing and also summarized in Table 2.
2
NOTE
Not
Allowed
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.
AN1574.2
November 29, 2010
ISL85033DUALEVAL1Z Schematic
SS1
3
A
0.01UF 7
L1
A
A
A
R20
DNP
PGOOD1
C7
A
PGOOD2
SGND
EN1
PGOOD2
A
COMP2
A
SYNCIN
A
SS2
C9
A
C8
10UF
A
VOUT2
VOUT2=3.3V
C12
47UF
DNP
A
BOOT2
D3
DNP
GND3
D4
VCC
EN2
BOOT1
DNP
A
BOOT2
D5
D6
DNP
DNP
EXT_5V
A
S2
A
SS1
SS2
0
FS
R10
DNP
A
R26
R17
DNP
R9
0
0
R6
EN2
ON
OPEN
OFF
R8
SYNCIN
R18
0
ON
OPEN
S1
OFF
100K
R4
AN1574.2
November 29, 2010
EN1
100K
VCC
R7
A
DNP
VOUT1
VO2
VIN2
A
BOOT1
A
VIN1
R22
JLX2
7UH
C17
VIN2
R21
DNP
VOUT2
0
VIN2
GND4
A
L2
D2
VOUT1
R16
8.06K
A
B340B
A
A
FB2
C11
OPEN
15 0.01UF
VIN1
C6
10UF
R15
0
470PF
BOOT2
16
A
C18
10UF
R19
DNP
A
PHASE2
D1
VCC
GND2
PHASE1
EP
C16
68PF
C10
18
17
JVO2
R14
25.5K
SS2
19
BOOT2
PHASE2
B340B
47UF
A
ISL85033IRTZ
PHASE1
A
7UH
C14
C2
DNP
VIN1
29
A
JLX1
VOUT1
VOUT1=5V
BOOT1
6
12PF
R11
20 69.8K
PGND2
EN1
VCC
EN2
A
A
PGND1
C15
21
SS2
U1
DNP
VOUT2
VIN1
VIN1
EN1
VCC
EN2
VIN2
VIN2
GND1
R13
R27
DNP
VOUT2
FB1
R23
COMP1
R24
SS1
R25
DNP
DNP
DNP
FB2
COMP2
SS2
Application Note 1574
C5
DNP
FB2
SS1
BOOT1 5
R12
COMP2
FB1
4
C3
OPEN
VCC
PG2
8
9
10
11
12
13
14
SS1
R2
8.06K
COMP1
470PF 69.8K 2
A
FB1
1
4.7UF
C4
SO
PGOOD1
FS
NC
SGND
SYNCIN
SYNCOUT
PGOOD2
12PF
R5
A
3
R1
0
A
C13
R3
42.2K
COMP1
C1
68PF
JVO1
A
SI
28
27
26
25
24
23
22
VOUT1
VO1
FS GND
PGOOD1
FS
PG1
Application Note 1574
TABLE 3. BILL OF MATERIALS
PART NUMBER
REFERENCE
DESIGNATOR
QTY UNITS
DESCRIPTION
MANUFACTURER
MANUFACTURER
PART #
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
H1044-00120-50V5-T
2
ea
C13, C15
CAP, SMD, 0402,
12pF, 50V, 5%,
NPO, ROHS
AVX
04025C120JAT
VENKEL
C0402C0G500-120JNE
CAP, SMD, 0402,
68pF, 50V, 5%,
NPO, ROHS
MURATA
GRM36COG680J050AQ
PANASONIC
ECJ-0EC1H680J
VENKEL
C0402COG500-680JNE
MURATA
GRM39X7R103K050
AVX
06035C103KAT2A
VENKEL
C0603X74500-103KNE
CAP, SMD, 0603,
470pF, 50V, 5%,
NPO, ROHS
PANASONIC
ECJ-1VC1H471J
VENKEL
C0603COG500-471JNE
CAP, SMD, 0603,
4.7µF, 6.3V, 10%,
X5R, ROHS
VENKEL
C0603X5R6R3-475KNE
TDK
C1608X5R0J475K
PANASONIC
ECJ-1VB0J475K
MURATA
GRM188R60J475KE19D
KEMET
C0603C475K9PACTU
TAIYO YUDEN
JMK107BJ475KA-T
H1044-00680-50V5-T
H1045-00103-50V10-T
H1045-00471-50V5-T
H1045-00475-6R3V10-T
2
ea
2
ea
2
ea
1
ea
C1, C16
C5, C9
C4, C10
C7
CAP, SMD, 0603,
0.01µF, 50V, 10%,
X7R, ROHS
H1045-DNP
0
ea
C3, C11
CAP, SMD, 0603,
DNP-PLACE
HOLDER, ROHS
H1082-00106-50V10-T
1
ea
C18
CAP, SMD, 1210,
10µF, 50V, 10%,
X5R, ROHS
TAIYO YUDEN
UMK325BJ106KM-T
H1082-00476-16V20-T
2
ea
C14, C17
CAP, SMD, 1210,
47µF, 16V, 20%,
X5R, ROHS
TDK
C3225X5R1C476M
PANASONIC
ECJ-4YB1C476M
MURATA
GRM32ER61C476ME15L
TAIYO YUDEN
EMK325BJ476MM-T
KEMET
C1210C476M4PACTU
VENKEL
C1210X5R160-476MNE
FALCO
SQL004
TEKTRONIX
131-4353-00
SQL004
2
ea
L1, L2
131-4353-00
4
ea
JLX1, JLX2, JVO1, JVO2 CONN-SCOPE
PROBE TEST PT,
COMPACT, PCB
MNT, ROHS
4
COIL-PWR
INDUCTOR, SMD,
10mm, 7µH, 25%,
4.8A, ROHS
AN1574.2
November 29, 2010
Application Note 1574
TABLE 3. BILL OF MATERIALS (Continued)
PART NUMBER
REFERENCE
DESIGNATOR
QTY UNITS
DESCRIPTION
MANUFACTURER
MANUFACTURER
PART #
KEYSTONE
1514-2
a) FS, SI, SO, EN1, EN2, CONN-MINI TEST
GND, PG1, PG2
POINT, VERTICAL,
WHITE, ROHS
KEYSTONE
5002
ea
b) SS1, SS2, EXT_5V
CONN-MINI TEST
POINT, VERTICAL,
WHITE, ROHS
KEYSTONE
5002
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,
R23-R27
RESISTOR, SMD,
0603, 0.1%, MF,
DNP-PLACE
HOLDER
H2510-00R00-1/16W-T
2
ea
R1, R15
VENKEL
RES, SMD, 0402,
0Ω, 1/16W, 5%, TF,
PANASONIC
ROHS
1514-2
8
ea
VO1, VO2, GND1GND4, VIN1, VIN2
5002
11
ea
5002
0
B340B-13-F-T
H2510-02552-1/16W1-T
H2510-04222-1/16W1-T
H2510-08061-1/16W1-T
H2511-00R00-1/10W-T
H2511-01004-1/10W1-T
1
ea
1
ea
2
ea
4
ea
2
ea
5
R14
R3
R2, R16
R7-R9, R18
R4, R6
CONN-TURRET,
TERMINAL POST,
TH, ROHS
INTERSIL
B340B-13-F
ISL85033IRTZ
CR0402-16W-00T
ERJ-2GE0JR00
VENKEL
CR0402-16W-2552FT
PANASONIC
ERJ-2RKF2552X
VISHAY/DALE
CRCW040225K5FKED
STACKPOLE
RMC 1/16S 25.5K 1% R
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
PANASONIC
ERJ-3GEY0R00V
YAGEO
RC0603JR-070RL
VISHAY/DALE
CRCW06030000Z0EA
RES,SMD, 0402,
25.5k, 1/16W, 1%,
TF, ROHS
RES, SMD, 0603,
0Ω, 1/10W, TF,
ROHS
PANASONIC
RES, SMD, 0603,
1M, 1/10W, 1%, TF,
VENKEL
ROHS
ERJ-3EKF1004V
CR0603-10W-1004FT
YAGEO
RC0603FR-071ML
ROHM
MCR03EZPFX1004
KOA
RK73H1JTTD1004F
VISHAY/DALE
CRCW06031M00FKEA
AN1574.2
November 29, 2010
Application Note 1574
TABLE 3. BILL OF MATERIALS (Continued)
PART NUMBER
H2511-06982-1/10W1-T
REFERENCE
DESIGNATOR
QTY UNITS
2
ea
R5, R11
DESCRIPTION
RES, SMD, 0603,
69.8k, 1/10W, 1%,
TF, ROHS
MANUFACTURER
MANUFACTURER
PART #
VENKEL
CR0603-10W-6982FT
YAGEO
RC0603FR-0769K8L
VISHAY/DALE
CRCW060369K8FKEA
KOA
RK73H1JTTD6982F
H2511-DNP
0
ea
R12, R13
RES, SMD, 0603,
DNP-PLACE
HOLDER, ROHS
H2514-00R00-1/4W-T
1
ea
R22
RES, SMD, 1210,
VENKEL
0Ω, 1/4W, TF, ROHS
H2514-DNP
0
ea
R21
RES, SMD, 1210,
DNP, DNP, DNP, TF,
ROHS
GT13MCBE
2
ea
S1, S2
SWITCH-TOGGLE,
THRU-HOLE, 5PIN,
SPDT, 3POS, ONOFF-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:
ISL85033DUALEVAL1Z
LABEL, TO RENAME INTERSIL
BOARD
LABEL-SERIAL NUMBER
1
ea
6
CR1210-4W-000
LABEL-RENAME BOARD
LABEL, FOR SERIAL
NUMBER AND BOM
REV #
AN1574.2
November 29, 2010
Application Note 1574
ISL85033DUALEVAL1Z Board Layout
FIGURE 1. TOP LAYER COMPONENTS
FIGURE 2. TOP LAYER ETCH
7
AN1574.2
November 29, 2010
Application Note 1574
ISL85033DUALEVAL1Z Board Layout (Continued)
FIGURE 3. SECOND LAYER ETCH
FIGURE 4. THIRD LAYER ETCH
8
AN1574.2
November 29, 2010
Application Note 1574
ISL85033DUALEVAL1Z 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
9
AN1574.2
November 29, 2010
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