USER GUIDES

ISL6740EVAL3Z
®
Application Note
AN1127.2
-11.8
-12VO, REG/DSL 14 OUTPUTS (200kHz/300kHz)
-12.0
-12.2
VOUT (V)
The ISL6740EVAL3Z serves as a reference design for a 48V
to ±12V, 3.3V and 1.5V isolated power supply. It utilizes an
ISL6740 double-ended voltage mode controller in half bridge
topology to provide an isolated 48V to ±12V conversion. An
ISL6402 dual PWM controller in synchronous buck topology
provides the 3.3V and 1.5V outputs from the +12V rail. The
reference design also provides pads to implement an
optional LDO using the ISL6402 as a controller.
August 1, 2007
36VI/-12VO
48VI/-12VO
60VI/-12VO
-12.4
-12.6
72VI/-12VO
-12.8
Specifications
-13.0
• Input Voltage: 36V to 72V
-13.2
• Outputs:
-13.4
0
2
1
4
3
6
5
7
IO, STEP ON 1.5VO (A)
3.3V ±1% @ 4A
1.5V ±1% @ 7A
12V +3.5%/-10% (typical) @ 1.5A
-12V +3.5%/-10% (typical) @ 1.5A
FIGURE 2. -12V OUTPUT VOLTAGE AS ALL OTHER OUTPUT
ARE STEPPED FROM UNLOADED TO FULLY
LOADED
• Efficiency at full load: 86.8% (72V input) to 90.3% (36V input)
100
3.3255
3.3250
3.3245
VOUT (V)
Efficiency is plotted in Figure 1 overload, and for various
input voltages VI. The current shown on the X axis
represents load current on the 1.5V output. In this test, the
loads on the 3.3V, +12V and -12V outputs were all varied
proportionately to the 1.5V load. At 7A (maximum 1.5A
load), for example, the 3.3V output load is 4A and the +12V
and -12V outputs are loaded at 1.5A each.
72VI/3.3VO
3.3235
60VI/3.3VO
3.3230
90
80
EFFICIENCY (%)
3.3240
60
50
36VI/3.3VO
3.3225
36VI
48VI
60VI
72VI
70
48VI/3.3VO
3.3220
0
1
2
4
3
IO (A)
FIGURE 3. +3.3V OUTPUT VOLTAGE vs LOAD
40
30
20
10
0
2
4
1.5V LOAD CURRENT (A)
1.4964
6
1.4962
FIGURE 1. EFFICIENCY vs LOAD ON 1.5V OUTPUT. ALL
OUTPUTS ARE LOADED IN PROPORTION TO
THE 1.5V OUTPUTS’ FULL LOAD.
1
VOUT (V)
Regulation on the 1.5V and 3.3V outputs is very good over line
and load due to individual control loops. The ±12V outputs,
however, are regulated together. While this saves cost and
board space by eliminating additional feedback circuitry, there
is a penalty in terms of regulation performance. Figure 2 shows
the worst case scenario of an unloaded -12V output with the
remaining outputs being stepped from no load to fully loaded.
When full load on the +12V, +3.3V and +1.5V outputs is
reached, a worst case error of about -10% is seen. Figures 3
and 4 show typical 3.3V and 1.5V output regulation over load.
1.4960
60VI/1.5VO
72VI/1.5VO
1.4958
1.4956
48VI/1.5VO
1.4954
36VI/1.5VO
1.4952
1.4950
0
2
4
6
IO (A)
FIGURE 4. +1.5V OUTPUT VOLTAGE vs LOAD
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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Application Note 1127
Ripple and noise measurements are illustrated in Figure 5
for an input of 48V, with all outputs fully loaded. In general
peak noise + ripple on the test board is 80mVP-P.
FIGURE 7. TRANSIENT RESPONSE: 3.3V LINE STEPPED
FROM 0% TO 50% LOAD. TOP TRACE: 3.3VOUT.
BOTTOM TRACE: LOAD (A).
FIGURE 5. NOISE AND RIPPLE AT 48VIN, ALL OUTPUTS
FULLY LOADED. FROM TOP TO BOTTOM: +3.3V,
+1.5V, AND +12V
Start-up response is shown in Figure 6 for 48VIN, with all
outputs fully loaded except for -12V, which is unloaded. The
3.3V and 1.5V start-up responses are independent of input
voltage. The 12V output exhibits from 0V to 1V of overshoot
as input voltage varies from 36V to 72V.
Figures 7 and 8 show transient responses on the 3.3V line
as its load is stepped from 0% to 50% (2A), and from 50% to
0%. Likewise, the transient responses of the 1.5V line are
shown in Figures 9 and 10. Figures 11 and 12 show the 24V
(+12V to -12V) responses to 25% to 75% and 75% to 25%
load steps.
FIGURE 8. TRANSIENT RESPONSE: 3.3V LINE STEPPED
FROM 50% TO 0% LOAD. TOP TRACE: 3.3VOUT.
BOTTOM TRACE: LOAD (A).
FIGURE 6. START-UP RESPONSE WITH 48VIN AND ALL
OUTPUTS FULLY LOADED EXCEPT -12V, WHICH
IS OPEN. TOP TO BOTTOM: +12V, +3.3V, +1.5V
FIGURE 9. TRANSIENT RESPONSE: 1.5V LINE STEPPED
FROM 0% TO 50% LOAD. TOP TRACE: 1.5VOUT.
BOTTOM TRACE: LOAD (A).
2
AN1127.2
August 1, 2007
Application Note 1127
120
110
100LFM
200LFM
300LFM
400LFM
500LFM
100
90
80
70
60
50
40
30
FIGURE 10. TRANSIENT RESPONSE: 1.5V LINE STEPPED
FROM 50% TO 0% LOAD. TOP TRACE: 1.5VOUT.
BOTTOM TRACE: LOAD (A).
40
70
50
60
AMBIENT TEMPERATURE (°C)
80
FIGURE 13. HOTTEST PART TEMPERATURE (°C) vs
AMBIENT TEMPERATURE (°C) AND AIR FLOW
AT 36V INPUT
120
110
100
90
100LFM
200LFM
300LFM
400LFM
500LFM
80
70
60
50
40
30
40
50
60
70
80
AMBIENT TEMPERATURE (°C)
FIGURE 11. TRANSIENT RESPONSE: 24V LINE STEPPED
FROM 25% TO 75% LOAD. TOP TRACE: 1.5VOUT.
BOTTOM TRACE: LOAD (A).
FIGURE 14. HOTTEST PART TEMPERATURE (°C) vs
AMBIENT TEMPERATURE (°C) AND AIR FLOW
AT 72V INPUT
Thermal data is provided in Figures 13 and 14 for input
voltages of 36V and 72V, respectively. These plots show the
temperature of the hottest component vs ambient
temperature for air flow rates of 100LFM to 500LFM.
Figure 15 shows a thermal image of the board running at an
input voltage of 48V. This image was taken with the board
running at full power with a 300LFM air flow rate.
Figures 16 through 21 show the layout of the evaluation
board. The bill of materials (BOM) and the schematics are
shown in the following. This evaluation board has been
designed to meet ROHS compliance.
FIGURE 12. TRANSIENT RESPONSE 24V LINE STEPPED
FROM 75% LOAD TO 25% LOAD. BOTTOM
TRACE: LOAD (A).
3
AN1127.2
August 1, 2007
Application Note 1127
FIGURE 15. THERMAL IMAGE: 48V INPUT, 300LFM AIR FLOW
TABLE 1. COMPONENT LIST
REFERENCE DESIGNATOR
VALUE
MANUFACTURER
PARTS
CR1, CR2
Schottky SMD, 30V, 200mA
Fairchild
BAT54S-T
D3, CR3, D4, CR7, CR8, CR9
Schottky SMD, 30V, 200mA
Fairchild
BAT54-T
CR4
DPAK, 60V, 12A, ROHS
IR
12CWQ06FNPBF
CR6, CR5
100V, 3A, ROHS
IR
30BQ100PBF
C1
1µF, 100V, 20%, X7R, ROHS
VENKEL
H1087-00105-100V20-T
C3,C2
3.3µF, 50V, 20%, X7R, ROHS
TDK
H1087-00335-50V20-T
C4, C6, C24, C45, C57
1µF,16V, 10%, X7R, ROHS
VENKEL
H1046-00105-16V10-T
C5, C31, C52
0.1µF, 50V, 10%, X7R, ROHS
TDK
H1045-00104 -50V10-T
C7
1000pF, 16V, 10%, X7R, ROHS
VENKEL
H1045-00102 -16V10-T
C8, C23, C26, C49
22µF, 16V, 20%, X5R, ROHS
TDK
H1087-00226-16V20-T
C9, C22, C32, C34, C39, C59
47µF, 16V, 20%, ROHS
Sanyo
16TQC47M
C10, C14, C50, C51, C54, C55
1000pF, 50V, 10%, X7R, ROHS
MURATA
H1045-00102-50V10-T
C12, C11
1000pF, 100V, 10%, X7R, ROHS
VENKEL
H1045-00102-100V10-T
C13
560pF, 100V, 5%, NPO, ROHS
TDK
H1045-00561-100V5-T
C15, C16, C18, C41, C44, C47
0.1µF, 16V, 10%, X7R, ROHS
MURATA
H1045-00104-16V10-T
C17
220pF, 16V, 10%, X7R, ROHS
TDK
H1045-00221-16V5-T
C19
0.22µF, 16V, 10%, X7R, ROHS
TDK
H1045-00224-16V10-T
C20
220pF, 50V, 5%, C0G, ROHS
VENKEL
H1045-00221-50V5-T
R14, R20, R22, R30, R31, R41,
R42, D5, Q6, Q9, C60, C61
DNP
C25, C58
4.7µF, 25V,10%, X5R, ROHS
PANASONIC
H1082-00475-25V10-T
C27, C30, C38, C40
220µF, 10V, 20%, ROHS
Sanyo
10TPB220M, RADIAL
PHILLIPS
BZX84C10-T
DNP
C21, C28, C33, C35, C36, C43, C48 DNP
D1
10V, 200mA, ZENER, SMD
D2
6.8V, 350mW, ROHS
Fairchild
BZX84C6V8-T
L1, L3
1µH, 5.28A, ROHS
Cooper Electronic Tech.
DR73-1R0-R
L2
4.5µH, ROHS
Midcom
40748-LF1
4
AN1127.2
August 1, 2007
Application Note 1127
TABLE 1. COMPONENT LIST (Continued)
REFERENCE DESIGNATOR
VALUE
MANUFACTURER
PARTS
L5, L6
4µH, 10.3A, ROHS
Bitech
HM65-H4R0LF
QR1, QR4, QL, QH
N-CHANNEL, 100V, 7.5A, ROHS
Fairchild
FDS3672-T
Q3, Q1
N-CHANNEL, 30V, 30A, LEAD FREE
RENESAS TECHNOLOGY
HAT2116H-EL-E
Q4, Q2
N-CHANNEL, LFPAK, 30V, 40A
RENESAS TECHNOLOGY
HAT2096H-EL-E
Q5
NPN, D-PAK369C, 100V, 3A, ROHS
ON Semiconductor
MJD31CG
RT1
10k, ROHS
KOA
H2511-01002-1/10W1-T
R1
3.3, 1%, 1W, ROHS, 2512
VENKEL
H2515-03R32-1W1-T
R2
3.01k, 1%, 1W, ROHS, 2512
KOA
H2515-03011-1W1-T
R3
10, ROHS
KOA
H2512-00100-1/8W1-T
R4, R5, R44, R45, R46
2.2, ROHS
PANASONIC
H2512-002R2-1/8W1-T
R6
200, ROHS
PANASONIC
H2511-02000-1/10W1-T
R7
75k, ROHS
KOA
H2512-07502-1/8W1-T
R8, R9, R10
18.2, ROHS, 2512
KOA
H2515-018R2-1W1-T
R11
100, ROHS
KOA
H2511-01000-1/10W1-T
R12
8.06k, ROHS
KOA
H2511-08061-1/10W1-T
R13
18.2, ROHS
PANASONIC
H2511-01822-1/10W1-T
R15
1.27k, ROHS
KOA
H2511-01271-1/10W1-T
R16, R33
1k, ROHS
KOA
H2511-01001-1/10W1-T
R17
97.6k, ROHS
KOA
H2511-09762-1/10W1-T
R18
3.01k, ROHS
KOA
H2511-03011-1/10W1-T
R19, R34, R39
499, ROHS
KOA
H2511-04990-1/10W1-T
R21
4.99k, ROHS
PANASONIC
H2511-04991-1/10W1-T
R23
21.5k, MF
VISHAY
H2505-02152-1/16WR1-T
R24
2.49k, MF
VISHAY
H2505-02491-1/16WR1-T
R25
10.5k, MF
VISHAY
H2505-01052-1/16WR1-T
R26
12.1k, MF
VISHAY
H2505-02372-1/16WR1-T
R27
7.5k, MF
VISHAY
H2505-07501-1/16WR1-T
R28
23.7k, MF
VISHAY
H2505-02372-1/16WR1-T
R29, R32, R36, R48
100k, ROHS
R37
301, ROHS
KOA
H2511-03010-1/10W1-T
R49, R38
5.11, ROHS
YAGEO
H2512-05R11-1/8W1-T
R47
68.1k, ROHS
VENKEL
H2511-06812-1/10W1-T
R40
86.6k, ROHS
PANASONIC
H2511-05762-1/10W1-T
T1
6,83µH, 25%,10kHz, CUSTOM,ROHS
Midcom
31660-LF1
T2
CT, SMD, 8P, 500µH, 10A, ROHS
Pulse
P8205NL
U1
HALF BRIDGE DRIVER, ROHS
Intersil
HIP2101IBZ
U2
ISO PHOTOCOUPLER, 4P, ROHS
Cal. Eastern Lab
PS2801-1-A
U3
IC-PWM CONTROLLER, ROHS
Intersil
ISL6740IBZ
U4
ROHS
National Semi
LM431BIM3/NOPB
U5
DUAL PWM CONTROLLER, ROHS
Intersil
ISL6402IVZ
5
H2511-01003-1/10W1-T
AN1127.2
August 1, 2007
Application Note 1127
ISL6740EVAL3Z Schematics
D3
BAT54-T
L1
VIN +
1
2
T1
Midcom 31660-LF1
VS
+/- 12V: 1.5A max (beyond requirements of Page 2)
C11
R8
1000pF 20
CR4
12CWQ06FN
CR5 30BQ100PBF
1uH
R7
75k
QR1
FDS3672-T
R38
5.11
QH
R2
3.01k
CR3
C1
BAT54-T 1uF
C22 C9
C8
C49
47uF 47uF 22uF 22uF
L2
4.5uH
C2
3.3uF
+12V
FDS3672-T
C13
560pF
Q5
GND
MJD31CG
D1
10V
R1
3.3
C6
1uF
R10
20
QL
-12V
C3
3.3uF
C34 C32 C23 C21
47uF 47uF 22uF DNP
CR6 30BQ100PBF
FDS3672-T
VIN -
T2
P8205NL
R9
20
C12
1000pF
R49
5.11
C14
R11
1000pF 100
FDS3672-T
QR4
C52
0.1uF
D2
6.8V
R33
1k
D4
BAT54-T
U1
C4
1uF
C5
0.1uF
VDD LO
HB VSS
HO
LI
HS
HI
CR1
BAT54S-T
8
7
6
5
CR2
BAT54S-T
R34
499
1
2
R5
2.2
HIP2101IBZ
R23
21.5k
U2
4
3
1
2
3
4
C7
1000pF
R19
499
PS2801-1-A
R20
DNP
R21
4.99k
C19
0.01uF
C15
0.1uF
R6
200
R3 10
U4
C20
100pF
LM431BIM3
U3
1
2
3
4
5
6
7
8
R13
18.2k
R15
1.27k
C17
220pF
C10
1000pF
ISL6740IBZ
OUTA
OUTB
GND
VREF
SCSET
VDD
CT
RTD
SYNC
RTC
CS
OTS
VERROR FAULT
UV
SS
16
15
14
13
12
11
10
9
R16
1k
C16
0.1uF
R12
8.06k
R24
2.49k
RT1 10k
R14 DNP
C31 0.1uF
VS
R17
97.6k
6
C18
0.1uF
R18 3.32k
AN1127.2
August 1, 2007
Application Note 1127
ISL6740EVAL3Z Schematics (Continued)
C59
1800uF
L3
+12V
1
2
+12A
1uH
VCC_5V
C39
1800uF
C26
1uF
CR7
BAT54
U5
R22
75k
D5
5.6V
Q6
FMMT491A
R32
100k
C61
1uF
1
2
3
4
5
6
7
8
9
10
11
12
13
14
ISL6402IVZ
LGATE2
BOOT2
UGATE2
PHASE2
ISEN2
PGOOD
VCC_5V
SD2
SS2
OCSET2
FB2
VOUT2
VIN
SYNC
R47
64.9k
C58
4.7uF
Q1
HAT2116H-EL-E
C50
DNP
R51
10
R39
1
464
+1.5V
R4
DNP
L5
C41
0.1uF
Q2
HAT2096H-EL-E
4uH
C51
DNP
C57
0.1uF
2
C27
470uF
R44
DNP
R25
10.5k
C38
470uF C33
DNP
VCC_5V
R36
100k
R48
100k
LGATE1
BOOT1
UGATE1
PHASE1
ISEN1
PGND
SD1
SS1
SGND
OCSET1
FB1
VOUT1
GATE3
FB3
28
27
26
25
24
23
22
21
20
19
18
17
16
15
C47
0.1uF
R40
64.9k
VCC_5V
CR8
BAT54-T
R26
12.1k
+12A
Q3
HAT2116H-EL-E
R52
10
C54
DNP
GND
R37
464
Q4
HAT2096H-EL-E
1
4uH
C55
DNP
R46
DNP
Connect at layout at a single
point as close as possible to
U1 pins 20 and 23.
+3.3V
R45
DNP
L6
C44
0.1uF
2
C45
0.1uF
C40
470uF
C30
470uF
C43
DNP
R28
23.7k
R27
7.5k
ISL6740EVAL3Z Board Layout
FIGURE 16. TOP LAYER SILKSCREEN
7
AN1127.2
August 1, 2007
Application Note 1127
ISL6740EVAL3Z Board Layout
(Continued)
FIGURE 17. TOP LAYER ETCH
FIGURE 18. LAYER 2
8
AN1127.2
August 1, 2007
Application Note 1127
ISL6740EVAL3Z Board Layout
(Continued)
FIGURE 19. LAYER 3
FIGURE 20. BOTTOM LAYER ETCH
9
AN1127.2
August 1, 2007
Application Note 1127
ISL6740EVAL3Z Board Layout
(Continued)
FIGURE 21. BOTTOM LAYER SILKSCREEN
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
10
AN1127.2
August 1, 2007