an1194

ISL6269EVAL2Z User Guide
®
Application Note
Introduction
The ISL6269EVAL2Z evaluation board demonstrates the
performance of the ISL6269 single-phase synchronous-buck
PWM controller featuring Intersil's Robust Ripple Regulator
(R3) technology. An on-board dynamic-load generator is
included for evaluating the transient-load response, which
applies a 2.5ms pulse of 120mΩ across VOUT and GND
every 30ms. Contents of this document include:
• Design Criteria
• Recommended Test Equipment
• Interface Connections
• Switch Descriptions
• Jumper Descriptions
• Test Point Descriptions
• Typical Waveforms
- Start-up
- Static continuous conduction mode
- Static diode-emulation mode
- Load-transient response
• Evaluation Board Documentation
- Schematic
- Silk-screen plots
- Board layer plots
- Bill of materials
September 11, 2007
I PP
⎛ I + --------⎞ • OC SP • r DS ( ON )
⎝ FL
2 ⎠
R SEN = ---------------------------------------------------------------------------I OC
PARAMETER
VALUE
UNITS
VIN
7 to 25
VDC
VOUT
1.10 or 1.20
VDC
FULL-LOAD
20.0
ADC
PWM FREQUENCY
300 or 600
kHz
The design criteria listed in Table 1 was, to a large extent,
influenced by customer input. The PWM switching frequency
can be programmed to any frequency between 200kHz and
600kHz. If only one PWM frequency setting is desired, this
can be accomplished by simply not populating R17. The
output voltage can be programmed to any voltage between
0.6V and 3.3V. If only one output voltage setting is desired,
this can be accomplished by simply not populating R16.
(EQ. 2)
The output voltage is programmed for 1.10V using resistors
R19 (RTOP) and R20 (RBOTTOM) when switch S3 is in the
LOWER position. Setting switch S3 in the UPPER position
will program the output voltage for 1.20V using resistor R19
(RTOP) and the parallel resistance of R20 and R16
(RBOTTOM). The loop compensation is usually responsible
for selecting RTOP (R19) which in this case is 3.01kΩ. The
voltage setpoint programming resistance RBOTTOM is
calculated using Equation 3 where:
( V REF ⋅ R TOP )
R BOTTOM = -----------------------------------------( V OUT – V REF )
Design Criteria
(EQ. 1)
- rDS(ON) of Q8||Q10 low-side MOSFETs is 2mΩ
- IOC is 26µA
- IFL is 20A continuous
- IPP is 5.0APP (25% of IFL 20A)
- OCSP is 1.8 (180% of IFL)
The PWM switching frequency fSW is programmed for
300kHz by resistance RFSET (R12) when switch S2 is in the
LOWER position. Setting switch S2 in the UPPER position
will program fSW for approximately 600kHz with the parallel
resistance of R12 and R17. Using Equation 2 finds the value
for RFSET (R12) = 57.6kΩ. The “K” constant in Equation 2 is
ideally 66.8 x 10-12 however, this value can be affected by
the ripple voltage on the COMP pin. The ripple voltage on
the COMP pin increases with the bandwidth of the feedback
loop compensation, effectively reducing the value of “K”. The
ISL6269EVAL2Z evalualtion board is aggressively
compensated for approximately 100kHz bandwidth, making
the value of “K” effectively 58 x 10-12.
1
R FSET = -----------------K • f SW
TABLE 1. DC/DC DESIGN CRITERIA
AN1194.0
(EQ. 3)
- VREF = 600mV
- RTOP = 3.01kΩ
- VOUT = 1.10V or 1.20V
Begin by finding the value of R20 for VOUT = 1.10V from
Equation 2: R20 = 3.57kΩ. Find the value of parallel
resistance R20 and R16 for VOUT = 1.20V from Equation 3:
R20||R16 = 3.01kΩ, therefore R16 = 19.1kΩ.
The OCP setpoint resistor RSEN (R13) is selected to protect
the output load, without nuisance shutdowns due to
component tolerances and temperature effects. Using
Equation 1 finds RSEN (R13) = 2.96kΩ. Using the next highest
standard 1% value yields. RSEN (R13) = 3.01kΩ where:
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2007. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
Application Note 1194
Recommended Equipment
• (QTY 1) Adjustable 25V, 5A Power Supply
• (QTY 1) Fixed 12V, 100mA Power Supply
• (QTY 1) Fixed 5V, 100mA Power Supply
• (QTY 1) Adjustable 20A Constant Current Electronic Load
• (QTY 1) DVM
• JP3: Isolates the EN input pin from switch S1 so that an
external signal can be used.
• JP4: Isolates the frequency range selection switch S2 so
that an external signal can be used.
• JP5: Isolates the VOUT selection switch S3 so that an
external signal can be used.
• (QTY 1) Four Channel Oscilloscope
• JP6: Isolates the FCCM input pin from switch S4 so that
an external signal can be used.
Interface Connections
• JP7: Isolates the PGOOD input pin from the LED circuit so
that the pull-down resistance can be measured.
• VIN: Input voltage to the power stage of the converter
- J5: VIN positive power input
- J7: VIN return power input
• VOUT: Regulated output voltage from the converter
- J6: VOUT positive power output
- J8: VOUT return power output
• +5VIN: +5V input voltage for PVCC, PGOOD-LED, and
pull-up voltage rail
- J2: 5V positive input
- J1: 5V return input
• JP8: Opens the circuit path to the VIN pin so that an ammeter
can be inserted for measuring current into the VIN pin.
TABLE 2. JUMPER JP1 CONFIGURATIONS
JP1
SOURCE OF 5V
PIN 1 TO 2 PIN 3 TO 4 PIN 5 TO 6
VCC
PVCC
AUX
OPEN
SHORT
SHORT
LDO
J2
J2
SHORT
OPEN
SHORT
LDO
LDO
J2
Test-point Descriptions
• +12V: Input voltage for the dynamic-load generator
- J4: 12V positive input
- J3: 12V return input
• TP1 to TP5: Signal ground
Switch Descriptions
• TP8: Monitors the voltage of JP1 pins 2, 4 and 6
• S1: ENABLE
- OFF: Shorts the EN pin to GND (disable PWM)
- ON: Allows the EN pin to pull-up to +5V (enable PWM)
• TP9: Monitors the voltage at JP4 pin 1
• S2: DYNAMIC FPWM
- LOWER: Selects the lower of two programmed fSW
- UPPER: Selects the higher of two programmed fSW
• TP6: Scope-probe socket for measuring VIN
• TP7: Monitors the voltage at the PVCC pin
• TP10: Monitors the voltage at JP5 pin 1
• TP11: Monitors the voltage at the PGOOD pin
• TP12: Monitors the voltage at the FSET pin
• TP13: Monitors the voltage at the upper feedback resistor
• S3: DYNAMIC VOUT
- LOWER: Selects the lower of two programmed output
voltages
- UPPER: Selects the higher of two programmed output
voltages
• TP14: Monitors the voltage at the FB pin (SENSITIVE)
• S4: FCCM
- DEM: Enables diode-emulation-mode
- CCM: Inhibits diode-emulation-mode
• TP18: Monitors the voltage at the VCC pin
• TP15: Monitors the voltage at the COMP pin (SENSITIVE)
• TP16: Monitors the voltage at the EN pin
• TP17: Monitors the voltage at the FCCM pin
• TP19: Scope-probe socket for measuring VOUT
• TP20: VIN positive voltage sense
• S5: DYNAMIC LOAD
- OFF: Load disabled
- ON: Load enabled
• TP21: VIN return voltage sense
Jumper Descriptions
• TP23: VOUT positive voltage sense
• JP1: Selects the +5V source for PVCC and auxiliary
circuits. See Table 1 for list of configurations.
• TP24: VOUT return voltage sense
• TP22: Monitors the voltage at the VIN pin
• JP2: Connects +5V supply to the PGOOD LED circuit and
pull-up resistors. The shunt jumper is normally installed
and should be removed when making low power efficiency
measurements.
2
• TP25: Scope-probe socket for measuring the voltage of
the PHASE node
• TP26: Scope-probe socket for measuring voltage across
the dynamic-load resistors (hence load current)
• TP27: Monitors the voltage at the gate terminal of the
dynamic load MOSFET
AN1194.0
September 11, 2007
Application Note 1194
Typical Waveforms
VOUT
VOUT
VCC
VCC
EN
EN
PGOOD
PGOOD
FIGURE 1. SOFT-START: 50Ω-LOAD, FCCM = HIGH
FIGURE 2. SOFT-START: 50Ω-LOAD, FCCM = HIGH,
1V VOUT-PREBIAS
I-LOAD
I-LOAD
I-CHOKE
VOUT
VOUT
PHASE
PHASE
I-CHOKE
FIGURE 3. CCM INDUCTOR CURRENT: NO-LOAD
FIGURE 4. CCM INDUCTOR CURRENT: 20A LOAD
I-CHOKE
I-CHOKE
VOUT
VOUT
I-LOAD
I-LOAD
PHASE
FIGURE 5. DCM INDUCTOR CURRENT: NO-LOAD
3
PHASE
FIGURE 6. DCM INDUCTOR CURRENT: 500mA LOAD
AN1194.0
September 11, 2007
Application Note 1194
Typical Waveforms (Continued)
V120mΩ-LOAD
VOUT
V120mΩ-LOAD
VOUT
I-CHOKE
I-CHOKE
OFF
FIGURE 7. CCM TRANSIENT LOAD-STEP: 10A STATIC LOAD
V120mΩ-LOAD
VOUT
FIGURE 8. CCM TRANSIENT LOAD-DUMP: 10A STATIC LOAD
V120mΩ-LOAD
VOUT
I-CHOKE
I-CHOKE
FIGURE 9. CCM TRANSIENT LOAD-STEP: NO STATIC LOAD
V120mΩ-LOAD
VOUT
FIGURE 10. CCM TRANSIENT LOAD-DUMP: NO STATIC LOAD
V120mΩ-LOAD
VOUT
I-CHOKE
I-CHOKE
FIGURE 11. DCM TRANSIENT LOAD-STEP: NO STATIC LOAD
4
FIGURE 12. DCM TRANSIENT LOAD-DUMP: NO STATIC LOAD
AN1194.0
September 11, 2007
5
8
C7
7
1
3
4
DNP
IRF7821
6
2
5
8
3
7
IRF7821
6
1
5
3
2
Q4
6
Q9
0.47UF
Q11
J5
J6
L1
TP25
0.82UH
JP1
C22
4.7UF
C19
150UF
C16
150UF
4.7UF
C21
150UF
C18
TP14
R16
3
1
+5VIN_B
TP12
R17
57.6K
1000PF
2
C9
2
R12
R9
1
BSS138
71.5K
3
4
JP7
1
Q3
BSS138
FREQUENCY
DEMONSTRATOR
TP9
600KHZ
3
C6
Q7
2200PF
R24
1
HS
4
R11
HIP2100
249
AN1194.0
September 11, 2007
TRANSIENT
A
R32
1.91
R30
0.39
TP4
TP3
TP2
OFF
TP16
TP5
DEMONSTRATOR
FIGURE 1. ISL6269EVAL2Z CIRCUIT SCHEMATIC
TP1
2
2
10K
10K
R22
0.1UF
C13
BSS138
2
3
U2
R28
HI
0.39
5
2
10UF
C1
J3
3
S2
P4
1
2
2
LI
1.91
1
6
R33
JP3
HB 2
HO 3
7 VSS
TP26
OM
R31
1
10K
2
2
OFF
VDD
SUD50N03_07
0.007OHM
1
0.39
3
3
1
Q5
R10
249
8 LO
BAT54S
S1
ON
1
1
Q2
BSS138 2
ON
N/C
CONVERTER
S5
10UF
ENABLE
LOAD
499
TRANSIENT
TP27
49.9K
1
ENABLE
DCM
TP17
VO
R1
J4
D3
2
1000PF
1
R29
JP6
3
2
1
MODE
12V
S4
R5
100K
EMULATION
3
C2
CCM
C23
MODE OR DIODE
CONDUCTION
1.91
CHOOSE CONTINUOUS
R4
3
1.10V
10K
R21
C10
DYNAMIC
57.6K
1
3
2
C5
TP15
15PF
1
R3
S3
2
8
VO
2
3
5
EP
FSET
17
0.1UF
9
1
10K
C12
ISEN
JP5
R23
1
2
BSS138
EN
1.20V
Q6
11
4.7UF
10
19.1K
R13
PGND
ISL6269CRZ
3.01K
13
FCCM
LG
TP10
GRN
RED
D1
14
3
U1
FB
4.7UF
C4
C3
0.01UF
10K
PVCC
VCC
4
TP11
2
BOOT
15
VIN
12
2
COMP
CIRCUIT
R8
R7
10K
249
R6
R2
249
INDICATOR
UG
16
1
PHASE
PGOOD
TP7
7
5 6
PGOOD LED
VOUT
DEMONSTRATOR
TP8
PVCC
Q1
150UF
DYNAMIC
TP18
2
3 4
6
C24
1
+5VIN_B
VCC
4.7
10UF
R14
300KHZ
3
1
Application Note 1194
SOURCE SELECTOR
J2
J1
J8
AND
+5VIN_A
2
1
TP24
3.57K
TP6
JP2
+5VIN_B
R20
TP19
TP23
3.01K
C15
DNP
R19
R15
DNP
0
C11
D5
B340LB
8
7
DNP
1
R18
TP21
J7
20A
TP13
2
C8
0.22UF
1
2
3
4
3
1
TP22
2
4
C17
10UF
10UF
56UF
C14
C20
5
TP20
IRF7832
7
8
Q4
IRF7832
6
54
Q8
8
7
54
6
2
Q10
1
JP8
1.1V/1.2V
Application Note 1194
FIGURE 13. PCB TOP SILK SCREEN
6
AN1194.0
September 11, 2007
Application Note 1194
FIGURE 14. PCB BOTTOM SILK SCREEN (MIRRORED)
7
AN1194.0
September 11, 2007
Application Note 1194
FIGURE 15. PCB TOP LAYER ETCH
8
AN1194.0
September 11, 2007
Application Note 1194
FIGURE 16. PCB LAYER 2 ETCH
9
AN1194.0
September 11, 2007
Application Note 1194
FIGURE 17. PCB LAYER 3 ETCH
10
AN1194.0
September 11, 2007
Application Note 1194
FIGURE 18. PCB BOTTOM LAYER ETCH
11
AN1194.0
September 11, 2007
Application Note 1194
Bill of Materials
QTY
REFERENCE
5
C1, C2, C14, C17, C24
CAP, SMD, 1206, 10µF, 25V, 20%, X5R, ROHS
PANASONIC
ECJ-3YB1E106M
2
C12, C13
CAP, SMD, 0402, 0.1µF, 25V, 10%, X5R, ROHS
TDK
C1005X5R1E104K
4
C15, C16, C18, C19
CAP, SMD, 7.3mmx4.3mm, 150µF, 4V, 20%, SP-CAP
PANASONIC
EEF-SD0G151R
1
C20
CAP, RADIAL, 56µF, 25V, OSCON
SANYO
25SP56M
2
C21, C22
CAPACITOR, SMD, 0612, 4.7µF, 6.3V, 10%, X5R
TDK
C1632X5R0J475K
1
C3
CAP, SMD, 0402, 0.01µF, 25V, 10%, X7R, ROHS
AVX
04023C103KAT
2
C4, C10
CAP, SMD, 0603, 4.7µF, 6.3V, 20%, X5R, ROHS
TDK
C1608X5R0J475M
1
C5
CAP, SMD, 0402, 15pF, 50V, 5%, NPO, ROHS
MURATA
GRM36COG150J050AQ
1
C6
CAP, SMD, 0402, 2200pF, 50V, 10%, X7R, ROHS
PANASONIC
ECJ-0EB1H222K
1
C7
CAPACITOR, SMD, 0612, 0.47µF, 25V, 10%, X7R
TDK
C1632X7R1E474K
1
C8
CAP, SMD, 0603, 0.22µF, 25V, 20%, X7R, ROHS
VISHAY
VJ0603X224MXXAT
2
C9, C23
CAP, SMD, 0402, 1000pF, 50V, 5%, C0G, ROHS
MURATA
GRM1555C1H102JA01D
1
D1
LED, SMD, 3mmx2.5mm, 4P, RED/GREEN, 12/20MCD, 2V LUMEX
SSL-LXA3025IGC-TR
1
D3
DIODE, SCHOTTKY, DUAL, SOT23, 30V, 200mA
FAIRCHILD
BAT54S
1
D5
DIODE-SCHOTTKY, SMB, 40V, 3A, LOW-VF, ROHS
DIODES INC.
B340LB-13-F
4
J1 to J4
TERMINAL, TURRET-POST, TH, ROHS
KEYSTONE
1514-2
2
J5, J6
PLUG, BANANA, THRU-HOLE, RED, 4.23mm, ROHS
MOUSER
164-6219
2
J7, J8
PLUG, BANANA, THRU-HOLE, BLKD, 4.23mm, ROHS
MOUSER
164-6218
1
JP1
HEADER, 2x3, BRKAWY 2x36, 2.54mm, ST
BERG/FCI
67996-272
7
JP2 to JP8
HEADER, 1x2, RETENTIVE, 2.54mm, ST, ROHS
BERG/FCI
69190-202
BERG/FCI
71363-102
10
DESCRIPTION/COMMENT
JP1(1 to 2, 3 to 4, 5 to 6), JP2 to JP8 JUMPER, 2PIN, HIGHBDY, SHUNT
1
L1
5
Q1, Q2, Q3, Q6, Q7
2
MFG NAME
MFG NUMBER
INDUCTOR, SMD, 13mm, 0.82µH, 20%, 44A, SHIELDED VISHAY
IHLP5050CEERR82M01
MOSFET, N-CH, SMD, 3P, SOT23, 50V, 0.2A, Pb-free
DIODES INC.
BSS138-7-F
Q8, Q10
MOSFET, N-CH, 8P, SOIC, 30V, 4mΩ
IR
IRF7832PBF
2
Q8, Q9
MOSFET, N-CH, 8P, SOIC, 30V, 9.1mΩ
IR
IRF7821PBF
1
Q5
MOSFET, N-CH, SMD, TO-252AA, 30V, 7mΩ
VISHAY
SUD50N03-07
1
R1
RES, SMD, 0402, 49.9k, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ-2RKF4992
2
R12, R17
RES, SMD, 0402, 57.6k, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ-2RKF5762X
1
R14
RES, SMD, 0805, 4.7Ω, 1/8W, 5%, TF, ROHS
PANASONIC
ERJ-6GEYJ4R7V
1
R16
RES, SMD, 0402, 19.1k, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ-2RKF1912
1
R18
RES, SMD, 0402, 0Ω, 1/16W, 5%, TF, ROHS
PANASONIC
ERJ-2GE0JR00
2
R13, R19
RES, SMD, 0402, 3.01k, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ-2RKF3011
4
R2, R6, R10, R11
RES, SMD, 0603, 249Ω, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ-3EKF2490
1
R20
RES, SMD, 0402, 3.57k, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ-2RKF3571X
3
R28, R29, R30
RES, SMD, 1206, 0.39Ω, 1/4W, 1%, TF, ROHS
PANASONIC
ERJ-8RQFR39V
1
R3
RES, SMD, 0402, 100k, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ2RKF1003
3
R31, R32, R33
RES, SMD, 1206, 1.91Ω, 1/4W, 1%, TF, ROHS
YAGEO
9C12063A1R91FGHFT
7
R4, R7, R8, R21 to R24
RES, SMD, 0402, 10k, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ-2RKF1002
1
R5
RES, SMD, 0402, 499Ω, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ-2RKF4990X
12
AN1194.0
September 11, 2007
Application Note 1194
Bill of Materials (Continued)
QTY
REFERENCE
1
R9
5
S1 to S5
7
DESCRIPTION/COMMENT
MFG NAME
MFG NUMBER
RES, SMD, 0402, 71.5k, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ-2RKF7152X
SWITCH-TOGGLE, SMD, ULTRAMINI, 1P, SPST, MINI
C&K
GT11MSCKE
TP1 to TP5, TP21, TP24
COMPACT TEST PT, VERTICAL, BLK, ROHS
KEYSTONE
5006
1
TP27
COMPACT TEST PT, VERTICAL, WHT, ROHS
KEYSTONE
5007
4
TP6, TP19, TP25, TP26
SCOPE PROBE TEST POINT, PCB MNT
TEKTRONIX
131-4353-00
5
TP7, TP8, TP18, TP20, TP23
COMPACT TEST PT, VERTICAL, RED, ROHS
KEYSTONE
5005
10
TP9 to TP17, TP22
MINI TEST POINT, SMD
KEYSTONE
5015
1
U1
IC-PWM CONTROLLER, 16P, QFN, 4x4, Pb-free
INTERSIL
ISL6269CRZ
1
U2
IC-HI FREQ BRIDGE DRIVER, 8P, SOIC, 100V
INTERSIL
HIP2100IB
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
13
AN1194.0
September 11, 2007
Similar pages