an1273

ISL6269AEVAL2Z User Guide For ISL6269A and
ISL6269B PWM Controllers
®
Application Note
Introduction
The ISL6269AEVAL2Z evaluation board demonstrates the
performance of the ISL6269A or ISL6269B single-phase
synchronous-buck PWM controller featuring Intersil's Robust
Ripple Regulator (R3) technology. The ISL6269AEVAL2Z is
shipped with the ISL6269A controller installed. The
ISL6269B controller can be evaluated using the
ISL6269AEVAL2Z with no further circuit modifications
beyond changing the IC. An on-board dynamic-load
generator is included for evaluating the transient-load
response, that applies a 2.5ms pulse of 250mΩ 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
- Shut-down
- Diode-emulation
- Load-transient response
- Line-transient response
• Evaluation Board Documentation
- Schematic
- Bill of materials
- Silk-screen plots
- Board layer plots
PARAMETER
VALUE
UNITS
VIN
5 to 25
VDC
VOUT
1.10 or 1.20
VDC
FULL-LOAD
5.0
ADC
PWM FREQUENCY
300 or 600
kHz
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) = 6.49kΩ where:
I PP
⎛ I + --------⎞ • OC SP • r DS ( ON )
⎝ FL
2 ⎠
R SEN = ---------------------------------------------------------------------------I OC
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
(EQ. 1)
- rDS(ON) of Q4 low-side MOSFETs is 15mΩ
- IOC is 26µA
- IFL is 5A continuous
- IPP is 1.5APP (30% of IFL 5A)
- OCSP is 2.1 (210% 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
ISL6269AEVAL2Z evaluation board is aggressively
compensated for approximately 100kHz bandwidth, making
the value of “K” effectively 58 x 10-12.
(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
AN1273.2
0.6V and 3.3V. If only one output voltage setting is desired,
this can be accomplished by simply not populating R16.
1
R FSET = -----------------K • f SW
TABLE 1. DC/DC DESIGN CRITERIA
1
November 14, 2007
(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.
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. 2006, 2007. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
Application Note 1273
Recommended Equipment
Jumper Descriptions
• (QTY 1) Adjustable 25V, 3A Power Supply
• JP1: Selects the +5V source for VCC, PVCC and auxiliary
circuits. See Table 1 for list of configurations.
• (QTY 1) Fixed 12V, 100mA Power Supply
• (QTY 1) Fixed 5V, 100mA Power Supply
• (QTY 1) Adjustable 5A Constant Current Electronic Load
• (QTY 1) DVM
• (QTY 1) Four Channel Oscilloscope
Interface Connections
• 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
• +12V: Input voltage for the dynamic-load generator
- J4: 12V positive input
- J3: 12V return input
Switch Descriptions
• S1: ENABLE
- OFF: Shorts the EN pin to GND (disable PWM)
- ON: Allows the EN pin to pull-up to +5V (enable PWM)
• JP2: Connects +5V supply to the PGOOD LED circuit and
pull-up resistors. The shunt jumper is normally installed.
Remove the shunt jumper when making low power
efficiency measurements.
• 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.
• JP6: Isolates the FCCM input pin from switch S4 so that
an external signal can be used.
• JP7: Isolates the PGOOD input pin from the LED circuit so
that the pull-down resistance can be measured.
• 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
SHORT
SHORT
SHORT
J2
J2
J2
SHORT
OPEN
SHORT
TP8
TP8
J2
SHORT
SHORT
OPEN
J2
TP7
J2
• S2: DYNAMIC FPWM
- LOWER: Selects the lower of two programmed fSW
- UPPER: Selects the higher of two programmed fSW
• S3: DYNAMIC VOUT
- LOWER: Selects the lower of two programmed output
voltages
- UPPER: Selects the higher of two programmed output
voltages
• S4: FCCM
- DEM: Enables diode-emulation-mode
- CCM: Inhibits diode-emulation-mode
• S5: DYNAMIC LOAD
- OFF: Load disabled
- ON: Load enabled
2
AN1273.2
November 14, 2007
Application Note 1273
Test-point Descriptions
• TP1 to TP5: Signal ground
• TP6: Scope-probe socket for measuring VIN
• TP7: Monitors the voltage at the PVCC pin
• TP8: Monitors the voltage of JP1 pins 2, 4 and 6
• TP9: Monitors the voltage at JP4 pin 1
• 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
• TP14: Monitors the voltage at the FB pin (SENSITIVE)
• 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
• TP18: Monitors the voltage at the VCC pin
• TP19: Scope-probe socket for measuring VOUT
• TP20: VIN positive voltage sense
• TP21: VIN return voltage sense
• TP22: Monitors the voltage at the VIN pin
• TP23: VOUT positive voltage sense
• TP24: VOUT return voltage sense
• 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
3
AN1273.2
November 14, 2007
Application Note 1273
Typical Waveforms
VOUT
VOUT
VCC
VCC
EN
EN
PGOOD
FIGURE 1. SOFT-START: 250mΩ LOAD, FCCM = HIGH
PGOOD
FIGURE 2. SOFT-START: NO-LOAD, FCCM = HIGH,
1V VOUT-PREBIAS
VOUT
EN
VOUT
EN
I-CHOKE
I-CHOKE
PGOOD
FIGURE 3. OUTPUT CAPACITOR IN-RUSH CURRENT: 50Ω
LOAD, FCCM = LOW, 1V VOUT-PREBIAS
PGOOD
FIGURE 4. OUTPUT CAPACITOR IN-RUSH CURRENT: 50Ω
LOAD, FCCM = HIGH, 1V VOUT-PREBIAS
UG
LG
I-CHOKE
PHASE
FIGURE 5. SHUTDOWN: EN PULLED LOW, NO-LOAD
4
UG
LG
I-CHOKE
PHASE
FIGURE 6. SHUTDOWN: EN FALLING, 250mΩ-LOAD
AN1273.2
November 14, 2007
Application Note 1273
Typical Waveforms (Continued)
PGOOD
FSET
EN
LG
VOUT
PHASE
FIGURE 7. SHUTDOWN: VOUT DECAY, NO-LOAD
I-CHOKE
FIGURE 8. ENTERING DEM: 250mΩ LOAD-DUMP (UG TOO
NARROW TO SEE)
FSET
VOUT
LG
VLOAD
UG
VCOMP
I-CHOKE
FIGURE 9. EXITING DEM: 250mΩ LOAD-STEP
FIGURE 10. LOAD TRANSIENT: FCCM = HIGH, IN CCM
BEFORE 250mΩ LOAD-STEP
VOUT
VOUT
VLOAD
VIN
VCOMP
VCOMP
PHASE
FIGURE 11. LOAD TRANSIENT: FCCM = LOW, IN DEM
BEFORE 250mΩ LOAD-STEP
5
FIGURE 12. LINE TRANSIENT: 5V TO 25V STEP, 250mΩ LOAD
AN1273.2
November 14, 2007
A
B
C
2
8
10K
R4
+5VIN_A
VCC AND PVCC
VCC
1
BSS138
Q3
1
BSS138
1
2
JP7
1
3
S4
2
OFF
ON
3
1
S1
2
2
1
TP16
2
JP3
7
MODE
TP17
1
JP6
EMULATION
ENABLE CONVERTER
DCM
CCM
MODE OR DIODE
TP7
TP8
TP18
TP11
CIRCUIT
PVCC
1 2
3 4
5 6
JP1
PGOOD LED INDICATOR
4.7
R14
SOURCE SELECTOR
CHOOSE CONTINUOUS CONDUCTION
100K
R3
Q1
J1
J2
1
JP2
R6
TP21
10UF
249
D
J7
10UF
10K
E
56UF
C24
C17
R8
TP20
C20
249
1
2
3
4
R2
D1
3
2
C14
R7
3
2
10UF
10K
J5
TP6
TP22
JP8
J3
J4
6
12V
N/C
10UF
C3
+5VIN_B
2
1
1
3
S5
ON
OFF
LOAD
TRANSIENT
2
7
Q10
8
1
TP15
7
4
ENABLE
TP25
3
0.01UF
DNP
DNP
5
6
3
5
6
4
2
8
1
4
4
Q2
4.7UF
2
R5
C2
C4
499
10UF
5
6
3
Q8
8
17
1
4
3
2
1
5
C5
EP
5
U2
1
4
C8
TRANSIENT
HS
HB 2
HO 3
VDD
HIP2100
HI
LI
R1
49.9K
7 VSS
6
U1
ISL6269ACRZ
8 LO
470PF
C6
4.7PF
EN
FCCM
VCC
VIN
5
6
1
3
R9
DNP
DNP
7
2
7
3
COMP
5
8
BSS138 2
FB
1
C23
16
PGOOD
FSET
7
6
R12
LG
ISEN
PGND
Q4
3
9
10
11
12
FDS6982AS
TP27
3
1
4
LOAD DEMONSTRATOR
249
R11
249
R10
0.22UF
PVCC
Q4
5
4
2
D3
2
150K
1000PF
15
PHASE
C7
14
UG
0.47UF
13
BOOT
VO
8
57.6K
B340LB
.007OHM
VO
0.238_OHM
Q5
SUD50N03_07
2.2UH
L1
3
TP19
3
TP26
0
R18
R15
C11
Q9
C9
1
1000PF
DNP
DNP
6
8
6.49K
7
R13
2
1
D5
2
3
R28
FDS6982AS
C10
BAT54S
4.7UF
1.43
R29
TP13
R19
TP1
TP2
TP3
TP4
TP5
R20
Q11
R30
1.43
3.01K
3.57K
2
1
Q6
2
1
Q7
1.1V/1.2V
10K
R23
TP10
DEMONSTRATOR
DYNAMIC VOUT
1
ISL6269A
1.1V/1.2V
NATHAN MITCHELL
ENGINEER:
ISL6269EVAL2
10K
R24
TP9
DEMONSTRATOR
5A
S2
2
1
1
3
1
3
C
J8
J6
1
SHEET:
OF
09/30/05
DATE:
REV:
300KHZ
2
JP4
1
1.10V
2
S3
TP24
TP23
5A
1.20V
1
600KHZ
2
JP5
DYNAMIC FREQUENCY
TITLE:
C16
150UF
4
1.43
R31
4.7UF
5
1.43
R33
150UF
C18
10K
F
6
R32
1.43
R16
3
2
R17
3
2
BSS138
BSS138
C19
150UF
TP14
0.1UF
C15
19.1K
57.6K
150UF
C21
R21
7
1.43
C12
C13
C22
4.7UF
TP12
0.1UF
RED
10K
GRN
R22
+5VIN_B
6
+5VIN_B
8
1
A
B
C
D
E
F
Application Note 1273
FIGURE 13. ISL6269AEVAL2Z REV C CIRCUIT SCHEMATIC
AN1273.2
November 14, 2007
C1
Application Note 1273
μ
FIGURE 14. PCB TOP SILK SCREEN
7
AN1273.2
November 14, 2007
Application Note 1273
μ
FIGURE 15. PCB BOTTOM SILK SCREEN (MIRRORED)
8
AN1273.2
November 14, 2007
Application Note 1273
μ
FIGURE 16. PCB TOP LAYER ETCH
9
AN1273.2
November 14, 2007
Application Note 1273
FIGURE 17. PCB LAYER 2 ETCH
10
AN1273.2
November 14, 2007
Application Note 1273
μ
FIGURE 18. PCB LAYER 3 ETCH
11
AN1273.2
November 14, 2007
Application Note 1273
FIGURE 19. PCB BOTTOM LAYER ETCH
12
AN1273.2
November 14, 2007
Application Note 1273
Bill of Materials
QTY
REFERENCE
DESCRIPTION/COMMENT
MFG NAME
MFG NUMBER
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, 16V, 10%, X7R, ROHS
MURATA
GRM36X7R104K016AD
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, 4.7pF, 50V, 0.25pF, NPO, ROHS
MURATA
GRM36COG4R7C050AQ
1
C6
CAP, SMD, 0402, 470pF, 50V, 10%, X7R, ROHS
PANASONIC
ECJ-0EB1H471K
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
10
JP1(1 to 2, 3 to 4, 5 to 6), JP2 to JP8 JUMPER, 2 PIN, HIGHBDY, SHUNT
BERG/FCI
71363-102
1
L1
INDUCTOR, SMD, 13mm, 2.2µH, 20%, 29A, SHIELDED VISHAY
IHLP5050CEER2R2M01
5
Q1, Q2, Q3, Q6, Q7
MOSFET, N-CH, SMD, 3P, SOT23, 50V, 0.2A, Pb-free
DIODES INC.
BSS138-7-F
1
Q4
MOSFET, N-CH, DUAL, 8P, SOIC, 30V, 17mΩ
FAIRCHILD
FDS6982AS
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
R13
RES, SMD, 0402, 6.49k, 1/16W, 1%, TF, ROHS
YAGEO
RC0402FR-076K49L
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
1
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
6
R28 to R33
RES, SMD, 1206, 1.43Ω, 1/4W, 1%, TF, ROHS
YAGEO
RC1206FR-071R43L
1
R3
RES, SMD, 0402, 100k, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ2RKF1003
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
1
R9
RES, SMD, 0402, 150k, 1/16W, 1%, TF, ROHS
YAGEO
RC0402FR-07150KL
13
AN1273.2
November 14, 2007
Application Note 1273
Bill of Materials (Continued)
QTY
REFERENCE
DESCRIPTION/COMMENT
MFG NAME
MFG NUMBER
5
S1 to S5
SWITCH-TOGGLE, SMD, ULTRAMINI, 1P, SPST, MINI
C&K
COMPONENTS
GT11MSCKE
7
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-GPU CONTROLLER, 16P, QFN, 4x4, Pb-free
INTERSIL
ISL6269ACRZ
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
14
AN1273.2
November 14, 2007
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