The ISL6605 is a high frequency, MOSFET driver optimized
to drive two N-Channel power MOSFETs in a synchronousrectified buck converter topology. This driver combined with
an Intersil HIP63xx or ISL65xx Multi-Phase Buck PWM
controller forms a complete single-stage core-voltage
regulator solution with high efficiency performance at high
switching frequency for advanced microprocessors.
The IC is biased by a single low voltage supply (5V) and
minimizes low driver switching losses for high MOSFET gate
capacitance and high switching frequency applications.
Each driver is capable of driving a 3000pF load with an 8ns
propagation delay and less than 10ns transition time. This
product implements bootstrapping on the upper gate with an
internal bootstrap Schottky diode, reducing implementation
cost, complexity, and allowing the use of higher
performance, cost effective N-Channel MOSFETs. Adaptive
shoot-through protection is integrated to prevent both
MOSFETs from conducting simultaneously.
The ISL6605 features 4A typical sink current for the lower
gate driver, which is capable of holding the lower MOSFET
gate during the Phase node rising edge to prevent shootthrough power loss caused by the high dv/dt of the Phase
node.
Features
• Drives Two N-Channel MOSFETs
• Adaptive Shoot-Through Protection
•0.4Ω On-Resistance and 4A Sink Current Capability
• Supports High Switching Frequency
- Fast Output Rise and Fall Time
- Ultra Low Propagation Delay 8ns
• Three-State PWM Input for Power Stage Shutdown
• Internal Bootstrap Schottky Diode
• Low Bias Supply Current (5V, 30µA)
• Enable Input
• QFN Package
- Compliant to JEDEC PUB95 MO-220 QFN-Quad Flat
No Leads-Product Outline.
- Near Chip-Scale Package Footprint; Improves PCB
Efficiency and Thinner in Profile.
• Pb-Free Plus Anneal Available (RoHS Compliant)
Applications
• Core Voltage Supplies for Intel® and AMD®
Microprocessors
• High Frequency Low Profile DC/DC Converters
• High Current Low Voltage DC/DC Converters
• Synchronous Rectification for Isolated Power Supplies
The ISL6605 also features a Three-State PWM input that,
working together with Intersil multi-phase PWM controllers,
will prevent a negative transient on the output voltage when
the output is being shut down. This feature eliminates the
Schottky diode that is usually seen in a microprocessor
power system for protecting the microprocessor from
reversed-output-voltage damage.
Pinouts
ISL6605
(8 LD SOIC)
TOP VIEW
UGATE
BOOT
PWM
GND
1
2
3
4
8
7
6
5
PHASE
EN
VCC
LGATE
Related Literature
• Technical Brief TB363 “Guidelines for Handling and
Processing Moisture Sensitive Surface Mount Devices
(SMDs)”
ISL6605
(8 LD QFN)
TOP VIEW
UGATE
PHASE
7
8
BOOT
PWM
1
2
43
GND
LGATE
EN
6
6
5
VCC
1
Intel® is a registered trademark of Intel Corporation. AMD® is a registered trademark of Advanced Micro Devices, Inc.
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.
All other trademarks mentioned are the property of their respective owners.
*Add “-T” suffix for tape and reel.
NOTE: Intersil Pb-free plus anneal products employ special Pb-free
material sets; molding compounds/die attach materials and 100% matt e
tin plate termination finish, which are RoHS compliant and comp atible
with both SnPb and Pb-free soldering operations. Intersil Pb-free
products are MSL classified at Pb-free peak reflow temper ature s that
meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
ti
PART
MARKING
TEMP.
RANGE (°C) PACKAGE
6605IBZ-40 to 858 Ld SOIC
(Pb-free)
05IZ-40 to 858 Ld 3x3 QFN
(Pb-free)
05IZ-40 to 858 Ld 3x3 QFN
(Pb-free)
PKG.
DWG. #
M8.15
L8.3x3
L8.3x3
VCC
EN
PWM
VCC
20K
20K
CONTROL
LOGIC
SHOOT-
THROUGH
PROTECTION
BOOT
UGATE
PHASE
VCC
LGATE
GND
2
FN9091.7
May 9, 2006
Page 3
ISL6605
Typical Application - Multi-Phase Converter Using ISL6605 Gate Drivers
V
IN
+5V
+5V
PGOOD
VID
(OPTIONAL)
+5V
FB
VCC
VSEN
PWM
CONTROL
(HIP63XX
or ISL65XX)
COMP
PWM1
PWM2
ISEN1
ISEN2
VCC
EN
PWM
499K*
+5V
ISL6605
BOOT
UGATE
PHASE
LGATE
V
IN
+V
CORE
VCC
FS/EN
GND
* 499K IS USED TO PULL DOWN THE PWM INPUT TO PREVENT THE PWM FROM FALSE TRIGGERING UGATE DURING STARTUP.
EN
PWM
499K*
BOOT
UGATE
PHASE
ISL6605
LGATE
3
FN9091.7
May 9, 2006
Page 4
ISL6605
Absolute Maximum RatingsRecommended Operating Conditions
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
1. θ
is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
JA
2. θ
is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features.
JA
, "case temperature" location is at the center of the package underside exposed pad. See Tech Brief TB379 for details.
3. θ
JC
Ambient Temperature Range . . . . . . . . . . . . . . . . . . .-40°C to 85°C
Maximum Operating Junction Temperature . . . . . . . . . . . . . 125°C
Maximum Storage Temperature Range . . . . . . . . . . -65°C to 150°C
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300°C
(SOIC - Lead Tips Only)
Electrical SpecificationsThese specifications apply for T
= -40°C to 85°C, unless otherwise noted
A
PARAMETERSYMBOLTEST CONDITIONSMINTYPMAXUNITS
VCC SUPPLY CURRENT
Bias Supply CurrentI
Bias Supply CurrentI
VCC
VCC
EN = LOW, TA = 0°C to 70°C--1.5μA
EN = LOW, T
PWM pin floating, V
= -40°C to 85°C--2μA
A
= 5V-30-μA
VCC
PWM INPUT
V
Input CurrentI
PWM
PWM Three-State Rising ThresholdV
PWM Three-State Falling ThresholdV
Three-State Shutdown Holdoff TimeV
= 5V-250-μA
PWM
= 0V--250-μA
V
PWM
= 5V, TA = 0°C to 70°C--1.70V
VCC
= 5V, TA = -40°C to 85°C--1.75V
V
VCC
= 5V3.3--V
VCC
= 5V, temperature = 25°C-420-ns
VCC
EN INPUT
EN LOW Threshold1.0--V
EN HIGH Threshold--2.0V
SWITCHING TIME
UGATE Rise Timet
LGATE Rise Timet
UGATE Fall Timet
LGATE Fall Timet
UGATE Turn-Off Propagation Delayt
LGATE Turn-Off Propagation Delayt
RUGATEVVCC
RLGATEVVCC
FUGATE
FLGATE
PDLUGATEVVCC
PDLLGATEVVCC
= 5V, 3nF Load-8-ns
= 5V, 3nF Load-8-ns
V
= 5V, 3nF Load-8-ns
VCC
V
= 5V, 3nF Load-4-ns
VCC
= 5V, 3nF Load-8-ns
= 5V, 3nF Load-8-ns
OUTPUT
Upper Drive Source ResistanceR
Upper Driver Source Current (Note 4)I
Upper Drive Sink ResistanceR
Upper Driver Sink Current (Note 4)I
Lower Drive Source ResistanceR
Lower Driver Source Current (Note 4)I
Lower Drive Sink ResistanceR
Lower Driver Sink Current (Note 4)I
UGATE
UGATE
UGATE
UGATE
LGATE
LGATE
LGATE
LGATE
500mA Source Current-1.02.5Ω
V
UGATE-PHASE
= 2.5V-2.0-A
500mA Sink Current-1.02.5Ω
V
UGATE-PHASE
= 2.5V-2.0-A
500mA Source Current-1.02.5Ω
V
= 2.5V-2.0-A
LGATE
500mA Sink Current-0.41.0Ω
V
= 2.5V-4.0-A
LGATE
NOTE:
4. Guaranteed by design. Not 100% tested in production.
4
FN9091.7
May 9, 2006
Page 5
ISL6605
Functional Pin Description
Note: Pin numbers refer to the SOIC package. Check
PINOUT diagrams for QFN pin numbers.
UGATE (Pin 1)
Upper gate drive output. Connect to gate of high-side power
N-Channel MOSFET.
BOOT (Pin 2)
Floating bootstrap supply pin for the upper gate drive.
Connect the bootstrap capacitor between this pin and the
PHASE pin. The bootstrap capacitor provides the charge to
turn on the upper MOSFET. See the Bootstrap Diode and
Capacitor section under DESCRIPTION for guidance in
choosing the appropriate capacitor value.
PWM (Pin 3)
The PWM signal is the control input for the driver. The PWM
signal can enter three distinct states during operation (see the
three-state PWM Input section under DESCRIPTION for further
details). Connect this pin to the PWM output of the controller.
GND (Pin 4)
Ground pin. All signals are referenced to this node.
LGATE (Pin 5)
Lower gate drive output. Connect to gate of the low-side
power N-Channel MOSFET.
VCC (Pin 6)
Connect this pin to a +5V bias supply. Place a high quality
bypass capacitor from this pin to GND.
EN (Pin 7)
Enable input pin. Connect this pin to HIGH to enable and
LOW to disable the IC. When disabled, the IC draws less
than 1μA bias current.
PHASE (Pin 8)
Connect this pin to the source of the upper MOSFET and the
drain of the lower MOSFET. This pin provides a return path
for the upper gate driver.
Thermal Pad (in QFN only)
In the QFN package, the pad underneath the center of the
IC is a thermal substrate. The PCB “thermal land” design
for this exposed die pad should include thermal vias that
drop down and connect to one or more buried copper
plane(s). This combination of vias for vertical heat escape
and buried planes for heat spreading allows the QFN to
achieve its full thermal potential. This pad should be either
grounded or floating, and it should not be connected to
other nodes. Refer to TB389 for design guidelines.
Description
Operation
Designed for speed, the ISL6605 MOSFET driver controls both
high-side and low-side N-Channel FETs from one externally
provided PWM signal.
A rising edge on PWM initiates the turn-off of the lower
MOSFET (see Timing Diagram). After a short propagation
delay [t
PDLLGATE
times [t
FLGATE
section. Adaptive shoot-through circuitry monitors the
LGATE voltage and determines the upper gate delay time
[t
PDHUGATE
drops below 1V. This prevents both the lower and upper
MOSFETs from conducting simultaneously or shootthrough. Once this delay period is completed the upper gate
drive begins to rise [t
on.
A falling transition on PWM indicates the turn-off of the upper
MOSFET and the turn-on of the lower MOSFET. A short
propagation delay [t
upper gate begins to fall [t
shoot-through circuitry determines the lower gate delay time,
t
PDHLGATE
and the lower gate is allowed to rise after the upper MOSFET
gate-to-source voltagedrops below 1V. The lower gate then
rises [t
RLGATE
], the lower gate begins to fall. Typical fall
] are provided in the Electrical Specifications
] based on how quickly the LGATE voltage
RUGATE
PDLUGATE
] and the upper MOSFET turns
] is encountered before the
FUGATE
]. Again, the adaptive
. The upper MOSFET gate voltage is monitored
], turning on the lower MOSFET.
Timing Diagram
PWM
UGATE
LGATE
t
PDLLGATE
t
PDHUGATE
t
5
FLGATE
t
RUGATE
t
PDLUGATE
t
t
PDHLGATE
FUGATE
t
RLGATE
FN9091.7
May 9, 2006
Page 6
0
ISL6605
This driver is optimized for voltage regulators with large step
down ratio. The lower MOSFET is usually sized much larger
compared to the upper MOSFET because the lower
MOSFET conducts for a much longer time in a switching
period. The lower gate driver is therefore sized much larger
to meet this application requirement. The 0.4Ω on-resistance
and 4A sink current capability enable the lower gate driver to
absorb the current injected to the lower gate through the
drain-to-gate capacitor of the lower MOSFET and prevent a
shoot through caused by the high dv/dt of the phase node.
Three-State PWM Input
A unique feature of the ISL6605 and other Intersil drivers is
the addition of a shutdown window to the PWM input. If the
PWM signal enters and remains within the shutdown window
for a set holdoff time, the output drivers are disabled and
both MOSFET gates are pulled and held low. The shutdown
state is removed when the PWM signal moves outside the
shutdown window. Otherwise, the PWM rising and falling
thresholds outlined in the ELECTRICAL SPECIFICATIONS
determine when the lower and upper gates are enabled.
Adaptive Shoot-Through Protection
Both drivers incorporate adaptive shoot-through protection
to prevent upper and lower MOSFETs from conducting
simultaneously and shorting the input supply. This is
accomplished by ensuring the falling gate has turned off one
MOSFET before the other is allowed to rise.
During turn-off of the lower MOSFET, the LGATE voltage is
monitored until it reaches a 1V threshold, at which time the
UGATE is released to rise. Adaptive shoot-through circuitry
monitors the upper MOSFET gate voltage during UGATE
turn-off. Once the upper MOSFET gate-to-source voltage
has dropped below a threshold of 1V, the LGATE is allowed
to rise.
Internal Bootstrap Diode
This driver features an internal bootstrap Schottky diode.
Simply adding an external capacitor across the BOOT and
PHASE pins completes the bootstrap circuit.The bootstrap
capacitor can be chosen from the following equation:
Q
GATE
BOOT
------------------------
≥
ΔV
BOOT
is the amount of gate charge required to fully
GATE
, of 65nC at 5V and also assume the droop in
GATE
BOOT
term is
C
where Q
charge the gate of the upper MOSFET. The ΔV
defined as the allowable droop in the rail of the upper drive.
The above relationship is illustrated in Figure 1.
As an example, suppose an upper MOSFET has a gate
charge, Q
the drive voltage over a PWM cycle is 200mV. One will find
that a bootstrap capacitance of at least 0.125μF is required.
The next larger standard value capacitance is 0.15μF. A
good quality ceramic capacitor is recommended.
2.0
2.0
1.8
1.8
1.6
1.6
1.4
1.4
1.2
1.2
(uF)
1.0
1.0
0.8
BOOT
0.8
C
0.6
0.6
0.4
0.4
0.2
20nC
0.2
0.0
20nC
0.00.10.20.30.40.50.60.70.80.91.
0.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
FIGURE 1. BOOTSTRAP CAPACITANCE vs. BOOT RIPPLE
Q
50nC
50nC
VOLTAGE
GATE
Q
GATE
= 100 nC
=100nC
ΔV
BOOT
(V)
Power Dissipation
Package power dissipation is mainly a function of the
switching frequency and total gate charge of the selected
MOSFETs. Calculating the power dissipation in the driver for
a desired application is critical to ensuring safe operation.
Exceeding the maximum allowable power dissipation level
will push the IC beyond the maximum recommended
operating junction temperature of 125°C. The maximum
allowable IC power dissipation for the SO-8 package is
approximately 800mW. When designing the driver into an
application, it is recommended that the following calculation
be performed to ensure safe operation at the desired
frequency for the selected MOSFETs. The power dissipated
by the driver is approximated as below and plotted as in
Figure 2.
Pf
where f
and V
and Q
MOSFET selection and any external capacitance added to
the gate pins. The I
of the driver and is typically negligible.
1.5VUQUVLQ
sw
sw
represent the upper and lower gate rail voltage. QU
L
are the upper and lower gate charge determined by
L
+()I
L
+=
DDQ
V
CC
is the switching frequency of the PWM signal. VU
DDQ VCC
product is the quiescent power
6
FN9091.7
May 9, 2006
Page 7
1000
1000
QU=100nC
900
900
800
800
700
700
600
600
500
500
400
400
POWER (mΩ)
300
300
200
200
100
100
=200nC
Q
L
0
0
0200400600800100012001400160018002000
0200 400 600 800 1000 1200 1400 1600 1800 2000
FIGURE 2. POWER DISSIPATION VS. FREQUENCY
QU=50nC
Q
=100nC
L
FREQUENCY (KHZ)
QU=50nC
QL=50nC
QU=20nC
Q
=50nC
L
Application Information
Fault Mode at Repetitive Startups
At a low VCC (<2V), the Thevenin equivalent of the 20k
divider at the PWM pin, as shown in the Block Diagram on
page 2, is no longer true; very high impedance will be seen
from the PWM pin to GND. Junction leakage currents from
the VCC to the resistor tub will tend to pull up the PWM input
and falsely trigger the UGATE. If the energy stored in the
bootstrap capacitor is not completely discharged during the
previous power-down period, then the upper MOSFET could
be turned on and generate a spike at the output when VCC
ramps up. A 499kΩ resistor at the PWM to GND, as shown
in Figure 3, helps bleed the leakage currents, thus
eliminating the startup spike.
voltage should be checked at the worst case (maximum
VCC and prior to overcurrent trip point), especially for
applications with higher than 20A per D
2
PAK FET.
MOSFETs with low parasitic lead inductances, such as
multi-SOURCE leads devices (SO-8 and LFPAK), are
recommended.
Careful layout would help reduce the negative ringing peak
significantly:
- Tie the SOURCE of the upper FET and the DRAIN of
the lower FET as close as possible;
- Use the shortest low-impedance trace between the
SOURCE of the lower FET and the power ground;
- Tie the GND of the ISL6605 closely to the SOURCE of
the lower FET.
PHASE
A resistor placement of R
, as shown in Figure 5, in the
BOOT
earlier design is recommended; it helps eliminate the
overcharge of the BOOT capacitor, in terms of voltage stress
across the BOOT to PHASE. When needed, 1 to 2 Ohm
R
is sufficient and has little impact on the overall
BOOT
efficiency. However, a design with good layout and using
MOSFETs with low parasitic lead inductances, such as
multi-SOURCE leads devices (SO-8 and LFPAK), is
generally not required such a resistor.
PWM
ISL6605
499K
FIGURE 3. 499kΩ RESISTOR
GND
Layout Considerations and MOSFET Selection
The parasitic inductances of the PCB and the power devices
(both upper and lower FETs) generate a negative ringing at
the trailing edge of the PHASE node. This negative ringing
plus the VCC adds charges to the bootstrap capacitor
through the internal bootstrap schottky diode when the
PHASE node is low. If the negative spikes are too large,
especially at high current applications with a poor layout, the
voltage on the bootstrap capacitor could exceed the VCC
and the device’s maximum rating. The V
7
BOOT-PHASE
When placing the QFN part on the board, no vias or trace
should be running in between pin numbers 1 and 8 since a
small piece of copper is underneath the corner for the
orientation. In addition, connecting the thermal pad of the
QFN part to the power ground with a via, or placing a low
noise copper plane underneath the SOIC part is strongly
recommended for high switching frequency, high current
applications. This is for heat spreading and allows the part
to achieve its full thermal potential.
8 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE
(COMPLIANT TO JEDEC MO-220VEEC ISSUE C)
MILLIMETERS
SYMBOL
A0.800.901.00-
A1--0.05-
A2--1.009
A30.20 REF9
b0.230.280.385, 8
D3.00 BSC-
D12.75 BSC9
D20.251.101.257, 8
E3.00 BSC-
E12.75 BSC9
E20.251.101.257, 8
e 0.65 BSC-
k0.25 - -
L0.350.600.758
L1 --0.1510
N82
Nd23
Ne23
P- -0.609
θ--129
NOTES:
1. Dimensioning and tolerancing conform to ASME Y14.5-1994.
2. N is the number of terminals.
3. Nd and Ne refer to the number of terminals on each D and E.
4. All dimensions are in millimeters. Angles are in degrees.
5. Dimension b applies to the metallized terminal and is measured
between 0.15mm and 0.30mm from the terminal tip.
6. The configuration of the pin #1 identifier is optional, but must be
located within the zone indicated. The pin #1 identifier may be
either a mold or mark feature.
7. Dimensions D2 and E2 are for the exposed pads which provide
improved electrical and thermal performance.
8. Nominal dimensions are provided to assist with PCB Land Pattern
Design efforts, see Intersil Technical Brief TB389.
9. Features and dimensions A2, A3, D1, E1, P & θ are present when
Anvil singulation method is used and not present for saw
singulation.
10. Depending on the method of lead termination at the edge of the
package, a maximum 0.15mm pull back (L1) maybe present. L
minus L1 to be equal to or greater than 0.3mm.
NOTESMINNOMINALMAX
Rev. 1 10/02
8
FN9091.7
May 9, 2006
Page 9
Small Outline Plastic Packages (SOIC)
ISL6605
N
INDEX
AREA
123
-A-
E
-B-
SEATING PLANE
D
A
-C-
0.25(0.010)BMM
H
L
h x 45°
α
e
B
0.25(0.010)C AMBS
M
NOTES:
1. Symbols are defined in the “MO Series Symbol List” in Section 2.2 of
Publication Number 95.
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
3. Dimension “D” does not include mold flash, protrusions or gate burrs.
Mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006
inch) per side.
4. Dimension “E” does not include interlead flash or protrusions. Interlead flash and protrusions shall not exceed 0.25mm (0.010 inch) per
side.
5. The chamfer on the body is optional. If it is not present, a visual index
feature must be located within the crosshatched area.
6. “L” is the length of terminal for soldering to a substrate.
7. “N” is the number of terminal positions.
8. Terminal numbers are shown for reference only.
9. The lead width “B”, as measured 0.36mm (0.014 inch) or greater
above the seating plane, shall not exceed a maximum value of
0.61mm (0.024 inch).
10. Controlling dimension: MILLIMETER. Converted inch dimensions
are not necessarily exact.
A1
C
0.10(0.004)
M8.15 (JEDEC MS-012-AA ISSUE C)
8 LEAD NARROW BODY SMALL OUTLINE PLASTIC PACKAGE
INCHESMILLIMETERS
SYMBOL
A0.05320.06881.351.75-
A10.00400.00980.100.25-
B0.0130.0200.330.519
C0.00750.00980.190.25-
D0.18900.19684.805.003
E0.14970.15743.804.004
e0.050 BSC1.27 BSC-
H0.22840.24405.806.20-
h0.00990.01960.250.505
L0.0160.0500.401.276
N887
α
0°8°0°8°-
NOTESMINMAXMINMAX
Rev. 1 6/05
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. 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 data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implicat ion or oth erwise u nde r any p a tent or p at ent r ights of Intersil or its subsidiari es.
For information regarding Intersil Corporation and its products, see www.intersil.com
9
FN9091.7
May 9, 2006
Loading...
+ hidden pages
You need points to download manuals.
1 point = 1 manual.
You can buy points or you can get point for every manual you upload.