ISL6208C [RENESAS]
High Voltage Synchronous Rectified Buck MOSFET Drivers;
| 型号： | ISL6208C |
| 厂家： | 
RENESAS TECHNOLOGY CORP |
| 描述： | High Voltage Synchronous Rectified Buck MOSFET Drivers |
| 文件： | 总12页 (文件大小：594K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
DATASHEET
ISL6208C
FN8395
Rev 1.00
Jun 1, 2016
High Voltage Synchronous Rectified Buck MOSFET Drivers
The ISL6208C is a high frequency, dual MOSFET driver,
Features
optimized to drive two N-channel power MOSFETs in a
synchronous-rectified buck converter topology. It is especially
suited for mobile computing applications that require high
efficiency and excellent thermal performance. The driver,
combined with an Intersil multiphase buck PWM controller,
forms a complete single-stage core-voltage regulator solution
for advanced mobile microprocessors.
• Dual MOSFET drives for synchronous rectified bridge
• Adaptive shoot-through protection
• 0.5Ω ON-resistance and 4A sink current capability
• Supports high switching frequency up to 2MHz
- Fast output rise and fall time
- Low propagation delay
The ISL6208C features 4A typical sinking current for the lower
gate driver. This current is capable of holding the lower
MOSFET gate off during the rising edge of the phase node. This
prevents shoot-through power loss caused by the high dv/dt of
phase voltages. The operating voltage matches the 30V
breakdown voltage of the MOSFETs commonly used in mobile
computer power supplies.
• Three-state PWM input for power stage shutdown
• Internal bootstrap Schottky diode
• Low bias supply current (5V, 80µA)
• Diode emulation for enhanced light load efficiency and
prebiased start-up applications
The ISL6208C also features a three-state PWM input that,
working together with Intersil’s multiphase PWM controllers,
will prevent negative voltage output during CPU shutdown. This
feature eliminates a protective Schottky diode usually seen in
microprocessor power systems.
• VCC POR (Power-On-Reset) feature integrated
• Low three-state shutdown holdoff time (typical 160ns)
• Pin-to-pin compatible with ISL6207
• DFN package
MOSFET gates can be efficiently switched up to 2MHz using
the ISL6208C. Each driver is capable of driving a 3000pF load
with propagation delays of 8ns and transition times under
10ns. Bootstrapping is implemented with an internal Schottky
diode. This reduces system cost and complexity, while allowing
the use of higher performance MOSFETs. Adaptive
• Pb-free (RoHS compliant)
Applications
• Core voltage supplies for Intel™ and AMD™ mobile
microprocessors
• High frequency low profile DC/DC converters
• High current low output voltage DC/DC converters
• High input voltage DC/DC converters
shoot-through protection is integrated to prevent both
MOSFETs from conducting simultaneously.
A diode emulation feature is integrated in the ISL6208C to
enhance converter efficiency at light load conditions. This
feature also allows for monotonic start-up into prebiased
outputs. When diode emulation is enabled, the driver will allow
discontinuous conduction mode by detecting when the
inductor current reaches zero and subsequently turning off the
low-side MOSFET gate.
Related Literature
• Technical Brief TB363 “Guidelines for Handling and
Processing Moisture Sensitive Surface Mount Devices
(SMDs)”
• Technical Brief TB389 “PCB Land Pattern Design and
Surface Mount Guidelines for MLFP Packages”
• Technical Brief TB447 “Guidelines for Preventing
Boot-to-Phase Stress on Half-Bridge MOSFET Driver ICs”
FN8395 Rev 1.00
Jun 1, 2016
Page 1 of 12
ISL6208C
Table of Contents
Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Typical Application with 2-Phase Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Pin Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Pin Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Thermal Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Functional Pin Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Theory of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Typical Performance Waveforms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Diode Emulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Three-State PWM Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Adaptive Shoot-Through Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Layout Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Reducing Phase Ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Thermal Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Revision History. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
About Intersil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Package Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
FN8395 Rev 1.00
Jun 1, 2016
Page 2 of 12
ISL6208C
Block Diagram
VCC
BOOT
FCCM
UGATE
PHASE
SHOOT-
THROUGH
PROTECTION
CONTROL
LOGIC
VCC
PWM
LGATE
GND
10kΩ
THERMAL PAD
FIGURE 1. BLOCK DIAGRAM
Typical Application with 2-Phase Converter
+5V
+5V
V
BAT
VCC
+V
CORE
BOOT
UGATE
+5V
FB
COMP
FCCM
VCC
VSEN
PWM
PHASE
LGATE
DRIVE
ISL6208C
PWM1
PWM2
PGOOD
THERMAL
PAD
FCCM
MAIN
CONTROL
ISEN1
VID
ISEN2
+5V
V
VCC
BAT
BOOT
FS
DACOUT
FCCM
PWM
UGATE
PHASE
GND
DRIVE
ISL6208C
LGATE
THERMAL
PAD
FIGURE 2. TYPICAL APPLICATION WITH 2-PHASE CONVERTER
FN8395 Rev 1.00
Jun 1, 2016
Page 3 of 12
ISL6208C
Ordering Information
PART NUMBER
(Notes 1, 2, 3)
PART
MARKING
TEMP. RANGE
(°C)
TAPE AND REEL
(UNITS)
PACKAGE
(RoHS Compliant)
PKG.
DWG. #
ISL6208CHRZ-T
8CH
8CI
-10 to +100
-40 to +100
6k
6k
8 Ld 2x2 DFN
8 Ld 2x2 DFN
L8.2x2D
L8.2x2D
ISL6208CIRZ-T
NOTES:
1. Please refer to TB347 for details on reel specifications.
2. These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte
tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations). Intersil
Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
3. For Moisture Sensitivity Level (MSL), please see device information page for ISL6208C. For more information on MSL please see techbrief TB363.
Pin Configuration
ISL6208C
(8 LD 2x2 DFN)
TOP VIEW
UGATE
8
PHASE
1
2
3
BOOT
PWM
7
FCCM
VCC
6
4
5
LGATE
GND
Pin Description
PIN
SYMBOL
UGATE
BOOT
DESCRIPTION
1
The UGATE pin is the upper gate drive output. Connect to gate of the high-side power N-channel MOSFET.
2
BOOT is the 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 “Internal
Bootstrap Diode” on page 9 for guidance in choosing the appropriate capacitor value.
3
PWM
The PWM signal is the control input for the driver. The PWM signal can enter three distinct states during operation. See
“Three-State PWM Input” on page 9 for further details. Connect this pin to the PWM output of the controller.
4
5
6
GND
LGATE
VCC
GND is the ground pin for the IC.
LGATE is the lower gate drive output. Connect to gate of the low-side power N-Channel MOSFET.
Connect the VCC pin to a +5V bias supply. Place a high quality bypass capacitor from this pin to GND. The VCC pin
of the driver(s) and related VCC or +5V bias supply pin of the Intersil controller must share a common +5V supply.
7
8
FCCM
The FCCM pin enables or disables Diode Emulation. When FCCM is LOW, diode emulation is allowed. Otherwise,
continuous conduction mode is forced. See “Diode Emulation” on page 9 for more detail.
PHASE
Connect the PHASE 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.
FN8395 Rev 1.00
Jun 1, 2016
Page 4 of 12
ISL6208C
Absolute Maximum Ratings
Thermal Information
Supply Voltage (VCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 7V
Thermal Resistance (Typical)
8 Ld 2x2 DFN Package (Notes 5, 6). . . . . .
(°C/W)
89
(°C/W)
24
JA
JC
Input Voltage (V
, V ) . . . . . . . . . . . . . . . . . . . . -0.3V to VCC + 0.3V
FCCM PWM
BOOT Voltage (V
BOOT To PHASE Voltage (V
) . . . . . . . . . . . -0.3V to 33V (DC) or 36V (<20ns)
Maximum Storage Temperature Range . . . . . . . . . . . . . .-65°C to +150°C
Pb-Free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see TB493
BOOT-GND
). . . . . . . . . . . . . . . . -0.3V to 7V (DC)
BOOT-PHASE
-0.3V to 9V (<10ns)
PHASE Voltage (Note 4). . . . . . . . . . . . . . . . . . . . . . . . . . (GND - 0.3V) to 30V
GND - 8V (<20ns Pulse Width, 10µJ)
Recommended Operating Conditions
UGATE Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . V
- 0.3V (DC) to V
Ambient Temperature Range
PHASE
- 5V (<20ns Pulse Width, 10µJ) to V
BOOT
BOOT
V
Industrial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +100°C
Hi-Temp Commercial . . . . . . . . . . . . . . . . . . . . . . . . . . . .-10°C to +100°C
Maximum Operating Junction Temperature . . . . . . . . . . . . . . . . . . +125°C
Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5V ±10%
PHASE
LGATE Voltage. . . . . . . . . . . . . . . . . . . . . . . . .GND - 0.3V (DC) to VCC + 0.3V
GND - 2.5V (<20ns Pulse Width, 5µJ) to VCC + 0.3V
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product
reliability and result in failures not covered by warranty.
NOTES:
4. The Phase Voltage is capable of withstanding -7V when the BOOT pin is at GND.
5. is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See Tech
JA
Brief TB379.
6. For , the “case temp” location is the center of the exposed metal pad on the package underside.
JC
Electrical Specifications Recommended operating conditions, unless otherwise noted. Boldface limits apply across the operating
temperature range, -40°C to +100°C (Industrial), -10°C to +100°C (Hi-Temp Commercial).
MIN
MAX
SYMBOL
SUPPLY CURRENT
PARAMETER
TEST CONDITIONS
(Note 7) TYP (Note 7) UNIT
V
CC
I
Bias Supply Current
PWM pin floating, V
= 5V
FCCM
-
80
-
µA
VCC
POR
V
V
Rising
Falling
-
2.40
-
3.40
2.90
500
3.90
V
V
CC
-
-
CC
Hysteresis
BOOTSTRAP DIODE
mV
V
Forward Voltage
V
= 5V, forward bias current = 2mA
0.50
0.55
0.65
V
F
VCC
PWM INPUT
I
Input Current
V
V
V
V
V
= 5V
= 0V
-
250
-250
1.00
3.8
-
µA
µA
V
PWM
PWM
-
-
PWM
PWM Three-State Rising Threshold
PWM Three-State Falling Threshold
Three-State Shutdown Hold-Off Time
= 5V
0.70
3.5
100
1.30
4.1
250
VCC
VCC
VCC
= 5V
V
t
= 5V, temperature = +25°C
175
ns
TSSHD
FCCM INPUT
FCCM LOW Threshold
FCCM HIGH Threshold
0.50
-
-
-
V
V
-
2.0
SWITCHING TIME
t
UGATE Rise Time
V
V
V
V
V
= 5V, 3nF load
-
-
-
-
-
8.0
8.0
8.0
4.0
18
-
-
-
-
-
ns
ns
ns
ns
ns
RU
VCC
VCC
VCC
VCC
VCC
t
t
LGATE Rise Time
= 5V, 3nF load
RL
FU
UGATE Fall Time
= 5V, 3nF load
t
LGATE Fall Time
= 5V, 3nF load
FL
t
UGATE Turn-Off Propagation Delay
= 5V, outputs unloaded
PDLU
FN8395 Rev 1.00
Jun 1, 2016
Page 5 of 12
ISL6208C
Electrical Specifications Recommended operating conditions, unless otherwise noted. Boldface limits apply across the operating
temperature range, -40°C to +100°C (Industrial), -10°C to +100°C (Hi-Temp Commercial). (Continued)
MIN
MAX
SYMBOL
PARAMETER
TEST CONDITIONS
= 5V, outputs unloaded
(Note 7) TYP (Note 7) UNIT
t
LGATE Turn-Off Propagation Delay
UGATE Turn-On Propagation Delay
LGATE Turn-On Propagation Delay
UG/LG Three-State Propagation Delay
Minimum LG ON-TIME in DCM
V
V
V
V
-
10
10
-
25
20
-
30
30
-
ns
ns
ns
ns
ns
PDLL
VCC
VCC
VCC
VCC
t
= 5V, outputs unloaded
= 5V, outputs unloaded
= 5V, outputs unloaded
PDHU
t
20
PDHL
t
35
PTS
t
-
400
-
LGMIN
OUTPUT
R
Upper Drive Source Resistance
Upper Driver Source Current
Upper Drive Sink Resistance
Upper Driver Sink Current
500mA source current
= 2.5V
-
-
-
-
-
-
-
-
1
2.5
Ω
A
Ω
A
Ω
A
Ω
A
U
I
V
2.00
1
-
U
UGATE-PHASE
500mA sink current
= 2.5V
R
2.5
U
I
V
2.00
1
-
2.5
-
U
UGATE-PHASE
500mA source current
= 2.5V
R
Lower Drive Source Resistance
Lower Driver Source Current
Lower Drive Sink Resistance
Lower Driver Sink Current
L
I
V
2.00
0.5
4.00
L
LGATE
500mA sink current
V = 2.5V
LGATE
R
1.0
-
L
I
L
NOTE:
7. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by characterization
and are not production tested.
Timing Diagram
2.5V
t
PWM
PDHU
t
t
PDLU
TSSHD
t
t
RU
RU
t
t
FU
FU
t
PTS
1V
UGATE
LGATE
t
PTS
1V
t
RL
t
FL
t
TSSHD
t
PDHL
t
PDLL
t
FL
FIGURE 3. TIMING DIAGRAM
FN8395 Rev 1.00
Jun 1, 2016
Page 6 of 12
ISL6208C
Functional Pin Description
UGATE
The UGATE pin is the upper gate drive output. Connect to gate of
the high-side power N-channel MOSFET.
Theory of Operation
Designed for speed, the ISL6208C dual 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
],
BOOT
PDLL
the lower gate begins to fall. Typical fall times [t ] are provided
FL
BOOT is the 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 “Internal Bootstrap Diode” on page 9 for
guidance in choosing the appropriate capacitor value.
in the “Electrical Specifications” on page 5. Adaptive
shoot-through circuitry monitors the LGATE voltage. When LGATE
has fallen below 1V, UGATE is allowed to turn ON. This prevents
both the lower and upper MOSFETs from conducting
simultaneously, or shoot-through.
PWM
A falling transition on PWM indicates the turn-off of the upper
MOSFET and the turn-on of the lower MOSFET. A short
The PWM signal is the control input for the driver. The PWM signal
can enter three distinct states during operation. See “Three-State
PWM Input” on page 9 for further details. Connect this pin to the
PWM output of the controller.
propagation delay (t
) is encountered before the upper gate
PDLU
begins to fall (t ). The upper MOSFET gate-to-source voltage is
FU
monitored, and the lower gate is allowed to rise after the upper
MOSFET gate-to-source voltage drops below 1V. The lower gate
then rises (t ), turning on the lower MOSFET.
GND
RL
GND is the ground pin for the IC.
This driver is optimized for converters with large step-down
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.
LGATE
LGATE is the lower gate drive output. Connect to gate of the
low-side power N-channel MOSFET.
The 0.5Ω ON-resistance and 4A sink current capability enables
the lower gate driver to absorb the current injected to the lower
gate through the drain-to-gate capacitor of the lower MOSFET and
prevents a shoot-through caused by the high dv/dt of the phase
node.
VCC
Connect the VCC pin to a +5V bias supply. Place a high quality
bypass capacitor from this pin to GND.
FCCM
The FCCM pin enables or disables Diode Emulation. When FCCM
is LOW, diode emulation is allowed. Otherwise, continuous
conduction mode is forced. See “Diode Emulation” on page 9 for
more detail.
PHASE
Connect the PHASE 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.
FN8395 Rev 1.00
Jun 1, 2016
Page 7 of 12
ISL6208C
Typical Performance Waveforms
FIGURE 4. LOAD TRANSIENT (0A TO 30A, 3-PHASE)
FIGURE 6. DCM TO CCM TRANSITION AT NO LOAD
FIGURE 8. PREBIASED START-UP IN CCM MODE
FIGURE 5. LOAD TRANSIENT (30A TO 0A, 3-PHASE)
FIGURE 7. CCM TO DCM TRANSITION AT NO LOAD
FIGURE 9. PREBIASED START-UP IN DCM MODE
FN8395 Rev 1.00
Jun 1, 2016
Page 8 of 12
ISL6208C
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.
Diode Emulation
Diode emulation allows for higher converter efficiency under light
load situations. With diode emulation active, the ISL6208C will
detect the zero current crossing of the output inductor and turn
off LGATE. This ensures that discontinuous conduction mode
(DCM) is achieved. Diode emulation is asynchronous to the PWM
signal. Therefore, the ISL6208C will respond to the FCCM input
immediately after it changes state. Refer to“Typical Performance
Waveforms” on page 8. Note: Intersil does not recommend Diode
2.0
1.8
1.6
1.4
1.2
1.0
0.8
Emulation use with r
current sensing topologies. The
DS(ON)
turn-OFF of the low-side MOSFET can cause gross current
measurement inaccuracies.
Q
= 100nC
0.6
0.4
0.2
0.0
GATE
Three-State PWM Input
A unique feature of the ISL6208C 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” table on page 5 determine when the
lower and upper gates are enabled.
20nC
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
V (V)
BOOT_CAP
FIGURE 10. BOOTSTRAP CAPACITANCE vs BOOT RIPPLE VOLTAGE
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 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 shown in Equation 2:
The VCC pin of the driver(s) and related VCC or +5V bias supply
pin of the Intersil controller must share a common +5V supply.
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 turn on.
P = f 1.5V Q + V Q + I V
VCC
CC
(EQ. 2)
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-to-source 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.
sw
U
L
U
L
Where f is the switching frequency of the PWM signal. V and
sw
U
V represent the upper and lower gate rail voltage. Q and Q is
L
U
L
the upper and lower gate charge determined by MOSFET
selection and any external capacitance added to the gate pins.
The lV product is the quiescent power of the driver and is
V
CC CC
typically negligible.
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 must have a maximum voltage rating
above the maximum battery voltage plus 5V. The bootstrap
capacitor can be chosen from Equation 1:
Q
GATE
(EQ. 1)
-----------------------
C
BOOT
V
BOOT
Where Q
is the amount of gate charge required to fully
GATE
charge the gate of the upper MOSFET. The V
term is
BOOT
defined as the allowable droop in the rail of the upper drive.
As an example, suppose an upper MOSFET has a gate charge,
Q
, of 25nC at 5V and also assume the droop in the drive
GATE
FN8395 Rev 1.00
Jun 1, 2016
Page 9 of 12
ISL6208C
Thermal Management
1000
Q
Q
= 50nC
= 100nC
=100nC
= 200nC
U
U
L
Q
Q
= 50nC
= 50nC
For maximum thermal performance in high current, high
switching frequency applications, connecting the thermal pad of
the DFN to the power ground with multiple vias is recommended.
This heat spreading allows the part to achieve its full thermal
potential.
U
L
Q
Q
900
800
700
600
500
400
300
200
100
0
L
Q
= 20nC
=50nC
U
L
Q
0
200 400 600 800 1000 1200 1400 1600 1800 2000
FREQUENCY (kHz)
FIGURE 11. POWER DISSIPATION vs FREQUENCY
Layout Considerations
Reducing Phase Ring
The parasitic inductances of the PCB and power devices (both
upper and lower FETs) could cause increased PHASE ringing,
which may lead to voltages that exceed the absolute maximum
rating of the devices. When PHASE rings below ground, the
negative voltage could add charge to the bootstrap capacitor
through the internal bootstrap diode. Under worst-case
conditions, the added charge could overstress the BOOT and/or
PHASE pins. To prevent this from happening, the user should
perform a careful layout inspection to reduce trace inductances,
2
and select low lead inductance MOSFETs and drivers. D PAK and
DPAK packaged MOSFETs have high parasitic lead inductances,
as opposed to SOIC-8. If higher inductance MOSFETs must be
used, a Schottky diode is recommended across the lower
MOSFET to clamp negative PHASE ring.
A good layout would help reduce the ringing on the phase and
gate nodes significantly:
• Avoid using vias for decoupling components where possible,
especially in the BOOT-to-PHASE path. Little or no use of vias
for VCC and GND is also recommended. Decoupling loops
should be short.
• All power traces (UGATE, PHASE, LGATE, GND, VCC) should be
short and wide, and avoid using vias. If vias must be used, two
or more vias per layer transition is recommended.
• Keep the SOURCE of the upper FET as close as thermally
possible to the DRAIN of the lower FET.
• Keep the connection in between the SOURCE of lower FET and
power ground wide and short.
• Input capacitors should be placed as close to the DRAIN of the
upper FET and the SOURCE of the lower FET as thermally
possible.
Note: Refer to Intersil Tech Brief TB447 for more information.
FN8395 Rev 1.00
Jun 1, 2016
Page 10 of 12
ISL6208C
Revision History The revision history provided is for informational purposes only and is believed to be accurate, but not warranted.
Please go to web to make sure you have the latest revision.
DATE
REVISION
FN8395.1
CHANGE
June 1, 2016
Added note to VCC pin description on page 4 and to “Three-State PWM Input” on page 9 that +5V supply
should be common with Intersil controller.
Added AC specification to BOOT-GND Absolute Maximum Rating on page 5.
On page 12 - Updated L8.2x2D POD from rev 0 to rev 1. Updates since rev 0:
Tiebar Note 5 updated From: "Tiebar shown (if present) is a non-functional feature."
To: "Tiebar shown (if present) is a non-functional feature and may be located on any of the 4 sides (or
ends)."
November 29, 2012
FN8395.0
Initial Release
About Intersil
Intersil Corporation is a leading provider of innovative power management and precision analog solutions. The company's products
address some of the largest markets within the industrial and infrastructure, mobile computing and high-end consumer markets.
For the most updated datasheet, application notes, related documentation and related parts, please see the respective product
information page found at www.intersil.com.
You may report errors or suggestions for improving this datasheet by visiting www.intersil.com/ask.
Reliability reports are also available from our website at www.intersil.com/support.
© Copyright Intersil Americas LLC 2012-2016. All Rights Reserved.
All trademarks and registered trademarks are the property of their respective owners.
For additional products, see www.intersil.com/en/products.html
Intersil products are manufactured, assembled and tested utilizing ISO9001 quality systems as noted
in the quality certifications found at www.intersil.com/en/support/qualandreliability.html
Intersil products are sold by description only. Intersil may modify the circuit design and/or specifications of products at any time without notice, provided that such
modification does not, in Intersil's sole judgment, affect the form, fit or function of the product. Accordingly, the reader is cautioned to verify that datasheets 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 implication or
otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
FN8395 Rev 1.00
Jun 1, 2016
Page 11 of 12
ISL6208C
Package Outline Drawing
L8.2x2D
8 LEAD DUAL FLAT NO-LEAD PLASTIC PACKAGE (DFN) WITH EXPOSED PAD
Rev 1, 3/15
2.00
6
A
PIN #1
6
B
INDEX AREA
PIN 1
INDEX AREA
8
1
6x 0.50
1.55±0.10
(4X)
0.15
0.22
0.10M C AB
( 8x0.30 )
4
TOP VIEW
0.90±0.10
BOTTOM VIEW
SEE DETAIL "X"
C
0 . 2 REF
0.10
C
C
0.90±0.10
BASE PLANE
0 . 00 MIN.
0 . 05 MAX.
SEATING PLANE
0.08
C
SIDE VIEW
DETAIL "X"
( 8x0.20 )
( 8x0.30 )
PACKAGE
OUTLINE
NOTES:
1. Dimensions are in millimeters.
Dimensions in ( ) for Reference Only.
( 6x0.50 )
2. Dimensioning and tolerancing conform to AMSE Y14.5m-1994.
3. Unless otherwise specified, tolerance: Decimal ± 0.05
1.55
2.00
4. Dimension applies to the metallized terminal and is measured
between 0.15mm and 0.30mm from the terminal tip.
( 8x0.22 )
5. Tiebar shown (if present) is a non-functional feature and may
be located on any of the 4 sides (or ends).
0.90
2.00
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.
6.
TYPICAL RECOMMENDED LAND PATTERN
FN8395 Rev 1.00
Jun 1, 2016
Page 12 of 12
相关型号：
ISL6208CBZ-T
High Voltage Synchronous Rectified Buck MOSFET Drivers; QFN8, SOIC8; Temp Range: See Datasheet
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