View ISL6609IBZ_4871654.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

(R)
ISL6609, ISL6609A
Data Sheet April 27, 2009 FN9221.2
Synchronous Rectified MOSFET Driver
The ISL6609, ISL6609A is a high frequency, MOSFET driver optimized to drive two N-Channel power MOSFETs in a synchronous-rectified buck converter topology. This driver combined with an Intersil ISL63xx or ISL65xx multiphase 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), minimizing driver switching losses in high MOSFET gate capacitance and high switching frequency applications. Each driver is capable of driving a 3nF load with less than 10ns rise/fall time. Bootstrapping of the upper gate driver is implemented via an internal low forward drop 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 ISL6609, ISL6609A features 4A typical sink current for the lower gate driver, enhancing the lower MOSFET gate hold-down capability during PHASE node rising edge, preventing power loss caused by the self turn-on of the lower MOSFET due to the high dV/dt of the switching node. The ISL6609, ISL6609A also features an input that recognizes a high-impedance state, working together with Intersil multiphase PWM controllers to prevent negative transients on the controlled output voltage when operation is suspended. This feature eliminates the need for the schottky diode that may be utilized in a power system to protect the load from negative output voltage damage. In addition, the ISL6609A's bootstrap function is designed to prevent the BOOT capacitor from overcharging, should excessively large negative swings occur at the transitions of the PHASE node.
Features
* Drives Two N-Channel MOSFETs * Adaptive Shoot-Through Protection * 0.4 On-Resistance and 4A Sink Current Capability * Supports High Switching Frequency - Fast Output Rise and Fall - Ultra Low Three-State Hold-Off Time (20ns) * ISL6605 Replacement with Enhanced Performance * BOOT Capacitor Overcharge Prevention (ISL6609A) * Low VF Internal Bootstrap Diode * Low Bias Supply Current * Enable Input and Power-On Reset * 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 (RoHS Compliant)
Applications
* Core Voltage Supplies for Intel(R) and AMD(R) Microprocessors * High Frequency Low Profile High Efficiency DC/DC Converters * High Current Low Voltage DC/DC Converters * Synchronous Rectification for Isolated Power Supplies
Related Literature
* Technical Brief TB363 "Guidelines for Handling and Processing Moisture Sensitive Surface Mount Devices (SMDs)"
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. 2005, 2006, 2009. All Rights Reserved. Intel(R) is a registered trademark of Intel Corporation. AMD(R) is a registered trademark of Advanced Micro Devices, Inc. All other trademarks mentioned are the property of their respective owners.
ISL6609, ISL6609A Ordering Information
PART NUMBER (Note) ISL6609CBZ ISL6609CBZ-T* ISL6609CRZ ISL6609CRZ-T* ISL6609IBZ ISL6609IBZ-T* ISL6609IRZ ISL6609IRZ-T* ISL6609ACBZ ISL6609ACBZ-T* ISL6609ACRZ ISL6609ACRZ-T* ISL6609AIBZ ISL6609AIBZ-T* ISL6609AIRZ ISL6609AIRZ-T* ISL6609AIRZ-TK* PART MARKING ISL66 09CBZ ISL66 09CBZ 609Z 609Z ISL66 09IBZ ISL66 09IBZ 09IZ 09IZ 6609 ACBZ 6609 ACBZ 09AZ 09AZ 6609 AIBZ 6609 AIBZ 9AIZ 9AIZ 9AIZ TEMP. RANGE (C) 0 to +70 0 to +70 0 to +70 0 to +70 -40 to +85 -40 to +85 -40 to +85 -40 to +85 0 to +70 0 to +70 0 to +70 0 to +70 -40 to +85 -40 to +85 -40 to +85 -40 to +85 -40 to +85 PACKAGE (Pb-Free) 8 Ld SOIC 8 Ld SOIC 8 Ld 3x3 QFN 8 Ld 3x3 QFN 8 Ld SOIC 8 Ld SOIC 8 Ld 3x3 QFN 8 Ld 3x3 QFN 8 Ld SOIC 8 Ld SOIC 8 Ld 3x3 QFN 8 Ld 3x3 QFN 8 Ld SOIC 8 Ld SOIC 8 Ld 3x3 QFN 8 Ld 3x3 QFN 8 Ld 3x3 QFN M8.15 M8.15 L8.3x3 L8.3x3 M8.15 M8.15 L8.3x3 L8.3x3 M8.15 M8.15 L8.3x3 L8.3x3 M8.15 M8.15 L8.3x3 L8.3x3 L8.3x3 PKG. DWG. #
*Please refer to TB347 for details on reel specifications. NOTE: 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.
Pinouts
ISL6609, ISL6609A (8 LD SOIC) TOP VIEW
UGATE BOOT PWM GND 1 2 3 4 8 7 6 5 PHASE EN VCC LGATE BOOT 1 PWM 2 3 GND 4 LGATE 6 6 EN 5 VCC
ISL6609, ISL6609A (8 LD QFN) TOP VIEW
PHASE 7 UGATE 8
2
FN9221.2 April 27, 2009
ISL6609, ISL6609A Block Diagram
ISL6609 and ISL6609A
RBOOT VCC EN VCC 4.25k PWM 4k CONTROL LOGIC SHOOTTHROUGH PROTECTION VCC LGATE GND PHASE BOOT UGATE
INTEGRATED 3 RESISTOR (RBOOT) AVAILABLE ONLY IN ISL6609A
3
FN9221.2 April 27, 2009
ISL6609, ISL6609A Typical Application - Multiphase Converter Using ISL6609 Gate Drivers
VIN +5V +5V +5V VCC FB VCC VSEN PWM1 PGOOD PWM2 PWM CONTROL (ISL63XX or ISL65XX) VID (OPTIONAL) ISEN1 ISEN2 +5V VIN COMP EN PWM ISL6609 PHASE LGATE UGATE RUGPH BOOT
+VCORE
VCC FS/EN GND EN PWM ISL6609
BOOT UGATE RUGPH
PHASE LGATE
RUGPH IS REQUIRED FOR SPECIAL POWER SEQUENCING APPLICATIONS (SEE APPLICATION INFORMATION SECTION ON PAGE 8)
4
FN9221.2 April 27, 2009
ISL6609, ISL6609A
Absolute Maximum Ratings
Supply Voltage (VCC) . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 7V Input Voltage (VEN, VPWM) . . . . . . . . . . . . . . . -0.3V to VCC + 0.3V BOOT Voltage (VBOOT-GND). . . -0.3V to 27V (DC) or 36V (<200ns) BOOT To PHASE Voltage (VBOOT-PHASE) . . . . . . -0.3V to 7V (DC) -0.3V to 9V (<10ns) PHASE Voltage . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to 27V (DC) GND -8V (<20ns Pulse Width, 10J) to 30V (<100ns) UGATE Voltage . . . . . . . . . . . . . . . . VPHASE - 0.3V (DC) to VBOOT VPHASE - 5V (<20ns Pulse Width, 10J) to VBOOT LGATE Voltage . . . . . . . . . . . . . . . GND - 0.3V (DC) to VCC + 0.3V GND - 2.5V (<20ns Pulse Width, 5J) to VCC + 0.3V Ambient Temperature Range . . . . . . . . . . . . . . . . . .-40C to +125C
Thermal Information
Thermal Resistance (Notes 1, 2, 3) JA(C/W) JC(C/W) SOIC Package (Note 1) . . . . . . . . . . . . 110 N/A QFN Package (Notes 2, 3). . . . . . . . . . 95 36 Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . 150C Maximum Storage Temperature Range . . . . . . . . . . . -65C to 150C Pb-Free Reflow Profile. . . . . . . . . . . . . . . . . . . . . . . . .see link below http://www.intersil.com/pbfree/Pb-FreeReflow.asp
Recommended Operating Conditions
Ambient Temperature Range . . . . . . . . . . . . . . . . . . .-40C to 100C Maximum Operating Junction Temperature . . . . . . . . . . . . . . 125C Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5V 10%
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: 1. JA is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details. 2. JA is measured in free air with the component mounted on a high effective thermal conductivity test board with "direct attach" features. 3. JC, "case temperature" location is at the center of the package underside exposed pad. See Tech Brief TB379 for details.
Electrical Specifications
These specifications apply for TA = -40C to 100C, unless otherwise noted. Parameters with MIN and/or MAX limits are 100% tested at +25C, unless otherwise specified. Temperature limits established by characterization and are not production tested. SYMBOL TEST CONDITIONS MIN TYP MAX UNITS
PARAMETER VCC SUPPLY CURRENT Bias Supply Current POR Rising POR Falling Hysteresis PWM INPUT Sinking Impedance Source Impedance Three-State Rising Threshold Three-State Falling Threshold Three-State Shutdown Holdoff Time EN INPUT EN LOW Threshold EN HIGH Threshold SWITCHING TIME (See Figure 1 on Page 7) UGATE Rise Time (Note 4) LGATE Rise Time (Note 4) UGATE Fall Time (Note 4) LGATE Fall Time (Note 4) UGATE Turn-Off Propagation Delay LGATE Turn-Off Propagation Delay
IVCC
PWM pin floating, VVCC = 5V
2.2 -
132 3.4 3.0 400
4.2 -
A
mV
RPWM_SNK RPWM_SRC VVCC = 5V (100mV Hysteresis) VVCC = 5V (100mV Hysteresis) tTSSHD tPDLU or tPDLL + Gate Falling Time
2.75 3 3.10 -
4 4.25 1.70 3.41 20
5.5 5.75 2.00 -
k k V V ns
1.0 -
1.3 1.6
2.0
V V
tRU tRL tFU tFL tPDLU tPDLL
VVCC = 5V, 3nF Load VVCC = 5V, 3nF Load VVCC = 5V, 3nF Load VVCC = 5V, 3nF Load VVCC = 5V, Outputs Unloaded VVCC = 5V, Outputs Unloaded
-
8.0 8.0 8.0 4.0 18 25
-
ns ns ns ns ns ns
5
FN9221.2 April 27, 2009
ISL6609, ISL6609A
Electrical Specifications
These specifications apply for TA = -40C to 100C, unless otherwise noted. Parameters with MIN and/or MAX limits are 100% tested at +25C, unless otherwise specified. Temperature limits established by characterization and are not production tested. (Continued) SYMBOL tPDHU tPDHL tPTS TEST CONDITIONS VVCC = 5V, Outputs Unloaded VVCC = 5V, Outputs Unloaded VVCC = 5V, Outputs Unloaded MIN TYP 18 23 20 MAX UNITS ns ns ns
PARAMETER UGATE Turn-On Propagation Delay LGATE Turn-On Propagation Delay Three-state to UG/LG Rising Propagation Delay OUTPUT Upper Drive Source Resistance Upper Drive Sink Resistance Lower Drive Source Resistance Lower Drive Sink Resistance NOTE:
RUG_SRC RUG_SNK RLG_SRC RLG_SNK
250mA Source Current 250mA Sink Current 250mA Source Current 250mA Sink Current
-
1.0 1.0 1.0 0.4
2.5 2.5 2.5 1.0

4. Limits established by characterization and are not production tested
Functional Pin Description
Note: Pin numbers refer to the SOIC package. Check diagram for corresponding QFN pinout.
LGATE (Pin 5)
Lower gate drive output. Connect to gate of the low side N-Channel power MOSFET. A gate resistor is never recommended on this pin, as it interferes with the operation shoot-through protection circuitry.
UGATE (Pin 1)
Upper gate drive output. Connect to gate of high-side N-Channel power MOSFET. A gate resistor is never recommended on this pin, as it interferes with the operation shoot-through protection circuitry.
VCC (Pin 6)
Connect this pin to a +5V bias supply. Locally bypass with a high quality ceramic capacitor to ground.
BOOT (Pin 2)
Floating bootstrap supply pin for the upper gate drive. Connect a bootstrap capacitor between this pin and the PHASE pin. The bootstrap capacitor provides the charge used to turn on the upper MOSFET. See "Bootstrap Considerations" on page 7 for guidance in choosing the appropriate capacitor value.
EN (Pin 7)
Enable input pin. Connect this pin high to enable and low to disable the driver.
PHASE (Pin 8)
Connect this pin to the source of the upper MOSFET. This pin provides the return path for the upper gate driver current.
PWM (Pin 3)
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 7 for further details. Connect this pin to the PWM output of the controller.
Thermal Pad (in QFN only)
The metal pad underneath the center of the IC is a thermal substrate. The PCB "thermal land" design for this exposed die pad should include 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.
GND (Pin 4)
Ground pin. All signals are referenced to this node.
6
FN9221.2 April 27, 2009
ISL6609, ISL6609A Timing Diagram
2.5V PWM tPDHU tPDLU tRU tPTS 1V UGATE tRU tTSSHD
tFU
LGATE 1V tRL tTSSHD tPDLL tPDHL tFL
tPTS
FIGURE 1. TIMING DIAGRAM
Operation and Adaptive Shoot-Through Protection
Designed for high speed switching, the ISL6609, ISL6609A MOSFET driver controls both high-side and low-side NChannel FETs from one externally provided PWM signal. A rising transition on PWM initiates the turn-off of the lower MOSFET (see "Timing Diagram"). After a short propagation delay [tPDLL], the lower gate begins to fall. Typical fall times [tFL] are provided in the "Electrical Specifications" table on page 5. Adaptive shoot-through circuitry monitors the LGATE voltage and turns on the upper gate following a short delay time [tPDHU] after the LGATE voltage drops below ~1V. The upper gate drive then begins to rise [tRU] and the upper MOSFET turns 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 [tPDLU] is encountered before the upper gate begins to fall [tFU]. The adaptive shoot-through circuitry monitors the UGATE-PHASE voltage and turns on the lower MOSFET a short delay time, tPDHL, after the upper MOSFET's gate voltage drops below 1V. The lower gate then rises [tRL], turning on the lower MOSFET. These methods prevent both the lower and upper MOSFETs from conducting simultaneously (shoot-through), while adapting the dead time to the gate charge characteristics of the MOSFETs being used. This driver is optimized for voltage regulators with large step down ratio. The lower MOSFET is usually sized larger compared to the upper MOSFET because the lower MOSFET conducts for a longer time during a switching period. The lower gate driver is therefore sized much larger to meet this application requirement. The 0.4 ON-resistance and 4A sink
current capability enable the lower gate driver to absorb the current injected into the lower gate through the drain-to-gate capacitor of the lower MOSFET and help prevent shoot through caused by the self turn-on of the lower MOSFET due to high dV/dt of the switching node.
Three-State PWM Input
A unique feature of the ISL6609, ISL6609A is the adaptable three-state PWM input. Once the PWM signal enters the shutdown window, either MOSFET previously conducting is turned off. If the PWM signal remains within the shutdown window for longer than the gate turn-off propagation delay of the previously conducting MOSFET, 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. The PWM rising and falling thresholds outlined in the "Electrical Specifications" table on page 5 determine when the lower and upper gates are enabled. During normal operation in a typical application, the PWM rise and fall times through the shutdown window should not exceed either output's turn-off propagation delay plus the MOSFET gate discharge time to ~1V. Abnormally long PWM signal transition times through the shutdown window will simply introduce additional dead time between turn off and turn on of the synchronous bridge's MOSFETs. For optimal performance, no more than 100pF parasitic capacitive load should be present on the PWM line of ISL6609, ISL6609A (assuming an Intersil PWM controller is used).
Bootstrap Considerations
This driver features an internal bootstrap diode. Simply adding an external capacitor across the BOOT and PHASE pins completes the bootstrap circuit. The ISL6609A's internal
7
FN9221.2 April 27, 2009
ISL6609, ISL6609A
bootstrap resistor is designed to reduce the overcharging of the bootstrap capacitor when exposed to excessively large negative voltage swing at the PHASE node. Typically, such large negative excursions occur in high current applications that use D2-PAK and D-PAK MOSFETs or excessive layout parasitic inductance. The following equation helps select a proper bootstrap capacitor size:
Q GATE C BOOT_CAP ------------------------------------V BOOT_CAP Q G1 * VCC Q GATE = ------------------------------ * N Q1 V GS1
(EQ. 1)
allowable power dissipation level will push the IC beyond the maximum recommended operating junction temperature of +125C. The maximum allowable IC power dissipation for the SO8 package is approximately 800mW at room temperature, while the power dissipation capacity in the QFN package, with an exposed heat escape pad, is slightly better. See "Layout Considerations" on page 9 for thermal transfer improvement suggestions. When designing the driver into an application, it is recommended that the following calculation is used to ensure safe operation at the desired frequency for the selected MOSFETs. The total gate drive power losses due to the gate charge of MOSFETs and the driver's internal circuitry and their corresponding average driver current can be estimated with Equations 2 and 3, respectively,
P Qg_TOT = P Qg_Q1 + P Qg_Q2 + I Q * VCC Q G1 * VCC 2 P Qg_Q1 = ---------------------------------- * F SW * N Q1 V GS1 Q G2 * VCC 2 P Qg_Q2 = ---------------------------------- * F SW * N Q2 V GS2 Q G1 * UVCC * N Q1 Q G2 * LVCC * N Q2 I DR = ----------------------------------------------------- + ---------------------------------------------------- * F SW + I Q V GS1 V GS2 (EQ. 3) (EQ. 2)
where QG1 is the amount of gate charge per upper MOSFET at VGS1 gate-source voltage and NQ1 is the number of control MOSFETs. The VBOOT_CAP term is defined as the allowable droop in the rail of the upper gate drive. As an example, suppose two IRLR7821 FETs are chosen as the upper MOSFETs. The gate charge, QG, from the data sheet is 10nC at 4.5V (VGS) gate-source voltage. Then the QGATE is calculated to be 22nC at VCC level. We will assume a 200mV droop in drive voltage over the PWM cycle. We find that a bootstrap capacitance of at least 0.110F is required. The next larger standard value capacitance is 0.22F. A good quality ceramic capacitor is recommended.
2.0 1.8 1.6 1.4 CBOOT_CAP (F) 1.2 1.0 0.8 0.6 QGATE = 100nC 0.4 50nC 0.2 20nC 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.0 0.0
where the gate charge (QG1 and QG2) is defined at a particular gate to source voltage (VGS1and VGS2) in the corresponding MOSFET datasheet; IQ is the driver's total quiescent current with no load at both drive outputs; NQ1 and NQ2 are number of upper and lower MOSFETs, respectively. The IQ VCC product is the quiescent power of the driver without capacitive load and is typically negligible. The total gate drive power losses are dissipated among the resistive components along the transition path. The drive resistance dissipates a portion of the total gate drive power losses, the rest will be dissipated by the external gate resistors (RG1 and RG2, should be a short to avoid interfering with the operation shoot-through protection circuitry) and the internal gate resistors (RGI1 and RGI2) of MOSFETs. Figures 3 and 4 show the typical upper and lower gate drives turn-on transition path. The power dissipation on the driver can be roughly estimated as:
P DR = P DR_UP + P DR_LOW + I Q * VCC R LO1 R HI1 P Qg_Q1 P DR_UP = -------------------------------------- + --------------------------------------- * --------------------R HI1 + R EXT1 R LO1 + R EXT1 2 R LO2 R HI2 P Qg_Q2 P DR_LOW = -------------------------------------- + --------------------------------------- * --------------------2 R HI2 + R EXT2 R LO2 + R EXT2 R GI1 R EXT2 = R G1 + ------------N
Q1
VBOOT (V)
FIGURE 2. BOOTSTRAP CAPACITANCE vs BOOT RIPPLE VOLTAGE
(EQ. 4)
Power Dissipation
Package power dissipation is mainly a function of the switching frequency (FSW), the output drive impedance, the external gate resistance, and the selected MOSFET's internal gate resistance and total gate charge. Calculating the power dissipation in the driver for a desired application is critical to ensure safe operation. Exceeding the maximum
R GI2 R EXT2 = R G2 + ------------N
Q2
8
FN9221.2 April 27, 2009
ISL6609, ISL6609A
VCC BOOT D CGD RHI1 RLO1 G RG1 RGI1 CGS S PHASE Q1 CDS
Layout Considerations
A good layout helps reduce the ringing on the switching node (PHASE) and significantly lower the stress applied to the output drives. The following advice is meant to lead to an optimized layout: * Keep decoupling loops (VCC-GND and BOOT-PHASE) as short as possible. * Minimize trace inductance, especially on low-impedance lines. All power traces (UGATE, PHASE, LGATE, GND, VCC) should be short and wide, as much as possible. * Minimize the inductance of the PHASE node. Ideally, the source of the upper and the drain of the lower MOSFET should be as close as thermally allowable.
UGATE
FIGURE 3. TYPICAL UPPER-GATE DRIVE TURN-ON PATH
VCC D CGD RHI2 RLO2 LGATE G RG2 RGI2 CGS GND S Q2 CDS
* Minimize the current loop of the output and input power trains. Short the source connection of the lower MOSFET to ground as close to the transistor pin as feasible. Input capacitors (especially ceramic decoupling) should be placed as close to the drain of upper and source of lower MOSFETs as possible. In addition, connecting the thermal pad of the QFN package to the power ground through a via, or placing a low noise copper plane underneath the SOIC part is recommended for high switching frequency, high current applications. This is to improve heat dissipation and allow the part to achieve its full thermal potential.
FIGURE 4. TYPICAL LOWER-GATE DRIVE TURN-ON PATH
Application Information
MOSFET and Driver Selection
The parasitic inductances of the PCB and of the power devices' packaging (both upper and lower MOSFETs) can cause serious ringing, exceeding absolute maximum rating of the devices. The negative ringing at the edges of the PHASE node could increase the bootstrap capacitor voltage through the internal bootstrap diode, and in some cases, it may overstress the upper MOSFET driver. Careful layout, proper selection of MOSFETs and packaging, as well as the proper driver can go a long way toward minimizing such unwanted stress. The selection of D2-PAK, or D-PAK packaged MOSFETs, is a much better match (for the reasons discussed) for the ISL6609A. Low-profile MOSFETs, such as Direct FETs and multi-SOURCE leads devices (SO-8, LFPAK, PowerPAK), have low parasitic lead inductances and can be driven by either ISL6609 or ISL6609A (assuming proper layout design). The ISL6609, missing the 3 integrated BOOT resistor, typically yields slightly higher efficiency than the ISL6609A.
Upper MOSFET Self Turn-On Effects at Startup
Should the driver have insufficient bias voltage applied, its outputs are floating. If the input bus is energized at a high dV/dt rate while the driver outputs are floating, because of self-coupling via the internal CGD of the MOSFET, the UGATE could momentarily rise up to a level greater than the threshold voltage of the MOSFET. This could potentially turn on the upper switch and result in damaging inrush energy. Therefore, if such a situation (when input bus powered up before the bias of the controller and driver is ready) could conceivably be encountered, it is a common practice to place a resistor (RUGPH) across the gate and source of the upper MOSFET to suppress the Miller coupling effect. The value of the resistor depends mainly on the input voltage's rate of rise, the CGD/CGS ratio, as well as the gate-source threshold of the upper MOSFET. A higher dV/dt, a lower CDS/CGS ratio, and a lower gate-source threshold upper FET will require a smaller resistor to diminish the effect of the internal capacitive coupling. For most applications, a 5k to 10k resistor is typically sufficient, not affecting normal performance and efficiency. The coupling effect can be roughly estimated with the following equations, which assume a fixed linear input ramp and neglect the clamping effect of the body diode of the upper drive and the bootstrap capacitor. Other parasitic components such as lead inductances and PCB capacitances are also not taken into account. These equations are provided for guidance purpose only.
9
FN9221.2 April 27, 2009
ISL6609, ISL6609A
Therefore, the actual coupling effect should be examined using a very high impedance (10M or greater) probe to ensure a safe design margin.
DS --------------------------------- dV ------ R C dV iss 1 - e dt V GS_MILLER = ------- R C rss dt -V
(EQ. 5)
R = R UGPH + R GI
C rss = C GD
C iss = C GD + C GS
VCC
BOOT CBOOT CGD
VIN D
ISL6609/A
DU DL
UGATE RUGPH
G RGI CGS S
CDS
QUPPER
PHASE
FIGURE 5. GATE TO SOURCE RESISTOR TO REDUCE UPPER MOSFET MILLER COUPLING
10
FN9221.2 April 27, 2009
ISL6609, ISL6609A
Package Outline Drawing
L8.3x3
8 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE Rev 2, 3/07
3.00 A B 6 PIN 1 INDEX AREA 6 3.00 1 1 .10 0 . 15 5 2 7 4X 0.65 8 6 PIN #1 INDEX AREA
(4X)
0.15 4 3 0.10 M C A B 4 8X 0.28 0.05 8X 0.60 0.15
TOP VIEW
BOTTOM VIEW
SEE DETAIL "X"
0.10 C
0 . 90 0.1 ( 2. 60 TYP ) ( 4X 0 . 65 ) BASE PLANE
C
SEATING PLANE 0.08 C
(
1. 10 )
SIDE VIEW
( 8X 0 . 28 )
C
0 . 2 REF
5
( 8X 0 . 80)
0 . 00 MIN. 0 . 05 MAX.
TYPICAL RECOMMENDED LAND PATTERN
DETAIL "X"
NOTES: 1. Dimensions are in millimeters. Dimensions in ( ) for Reference Only. 2. Dimensioning and tolerancing conform to AMSE Y14.5m-1994. 3. Unless otherwise specified, tolerance : Decimal 0.05 4. Dimension b applies to the metallized terminal and is measured between 0.15mm and 0.30mm from the terminal tip. 5. Tiebar shown (if present) is a non-functional feature. 6. The configuration of the pin #1 identifier is optional, but must be located within the zone indicated. The pin #1 indentifier may be either a mold or mark feature.
11
FN9221.2 April 27, 2009
ISL6609, ISL6609A Small Outline Plastic Packages (SOIC)
N INDEX AREA E -B1 2 3 SEATING PLANE -AD -CA h x 45 H 0.25(0.010) M BM
M8.15 (JEDEC MS-012-AA ISSUE C)
8 LEAD NARROW BODY SMALL OUTLINE PLASTIC PACKAGE INCHES SYMBOL A A1
L
MILLIMETERS MIN 1.35 0.10 0.33 0.19 4.80 3.80 5.80 0.25 0.40 8 8 0 8 MAX 1.75 0.25 0.51 0.25 5.00 4.00 6.20 0.50 1.27 NOTES 9 3 4 5 6 7 Rev. 1 6/05
MIN 0.0532 0.0040 0.013 0.0075 0.1890 0.1497 0.2284 0.0099 0.016 8 0
MAX 0.0688 0.0098 0.020 0.0098 0.1968 0.1574 0.2440 0.0196 0.050
B C D E e H
C
A1 0.10(0.004)
0.050 BSC
1.27 BSC
e
B 0.25(0.010) M C AM BS
h L N
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.
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 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 12
FN9221.2 April 27, 2009

▲Up To Search▲

Price & Availability of ISL6609IBZ

	To Download ISL6609IBZ Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .