High Voltage Synchronous Rectified Buck MOSFET Drivers ISL6208C Features The ISL6208C is a high frequency, dual MOSFET driver, 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 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. 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. 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 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 pre-biased 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. • 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 • 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 pre-biased start-up applications • VCC POR (Power-On-Reset) feature integrated • Low three-state shutdown holdoff time (typical 160ns) • Pin-to-pin compatible with ISL6207 • DFN package • 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 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” November 29, 2012 FN8395.0 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas Inc. 2012. All Rights Reserved Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. All other trademarks mentioned are the property of their respective owners. ISL6208C Ordering Information PART NUMBER (Notes 1, 2, 3) PART MARKING TEMP. RANGE (°C) PACKAGE (Pb-free) PKG. DWG. # ISL6208CHRZ 8CH -10 to +100 8 Ld 2x2 DFN L8.2x2D ISL6208CIRZ 8CI -40 to +100 8 Ld 2x2 DFN L8.2x2D NOTES: 1. Add “-T*” suffix for tape and reel. 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 1 86 PHASE BOOT 2 7 FCCM PWM 3 66 VCC GND 4 5 LGATE Pin Description PIN SYMBOL DESCRIPTION 1 UGATE The UGATE pin is the upper gate drive output. Connect to gate of the high-side power N-Channel MOSFET. 2 BOOT 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 GND GND is the ground pin for the IC. 5 LGATE 6 VCC 7 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. 8 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. 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. 2 FN8395.0 November 29, 2012 ISL6208C Block Diagram VCC BOOT FCCM UGATE PHASE SHOOTTHROUGH PROTECTION CONTROL LOGIC PWM VCC LGATE 10kΩ GND THERMAL PAD FIGURE 1. BLOCK DIAGRAM 3 FN8395.0 November 29, 2012 ISL6208C Table of Contents Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Thermal Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Typical Application with 2-Phase Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Package Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4 FN8395.0 November 29, 2012 ISL6208C Absolute Maximum Ratings Thermal Information Supply Voltage (VCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 7V Input Voltage (VFCCM, VPWM) . . . . . . . . . . . . . . . . . . . . -0.3V to VCC + 0.3V BOOT Voltage (VBOOT-GND) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 33V BOOT To PHASE Voltage (VBOOT-PHASE). . . . . . . . . . . . . . . . -0.3V to 7V (DC) -0.3V to 9V (<10ns) PHASE Voltage (Note 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to 30V GND - 8V (<20ns Pulse Width, 10µJ) UGATE Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . VPHASE - 0.3V (DC) to VBOOT VPHASE - 5V (<20ns Pulse Width, 10µJ) to VBOOT LGATE Voltage . . . . . . . . . . . . . . . . . . . . . . . . .GND - 0.3V (DC) to VCC + 0.3V GND - 2.5V (<20ns Pulse Width, 5µJ) to VCC + 0.3V Thermal Resistance (Typical) θJA (°C/W) θJC (°C/W) 8 Ld 2x2 DFN Package (Notes 5, 6) . . . . . . 89 24 Maximum Storage Temperature Range . . . . . . . . . . . . . .-65°C to +150°C Pb-Free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see link below http://www.intersil.com/pbfree/Pb-FreeReflow.asp Recommended Operating Conditions Ambient Temperature Range 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% 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. θJA is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See Tech Brief TB379. 6. For θJC, the “case temp” location is the center of the exposed metal pad on the package underside. Electrical Specifications Recommended operating conditions, unless otherwise noted. Boldface limits apply over the operating temperature range, -40°C to +100°C (Industrial), -10°C to +100°C (Hi-Temp Commercial). PARAMETER SYMBOL TEST CONDITIONS MIN (Note 7) TYP MAX (Note 7) UNITS - 80 - µA VCC SUPPLY CURRENT Bias Supply Current IVCC PWM pin floating, VFCCM = 5V POR VCC Rising - 3.40 3.90 V VCC Falling 2.40 2.90 - V Hysteresis - 500 - mV 0.50 0.55 0.65 V VPWM = 5V - 250 - µA VPWM = 0V - -250 - µA PWM Three-State Rising Threshold VVCC = 5V 0.70 1.00 1.30 V PWM Three-State Falling Threshold VVCC = 5V 3.5 3.8 4.1 V VVCC = 5V, temperature = +25°C 100 175 250 ns FCCM LOW Threshold 0.50 - - V FCCM HIGH Threshold - - 2.0 V BOOTSTRAP DIODE Forward Voltage VF VVCC = 5V, forward bias current = 2mA PWM INPUT Input Current IPWM Three-State Shutdown Hold-off Time tTSSHD FCCM INPUT SWITCHING TIME UGATE Rise Time tRU VVCC = 5V, 3nF load - 8.0 - ns LGATE Rise Time tRL VVCC = 5V, 3nF load - 8.0 - ns UGATE Fall Time tFU VVCC = 5V, 3nF load - 8.0 - ns LGATE Fall Time tFL VVCC = 5V, 3nF load - 4.0 - ns 5 FN8395.0 November 29, 2012 ISL6208C Electrical Specifications Recommended operating conditions, unless otherwise noted. Boldface limits apply over the operating temperature range, -40°C to +100°C (Industrial), -10°C to +100°C (Hi-Temp Commercial). (Continued) PARAMETER SYMBOL TEST CONDITIONS MIN (Note 7) TYP MAX (Note 7) UNITS UGATE Turn-Off Propagation Delay tPDLU VVCC = 5V, outputs unloaded - 18 - ns LGATE Turn-Off Propagation Delay tPDLL VVCC = 5V, outputs unloaded - 25 - ns UGATE Turn-On Propagation Delay tPDHU VVCC = 5V, outputs unloaded 10 20 30 ns LGATE Turn-On Propagation Delay tPDHL VVCC = 5V, outputs unloaded 10 20 30 ns tPTS VVCC = 5V, outputs unloaded - 35 - ns - 400 - ns UG/LG Three-State Propagation Delay Minimum LG ON-TIME in DCM tLGMIN OUTPUT Upper Drive Source Resistance RU 500mA source current - 1 2.5 Ω Upper Driver Source Current IU VUGATE-PHASE = 2.5V - 2.00 - A Upper Drive Sink Resistance RU 500mA sink current - 1 2.5 Ω Upper Driver Sink Current IU VUGATE-PHASE = 2.5V - 2.00 - A Lower Drive Source Resistance RL 500mA source current - 1 2.5 Ω Lower Driver Source Current IL VLGATE = 2.5V - 2.00 - A Lower Drive Sink Resistance RL 500mA sink current - 0.5 1.0 Ω Lower Driver Sink Current IL VLGATE = 2.5V - 4.00 - A 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. Typical Application with 2-Phase Converter +5V VBAT +5V +5V VCC FB VSEN PWM1 PWM PWM2 PGOOD UGATE FCCM VCC PHASE DRIVE ISL6208C THERMAL PAD FCCM +VCORE BOOT COMP LGATE MAIN CONTROL ISEN1 VID ISEN2 +5V VBAT VCC BOOT FS DACOUT GND FCCM PWM UGATE DRIVE ISL6208C PHASE THERMAL LGATE PAD 6 FN8395.0 November 29, 2012 ISL6208C Timing Diagram 2.5V PWM tPDHU tPDLU tRU tTSSHD tRU tFU tFU tPTS 1V UGATE LGATE tPTS 1V tRL tFL tTSSHD tPDHL tPDLL tFL Functional Pin Description PHASE UGATE 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. The UGATE pin is the upper gate drive output. Connect to gate of the high-side power N-Channel MOSFET. BOOT 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. 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. GND GND is the ground pin for the IC. LGATE LGATE is the lower gate drive output. Connect to gate of the low-side power N-Channel MOSFET. 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. 7 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 [tPDLL], the lower gate begins to fall. Typical fall times [tFL] are provided 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. 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 upper MOSFET gate-to-source voltage is 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 (tRL), turning on the lower MOSFET. 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. 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. FN8395.0 November 29, 2012 ISL6208C Typical Performance Waveforms FIGURE 2. LOAD TRANSIENT (0A TO 30A, 3-PHASE) FIGURE 3. LOAD TRANSIENT (30A TO 0A, 3-PHASE) FIGURE 4. DCM TO CCM TRANSITION AT NO LOAD FIGURE 5. CCM TO DCM TRANSITION AT NO LOAD FIGURE 6. PRE-BIASED START-UP IN CCM MODE FIGURE 7. PRE-BIASED START-UP IN DCM MODE 8 FN8395.0 November 29, 2012 ISL6208C 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 Emulation use with rDS(ON) current sensing topologies. The turnOFF of the low-side MOSFET can cause gross current measurement inaccuracies. larger standard value capacitance is 0.15µF. A good quality ceramic capacitor is recommended. 2.0 1.8 1.6 CBOOT_CAP (µF) Diode Emulation 1.0 0.8 QGATE = 100nC nC 50 0.4 0.2 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. 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. 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: (EQ. 1) where QGATE is the amount of gate charge required to fully charge the gate of the upper MOSFET. The ΔVBOOT term is defined as the allowable droop in the rail of the upper drive. As an example, suppose an upper MOSFET has a gate charge, QGATE , of 25nC at 5V and also assume the droop in 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 20nC 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 ΔVBOOT_CAP (V) 0.8 0.9 1.0 FIGURE 8. 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: P = f sw ( 1.5V U Q + V L Q ) + I VCC V U L CC (EQ. 2) where fsw is the switching frequency of the PWM signal. VU and VL represent the upper and lower gate rail voltage. QU and QL is the upper and lower gate charge determined by MOSFET selection and any external capacitance added to the gate pins. The lVCC VCC product is the quiescent power of the driver and is typically negligible. 1000 QU =100nC QL = 200nC 900 QU = 50nC QL = 100nC QU = 50nC QL = 50nC 800 700 POWER (mW) 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. 9 1.2 0.6 Three-State PWM Input Q GATE C BOOT ≥ -----------------------ΔV BOOT 1.4 600 QU = 20nC QL =50nC 500 400 300 200 100 0 0 200 400 600 800 1000 1200 1400 1600 1800 2000 FREQUENCY (kHz) FIGURE 9. POWER DISSIPATION vs FREQUENCY FN8395.0 November 29, 2012 ISL6208C 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, and select low lead inductance MOSFETs and drivers. D2PAK 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. Thermal Management 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. 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 November 29, 2012 FN8395.0 CHANGE Initial Release. About Intersil Intersil Corporation is a leader in the design and manufacture of high-performance analog, mixed-signal and power management semiconductors. The company's products address some of the fastest growing markets within the industrial and infrastructure, personal computing and high-end consumer markets. For more information about Intersil or to find out how to become a member of our winning team, visit our website and career page at www.intersil.com. For a complete listing of Applications, Related Documentation and Related Parts, please see the respective product information page. Also, please check the product information page to ensure that you have the most updated datasheet: ISL6208C To report errors or suggestions for this datasheet, please go to: www.intersil.com/askourstaff Reliability reports are available from our website at: http://rel.intersil.com/reports/search.php For additional products, see www.intersil.com/en/products.html Intersil products are manufactured, assembled and tested utilizing ISO9000 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 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 10 FN8395.0 November 29, 2012 ISL6208C Package Outline Drawing L8.2x2D 8 LEAD DUAL FLAT NO-LEAD PLASTIC PACKAGE (DFN) WITH EXPOSED PAD Rev 0, 3/11 2.00 6 PIN 1 INDEX AREA 6 PIN #1 INDEX AREA A B 8 1 2.00 6x 0.50 (4X) 1.55±0.10 0.15 0.10M C A B 0.22 4 TOP VIEW ( 8x0.30 ) 0.90±0.10 BOTTOM VIEW SEE DETAIL "X" C 0.10 C 0.90±0.10 C BASE PLANE 0 . 00 MIN. 0 . 05 MAX. SEATING PLANE 0.08 C SIDE VIEW 0 . 2 REF DETAIL "X" ( 8x0.20 ) PACKAGE OUTLINE ( 8x0.30 ) 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 applies to the metallized terminal and is measured ( 6x0.50 ) 1.55 2.00 between 0.15mm and 0.30mm from the terminal tip. ( 8x0.22 ) 0.90 2.00 TYPICAL RECOMMENDED LAND PATTERN 11 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 identifier may be either a mold or mark feature. FN8395.0 November 29, 2012