ISL6594A, ISL6594B ® Data Sheet July 31, 2006 Advanced Synchronous Rectified Buck MOSFET Drivers with Protection Features The ISL6594A and ISL6594B are high frequency MOSFET drivers specifically designed to drive upper and lower power N-Channel MOSFETs in a synchronous rectified buck converter topology. These drivers combined with the ISL6592 Digital Multi-Phase Buck PWM controller and N-Channel MOSFETs form a complete core-voltage regulator solution for advanced microprocessors. The ISL6594A drives the upper gate to 12V, while the lower gate can be independently driven over a range from 5V to 12V. The ISL6594B drives both upper and lower gates over a range of 5V to 12V. This drive-voltage provides the flexibility necessary to optimize applications involving tradeoffs between gate charge and conduction losses. An adaptive zero shoot-through protection is integrated to prevent both the upper and lower MOSFETs from conducting simultaneously and to minimize the dead time. These products add an overvoltage protection feature operational before VCC exceeds its turn-on threshold, at which the PHASE node is connected to the gate of the low side MOSFET (LGATE). The output voltage of the converter is then limited by the threshold of the low side MOSFET, which provides some protection to the microprocessor if the upper MOSFET(s) is shorted during initial start-up. These drivers also feature a three-state PWM input which, working together with Intersil’s multi-phase PWM controllers, prevents a negative transient on the output voltage when the output is shut down. This feature eliminates the Schottky diode that is used in some systems for protecting the load from reversed output voltage events. FN9157.3 Features • Dual MOSFET Drives for Synchronous Rectified Bridge • Adjustable Gate Voltage (5V to 12V) for Optimal Efficiency • 36V Internal Bootstrap Schottky Diode • Bootstrap Capacitor Overcharging Prevention • Supports High Switching Frequency (up to 2MHz) - 3A Sinking Current Capability - Fast Rise/Fall Times and Low Propagation Delays • Three-State PWM Input for Output Stage Shutdown • Three-State PWM Input Hysteresis for Applications With Power Sequencing Requirement • Pre-POR Overvoltage Protection • VCC Undervoltage Protection • Expandable Bottom Copper Pad for Enhanced Heat Sinking • Dual Flat No-Lead (DFN) Package - Near Chip-Scale Package Footprint; Improves PCB Efficiency and Thinner in Profile • Pb-Free Plus Anneal Available (RoHS Compliant) Applications • Core Regulators for Intel® and AMD® Microprocessors • High Current DC/DC Converters • High Frequency and High Efficiency VRM and VRD Related Literature • Technical Brief TB363 “Guidelines for Handling and Processing Moisture Sensitive Surface Mount Devices (SMDs)” • Technical Brief TB417 for Power Train Design, Layout Guidelines, and Feedback Compensation Design 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. 2004, 2005. All Rights Reserved All other trademarks mentioned are the property of their respective owners. ISL6594A, ISL6594B Ordering Information PART NUMBER TEMP. RANGE (°C) PART MARKING ISL6594ACB ISL6594ACB ISL6594ACB-T ISL6594ACB ISL6594ACBZ (Note) 6594ACBZ PKG. DWG. # PACKAGE 0 to 85 8 Ld SOIC M8.15 8 Ld SOIC (Pb-free) M8.15 8 Ld SOIC Tape and Reel 0 to 85 ISL6594ACBZ-T (Note) 6594ACBZ ISL6594ACR 94AC 8 Ld SOIC Tape and Reel (Pb-free) 0 to 85 ISL6594ACR-T 94AC 10 Ld 3x3 DFN Tape and Reel ISL6594ACRZ (Note) 94AZ 0 to 85 ISL6594ACRZ-T (Note) 94AZ ISL6594BCB ISL6594BCB ISL6594BCB-T ISL6594BCB ISL6594BCBZ (Note) 6594BCBZ 10 Ld 3x3 DFN L10.3x3 10 Ld 3x3 DFN (Pb-free) L10.3x3 10 Ld 3x3 DFN Tape and Reel (Pb-Free) 0 to 85 8 Ld SOIC M8.15 8 Ld SOIC (Pb-free) M8.15 8 Ld SOIC Tape and Reel 0 to 85 ISL6594BCBZ-T (Note) 6594BCBZ ISL6594BCR 94BC 8 Ld SOIC Tape and Reel (Pb-Free) 0 to 85 ISL6594BCR-T 94BC 10 Ld 3x3 DFN Tape and Reel ISL6594BCRZ (Note) 94BZ 0 to 85 ISL6594BCRZ-T (Note) 94BZ 10 Ld 3x3 DFN L10.3x3 10 Ld 3x3 DFN (Pb-free) L10.3x3 10 Ld 3x3 DFN Tape and Reel (Pb-free) NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which are 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 ISL6594ACB, ISL6594BCB (SOIC) TOP VIEW UGATE 1 8 PHASE BOOT 2 7 PVCC PWM 3 6 VCC 4 GND 5 ISL6594ACR, ISL6594BCR (10 LD 3x3 DFN) TOP VIEW LGATE CRD L UGATE 1 10 BAT PHASE BOOT USB 2 9 PVCC ICDL N/C PPR 3 8 GND N/C PW M C HG 4 7 VCC USBP NTC orGND OVP 5 6 IUSB LGATE or EN Block Diagram ISL6594A AND ISL6594B UVCC BOOT VCC UGATE Pre-POR OVP FEATURES +5V 10K POR/ PWM SHOOTTHROUGH PROTECTION PHASE (LVCC) PVCC UVCC = VCC FOR ISL6594A UVCC = PVCC FOR ISL6594B CONTROL 8K LOGIC LGATE GND PAD 2 FOR DFN -DEVICES, THE PAD ON THE BOTTOM SIDE OF THE PACKAGE MUST BE SOLDERED TO THE CIRCUIT’S GROUND. FN9157.3 July 31, 2006 Typical Application - 4 Channel Converter Using ISL6592 and ISL6594A Gate Drivers +12V ISL6594 +5V 1 UGATE PHASE 8 2 BOOT PVCC 7 3 PWM VCC 6 4 GND LGATE 5 3 +3.3V VDD V12_SEN PHASE 8 OUT1 2 BOOT PVCC 7 VID4 OUT2 3 PWM VCC 6 VID3 ISEN1 4 GND LGATE 5 VID2 OUT3 VID1 OUT4 VID0 ISEN2 VID5 OUT5 LL0 OUT6 LL1 ISEN3 OUTEN OUT7 OUT8 TO µP VCC_PWRGD Vout ISL6594 1 UGATE PHASE 8 2 BOOT PVCC 7 3 PWM VCC 6 4 GND LGATE 5 RTN ISEN4 OUT9 RESET_N OUT10 ISL6594 ISEN5 1 UGATE PHASE 8 PVCC 7 FAULT FAULT1 OUT11 2 BOOT OUTPUTS FAULT2 OUT12 3 PWM VCC 6 ISEN6 4 GND LGATE 5 I2C I/F BUS SDA TEMP_SEN SCL CAL_CUR_EN RTHERM FN9157.3 July 31, 2006 SADDR CAL_CUR_SEN VSENP VSENN ISL6594A, ISL6594B 1 UGATE ISL6592 FROM µP ISL6594 GND ISL6594A, ISL6594B Absolute Maximum Ratings Thermal Information Supply Voltage (VCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15V Supply Voltage (PVCC) . . . . . . . . . . . . . . . . . . . . . . . . . VCC + 0.3V BOOT Voltage (VBOOT). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36V Input Voltage (VPWM) . . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to 7V UGATE. . . . . . . . . . . . . . . . . . . VPHASE - 0.3VDC to VBOOT + 0.3V VPHASE - 3.5V (<100ns Pulse Width, 2µJ) to VBOOT + 0.3V LGATE . . . . . . . . . . . . . . . . . . . . . . GND - 0.3VDC to VPVCC + 0.3V GND - 5V (<100ns Pulse Width, 2µJ) to VPVCC + 0.3V PHASE. . . . . . . . . . . . . . . GND - 0.3VDC to 15VDC (VPVCC = 12V) Thermal Resistance θJA (°C/W) θJC (°C/W) SOIC Package (Note 1) . . . . . . . . . . . . 100 N/A DFN Package (Notes 2, 3) . . . . . . . . . . 48 7 Maximum Junction Temperature (Plastic Package) . . . . . . . . 150°C Maximum Storage Temperature Range . . . . . . . . . . . -65°C to 150°C Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300°C (SOIC - Lead Tips Only) GND - 8V (<400ns, 20µJ) to 30V (<200ns, VBOOT-GND<36V) ESD Rating Human Body Model . . . . . . . . . . . . . . . . . . . . Class I JEDEC STD Recommended Operating Conditions Ambient Temperature Range . . . . . . . . . . . . . . . . . . . . . 0°C to 85°C Maximum Operating Junction Temperature . . . . . . . . . . . . . . 125°C Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12V ±10% Supply Voltage Range, PVCC . . . . . . . . . . . . . . . . 5V to 12V ±10% 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. NOTES: 1. θJA is measured with the component mounted on a high effective thermal conductivity test board in free air. 2. 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. 3. 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. PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS IVCC ISL6594A, fPWM = 300kHz, VVCC = 12V - 8 - mA ISL6594B, fPWM = 300kHz, VVCC = 12V - 4.5 - mA ISL6594A, fPWM = 1MHz, VVCC = 12V - 10.5 - mA ISL6594B, fPWM = 1MHz, VVCC = 12V - 5 - mA ISL6594A, fPWM = 300kHz, VPVCC = 12V - 4 - mA ISL6594B, fPWM = 300kHz, VPVCC = 12V - 7.5 - mA ISL6594A, fPWM = 1MHz, VPVCC = 12V - 5 - mA ISL6594B, fPWM = 1MHz, VPVCC = 12V - 8.5 - mA VCC Rising Threshold 9.35 9.8 10.0 V VCC Falling Threshold 7.35 7.6 8.0 V - 505 - µA VCC SUPPLY CURRENT Bias Supply Current IVCC Gate Drive Bias Current IPVCC IPVCC (Note 4) POWER-ON RESET AND ENABLE PWM INPUT (See Timing Diagram on Page 6) Input Current IPWM VPWM = 3.3V VPWM = 0V - -460 - µA PWM Rising Threshold (Note 4) VCC = 12V - 1.70 - V PWM Falling Threshold (Note 4) VCC = 12V - 1.30 - V Typical Three-State Shutdown Window VCC = 12V 1.23 - 1.82 V Three-State Lower Gate Falling Threshold VCC = 12V - 1.18 - V Three-State Lower Gate Rising Threshold VCC = 12V - 0.76 - V Three-State Upper Gate Rising Threshold VCC = 12V - 2.36 - V 4 FN9157.3 July 31, 2006 ISL6594A, ISL6594B Electrical Specifications Recommended Operating Conditions, Unless Otherwise Noted. (Continued) PARAMETER SYMBOL Three-State Upper Gate Falling Threshold Shutdown Holdoff Time TEST CONDITIONS VCC = 12V tTSSHD MIN TYP MAX UNITS - 1.96 - V - 245 - ns UGATE Rise Time tRU VPVCC = 12V, 3nF Load, 10% to 90% - 26 - ns LGATE Rise Time tRL VPVCC = 12V, 3nF Load, 10% to 90% - 18 - ns UGATE Fall Time (Note 4) tFU VPVCC = 12V, 3nF Load, 90% to 10% - 18 - ns LGATE Fall Time (Note 4) tFL VPVCC = 12V, 3nF Load, 90% to 10% - 12 - ns UGATE Turn-On Propagation Delay (Note 4) tPDHU VPVCC = 12V, 3nF Load, Adaptive - 10 - ns LGATE Turn-On Propagation Delay (Note 4) tPDHL VPVCC = 12V, 3nF Load, Adaptive - 10 - ns UGATE Turn-Off Propagation Delay (Note 4) tPDLU VPVCC = 12V, 3nF Load - 10 - ns LGATE Turn-Off Propagation Delay (Note 4) tPDLL VPVCC = 12V, 3nF Load - 10 - ns LG/UG Three-State Propagation Delay (Note 4) tPDTS VPVCC = 12V, 3nF Load - 10 - ns Upper Drive Source Current (Note 4) IU_SOURCE VPVCC = 12V, 3nF Load - 1.25 - A Upper Drive Source Impedance RU_SOURCE 150mA Source Current 1.4 2.0 3.0 Ω - 2 - A 0.9 1.65 3.0 Ω - 2 - A 0.85 1.3 2.2 Ω - 3 - A 0.60 0.94 1.35 Ω OUTPUT Upper Drive Sink Current (Note 4) IU_SINK VPVCC = 12V, 3nF Load Upper Drive Sink Impedance RU_SINK 150mA Sink Current Lower Drive Source Current (Note 4) IL_SOURCE Lower Drive Source Impedance RL_SOURCE 150mA Source Current VPVCC = 12V, 3nF Load Lower Drive Sink Current (Note 4) IL_SINK VPVCC = 12V, 3nF Load Lower Drive Sink Impedance RL_SINK 150mA Sink Current NOTE: 4. Guaranteed by design. Not 100% tested in production. Functional Pin Description PACKAGE PIN # SOIC DFN PIN SYMBOL 1 1 UGATE Upper gate drive output. Connect to gate of high-side power N-Channel MOSFET. 2 2 BOOT 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 Internal Bootstrap Device section under DESCRIPTION for guidance in choosing the capacitor value. - 3,8 N/C 3 4 PWM 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. 4 5 GND Bias and reference ground. All signals are referenced to this node. It is also the power ground return of the driver. 5 6 LGATE 6 7 VCC 7 9 PVCC This pin supplies power to both upper and lower gate drives in ISL6594B; only the lower gate drive in ISL6594A. Its operating range is +5V to 12V. Place a high quality low ESR ceramic capacitor from this pin to GND. 8 10 PHASE 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 drive. 9 11 PAD FUNCTION No Connection. Lower gate drive output. Connect to gate of the low-side power N-Channel MOSFET. Connect this pin to a +12V bias supply. Place a high quality low ESR ceramic capacitor from this pin to GND. Connect this pad to the power ground plane (GND) via thermally enhanced connection. 5 FN9157.3 July 31, 2006 ISL6594A, ISL6594B Description 1.18V<PWM<2.36V 0.76V<PWM<1.96V PWM tPDLU tPDHU tTSSHD tPDTS tPDTS UGATE tFU tRU LGATE tFL tRL tTSSHD tPDLL tPDHL FIGURE 1. TIMING DIAGRAM Operation Adaptive Zero Shoot-Through Deadtime Control Designed for versatility and speed, the ISL6594A and ISL6594B MOSFET drivers control both high-side and lowside N-Channel FETs of a half-bridge power train from one externally provided PWM signal. These drivers incorporate an adaptive deadtime control technique to minimize deadtime, resulting in high efficiency from the reduced freewheeling time of the lower MOSFETs’ body-diode conduction, and to prevent the upper and lower MOSFETs from conducting simultaneously. This is accomplished by ensuring either rising gate turns on its MOSFET with minimum and sufficient delay after the other has turned off. Prior to VCC exceeding its POR level, the Pre-POR overvoltage protection function is activated during initial startup; the upper gate (UGATE) is held low and the lower gate (LGATE), controlled by the Pre-POR overvoltage protection circuits, is connected to the PHASE. Once the VCC voltage surpasses the VCC Rising Threshold (See Electrical Specifications), the PWM signal takes control of gate transitions. 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 section. Adaptive shoot-through circuitry monitors the LGATE voltage and determines the upper gate delay time [tPDHU]. This prevents both the lower and upper MOSFETs from conducting simultaneously. Once this delay period is complete, the upper gate drive begins to rise [tRU] and the upper MOSFET turns on. A falling transition on PWM results in 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]. Again, the adaptive shoot-through circuitry determines the lower gate delay time, tPDHL. The PHASE voltage and the UGATE voltage are monitored, and the lower gate is allowed to rise after PHASE drops below a level or the voltage of UGATE to PHASE reaches a level depending upon the current direction (See next section for details). The lower gate then rises [tRL], turning on the lower MOSFET. During turn-off of the lower MOSFET, the LGATE voltage is monitored until it drops below 1.75V, at which time the UGATE is released to rise after 20ns of propagation delay. Once the PHASE is high, the adaptive shoot-through circuitry monitors the PHASE and UGATE voltages during a PWM falling edge and the subsequent UGATE turn-off. If either the UGATE falls to less than 1.75V above the PHASE or the PHASE falls to less than +0.8V, the LGATE is released to turn on. Three-State PWM Input A unique feature of these drivers 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 driver outputs 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. This feature helps prevent a negative transient on the output voltage when the output is shut down, eliminating the Schottky diode that is used in some systems for protecting the load from reversed output voltage events. In addition, more than 400mV hysteresis also incorporates into the three-state shutdown window to eliminate PWM 6 FN9157.3 July 31, 2006 ISL6594A, ISL6594B input oscillations due to the capacitive load seen by the PWM input through the body diode of the controller’s PWM output when the power-up and/or power-down sequence of bias supplies of the driver and PWM controller are required. 200mV droop in drive voltage over the PWM cycle. We find that a bootstrap capacitance of at least 0.267µF is required. 1.6 Power-On Reset (POR) Function 1.4 Pre-POR Overvoltage Protection Prior to VCC exceeding its POR level, the upper gate is held low and the lower gate is controlled by the overvoltage protection circuits during initial startup. The PHASE is connected to the gate of the low side MOSFET (LGATE), which provides some protection to the microprocessor if the upper MOSFET(s) is shorted during initial startup. For complete protection, the low side MOSFET should have a gate threshold well below the maximum voltage rating of the load/microprocessor. When VCC drops below its POR level, both gates pull low and the Pre-POR overvoltage protection circuits are not activated until VCC resets. Internal Bootstrap Device Both drivers feature an internal bootstrap schottky diode. Simply adding an external capacitor across the BOOT and PHASE pins completes the bootstrap circuit. The bootstrap function is also designed to prevent the bootstrap capacitor from overcharging due to the large negative swing at the trailing-edge of the PHASE node. This reduces voltage stress on the boot to phase pins. The bootstrap capacitor must have a maximum voltage rating above UVCC + 5V and its capacitance value can be chosen from the following equation: Q GATE C BOOT_CAP ≥ -------------------------------------∆V BOOT_CAP (EQ. 1) Q G1 • UVCC Q GATE = ------------------------------------ • N Q1 V GS1 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 53nC for UVCC (i.e. PVCC in ISL6594B, VCC in ISL6594A) = 12V. We will assume a 7 1.2 CBOOT_CAP (µF) During initial startup, the VCC voltage rise is monitored. Once the rising VCC voltage exceeds 9.8V (typically), operation of the driver is enabled and the PWM input signal takes control of the gate drives. If VCC drops below the falling threshold of 7.6V (typically), operation of the driver is disabled. 1. 0.8 0.6 QGATE = 100nC 0.4 50nC 0.2 20nC 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 ∆VBOOT_CAP (V) FIGURE 2. BOOTSTRAP CAPACITANCE vs BOOT RIPPLE VOLTAGE Gate Drive Voltage Versatility The ISL6594A and ISL6594B provide the user flexibility in choosing the gate drive voltage for efficiency optimization. The ISL6594A upper gate drive is fixed to VCC [+12V], but the lower drive rail can range from 12V down to 5V depending on what voltage is applied to PVCC. The ISL6594B ties the upper and lower drive rails together. Simply applying a voltage from 5V up to 12V on PVCC sets both gate drive rail voltages simultaneously. 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 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 SO8 package is approximately 800mW at room temperature, while the power dissipation capacity in the DFN package with an exposed heat escape pad is more than 1.5W. The DFN package is more suitable for high frequency applications. See Layout Considerations paragraph 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 FN9157.3 July 31, 2006 ISL6594A, ISL6594B driver current can be estimated with Equations 2 and 3, respectively, P Qg_TOT = P Qg_Q1 + P Qg_Q2 + I Q • VCC BOOT UVCC D CGD (EQ. 2) RHI1 Q G1 • UVCC 2 P Qg_Q1 = --------------------------------------- • F SW • N Q1 V GS1 RLO1 G RG1 CDS RGI1 CGS Q1 • LVCC 2 Q G2 P Qg_Q2 = -------------------------------------- • F SW • N Q2 V GS2 S PHASE FIGURE 3. TYPICAL UPPER-GATE DRIVE TURN-ON PATH ⎛ Q G1 • UVCC • NQ1 Q G2 • LVCC • N Q2⎞ - + -----------------------------------------------------⎟ • F SW + I Q I DR = ⎜ ----------------------------------------------------V GS1 V GS2 ⎝ ⎠ (EQ. 3) 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; UVCC and LVCC are the drive voltages for both upper and lower FETs, respectively. The IQ*VCC product is the quiescent power of the driver without capacitive load and is typically 116mW at 300kHz. 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) 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 (EQ. 4) R LO1 R HI1 ⎛ ⎞ P Qg_Q1 P DR_UP = ⎜ -------------------------------------+ ---------------------------------------⎟ • --------------------2 ⎝ R HI1 + R EXT1 R LO1 + R EXT1⎠ R HI2 R LO2 ⎛ ⎞ P Qg_Q2 + ---------------------------------------⎟ • --------------------P DR_LOW = ⎜ -------------------------------------2 R + R R + R ⎝ HI2 EXT2 LO2 EXT2⎠ R GI1 R EXT1 = R G1 + ------------N Q1 R GI2 R EXT2 = R G2 + ------------N Q2 8 LVCC D CGD RHI2 RLO2 G RG2 CDS RGI2 CGS Q2 S FIGURE 4. TYPICAL LOWER-GATE DRIVE TURN-ON PATH Layout Considerations For heat spreading, place copper underneath the IC whether it has an exposed pad or not. The copper area can be extended beyond the bottom area of the IC and/or connected to buried copper plane(s) with thermal vias. This combination of vias for vertical heat escape, extended copper plane, and buried planes for heat spreading allows the IC to achieve its full thermal potential. Place each channel power component as close to each other as possible to reduce PCB copper losses and PCB parasitics: shortest distance between DRAINs of upper FETs and SOURCEs of lower FETs; shortest distance between DRAINs of lower FETs and the power ground. Thus, smaller amplitudes of positive and negative ringing are on the switching edges of the PHASE node. However, some space in between the power components is required for good airflow. The traces from the drivers to the FETs should be kept short and wide to reduce the inductance of the traces and to promote clean drive signals. FN9157.3 July 31, 2006 ISL6594A, ISL6594B Dual Flat No-Lead Plastic Package (DFN) 2X 0.15 C A D A L10.3x3 10 LEAD DUAL FLAT NO-LEAD PLASTIC PACKAGE MILLIMETERS 2X 0.15 C B SYMBOL MIN 6 INDEX AREA 0.80 0.90 1.00 - - - 0.05 - 0.28 5,8 2.05 7,8 1.65 7,8 0.20 REF 0.18 D 1.95 E 0.10 C 0.08 C SIDE VIEW C SEATING PLANE 1 e 1.60 - 0.50 BSC - k 0.25 - - L 0.30 0.35 0.40 N 10 Nd 5 8 2 3 1. Dimensioning and tolerancing conform to ASME Y14.5-1994. 2. N is the number of terminals. NX k E2/2 N-1 7. Dimensions D2 and E2 are for the exposed pads which provide improved electrical and thermal performance. NX b 5 (Nd-1)Xe REF. 4. All dimensions are in millimeters. Angles are in degrees. 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. NX L e 3. Nd refers to the number of terminals on D. 5. Dimension b applies to the metallized terminal and is measured between 0.15mm and 0.30mm from the terminal tip. E2 8 1.55 NOTES: D2/2 2 N - Rev. 3 6/04 D2 (DATUM B) 2.00 8 7 6 INDEX AREA (DATUM A) A3 - 3.00 BSC E2 A 0.23 3.00 BSC D2 B NOTES A b TOP VIEW MAX A1 A3 E NOMINAL 0.10 M C A B 8. Nominal dimensions are provided to assist with PCB Land Pattern Design efforts, see Intersil Technical Brief TB389. BOTTOM VIEW C L 0.415 NX (b) (A1) 0.200 5 L NX L e SECTION "C-C" NX b C C C TERMINAL TIP FOR ODD TERMINAL/SIDE 9 FN9157.3 July 31, 2006 ISL6594A, ISL6594B Small Outline Plastic Packages (SOIC) M8.15 (JEDEC MS-012-AA ISSUE C) N 8 LEAD NARROW BODY SMALL OUTLINE PLASTIC PACKAGE INDEX AREA H 0.25(0.010) M B M INCHES E SYMBOL -B- 1 2 3 L SEATING PLANE -A- A D h x 45° -C- e A1 B 0.25(0.010) M C 0.10(0.004) C A M MIN MAX MIN MAX NOTES A 0.0532 0.0688 1.35 1.75 - A1 0.0040 0.0098 0.10 0.25 - B 0.013 0.020 0.33 0.51 9 C 0.0075 0.0098 0.19 0.25 - D 0.1890 0.1968 4.80 5.00 3 E 0.1497 0.1574 3.80 4.00 4 e α B S 0.050 BSC 1.27 BSC - H 0.2284 0.2440 5.80 6.20 - h 0.0099 0.0196 0.25 0.50 5 L 0.016 0.050 0.40 1.27 6 N α NOTES: MILLIMETERS 8 0° 8 8° 0° 7 8° 1. Symbols are defined in the “MO Series Symbol List” in Section 2.2 of Publication Number 95. Rev. 1 6/05 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 10 FN9157.3 July 31, 2006