Driver plus FET Multi-chip Module

FDMF8705 Driver plus FET Multi-chip Module April 2007 FDMF8705 Driver plus FET Multi-chip Module Benefits Fully optimized system efficiency. Higher efficiency levels are achievable compared with conventional discrete components. Space savings of up to 50% PCB versus discrete solutions. Higher frequency of operation. Simpler system design and board layout. Reduced time in component selection and optimization. tm General Description The FDMF8705 is a fully optimized integrated 12V Driver plus MOSFET power stage solution for high current synchronous buck DC-DC applications. The device integrates a driver IC and two Power MOSFETs into a space saving, 8mm x 8mm, 56-pin Power88™ package. Fairchild Semiconductor’s integrated approach optimizes the complete switching power stage with regards to driver to FET dynamic performance, system inductance and overall solution ON resistance. Package parasitics and problematical layouts associated with conventional discrete solutions are greatly reduced. This integrated approach results in significant board space saving, therefore maximizing footprint power density. This solution is based on the Intel™ DrMOS specification. Features 12V typical Input Voltage Output current up to 18A 500KHz switching frequency capable Internal adaptive gate drive Integrated bootstrap diode Peak Efficiency >85% Under-voltage Lockout Output disable for lost phase shutdown Low profile SMD package RoHS Compliant Applications Desktop and server non V-core buck converters. CPU/GPU power train in game consoles and high end desktop systems. High-current DC-DC Point of Load (POL) converters Networking and telecom microprocessor voltage regulators www.DataSheet4U.com Small form factor voltage regulator modules Powertrain Application Circuit 12V CVCC VCIN DISB PWM Input DISB VIN BOOT CBOOT PWM CGND VSWH PGND COUT OUTPUT Figure 1. Powertrain Application Circuit Ordering Information Current Rating Max [A] 18 Input Voltage Typical [V] 12 1 Frequency Max [KHz] 500 Device Marking FDMF8705 www.fairchildsemi.com Part FDMF8705 ©2007 Fairchild Semiconductor Corporation FDMF8705 Rev. C FDMF8705 Driver plus FET Multi- chip Module Functional Block Diagram BOOT VCIN HDRV VIN DISB PWM 2.2 1.2 VSWH 1.2 VCIN CGND LDRV PGND Figure 2. Functional Block Diagram Pin Configuration CGND NC NC VCIN BOOT CGND VSWH VIN VIN TEST PAD1 VIN VIN VIN VIN 1 PWM 56 DISB NC NC NC CGND VSWH VSWH VSWH VSWH VSWH VSWH VSWH VSWH 43 14 15 VIN VIN VIN VIN VIN VIN VSWH NC NC NC NC NC NC 28 NC 29 (CGND) (VIN) (VSWH) 42 Figure 3. Power88 56L Bottom View VSWH VSWH VSWH TEST PAD2 PGND PGND PGND PGND PGND PGND PGND PGND PGND PGND 2 FDMF8705 Rev. C www.fairchildsemi.com FDMF8705 Driver plus FET Multi- chip Module Pin Description Pin 1,6,51 2,3,22-28,52-54 4 5 7,21,40-50 8,9,11-20 10 29-38 39 55 56 Name CGND NC VCIN BOOT VSWH VIN TEST PAD 1 PGND TEST PAD 2 DISB PWM IC Ground. Ground return for driver IC. No connect Function IC Supply. +12V chip bias power. Bypass with a 1µF ceramic capacitor. Bootstrap Supply Input. Provides voltage supply to high-side MOSFET driver. Connect bootstrap capacitor. Switch Node Input. SW Provides return for high-side bootstrapped driver and acts as a sense point for the adaptive shoot-thru protection. Power Input. Output stage supply voltage. For manufacturing test only. HDRV pin. This pin must be floated. Must not be connected to any pin. Power ground. Output stage ground. Source pin of low side MOSFET(s). For manufacturing test only. LDRV pin. This pin must be floated. Must not be connected to any pin. Output Disable. When low, this pin disable FET switching (HDRV and LDRV are held low). PWM Signal Input. This pin accepts a logic-level PWM signal from the controller. Absolute Maximum Rating Parameter VCIN to PGND VIN to PGND PWM, DSIB to GND VSWH to PGND BOOT to VSWH BOOT to PGND IO(AV) IO(PK) RJPCB PD Continuous Transient (t = 100ns, fsw = 500KHz) VIN = 12V, VO = 1.3V, fsw = 500KHz, TPCB = 100°C VIN = 12V, tPULSE = 10µs Junction to PCB Thermal Resistance (note 1) TPCB = 100°C (note 1) -55 Continuous Transient (t = 100ns, fsw = 500KHz) Min. -0.5 -0.5 -0.3 -1 -5 -0.3 -0.3 -0.3 Max. 15 15 5.5 15 25 15 30 33 18 65 8 6.25 150 Units V V V V V V V V A A °C/W W °C Operating and Storage Junction Temperature Range Recommended Operating Range Parameter VCIN VIN Control Circuit Supply Voltage Output Stage Supply Voltage Min. 6.4 6.4 Typ. 12 12 Max. 13.5 14 Units V V Electrical Characteristics VIN = 12V, TA = 25°C unless otherwise noted. Parameter Control Circuit Supply Current Undervoltage lockout threshold PWM Input High Voltage Symbol ICIN VTH(UVLO)(2) VIH(PWM) Conditions fSW = 0Hz, VDISB = 0V fSW = 500KHz, VDISB = 5V Turn-on Turn-off Min. Typ. 3.5 18 6 5.25 Max. 8 Units mA V V V 3.5 FDMF8705 Rev. C 3 www.fairchildsemi.com FDMF8705 Driver plus FET Multi- chip Module Electrical Characteristics VIN = 12V, TA = 25°C unless otherwise noted. Parameter PWM Input Low Voltage PWM Input Current Output Disable Input High Voltage Output Disable Input Low Voltage Output Disable Input Current Output Stage Leakage Current Symbol VIL(PWM) IIL(PWM) VIH(DISB) VIL(DISB) IDISB IIN_LEAKAGE tPDL(LDRV)(3) tPDL(HDRV)(3) tPDH(LDRV)(3) tPDH(HDRV)(3) Conditions Min. -1 2.5 Typ. Max. 0.8 1 0.8 Units V µA V V µA µA ns ns ns ns -1 VDISB = 0V VIN = 12V, VOUT = 1.3V, fsw = 500KHz, IO = 18A 250 51 39 47 46 1 Propagation Delay Note 1: Package power dissipation based on 4 layer, 2 square inch, 2 oz. copper pad. RJPCB is the steady state junction to PCB thermal resistance with PCB temperature referenced at VSWH pin. Note 2: When combined with controller, driver UVLO must be less than that of controller. Note 3: tPDL(LDRV/HRDV) refers to HIGH-to-LOW transition, tPDH(LDRV/HDRV) refers to LOW-to-HIGH transition. FDMF8705 Rev. C 4 www.fairchildsemi.com FDMF8705 Driver plus FET Multi-chip Module Typical Characteristics 20 6 5 15 4 PLOSS, W ILOAD, A 10 3 2 5 VIN = 12V VOUT = 1.3V fSW = 500KHz L = 0.68uH 0 25 50 75 100 PCB Temperature, oC 125 150 1 0 0 3 6 9 ILOAD, A 12 15 18 fSW = 300KHz VIN = 12V VOUT = 1.3V L = 0.68uH fSW = 500KHz 0 Figure 4. Safe Operating Area vs. PCB Temperature Figure 5. Module Power Loss vs. Output Current (VO measured at VSWH pin) 1.20 1.15 PLOSS (NORMALIZED) 1.10 1.05 1.00 0.95 0.90 VIN = 12V VOUT = 1.3V IOUT = 18A L = 0.68uH PLOSS (NORMALIZED) 1.10 1.05 1.00 0.95 VOUT = 1.3V IOUT = 18A L = 0.68uH fSW = 300KHz 6 7 8 9 10 11 12 13 14 15 0.90 200 250 300 350 400 450 500 Switching Frequency, KHz Input Voltage, V Figure 6. Power Loss vs. Switching Frequency Figure 7. Power Loss vs. Input Voltage 1.10 1.08 1.20 1.15 PLOSS (NORMALIZED) 1.10 1.05 1.00 0.95 0.90 7 8 9 10 11 12 13 PLOSS (NORMALIZED) VIN = 12V IOUT = 18A L = 0.68uH fSW = 300KHz 1.05 1.03 1.00 0.98 0.95 Driver Supply Voltage, V VIN = 12V VOUT = 1.3V IOUT = 18A L = 0.68uH fSW = 300KHz 0.8 1.2 1.6 2.0 Output Voltage, V 2.4 2.8 3.2 Figure 8. Power Loss vs. Driver Supply Voltage Figure 9. Power Loss vs. Output Voltage FDMF8705 Rev. C 5 www.fairchildsemi.com FDMF8705 Driver plus FET Multi-chip Module 1.10 4.4 4.2 PLOSS (NORMALIZED) 4.0 1.05 Supply Current, mA 3.8 3.6 3.4 3.2 3.0 2.8 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 6 7 8 9 10 11 12 13 14 15 Output Inductance, uH Supply Voltage, V PWM=DISB=0V PWM=DISB=5V 1.00 VIN = 12V VOUT = 1.3V IOUT = 18A fSW = 300KHz 0.95 Figure 10. Power Loss vs. Output Inductance Figure 11. Supply Current vs. Supply Voltage 3.3 20 VCIN = 12V IQ 16 Supply Current, mA IQ_OFF VCIN = 12V 3.2 Supply Current, mA 3.1 12 3.0 8 2.9 4 2.8 -50 -25 0 25 50 o 75 100 125 150 0 0 100 200 300 Frequency, KHz 400 500 Temperature, C Figure 12. Supply Current vs. Temperature Figure 13. Supply Current vs. Frequency 2.0 VIH 1.9 DISB Threshold Voltage, V DISB Threshold Voltage, V 1.8 1.7 1.6 VIL 1.5 1.4 6 7 8 9 10 11 12 13 14 15 Driver Supply Voltage, V 2.0 VCIN = 12V 1.9 VIH 1.8 1.7 1.6 VIL 1.5 1.4 -50 -25 0 25 50 75 100 125 150 Temperature, oC Figure 14. DISB Threshold Voltage vs. Driver Supply Voltage Figure 15. DISB Threshold Voltage vs. Temperature FDMF8705 Rev. C 6 www.fairchildsemi.com FDMF8705 Driver plus FET Multi-chip Module 3.0 VIH 2.7 PWM Threshold Voltage, V 2.4 2.1 1.8 1.5 1.2 6 7 8 9 10 11 12 13 14 15 Driver Supply Voltage, V VIL PWM Threshold Voltage, V 3.0 VCIN = 12V 2.7 2.4 2.1 1.8 1.5 1.2 -50 -25 0 25 50 75 100 125 150 Temperature, oC VIL VIH Figure 16. PWM Threshold Voltage vs. Driver Supply Voltage Figure 17. PWM Threshold Voltage vs. Temperature -13 36 35 34 33 32 31 30 0 100 200 300 400 500 0 100 200 300 400 500 Transient Duration, nsec Transient Duration, nsec -11 VBOOT - GND, V VSW , V -9 -7 -5 -3 Figure 18. VSWH vs. Transient Duration Figure 19. Boot to Ground Voltage vs. Transient Duration PWM PWM HDRV HDRV LDRV VSWH VIN = 12V VCIN = 12V VOUT = 1.3V fsw = 500KHz IOUT = 0A LDRV VSWH VIN = 12V VCIN = 12V VOUT = 1.3V fsw = 500KHz IOUT = 18A Figure 20. Switching Waveform at Iout = 0A Figure 21. Switching Waveform at Iout = 18A FDMF8705 Rev. C 7 www.fairchildsemi.com FDMF8705 Driver plus FET Multi-chip Module PWM HDRV LDRV VIN = 12V VCIN = 12V VOUT = 1.3V fsw = 500KHz IOUT = 18A VSWH PWM HDRV LDRV VSWH VIN = 12V VCIN = 12V VOUT = 1.3V fsw = 500KHz IOUT = 18A Figure 22. Switching Waveform (Rising edge) Figure 23. Switching Waveform (Falling Edge) FDMF8705 Rev. C 8 www.fairchildsemi.com FDMF8705 Driver plus FET Multi-chip Module Description of Operation Circuit Description The FDMF8705 is a driver plus FET module optimized for synchronous buck converter topology. A single PWM input signal is all that is required to properly drive the high-side and the low-side MOSFETs. Each part is capable of driving speeds up to 500KHz. Adaptive Gate Drive Circuit The driver IC embodies an advanced design that ensures minimum MOSFET dead-time while eliminating potential shoot-through (cross-conduc