WWW.Microsemi .COM LX1675 LX1675 LX1675 TM Multiple Output LoadSHARE PWM PRODUCTION DATA SHEET DESCRIPTION KEY FEATURES Four Independently Regulated The LX1675 is a highly integrated High current MOSFETs can be directly Outputs power supply controller IC featuring driven to provide an LDO output of 5A Single Input Supply with Wide three voltage mode PWM switching and 15A for each PWM controller. This Voltage Range: 4.5-24V regulator stages with an additional is useful for I/O, memory, termination, Outputs As Low As 0.8V onboard linear regulator driver. and other supplies surrounding todays Generated From a Precision Two of the constant frequency PWM micro-processor based designs. Internal Reference phases can be easily configured for a The LX1675 accepts a wide range of Selectable PWM Frequency of single Bi-Phase high current output or supply voltage ranging from 4.5V to 24V. 300KHz or 600KHz operated as two independently regulated Each PWM regulator output voltage is Buffered Reference Voltage outputs. All outputs (PWM phases and programmed via a simple voltage-divider Output LDO) have separate, programmable soft- network. The LX1675 design gives Multiphase Output Reduces start sequencing. This versatility yields engineers maximum flexibility with Need for Large Input either three or four independently respect to the MOSFET supply. Each Capacitance at High Currents regulated outputs with full power phase can utilize different supply voltages Integrated High Current sequencing capability giving system for efficient use of available supply rails. MOSFET Drivers designers the ultimate flexibility in power Additionally, when two phases are Independent Soft-Start and supply design. configured in Bi-Phase output, the Power Sequencing Current limit for each PWM regulator LoadSHARE topology can be Adjustable Linear Regulator is provided by monitoring the voltage programmed via inductor ESR selection. Driver Output No Current-Sense Resistors drop across the lower MOSFET power The split phase operation reduces power DDR Termination Compliant stage during conduction, utilizing the loss, noise due to the ESR of the input RoHS Compliant for Pb Free Rds(on) impedance. This eliminates the capacitors and allows for reduction in need for expensive current sense capacitance values while maximizing resistors. Once current limit has been regulator response time. The internal APPLICATIONS reached and persist for 4 clock cycles, the reference voltage is buffered and brought output is shut off and Soft Start is out on a separate pin to be used as an Multi-Output Power Supplies Video Card Power Supplies initialized to force a hiccup mode for external reference voltage. PC Peripherals protection. Portable PC Processor and I/O IMPORTANT: For the most current data, consult MICROSEMIs website: WWW.Microsemi .COM PACKAGE DATA PACKAGE DATA LX1675 TM Multiple Output LoadSHARE PWM PRODUCTION DATA SHEET ABSOLUTE MAXIMUM RATINGS PACKAGE PIN OUT Supply Voltage (VIN VSLR, HRX) ............................................................... -0.3V to 24V , Supply Voltage (VCCL) ................................................................................ -0.3V to 6.0V Driver Supply Voltage (VCX) ........................................................................ -0.3V to 30V 38 37 36 35 34 33 32 1 Current Sense Inputs (CSX)............................................................................ -0.3V to 30V LO2 31 HR3 2 Error Amplifier Inputs (FB , RF2, LDFB) .................................................... -0.3V to 5.5V HR2 30 LO3 X 3 29 Internal regulator Current (I )............................................................................... 50mA HO2 PG3 VCCL 4 Output Drive Peak Current Source (HO , LO ) ................................................ 1A (200ns) VC2 28 VCCL X X 5 CS2 27 Output Drive Peak Current Sink (HO , LO )................................................. 1.5A (200ns) VIN X X 6 Connect Bottom to 26 Differential Voltage: V V (High Side Return).................................... -0.3V to 6V SF CS1 HOX HRX Power GND 7 25 Soft Start Input (SSX, SSL) ............................................................................-0.3V to V EO2 DGND REF 8 24 FB2 Logic Inputs (SF, FS)..........................................................................-0.3V to V + 0.5V CS3 CCL 23 9 LDO Gate Drive (LDGD) Output Drive can source .................................................. 10mA SS2 FS 10 22 LDO Feedback (LDFB) Input.......................................................................................6.0V RF2 EO3 11 21 EO1 Operating Junction Temperature................................................................................ 150C FB3 FB1 12 20 Operating Temperature Range .......................................................................-40C to 85C SS3 13 14 15 16 17 18 19 Storage Temperature Range.........................................................................-65 C to 150C Peak Package Solder Reflow Temp. (40 seconds maximum exposure)......... 260C (+0 -5) Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to LQ PACKAGE (Top View) Ground. Currents are positive into, negative out of specified terminal. Limitations affecting transient pulse duration is thermally related to the clamping zener RoHS / Pb-free 100% Matte Tin Lead Finish diodes connected to the supply pins, application of maximum voltage will increase current into that pin and increase power dissipation. x denotes respective pin designator 1, 2, or 3. THERMAL DATA Plastic MLPQ 38-Pin LQ THERMAL RESISTANCE-JUNCTION TO AMBIENT, 30 to 55C/W JA Junction Temperature Calculation: T = T + (P x ). J A D JA The numbers are dependent on heat spreading and layout considerations for the thermal JA performance of the device/pc-board system. All of the above assume no ambient airflow. Copyright 2004 Microsemi Page 2 Rev. 1.2a, 2006-02-16 Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 LDGD PG1 VSLR LO1 SSL HR1 LDFB HO1 SS1 VC1 AGND VC3 VREF HO3