WWW.Microsemi .COM LX1672 LX1672 LX1672 Multiple Output LoadSHARE PWM TM PRODUCTION DATA SHEET DESCRIPTION KEY FEATURES Up to Three Independently The LX1672 is a highly integrated This patented approach also gives Regulated Outputs power supply controller IC featuring system designers maximum flexibility with DDR Termination Compliant two PWM switching regulator stages respect to MOSFET supply. Each phase Bi-phase Current Sharing with an additional onboard linear can utilize different supply voltages, for Outputs As Low As 0.8V regulator driver. efficient use of available supplies, while Generated From An Internal 1% The two constant frequency voltage- programming the ratio of current pulled Reference mode PWM phases can be easily from each using one of three methods (see Multiphase High Current Output configured as a single Bi-Phase high application section). Reduces Required Capacitance current output, two independently The LX1672 incorporates fully Integrated High Current MOSFET Drivers regulated outputs, or as a DDR memory programmable soft-start sequencing 300KHz, 500KHz and 600KHz I/O supply with a tracking DDR capabilities. Each output can be High Frequency Operation termination voltage supply. Power loss configured to come up in any order Minimizes External Component and noise, due to the ESR of the input necessary as required by the application. Requirements capacitors, are minimized by operating The LX1672 features an additional Independent Phase Programmable each PWM output 180 out of phase. Linear Regulator Driver output, which Soft-Start and Power Sequencing This architecture also minimizes when coupled with an inexpensive Adjustable Linear Regulator Driver capacitor requirements while MOSFET is capable of supplying up to 5A Output maximizing regulator response. for I/O, memory, and other supplies No current-sense resistors In bi-phase operation, the high surrounding todays micro-processor current output utilizes a patented current designs. APPLICATIONS/BENEFITS sharing architecture, called Forced Each regulator voltage output is Current Sharing, to allow accurate programmed via a simple voltage-divider Multi-Output Power Supplies Video Card Power Supplies current sharing without the use of network. The LX1672, utilizing MOSFET DDR, VDDQ and Termination expensive current sense resistors. RDS(ON) impedance, monitors maximum Supply current limit conditions, in each PWM PC Peripherals phase without the use of expensive current Portable PC Processor and I/O sense resistors. Supply IMPORTANT: For the most current data, consult MICROSEMIs website: WWW.Microsemi .COM PACKAGE DATA PACKAGE DATA LX1672 Multiple Output LoadSHARE PWM TM PRODUCTION DATA SHEET ABSOLUTE MAXIMUM RATINGS PACKAGE PIN OUT Supply Voltage (V ) DC.................................................................-0.3V to 5.5V CC 1 28 HO2 VC2 Driver Supply Voltage (V , V ) DC ............................................-0.3V to 12V 2 27 Cx CCL LO2 VC1 3 26 PG2 HO1 Current Sense Inputs (V , C ) ....................................................... -0.3V to 12V SX SX 4 25 LDGD LO1 Error Amplifier Inputs (FB , RF , LDFB)........................................-0.3V to 5.5V X 2 5 24 LDFB PG1 6 23 LDDIS VCCL Input Voltage (SS / Enable, LDDIS) .................................................-0.3V to5.5V 7 22 DGND VCC Output Drive Peak Current Source (HOx, LOx)....................................1A (500ns) 8 AGND 21 VS1 9 Output Drive Peak Current Sink (HOx, LOx) .......................................1A (500ns) DIS2 20 CS1 10 SS2 19 EO1 Operating Junction Temperature.................................................................. 150C RF2 11 18 FB1 Storage Temperature Range...........................................................-65 C to 150 C FB2 12 17 SS1 13 16 EO2 DIS1 Peak Package Solder Reflow Temp.(40 second max. exposure) .... 260C (+0, -5) CS2 14 15 VS2 PW PACKAGE (Top View) Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground. Currents are positive into, negative out of specified terminal. 38 37 36 35 34 33 32 1 x= Denote Phases 1 & 2 HO2 31 N.C. VC2 2 30 N.C. LDGD 3 29 VCCL 4 28 LDFB VCC THERMAL DATA 5 LDDIS 27 DIS2 6 Connect Bottom to 26 DGND DIS1 Power GND 7 25 AGND N.C. Plastic TSSOP 28-Pin PW 8 24 RSVD N.C. THERMAL RESISTANCE-JUNCTION TO AMBIENT, 85C/W 9 23 JA SS2 PWGD 10 22 RF2 N.C. FB2 11 21 N.C. EO2 12 20 N.C. 13 14 15 16 17 18 19 Plastic MLPQ 38-Pin LQ THERMAL RESISTANCE-JUNCTION TO AMBIENT, 35C/W JA (N.C. No Internal Connection Junction Temperature Calculation: T = T + (P x ). JC J A D N/U Not Used) The numbers are guidelines for the thermal performance of the device/pc-board system. JA RoHS / Pb-free 100% Matte Tin Lead Finish All of the above assume no ambient airflow. Copyright 2000 Microsemi Page 2 Rev. 1.0, 2005-08-10 Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 LO2 CS2 PG1 VS2 LO1 SS1 HO1 FB1 VC1 EO1 N.C CS1 . N.C. VS1