LX3005CDM

LX3005 TM ® 2A STEP-DOWN CONVERTER P RODUCTION D ATASHEET KEY FEATURES            2A Constant Output Current 130m RDSON Internal Power MOSFET Up to 94% Efficiency Fixed 420kHz Frequency Wide 4.75V to 25V Input Voltage Range Output Voltage Adjustable from 0.8V to 21V Built-in Thermal Shutdown Function Built-in Current Limit Function Built-in Soft-start Function Support Ceramic or Electrolytic Capacitors Pb-free and RoHS Compliant AP P LIC ATI O NS      Portable DVD LCD Monitor/LCD TV Digital Photo Frame ADSL Set-Top Box DESCRIPTION The LX3005 is a 420kHz fixed frequency PWM buck (step-down) DC-DC converter, capable of driving a 2A load with high efficiency, low ripple and excellent line and load regulation. The device operates over a wide input voltage range of 4.75V to 25V, and the output voltage can be externally set from 0.8V to a voltage near VIN, as the PWM control circuit is able to adjust the duty ratio linearly from 0% to close to 100%. The LX3005 device integrates a high-side low RDSON PMOS for a low cost and high efficiency solution. An internal transconductance error amplifier is used in the control loop allowing flexibility to compensate the system using an all ceramic capacitor system. The LX3005 also features an enable function, internal circuitry for soft start, and protection schemes such as thermal shutdown, over-current protection, and short-circuit protection. When OCP or SCP is triggered, the device operating frequency will be reduced from typically 420kHz to typically 40kHz, limiting the output power capability. The LX3005 serves as an ideal power supply device for portable devices, especially for chipset power in portable systems. It’s widely used for PDVD, LCD monitor and DPF chipset power sources. The LX3005 is available in SOIC8 package and is functional from an ambient temperature range of 0˚C to 85˚C. W W W . Microsemi . C O M IMPORTANT: : For the most current data, consult MICROSEMI’s website: http://www.microsemi.com Patents Pending PRODUCT HIGHLIGHT VIN VIN ON OFF EN SW L1 D1 FB GND R1 R2 C1 CO VOUT @ 2A LX3005 CIN COMP CC RC LX3005 LX3005 PACKAGE ORDER INFO THERMAL DATA TA (C) 0 to 85 DM Plastic SOIC 8-pin RoHS Compliant / Pb-free JA = 100C/W THERMAL RESISTANCE-JUNCTION TO AMBIENT LX3005CDM Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX3005CDM-TR) Junction Temperature Calculation: TJ = TA + (PD x JA). The JA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow. Copyright  2010 Rev.1.0, 2010-02-05 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 800-8776458, 714-898-8121, Fax: 714-893-2570 Page 1 LX3005 TM ® 2A STEP-DOWN CONVERTER P RODUCTION D ATASHEET ABSOLUTE MAXIMUM RATINGS PACKAGE PIN OUT Supply Input Voltage (VIN)................................................................-0.3V to 30V FB Pin Voltage (VFB)...........................................................................-0.3V to 6V EN Pin Voltage (VEN) ......................................................................... -0.3V to VIN COMP Pin Voltage (VCOMP) ................................................................-0.3V to 6V SW Pin Voltage (VSW)........................................................................ -0.3V to VIN Power Dissipation (PD) ............................................................... Internally limited Maximum Operating Junction Temperature.................................................150C Storage Temperature Range .......................................................... -65C to 150C Lead Temperature (Soldering, 10 seconds) ..................................................260C 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. W W W . Microsemi . C O M NC VIN SW GND 1 8 NC EN COMP FB MSC 3005CDM xxxx 2 3 4 7 6 5 DM PACKAGE (Top View) xxxx = date/lot code RoHS / Pb-free 100% Matte Tin Pin Finish FUNCTIONAL PIN DESCRIPTION Name Pin # Description NC VIN SW GND 1 2 3 4 Pin not used. Supply Voltage Pin. The LX3005 operates from a 4.75V to 25V DC voltage. Bypass VIN to GND with a suitable large capacitor to eliminate noise on the input. Power Switch Output Pin. SW is the switch node that supplies power to the output. Ground for IC. Feedback Pin. Through an external resistor divider network, FB senses the output voltage and regulates it. To prevent current limit run away in a short circuit fault condition, the frequency feedback comparator lowers the oscillator frequency to 40kHz when the FB voltage is below 0.52V. The feedback threshold voltage is 0.8V. Compensation Pin. This pin is the output of the error amplifier. Frequency compensation is done at this pin by connecting a series RC to ground(parallel a capacitor if necessary) Enable Pin. Drive EN pin high to turn on the device, drive it low to turn off. Default of this pin is high level. Pin not used. FB 5 COMP 6 EN NC 7 8 LX3005 LX3005 Copyright  2010 Rev.1.0, 2010-02-05 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 800-8776458, 714-898-8121, Fax: 714-893-2570 Page 2 LX3005 TM ® 2A STEP-DOWN CONVERTER P RODUCTION D ATASHEET Thank you for your interest in Microsemi® Analog Mixed Signal products. W W W . Microsemi . C O M The full data sheet for this device contains proprietary information. To obtain a copy, please contact your local Microsemi sales representative. The name of your local representative can be obtained at the following link http://www.microsemi.com/contact/contactfind.asp or Contact us directly by sending an email to: IPGdatasheets@microsemi.com Be sure to specify the data sheet you are requesting and include your company name and contact information and or vcard. We look forward to hearing from you. LX3005 LX3005 Copyright  2010 Rev.1.0, 2010-02-05 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 800-8776458, 714-898-8121, Fax: 714-893-2570 Page 3