LX8821

LX8821 TM ® DUAL CHANNEL 2.5A LOW DROPOUT REGULATOR P RODUCTION DATA S HEET DESCRIPTION KEY FEATURES Two Independent Regulated Outputs Wide DC Supply Voltage of 3.0V to 10.0V Accurate Output Voltages Low Tolerance Line (0.5%) and Load (0.5%) Regulation Max. Dropout of 0.6V at Rated Current Independent Thermal and Current Limit Protection Loop Stability Independent of Output Capacitor Type SMT Power Package APPLICATIONS/BENEFITS ASIC, Memory, I/O Low Voltage Logic Supplies Active SCSI Terminators Battery Charging Circuits PC Peripherals Instrumentation The LX8821 is a positive-voltage linear regulator with one fixed and one adjustable output featuring lowdropout and high accuracy. To maximize efficiency, the LX8821 accepts two supply voltage inputs for the VCONTROL and VPOWER sections. This configuration reduces power dissipation by operating the regulator near dropout (VPWR-VOUT = VDO = 0.4V @ 2A) while providing sufficient operating headroom for the control logic. Each channel can supply up to 2.5A independently with a regulator design optimized for system efficiency by consuming minimal ground current and directing quiescent current to the load The internal voltage reference is trimmed at wafer level, enabling precise output voltages, typically ±1% of its specified value. Power sequencing logic ensures proper startup regardless of the level of VCTRL or VPWR. The LX8821 outputs remain off while VPWR < 2.2V. Thermal and Short Circuit Current Protection are integrated on-chip and operate independently for each regulator output. The LX8821 regulator is stable with a wide range of output capacitance and ESR; typically 10μF tantalum or ceramic on the outputs is sufficient. Microsemi uses a low profile power package with low thermal resistance and ease of assembly using surface mount technology. W WW . Microsemi . C OM IMPORTANT: For the most current data, consult Microsemi’s website: http://www.microsemi.com PRODUCT HIGHLIGHT VPOWER 10µF VPWR Part VCONTROL 1µF VOUT1 VOUT2 R1 33µF VOUT1 VOUT2 ⎡ R1 ⎤ VOUT2 = 1.25 • ⎢1 + ⎥ + I ADJ • R1 ⎣ R2 ⎦ VCONTROL GND LX8821 ADJ 33µF R2 GROUND LX8821 LX8821 PACKAGE ORDER INFO TA (°C) 0 to 100 Output V1 1.5V Output V2 Adjustable DF Plastic S-Pak 7-Pin RoHS Compliant LX8821CDF Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX8821CDF-TR) Copyright © 2005 Rev. 1.1, 2005-03-09 Microsemi Microsemi Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 1 LX8821 TM ® DUAL CHANNEL 2.5A LOW DROPOUT REGULATOR P RODUCTION DATA S HEET ABSOLUTE MAXIMUM RATINGS PACKAGE PIN OUT TAB is GND 7 6 5 4 3 2 1 Input Voltage (VCTRL, VPWR).........................................................................13.5V Load Current (Internally Limited) ..................................................................3.0A Power Dissipation ......................................................................Internally Limited Short-Circuit Protection .......................................................................... Indefinite Operating Junction Temperature.................................................................. 150°C Storage Temperature Range...........................................................-65°C to 150°C Peak Package Solder Reflow Temperature (40 second maximum exposure) ..................................................... 260°C (+0, -5) 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 WW . Microsemi . C OM NC ADJ V2 V OUT2 G ND V PW R V OUT1 V CTRL D F P ACKAGE (Top View) Pin 4 and Tab are common RoHS 100% Matte Tin Lead Finish THERMAL DATA DF Plastic S-Pak 7-Pin 4.5°C/W 20 - 50°C/W THERMAL RESISTANCE-JUNCTION TO TAB, θJT THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA Junction Temperature Calculation: TJ = TA + (PD x θJA). The θJA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow. θJA can vary from 10°C/W to > 50°C/W depending on mounting technique. (See Application Notes Section: Thermal considerations) FUNCTIONAL PIN DESCRIPTION PIN 1 2 3 4 5 6 7 NAME VCTRL VOUT1 VPWR GND VOUT2 ADJ V2 --DESCRIPTION Unregulated input voltage supply, provides bias for control circuitry, (VCTRL – VOUT) > 1V. Regulator #1 fixed output voltage, 1.5V nominal. Unregulated input voltage supply for power section. For proper operation: (VPWR – VOUT) > VDROPOUT. Common terminal for ground reference, Tab of package is internally connected to this pin. Regulator #2 output Regulator #2 feedback voltage, servos to 1.25V. Using external resistors to program VOUT2. Not used, no internal connection, may be left floating or connected to any other pin or voltage. PACKAGE DATA PACKAGE DATA Copyright © 2005 Rev. 1.1, 2005-03-09 Microsemi Microsemi Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 2 LX8821 TM ® DUAL CHANNEL 2.5A LOW DROPOUT REGULATOR P RODUCTION DATA S HEET Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C ≤ TA ≤ 100°C except where otherwise noted and the following test conditions: VCTRL = 5V, VPWR = 3.3V IOUT = 5mA, C1, 2, 3, 4 = 10μF (Tantalum), and TJ = TA using low duty cycling methods. Typical values represent performance @ 23°C Parameter FIXED OUTPUT: VOUT 1 Total Output Voltage Variation Line Regulation Load Regulation Current Limit Minimum Load Current ADJUSTABLEOUTPUT: VOUT 2 Output Voltage Line Regulation Load Regulation V2 ΔV2(VIN) ΔV2(I2) VPWR-V2 Dropout Voltage, VOUT 2 VCNTR-V2 Adjust Pin Current Current Limit Minimum Load Current ENTIRE REGULATOR Minimum Operating Voltage Under Voltage Lockout Quiescent Current Ripple Rejection RMS Output Noise Thermal Shutdown TJSD IQ PSRR VPWR VCONTROL VPWR Rising, 3.0V