LX8817

A MICROSEMI
 COMPANY LX8817 Dual Channel 2.5A Low Dropout Regulator P RELIMINARY
 The LX8817 is a dual channel positive-voltage linear regulator. This dual regulator has one fixed output coupled with an adjustable output. Each channel features low-dropout and high accuracy. The LX8817 utilizes dual inputs that can be used as separate sources for the control and power sections. This configuration reduces power dissipation by operating the regulator near dropout (VPWR-VOUT = VDO = 0.6V @ 2.5A) while providing sufficient operating headroom for the control logic. The LX8817 provides designers with an efficient flexible power management solution, minimal printed circuit board area, and shorter design cycles. 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 LX8817 features on-chip trimming of the internal voltage reference, enabling precise output voltages, typically ±1% of it’s specified value. Power sequencing logic ensures proper startup regardless of the level of VCTRL or VPWR. The LX8817 outputs remain off while VPWR < 2.7V. Thermal and Short Circuit Current Protection are integrated on-chip and operate independently for each regulator output. The LX8817 regulator is stable with a low-value output capacitor, typically 10µF tantalum or ceramic on the outputs, allowing designers flexibility in external component selection. Linfinity’s S-PAK power package offers maximum power dissipation and ease of assembly using surface mount technology.  
Two Independent Regulated W W W . Microsemi . COM Outputs
Accurate Output Voltages
Max. Dropout of 0.6V at Rated Current
Independent Thermal and Current Limit Protection
Low Profile 7 Lead SMT Power Package
Low Tolerance Line (0.2%) and Load (0.4%) Regulation
Wide DC Supply Voltage of 3.0V to 10.0V
Loop Stability Independent of Output Capacitor Type       
3.3V to 2.5V/ADJ Linear




Regulator Low Voltage Logic Supplies Active SCSI Terminators Battery Charging Circuits Instrumentation PC Peripherals IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com 
  V PW R 3 2 V1 L X 8817 V C TR L 1 4 5 6 V2 LX 8 8 1 7 LX 8 8 1 7
     TA (°C) 0 to 125 OUTPUT V1 2.5V OUTPUT V2 Adj DF Plastic S-PAK 7-PIN LX8817-2500CDF Note: Available in Tape & Reel. Append the letter “T” to the part number. (i.e. LX8817-xxxxC__T) Copyright © 2000 Rev. 0.2a, 2000-09-15 Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 1 A MICROSEMI
 COMPANY LX8817 Dual Channel 2.5A Low Dropout Regulator P RELIMINARY      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 Lead Temperature (Soldering 180 seconds) .................................................235 °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 .      T AB is G N D 7 6 5 4 3 2 1 W W W . Microsemi . COM NC A D J V2 V O UT2 GND V PW R V O UT1 V C TR L D F P A CK A G E (T op V iew) 
 DF Plastic S-PAK 7-PIN THERMAL RESISTANCE-JUNCTION TO TAB, θJT THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA 4.5°C/W 20°C/W 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 > 30°C/W depending on mounting technique. (See Application Notes Section: Thermal considerations) 
     



 1 2 3 4 5 6 7 VCTRL VOUT1 VPWR GND VOUT2 ADJV2 NC Unregulated input voltage supply, provides bias for control circuitry, (VCTRL – VOUT) > 1V. Regulator #1 fixed output voltage. 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 adjustable output. Regulator #2 voltage feedback. Sets the output voltage for regulator #2 via an external resistor divider. Not used. PACKAGE DATA PACKAGE DATA Copyright © 2000 Rev. 0.2a, 2000-09-15 Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 2 A MICROSEMI
 COMPANY LX8817 Dual Channel 2.5A Low Dropout Regulator P RELIMINARY Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C ≤ TA ≤ 135°C except where otherwise noted and the following test conditions: VCTRL = 5V, VPWR = 3.3V IOUT = 10mA, C1, 2, 3, 4 = 10µF (Tantalum), and TJ = TA using low duty cycling methods. Parameter Symbol Test Conditions LX8817-xx00 Min Typ Max Units   W W W . Microsemi . COM
FIXED OUTPUT Output Voltage • LX8815-2500 Line Regulation Load Regulation Dropout Voltage (PWR) Current Limit Minimum Load Current V1 ∆V1(VIN) ∆V1(I1) VPWR-V1 I1 (MAX) I1 I1 = 10mA, TJ = 25°C 5mA < I1 < 2.5A, 3.75V < VCTRL < 8V 3V < VPWR < 5.5V 3.3V