LX8610-XX

A MICROSEMI
 COMPANY LX8610-xx 1A BiCMOS Very Low Dropout Regulators P RELIMINARY D ATAS HEET
 The LX8610 family are positive very low dropout regulators. They are designed to provide a power supply for very low headroom applications, such as 3.3V– 2.5V. BiCMOS technology allows an effective series pass element resistance, RDS(ON) of 250m
      dropout voltage of 250mV at 1A. Low Quiescent Current and LogicControlled Shutdown help conserve battery life and increase system efficiency. Typical quiescent current is under 400µA irrespective of load current, while the shutdown current is only 10µA. The device will enter shutdown mode when the ENABLE pin is pulled low. Thermal & Short-Circuit Current Limiting: the LX8610 limits the current when the output is shorted, so protecting sensitive load circuits. The device will also turn off if the junction temperature exceeds 155°C. Available in small outline SOT-223 and 8-pin SOIC: Adjustable versions use the 8-pin SOIC and fixed output voltage devices are supplied in the 3-lead SOT-223.
 
Dropout Voltage Typically W W W . Microsemi . COM




250mA At 1A And 50mV At 10mA Low Quiescent Current, Under 400µA, Irrespective Of Load Shutdown Current 10µA Adjustable Output Version In 8-pin SOIC Package Fixed Outputs Of 2.5V, 3.3V Available In 3-Pin SOT-223 Package Low Reverse Leakage Current Short-Circuit And Thermal Shutdown Protection       
3.3V & 2.5V Supplies For IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com Memory, Microprocessors, Clock Circuits, Etc.
Portable Equipment 
  L X 86 1 0 -xx S im p lified B lock D ia gram V IN Current Lim it Reference Current Charge P um p RA V OUT A D J* 1 .2 5 V RB E N A B LE * GND V IN /2 RA RB 25K 25K Reverse V oltage S ense L X 8 6 1 0-0 0 25K 41K Therm al S hutdown * A d ju sta b le 8 le a d ve rsio n on ly L X 8 6 1 0-2 5 L X 8 6 1 0-3 3 LX8610-XX LX8610-XX
     TJ (°C) 0 to 125°C OUTPUT ST PLASTIC SOT-233 DM Plastic SOIC 8-PIN VOLTAGE 3-PIN 3.3 2.5 ADJ (00) LX8610-33CST LX8610-25CST – LX8610-33CDM LX8610-25CDM LX8610-00CDM Note: Available in Tape & Reel. Append the letter “T” to the part number. (i.e. LX8610CDMT) Copyright © 2000 Rev. 0.6f,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 LX8610-xx 1A BiCMOS Very Low Dropout Regulators P RELIMINARY D ATAS HEET      Input Voltage (VIN) ......................................................................................................6.5V Enable Pin ..............................................................................................-0.3V to V IN+0.3V Operating Junction Temperature Plastic (ST & DM) Packages .................................125°C Storage Temperature ................................................................................... -65°C to 150°C Lead Temperature (Soldering, 10 Seconds) ...............................................................300°C      T A B IS G N D 3 V OU T W W W . Microsemi . COM 2 GND 1 V IN 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. ST PACKAGE (Top View) V O UT 1 2 3 4 8 7 6 5 ADJ GND/ H E A T S IN K GND/ H E A T S IN K V IN 
 ST PLASTIC SOT-223 PACKAGE 15°C/W* 150°C/W THERMAL RESISTANCE-JUNCTION TO TAB, θJT THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA GND/ H E A T S IN K GND/ H E A T S IN K E N A B LE DM PACKAGE (Top View) DM PLASTIC SOIC PACKAGE 30°C/W 90°C/W θJLD THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA THERMAL RESISTANCE-JUNCTION TO AMBIENT,        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 be improved with package soldered copper area over backside ground plane or internal power plane. θJA can vary from 45°C/W > 75°C/W depending on mounting technique. See table below for thermal resistance guidelines: Copper Area (Topside)* 2.0 sq” (1290mm2) 1.0 sq” (645 mm2) 0.5 sq” (323 mm2) 0.25 sq” (161 mm2) 2.0 sq” (1290mm ) 1.0 sq” (645 mm2) 0.5 sq” (323 mm2) 0.25 sq” (161 mm2) 2 Copper Area (Backside)* 1.0 sq” (645 mm2) 0.5 sq” (323 mm2) 0.1 sq” (65 mm2) 0.1 sq” (65 mm2) 1.0 sq” (645 mm ) 0.5 sq” (323 mm2) 0.1 sq” (65 mm2) 0.1 sq” (65 mm2) 2 Board Area 2.0 sq” (1290mm2) 1.0 sq” (645 mm2) 0.5 sq” (323 mm2) 0.25 sq” (161 mm2) 2.0 sq” (1290mm ) 1.0 sq” (645 mm2) 0.5 sq” (323 mm2) 0.25 sq” (161 mm2) 2 Thermal Resistance (θJA) 45°C/W 50°C/W 60°C/W 70°C/W 60°C/W 67°C/W 70°C/W 75°C/W Possible Heat Sink Approaches using PCB Copper ST (SOT-223) 1 2 3 4 8 7 6 5 PACKAGE DATA PACKAGE DATA DM (SOIC) *Tab of device attached to topside copper, or leads 2,3,5,6 of SOIC package Copyright © 2000 Rev. 0.6f,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 LX8610-xx 1A BiCMOS Very Low Dropout Regulators P RELIMINARY D ATAS HEET 
     



 W W W . Microsemi . COM VIN Positive supply input for the regulator. Bypass to GND with at least 2.2µF of low ESR, ESL capacitance if supply source is further than 1 inch from the device. Output for the regulator. It is recommended to bypass to GND with at least 10µF although this is not required for regulation, rather it is needed for transient response. Size your output capacitor to meet the transient loading requirement. If you have a very dynamic load, a larger capacitor will improve the response to these load steps. Reference ground. The input and output bypass capacitors should be connected to this pin. In addition the tab on the SOT-223 package and pins 2,3,6, and 7 on the SOIC package are also used for heat sinking the device. Feedback pin for the regulator. For the LX8610-00, the output voltage can be set by two external resistors with the following relationship: VOUT = 1.25V * (1 + RA / RB) where RA is the resistor connected between VOUT and ADJ, and RB is the resistor connected between ADJ and GND. Enable input. This pin has a threshold of about VIN / 2, it should be actively pulled high to enable the regulator. This can be accomplished with a resistive pull-up. When low, it turns off the regulator and puts the device in a low current shutdown state. VOUT GND ADJ ENALBE    VIN 5 IN OUT 1 VOUT RA CIN LX8610-00 ENABLE 4 GND 2,3 6,7 ADJ 8 COUT RB VREF VOUT = VREF 1 +   RA  RB   PIN DESCRIPTION PIN DESCRIPTION Figure 1 – Typical Application Copyright © 2000 Rev. 0.6f,2000-09-15 Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 3 A MICROSEMI
 COMPANY Parameter LX8610-xx 1A BiCMOS Very Low Dropout Regulators P RELIMINARY D ATAS HEET  

  
  Symbol VIN Min 3 10 2.2 10 LX8610 Typ 5.5 1000 10 22* Max Units V mA µF µF W W W . Microsemi . COM Input Voltage Load Current (with adequate heatsinking) Input Capacitor (VIN to GND) Output Capacitor (VOUT to GND) these load steps. * Size your output capacitor to meet the transient loading requirement. If you have a very dynamic load, a larger capacitor will improve the response to
Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C ≤ TA ≤ 125°C except where otherwise noted. Test conditions: VIN = VOUT + 1.5V; IOUT = 10mA; CIN = 10µF; COUT = 22µF; TJ = TA. Parameter Symbol Test Conditions LX8610-xx Typ Max 3.3 4 5 0.25 0.15 0.05 1.25 400 400 0 VIN / 2 10 3.35 3.38 8 10 0.4 0.25 0.15 1.7 600 650 Units   Min 3.25 3.22
LX8610-33 FIXED 3.3V, 1A Output Voltage Line Regulation Load Regulation Dropout Voltage (VDO = VIN–VOUT) Short Circuit Current Quiescent Current Reverse Leakage Current Shutdown Threshold * Shutdown Current * VOUT VREG IREG VDO ISC IQ IREV VSD ISD TJ = 25°C Over Temperature VIN = 3.45V to 5.5V IOUT = 10mA to 1A IOUT = 1A, VOUT  OUT –1% IOUT = 0.5A, VOUT  OUT – 1% IOUT = 10mA, VOUT  OUT – 1% VOUT = 0V IOUT = 10mA to 1A 0V < VIN < VOUT, VOUT 3V IOUT = 10mA to 1A, VIN = 5.5V 0V < VIN < VOUT, VOUT < 5.5V (at VOUT) 0V < VIN < VOUT, VOUT