LX8940 ® TM 5V Low Dropout Regulator P RODUCTION D ATA S HEET KEY FEATURES DESCRIPTION 2% Internally Trimmed Output Output Current In Excess Of 1A Input-Output Differential Less Than 0.4V At 1A Reverse Battery Protection 60V Load Dump Protection -50V Reverse Transient Protection Short Circuit Protection Internal Thermal Overload Protection Available In 3-Lead Plastic TO220 Drops In Most lM2940 Sockets case supplies require a low input-output differential to maintain regulation. This feature makes it ideal for computer monitors that have to comply with energy-efficient / "Green PC" programs, where the input voltage drops to only a few tenths of a volt above the output when power supply enters sleep-mode operation. IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com PRODUCT HIGHLIGHT LX8940 VINPart OUT 5.3V 600 CO = 47µF Electrolytic VIN = 5.3V 500 5.00V 125°C Dropout Voltage (mV) (20mV/ Div.) Output Voltage Dropout Voltage vs. Output Current v.s Temperature CIN = 1µF (50mA/ Div.) 4.98V Output Current Small Headroom Battery Applications High Efficiency Linear Regulators Post Regulators For Switching Power Supplies Green PC Monitor Applications 10µF Load Transient Response TA = 25°C APPLICATIONS 5V / 100mA GND 0.1µF WWW . Microsemi .C OM The LX8940 is a 5V, low dropout, low quiescent current regulator rated for 1A of output current. It can regulate with as low as 0.4V headroom between the input and output voltages, thus minimizing power dissipation. In addition, it can be used in applications where worst 100mA 400 25°C 300 200 -40°C 100 0mA 0 100 Time (20µS / Div.) 500 1000 Output Current (mA) TA (°C) 0 to 125 -40 to 125 P LX8940 PACKAGE ORDER INFO Plastic TO-220 3-Pin RoHS Compliant / Pb-free Transition DC: 0543 LX8940CP LX8940IP Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX8940IP-TR) Copyright © 2000 Rev. 1.3a, 2005-11-18 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 1 LX8940 ® TM 5V Low Dropout Regulator P RODUCTION D ATA S HEET ABSOLUTE MAXIMUM RATINGS PACKAGE PIN OUT TAB is GND 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. Pin numbers refer to DIL packages only 3 Output 2 GND 1 Input P PACKAGE (Top View) RoHS / Pb-free 100% matte Tin Lead Finish WWW . Microsemi .C OM Input Voltage (VIN)......................................................................................... -15V to 26V Maximum Operating Junction Temperature .............................................................. 150°C Storage Temperature Range.........................................................................-65°C to 150°C Peak Package Solder Reflow Temp. (40 seconds max. exposure) ................. 260°C (+0,-5) THERMAL DATA P Plastic TO-220 3-Pin THERMAL RESISTANCE-JUNCTION TO TAB, θJT THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA 3.0°C/W 60°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. RECOMMENDED OPERATING CONDITIONS Parameter Symbol Input Voltage Load Current (with adequate heatsinking) Maximum Line Transient (Load Dump), VO < 5.5V Input Capacitor (VIN to GND) Output Capacitor with ESR of 10Ω max., (VOUT to GND & VSB to GND) VIN Min Note 2 5 0.1 10 LX8940 Typ Max 26 1000 60 Units V mA V µF µF Note 2: VIN(MIN) = 1.2∆V(MAX) See Dropout Voltage Maximum Limit. PACKAGE DATA Copyright © 2000 Rev. 1.3a, 2005-11-18 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 2 LX8940 ® TM 5V Low Dropout Regulator P RODUCTION D ATA S HEET Parameter ` Symbol Test Conditions Min LX8940 Typ Max Units SECTION HEADER Output Voltage Line Regulation Load Regulation Output Impedance (Note 3) Quiescent Current VO ∆VOI ∆VOL rO IO = 0A, TA = 25°C 7V < VIN < 26, IO =5mA 50mA < IO < 1A 100mADC and 20mARMS, fO = 120Hz IO < 5mA, 7 < VIN < 26V IO = 500mA IO = 1000mA 10Hz – 100kHz, IO = 5mA IQ Output Noise Voltage (Note 3) VORMS 4.85 Long Term Stability (Note 3) 5 1 10 200 3 30 115 150 5.15 50 50 15 50 180 20 Ripple Rejection (Note 3) RR Dropout Voltage ∆V Current Limit Maximum Operational Input Voltage Maximum Line Transient ICL fO = 120Hz, 1VRMS, IO = 100mA IO = 100mA IO = 500mA IO = 1A VIN = 26V VIN(MAX) VIN(TR) V mV mV mΩ mA mA mA µVRMS mV / 1000hr dB mV mV mV A 1 66 150 275 400 1.2 26 31 V 60 V RO = 100Ω, T < 100mS 300 500 800 WWW . Microsemi .C OM ELECTRICAL CHARACTERISTICS Unless otherwise specified, the following specifications apply over the operating ambient temperature -40°C to +125°C for the LX8940IP and 0°C to +125°C for LX8940CP; VIN = 10V, IO = 1A, COUT = 22µF, and for DC characteristics only. Low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal to the ambient temperature.) Note 3: These parameters, although guaranteed, are not tested in production. SIMPLIFIED BLOCK DIAGRAM Input Voltage C1 0.1µF 1 * Required if regulator is located far from power supply filter Input LX8940 Output 2 C2 10µF Overvoltage Thermal Shutdown Output Voltage + Regulator Bias ELECTRICALS _ GND 3 1.23V Reference Figure 1 – Simplified Block Diagram Copyright © 2000 Rev. 1.3a, 2005-11-18 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 3 LX8940 TM ® 5V Low Dropout Regulator P RODUCTION D ATA S HEET APPLICATION NOTE EXTERNAL CAPACITORS To stabilize the outputs and prevent oscillation (perhaps by many volts) external capacitors are required. The minimum recommended value for the output capacitors is 10μF, although the actual size and type will likely vary according to the particular application, e.g., operating temperature range and load. Another consideration is the effective series resistance (ESR) of the capacitor. Capacitor ESR will vary by manufacturer. Consequently, some evaluation may be required to determine the minimum value of the output capacitors. Generally worst case occurs at the maximum load and minimum ambient temperature. The size of the output capacitor can be increased to any value above the minimum. One possible advantage of this would be to maintain the output voltage during brief periods of negative input transients The output capacitors chosen should be rated for the full range of ambient temperature over which the circuit will be exposed and expected to operate. For example, many aluminum type electrolytic capacitors change values at cold temperatures. The effective capacitance is reduced and regulator stability is affected. Tantalum capacitors are a good choice for these types of environments. WWW . Microsemi .C OM The advantages of using a low-dropout regulator such as the LX8940 is the need for less “headroom” for full regulation, and the inherent reverse polarity protection provided by the PNP output device. A typical NPN regulator design requires an input to output differential of approximately two volts minimum. This is due to the 2Vbe + Vcesat of the NPN Darlington used in the output, coupled with the voltage drop across the current limit resistor. In contrast, the “PNP Regulator” uses a single series pass transistor with its single Vcesat, thus the lower input to output voltage differential or dropout voltage. In some applications the regulator output voltage is used not only as a power supply but also as a voltage reference for control systems. In such cases not just the temperature stability of the output is important but also the initial accuracy. LX8940 fills this need as the internal bandgap reference is trimmed allowing a typical output voltage tolerance of ±1%. OUTPUT PROTECTION The output features fault protection against over voltage as well as a thermal shutdown feature. If the input voltage rises above 33V (load dump), the output shuts down automatically. The internal circuitry is thus protected and the IC is able to survive higher voltage transients than might otherwise be expected. The thermal shutdown output effectively guards against overheating of the die and protects the device from being damaged. APPLICATIONS Copyright © 2000 Rev. 1.3a, 2005-11-18 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 4 LX8940 ® TM 5V Low Dropout Regulator P RODUCTION D ATA S HEET PACKAGE DIMENSIONS WWW . Microsemi .C OM P 3-Pin Plastic TO-220 B S F T Q U A 1 2 C 3 H R K D Dim A B C D F G H J K L N Q R S T U MILLIMETERS MIN MAX 14.22 15.88 9.65 10.67 3.56 4.83 0.51 1.14 3.53 4.09 2.54 BSC 6.35 0.30 1.14 12.70 14.73 1.14 1.27 5.08 TYP 2.54 3.05 2.03 2.92 1.14 1.40 5.84 6.86 0.508 1.14 INCHES MIN MAX 0.560 0.625 0.380 0.420 0.140 0.190 0.020 0.045 0.139 0.161 0.100 BSC 0.250 0.012 0.045 0.500 0.580 0.045 0.050 0.200 TYP 0.100 0.120 0.080 0.115 0.045 0.055 0.230 0.270 0.020 0.045 Note: L 1. Dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm(.006”) on any side. Lead dimension shall not include solder coverage. J G N MECHANICALS Copyright © 2000 Rev. 1.3a, 2005-11-18 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 5 LX8940 TM ® 5V Low Dropout Regulator P RODUCTION D ATA S HEET NOTES WWW . Microsemi .C OM NOTES PRODUCTION DATA – Information contained in this document is proprietary to Microsemi and is current as of publication date. This document may not be modified in any way without the express written consent of Microsemi. Product processing does not necessarily include testing of all parameters. Microsemi reserves the right to change the configuration and performance of the product and to discontinue product at any time. Copyright © 2000 Rev. 1.3a, 2005-11-18 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 6