PD-97308 OM186ST VADJ, 1.5A Adjustable Low Dropout Positive Voltage Regulator Product Summary Part Number Output Voltage Output Current Package OM186ST Adjustable 1.5A TO-257AA TO-257AA Description These three terminal positive adjustable voltage regulators are designed to provide 1.5A with higher efficiency than conventional voltage regulators. The devices are designed to operate to 1.5V input to output differential and the dropout voltage is specified as a function of load current. Devices are pin compatible with older three terminal regulators and are supplied in the easy-to-use hermetic metal TO-257 package. These devices are ideally suited for Military applications where small size, hermeticity and high reliability are required. Features n n n n n n n Operates Down to 1.5V Dropout @ Max Current 0.015% Line Regulation 0.01% Load Regulation 1% Reference Voltage Hermetic TO-257AA (Isolated Tab) Package Electrically Equivalent to LM1086 This part is also available in D2 Package as OM186SR Absolute Maximum Ratings @ TC = 25°C Parameter Output Current Input Voltage Thermal Resistance, Junction to Case Operating Junction Temperature Range Storage Temperature Range www.irf.com Symbol Value Units IO 1.5 A VIN 30 V RθJC 4.2 °C/W TJ -55 to +150 TSTG -65 to +150 °C 1 02/07/08 OM186ST Electrical Characteristics TJ = 25°C (Unless Otherwise Specified) Parameter Reference Voltage Line Regulation Load Regulation Dropout Voltage Test Conditions IOUT = 10mA, (VIN - VOUT) = 3.0V 10mA ≤ IOUT ≤ IFULL LOAD, 1.5V ≤ (VIN - VOUT) ≤ 25V ILOAD = 10mA, 1.5V d (VIN - VOUT) d15V cd (VIN - VOUT) = 3.0V, 10mA dIOUTdIFULL LOAD cde UVREF = 1%, IOUT = IFULL LOAD f e Min. Typ. Max. 1.238 1.250 1.262 1.220 1.250 1.270 - 0.015 0.2 - 0.035 0.2 - 0.5 0.8 - 0.8 1.0 Units V % - 1.3 1.5 (VIN - VOUT) = 5.0V 1.5 - - (VIN - VOUT) = 25V 0.075 - - Minimum Load Current (VIN - VOUT) = 25V - 5.0 10 mA Thermal Regulation - 0.010 0.05 %/W 60 75 - dB - 55 120 - 0.2 5.0 Current Limit Ripple Rejection 30ms Pulse Width (Guaranteed by design) f = 120Hz, CAdj = 25PF Tantalum IOUT - IFULL LOAD (VIN - VOUT) = 3.0V Adjust Pin Current Adjust Pin Current Change 10mA ≤ IOUT ≤ IFULL LOAD 1.5V ≤ (VIN - VOUT) ≤ 25V Temperature Stability -55°C ≤ TJ ≤ +125°C - 0.5 - Long Term Stability TJ = 125°C, t = 1000hrs - 0.3 1.0 V A µA % Notes 1. Load and line regulation are measured at a constant junction temperature by low duty cycle pulse testing. 2. Line and load regulation are guaranteed up to the maximum power dissipation. Power dissipation is determined by the input/output differential voltage and output current. Guaranteed maximum power dissipation will not be available over the full input/output voltage range. 3. I FULL LOAD curve is defined as the minimum value of current limit as a function of input to output voltage. Note that power dissipation is only achievable over a limited range of input to output voltage. 4. Dropout voltage is specified over the full output current range of the device. 2 www.irf.com OM186ST Short Circuit Current Dropout Voltage Fig 1: Typical Minimum Input/Output Differential Vs Output Current Fig 2: Typical Short Circuit Current Vs Input/Output Differential Load Regulation Fig 3: Typical Output Voltage Deviation Vs Temperature www.irf.com 3 OM186ST Application Notes: Stability The OM186ST Series requires the use of an output capacitor as part of the device frequency compensation. For all operating conditions, the addition of 150µF aluminum electrolytic or a 22µF solid tantalum on the output will ensure stability. Normally, capacitors much smaller than this can be used. Many different types of capacitors with widely varying characteristics are available. These capacitors differ in capacitor tolerance (sometimes ranging up to ±100%), equivalent series resistance, and capacitance temperature coefficient. The 150µF or 22µF values given will ensure stability. When the adjustment terminal is bypassed to improve the ripple rejection, the requirement for an output capacitor increases. The values of 22µF tantalum or 150µF aluminum cover all cases of bypassing the adjustment terminal. Without bypassing the adjustment terminal, smaller capacitors can be used with equally good results and the table below shows approximately what size capacitors are needed to ensure stability. Normally, capacitor values on the order of 100µF are used in the output of many regulators to ensure good transient response with heavy load current changes. Output capacitance can be increased without limit and larger values of output capacitor further improve stability and transient response of the regulators. Recommended Capacitor Values Input Output Adjustment 10µF 10µF Tantalum, 50µF Aluminum None 10µF 22µF Tantalum, 150µF Aluminum 20µF Output Voltage - Adjustable Regulators The OM186ST devices develop a 1.25V reference voltage between the output and the adjust terminal (see Fig 4). By placing a resistor, R1 between these two terminals, a constant current is caused to flow through R1 and down through R2 to set the overall output voltage. Normally this current is the specified minimum load current of 10mA. Because IADJ is very small and constant when compared with the current through R1, it represents a small error and can usually be ignored. VIN IN OM186ST VOUT OUT ADJ VADJ IADJ 50µA R1 R2 R VOUT = VREF 1+ R21 + IADJ R2 Fig 4. Basic Adjustable Regulator 4 www.irf.com OM186ST Case Outline and Dimensions - TO-257AA 3Pin (T-3) NOTES: 1. DIMENSIONING & TOLERANCING PER ASME Y14.5M-1994. 2. ALL DIMENSIONS ARE SHOWN IN MILLIMETERS (INCHES). 3. CONTROLLING DIMENSION: INCH. 4. TOLERANCES ARE ±0.010 U.O.S. 5. SEE INDIVIDUAL DATA SHEETS FOR OIN ASSIGNMENTS. 6. OUTLINE USED WITH OM PART NUMBERS ONLY. PIN ASSIGNMENTS Pin 1 - ADJUST Pin 2 - VOUT Pin 3 - VIN Part Numbering Nomenclature OM 186 S T M Screening Level Device Number Package Code T = TO-257AA Isolated / Non-Isolated S = Isolated IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: (310) 252-7105 IR LEOMINSTER : 205 Crawford St., Leominster, Massachusetts 01453, USA Tel: (978) 534-5776 Data and specifications subject to change without notice. 02/2008 www.irf.com 5