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Technical content

Features

 5V maximum dropout at full load current  Built-in thermal shutdown  Output current limiting  Adjustable output voltages  Fast transient response  Good noise rejection  Package: TO252, TO263, TO220

Applications

 High Efficiency Linear Regulators  Battery Chargers  Post Regulation for Switching Supply  Microprocessor Supply  Desktop PCs, RISC and Embedded Processors' Supply

Rev1.0 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., • www.seawardinc.com • Page 2 9/4/2012 SE1084 5A Low Dropout Linear Regulator Pin Configuration TO252:1 Adj(GND) 2 Vout 3 Vin TO263:1 Adj(GND) 2 Vout 3 Vin TO220:1 Adj(GND) 2 Vout 3 Vin Pin Description NO. Pin Name Pin Function Description

1 Adj (GND)

Adjustable (Ground only for fixed version) A resistor divider from this pin to the V OUT pin and ground sets the output voltage. 2 VOUT The output of the regulator. A minimum of 100uF (0.15Ω ≤ESR ≤10Ω) capacitor must be connected from this pin to ground to insure stability.

3 VIN

The input pin of regulator. Typically a large storage capacitor (0.15Ω ≤ESR ≤10Ω) is connected from this pin to ground to insure that the input voltage does not sag below the minimum dropout voltage during the load transient response. This pin must always be 1.4V higher than V OUT in order for the device to regulate properly. Functional Block Diagram

Rev1.0 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., • www.seawardinc.com • Page 3 9/4/2012 SE1084 5A Low Dropout Linear Regulator

Ordering Information

Part Number Marking Information Package Remarks SE1084J-LF SE1084J YYWW-LF TO252 YYWW means Production batch Adjustable output voltage. SE1084R-LF SE1084R YYWW-LF TO263 SE1084Q-LF SE1084Q YYWW-LF TO220 SE1084JXX-LF SE1084JXX YYWW-LF TO252 YYWW means Production batch Fixed output voltages; XX denotes voltage options SE1084RXX-LF SE1084RXX YYWW-LF TO263 SE1084QXX-LF SE1084QXX YYWW-LF TO220 Absolute Maximum Ratings Symbol Parameter Maximum Units VIN DC Supply Voltage -0.3 to 12 V PD Power Dissipation Internally Limited TST Storage Temperature -65 to +150 ℃ TOPJ Operating Junction Temperature Range -40to +125 ℃

Rev1.0 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., • www.seawardinc.com • Page 4 9/4/2012 SE1084 5A Low Dropout Linear Regulator

Electrical Characteristics

（Vin =3.6V ; Tj=25℃ unless otherwise specified） Symbol Characteristics Test Conditions Min Typ Max Unit VREF Reference Voltage IOUT=10mA, TJ=25℃, (VIN-VOUT)=1.5V 1.225 1.250 1.275 V VOUT Output Voltage (Fixed Version) IOUT= 10mA, TJ= 25℃, 3V≦VIN≦12V 1.470 1.500 1.530 V IOUT= 10mA, TJ= 25℃, 3.3V≦VIN≦12V 1.764 1.800 1.836 V IOUT= 10mA, TJ= 25℃, 4V≦VIN≦12V 2.450 2.500 2.550 V IOUT= 10mA, TJ= 25℃, 4.8V≦VIN≦12V 3.235 3.300 3.365 V IOUT= 10mA, TJ= 25℃, 6.5V≦VIN≦12V 4.900 5.000 5.100 V VLINE Line Regulation IOUT=10mA, VOUT+1.5V<VIN<12V, TJ=25℃ 0.2 0.5 % VLOAD Load Regulation VIN=3V, 10mAIOUT<5A, TJ=25℃(Note 1,2), ADJ Version 1 % VIN=3V, 10mA<IOUT<5A, TJ=25℃(Note 1,2), VOUT=1.5V Fixed Version 12 15 mV VIN=3.3V,10mA<IOUT<5A, TJ=25℃ (Note 1,2), VOUT=1.8V Fixed Version 15 18 mV VIN=4V, 10mA<IOUT<5A, TJ=25℃ (Note 1,2), VOUT=2.5V Fixed Version 20 25 mV VIN =5V,10mA<IOUT<5A, TJ=25℃(Note 1,2), VOUT=3.3V Fixed Version 26 33 mV

Rev1.0 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., • www.seawardinc.com • Page 5 9/4/2012 SE1084 5A Low Dropout Linear Regulator VIN =6.5V,10mA<IOUT<5A, TJ=25℃ (Note 1,2), VOUT=5V Fixed Version 40 50 mV  △Vo Dropout Voltage IOUT=5.0A (VOUT=1% VOUT) 1.3 1.5 V IL Current Limit VIN-VOUT=3V 5.1 A Io Minimum Load Current 5 10 mA Temperature Stability IOUT=10mA 0.5 % θJA Thermal Resistance Junction-to-Ambient (No heat sink ;No air flow) TO-252 TO-263 TO-220 ℃/W Thermal Resistance Junction-to-Ambient (Note 3) TO-252 TO-263 TO-220 θJC Thermal Resistance Junction-to-Case TO-252: Control Circuitry/Power Transistor TO-263: Control Circuitry/Power Transistor TO-220: Control Circuitry/Power Transistor 0.65/2.7 0.65/2.7 ℃/W Note 1: See thermal regulation specifications for changes in output voltage due to heating effects. Line and load regulation are measured at a constant junction temperature by low duty cycle pulse testing. Load regulation is measured at the output lead = 1/18” from the package. Note 2: Line and load regulation are guaranteed up to the maximum power dissipation of 15W. Power dissipation is determined by the difference between input and output and the output current. Guaranteed maximum power dissipation will not be available over the full input/output range. Note 3: Output is connected to the multi -layer PCB cupper area 10mm*5.5mm separately. If you need large PD or lower Tc and T j, please connect to the large cupper area >>10mm*5.5mm (like 10mm*10mm).

Rev1.0 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., • www.seawardinc.com • Page 6 9/4/2012 SE1084 5A Low Dropout Linear Regulator Typical Performance Characteristics

Rev1.0 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., • www.seawardinc.com • Page 7 9/4/2012 SE1084 5A Low Dropout Linear Regulator Applications Information Introduction The SE1084 adjustable Low Dropout (LDO) regulator is a 3 terminal device that can easily be programmed with the addition of two external resistors to any voltages within the range of 1.25V to V IN-1.5V. The SE1084 only needs 1.5V differential between VIN and VOUT to maintain output regulation. In addition, the output voltage tolerances are also extremely tight and they include the transient response as part of the specification. For example, Intel VRE specification calls for a total of +/-100mV including initial tolerance, load regulation and 0 to 5.0A load step. The SE1084 is specifically designed to meet the fast current transient needs as well as providing an accurate initial voltage, reducing the overall system cost with the need for fewer output capacitors. Output Voltage Setting The SE1084 can be programmed to any voltages in the range of 1.25V to V IN-1.5V with the addition of R1 and R2 external resistors according to the following formula: VOUT = V REF (1+ R2/R1) +Iadj *R2 , where VREF = 1.25 typically, Iadj = 50uA typically R1 and R2 as shown at below The SE1084 keeps a constant 1.25V between the output pin and the adjust pin. By placing a resistor R1 across these two pins a constant current flows through R1, adding to the Iadj current and into the R2 r esistor producing a voltage equal to the (1.25/R1)*R2+Iadj*R2 which will be added to the 1.25V to set the output voltage. This is summarized in the above equation. Since the minimum load current requirement of the SE1084 is 10mA, R1 is typically selected to be 121Ω resistor so that it automatically satisfies the minimum current requirement. Notice that since Iadj is typically in the range of 50uA it only adds a small error to the output voltage and should only be considered when a very precise output voltage setting is required. For example, in a typical 3.3V application where R1=121Ω and R2=200Ω the error due to Iadj is only 0.3% of the nominal set point. Load Regulation Since the SE1084 is only a 3 terminal device, it is not possible to provide true remote sensing of the output voltage at the load. The best load regulation is achieved when the bottom side of R2 is connected to the load and the top-side of R1 resistor is connected directly to the case or the V OUT pin of the regulator and not to the load. It is important to note that for high current applications, this can re-present a significant percentage of the overall load regulation and one must keep the path from the regulator to the load as short as possible to minimize this effect.

Rev1.0 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., • www.seawardinc.com • Page 8 9/4/2012 SE1084 5A Low Dropout Linear Regulator Stability The SE1084 requires the use of an output capacitor as part of the frequency compensation in order to make the regulator stable. For most applications a minimum of 100uF aluminum electrolytic capacitor insures both stability and good transient response. Thermal Design The SE1084 incorporates an internal thermal shutdown that protects the device when the junction temperature exceeds the maximum allowable junction temperature. Although this device can operate with junction temperatures in the range of 150 ℃, it is recommended that the selected heat sink be chosen such that during maximum continuous load operation the junction temperature is kept below the temperature. Layout Consideration The output capacitors must be located as close to the VOUT terminal of the device as possible. It is recommended to use a section of a layer of the PC board as a plane to connect the V OUT pin to the output capacitors to prevent any high frequency oscillation that may result due to excessive trace inductance.

Rev1.0 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., • www.seawardinc.com • Page 9 9/4/2012 SE1084 5A Low Dropout Linear Regulator Outline Drawing For SE1084 (1) TO252

Rev1.0 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., • www.seawardinc.com • Page 10 9/4/2012 SE1084 5A Low Dropout Linear Regulator (2) TO263

Rev1.0 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., • www.seawardinc.com • Page 11 9/4/2012 SE1084 5A Low Dropout Linear Regulator (3) TO220

Rev1.0 Preliminary and all contents are subject to change without prior notice. © Seaward Electronics, Inc., • www.seawardinc.com • Page 12 9/4/2012 SE1084 5A Low Dropout Linear Regulator 联系方式： 北京思旺电子技术有限公司–中国总部 地址：中国北京市海淀区信息路 22 号上地科技综合楼 B 座二层 邮编：100085 电话:010-82895700/1/5 传真:010-82895706 Seaward Electronics Corporation – 台湾办事处 2F, #181, Sec. 3, Minquan East Rd, Taipei, Taiwan R.O.C 电话: 886-2-2712-0307 传真: 886-2-2712-0191 Seaward Electronics Incorporated – 北美办事处 1512 Centre Pointe Dr. Milpitas, CA95035, USA 电话: 1-408-821-6600