UC385T-ADJ




 
 
 
 
  
        
 
  SLUS212E − NOVEMBER 1999 − REVISED FEBRUARY 2004 D D D D D D D D Fast Transient Response 10-mA to 5-A Load Current Short Circuit Protection Maximum Dropout of 500-mV at 5-A Load Current Separate Bias (VB) and VIN Pins Available in Adjustable or Fixed Output Voltages 5-Pin Package Allows Kelvin Sensing of Load Voltage Reverse Current Protection 5-PIN TO-220 T PACKAGE (TOP VIEW) 5-PIN TO-263 TD PACKAGE (TOP VIEW) Note: Tab = Ground description The UC385 is a low dropout linear regulator providing a quick response to fast load changes. Combined with its precision onboard reference, the UC385 excels at driving GTL and BTL buses. Due to its fast response to load transients, the total capacitance required to decouple the regulator’s output can be significantly decreased when compared to standard LDO linear regulators. Dropout voltage (VIN to VOUT) is only 490 mV maximum and 350 mV typical at 5-A load (0°C to 100°C). The onboard bandgap reference is stable with temperature and scaled for a 1.2 V input to the internal power amplifier. The UC385 is available in fixed output voltages of 1.5 V, 2.1 V, or 2.5 V. The output voltage of the adjustable version can be set with two external resistors. If the external resistors are omitted, the output voltage defaults to 1.2 V. block diagram VB 1 UC382−ADJ UC382−1 (1.5 V) UC382−2 (2.1 V) UC382−3 (2.5 V) R1 R2 OPEN 2 kΩ 2 kΩ 2 kΩ 0 500 Ω 1.5 k Ω 2.16 k Ω THERMAL SHUTDOWN 2 1.2 V BANDGAP REFERENCE VIN + R2 R1 SHORT CIRCUIT SENSE 3 5 4 GND ADJ VOUT UDG-00084 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners. Copyright  1998−2004, Texas Instruments Incorporated 
   !" # $%&" !#  '%()$!" *!"&+ *%$"# $ " #'&$$!"# '& ",& "&#  &-!# #"%&"# #"!*!* .!!"/+ *%$" '$&##0 *&# " &$&##!)/ $)%*& "&#"0  !)) '!!&"&#+ POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 


 
 
 
 
  
        
 
   SLUS212E − NOVEMBER 1999 − REVISED FEBRUARY 2004 absolute maximum ratings over operating free-air temperature (unless otherwise noted)† VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5 V Output voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 V to −6.0 V Storage temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65°C to 150°C Junction temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −55°C to 150°C Lead temperature (soldering, 10 seconds) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300°C † Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. AVAILABLE OPTIONS(1) PACKAGED DEVICES TO−263 (TD)(2) TO-220 (T) TJ OUTPUT VOLTAGE OUTPUT VOLTAGE 1.5 V 2.1 V 2.5 V 1.2 V or ADJ 1.5 V 2.1 V 2.5 V 1.2 V or ADJ –40°C to 100°C 285T-1 285T-2 285T-3 285T-ADJ 285TD-1 285TD-2 285TD-3 285TD-ADJ 0°C to 100°C 385T-1 385T-2 385T-3 385T-ADJ 385TD-1 385TD-2 385TD-3 385TD-ADJ 1. For more package and ordering information, see the Package Option Addendum located at the end of this data sheet. 2. For 50 piece reel, add KTTT (e.g., UC285TDKTTT−1); for 500 piece reel, add TR (e.g., UC285TDTR−1). electrical characteristics unless otherwise stated, these parameters apply for TA = −40°C to 100°C for the UC285-x series and 0°C to 100°C for the UC385-x, VB = 5 V; VIN = 3.3 V, VOUT = 2.5 V, TA = TJ. PARAMETER TEST CONDITION MIN TYP MAX UNIT 2.475 2.5 2.525 V 2.45 2.5 2.525 0.5 4 UC385-3 Fixed 2.5 V, 5-A Family Output voltage UC385-3 UC285-3 Load regulation IVOUT = 100 mA IVOUT = 100 mA IVOUT = 10 mA to 5 A VIN PSRR 80 VB PSRR 50 VIN dropout voltage (VIN - VOUT) UC385-3 UC285-3 VB dropout (VB - VOUT) IVOUT = 5 A, IVOUT = 5 A UC385-3 IVOUT = 5 A IVOUT = 5 A UC285-3 IVOUT = 5 A TJ = 25°C Short circuit current limit 110 IVOUT = 10 mA IVOUT = 5 A VIN current IVOUT = 5 A dB 65 dB 350 425 mV 350 490 mV 350 500 mV 1.8 2.1 V 1.8 2.2 V 5.1 VB current V mV 7.5 A 8 15 mA 40 100 mA 4.9 4.96 A 2.079 2.1 2.121 V 2.058 2.1 2.121 V 0.5 4 VIN PSRR 80 110 dB VB PSRR 50 67 dB UC385-2 Fixed 2.1 V, 5-A Family Output voltage UC385-2 UC285-2 Load regulation 2 IVOUT = 100 mA IVOUT = 100 mA IVOUT = 10 mA to 5 A POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 mV 


 
 
 
 
  
        
 
  SLUS212E − NOVEMBER 1999 − REVISED FEBRUARY 2004 electrical characteristics unless otherwise stated, these parameters apply for TA = −40°C to 100°C for the UC285-x series and 0°C to 100°C for the UC385-x, VB = 5 V; VIN = 3.3 V, VOUT = 2.5 V, TA = TJ. PARAMETER TEST CONDITION MIN TYP MAX UNIT 350 425 mV 350 490 mV 350 500 mV UC385-2 IVOUT = 5 A IVOUT = 5 A 1.8 2.1 V UC285-2 IVOUT = 5 A 1.8 2.2 V UC385−2 Fixed 2.1 V, 5-A Family (continued) VIN dropout voltage (VIN - VOUT) UC385-2 UC285-2 VB dropout (VB - VOUT) IVOUT = 5 A, IVOUT = 5 A TJ = 25°C Short circuit current limit 5.1 VB current IVOUT = 10 mA IVOUT = 5 A VIN current IVOUT = 5 A 7.5 A 8 15 mA 40 100 mA 4.9 4.96 A 1.485 1.5 1.515 1.470 1.5 1.515 0.5 4 UC385−1 Fixed 1.5 V, 5-A Family Output voltage UC385-1 UC285-1 Load regulation IVOUT = 100 mA IVOUT = 100 mA IVOUT = 10 mA to 5 A VIN PSRR 80 110 VB PSRR 50 65 VIN dropout voltage (VIN - VOUT) UC285-1 UC285-2 VB dropout (VB - VOUT) IVOUT = 5 A, IVOUT 5 A UC385-1 IVOUT = 5 A IVOUT = 5 A UC285-1 IVOUT = 5 A TJ = 25°C Short circuit current limit IVOUT = 10 mA IVOUT = 5 A VIN = current IVOUT = 5 A V mV dB dB 350 425 mV 350 490 mV 350 500 mV 1.8 2.1 V 1.8 2.2 V 7.5 A 8 15 mA 40 100 mA 5.1 VB current V 4.9 4.96 A 1.188 1.2 1.212 V 1.176 1.2 1.212 V 0.5 4 110 UC385-ADJ Adjustable, 5-A Family ADJ voltage UC385-ADJ UC285-ADJ Load regulation IVOUT - 100 mA IVOUT - 100 mA VIN PSRR IVOUT = 10 mA to 5 A VOUT programmed for 2.5 V 80 VB PSRR VOUT Programmed for 2.5 V 50 VIN dropout voltage (VIN - VOUT) IVOUT = 5 A, IVOUT = 5 A UC385-ADJ UC285-ADJ VB dropout (VB - VOUT) TJ = 25°C VIN current dB 65 dB 350 425 mV 350 490 mV IVOUT = 5 A IVOUT = 5 A 350 500 mV UC385-ADJ 1.8 2.1 V UC285-ADJ IVOUT = 5 A 1.8 2.2 V Short circuit current limit VB current mV 5.1 IVOUT = 10 mA IVOUT = 5 A IVOUT = 5 A POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 4.9 7.5 A 8 15 mA 40 100 mA 4.96 A 3 


 
 
 
 
  
        
 
   SLUS212E − NOVEMBER 1999 − REVISED FEBRUARY 2004 pin descriptions ADJ: In the adjustable version, the user programs the output voltage with two external resistors. The resistors should be 0.1% for high accuracy. The output amplifier is configured as a noninverting operational amplifier. The resistors should meet the criteria of R3 || R4 < 100 Ω. Connect ADJ to VOUT for an output voltage of 1.2 V. Note that the point at which the feedback network is connected to the output is the Kelvin sense point. GND: For accurate results, the GND pin should be referenced to the load ground. VB: Supplies power to all circuits of the regulator except the output power transistor. The 2-V headroom from VB to VOUT allows the use of a Darlington output stage for inherently low output impedance and fast response. (Dropout is derated for junction temperatures below 0°C.) VIN: Supplies the current to the collector of the output power transistor only. The dropout (VIN-VOUT) is under 100 mV for light loads; maximum dropout is 490 mV at 5 A for TJ = 0°C to 100°C. (Dropout is derated for junction temperatures over 100°C.) VOUT: This pin should be connected to the load via a low impedance path. Avoid connectors which add significant inductance and resistance. Note that even though a Kelvin sense is available through a 5-pin package, care must be taken since voltage drops along wire traces add to the dropout voltage. DROPOUT VOLTAGE (VIN − VOUT) vs. LOAD CURRENT DROPOUT VOLTAGE (VB − VOUT) vs. LOAD CURRENT 400 VDO - Dropout Voltage (VIN − VOUT) − mV VDO − Dropout Voltage (VB − VOUT) − V 1.7 TJ = 27°C 1.675 1.65 1.625 TJ = 27°C 300 200 100 1.6 0 1 2 4 3 5 IL− Load Current − A IL− Load Current − A Figure 2 Figure 1 4 5 100m POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 


 
 
 
 
  
        
 
   SLUS212E − NOVEMBER 1999 − REVISED FEBRUARY 2004 APPLICATION INFORMATION The UC385 is easy to use. The adjustable version requires two resistors to set the output voltage. The fixed versions of the UC385 require no external resistors. All versions of the UC385 require decoupling capacitors on the input and output. In a typical application, VB and VIN are driven from switching power supplies which may have large filter capacitors at their outputs. If the UC385 is further than 12 inches from the power supply, it is recommended to add local decoupling as close as possible to the linear regulator. Decouple the output of the UC385 with at least 100 µF of high quality tantalum or Sanyo OSCON capacitors close to the VOUT pin for maximum stability. Many applications involving ultrafast GTL or BTL applications require additional capacitance close to the load. The exact amount will vary according to speed and magnitude of the load transients and the tolerance allowed for transients on VOUT. When specifying the decoupling capacitors, the series resistance of the capacitor bank is an important factor in its ability to filter load transients. The UC385 allows for Kelvin sensing the voltage at the load. This improves regulation performance and eliminates the voltage drops due to wire trace resistance. This voltage drop must be added to the headroom (VIN to VOUT and VB to VOUT). The dropout of 350 mV is measured at the pins and does not include additional drops due to trace resistance. OPEN LOOP PHASE vs. FREQUENCY OPEN LOOP GAIN vs. FREQUENCY 0 70 60 CO = 100 µF IL = 1 A CO = 100 µF IL = 1 A Gain - dB Phase - deg 50 −90 40 30 20 10 0 −180 −10 100 1k 10 k 100 k 1M 10 M 100 1k 10 k 100 k 1M 10 M f − Frequency − Hz f − Frequency − Hz Figure 4 Figure 3 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5 


 
 
 
 
  
        
 
   SLUS212E − NOVEMBER 1999 − REVISED FEBRUARY 2004 APPLICATION INFORMATION PSSR - Power Supply Rejection Ratio (VB Input) − dB POWER SUPPLY REJECTION RATIO (VB INPUT) vs. FREQUENCY 60 50 40 30 20 10 0 100 1k 10 k 100 k 1M 10 M f − Frequency − Hz Figure 5 1µ F Ceramic + _ 5V 1 2 + + _ 3.3 V 4.7µ F Tantalum VIN VB VOUT 4 + UC385−ADJ GND ADJ IRF 520 VO = 1.2 V 100µ F Tantalum 121Ω R1 5 Pulse Generator 3 UDG-00085 Figure 6. Transient Test Circuit 6 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 


 
 
 
 
  
        
 
  SLUS212E − NOVEMBER 1999 − REVISED FEBRUARY 2004 APPLICATION INFORMATION 10 mA to 3 A/µs Load Transient Response 20 10 0 −10 3 −20 2 1 0 I O − Load Current − A ∆ VO − Change in Output Voltage − mV  2 µs/DIV Figure 7 +5 V + 4.7µ F Kelvin Sense Point 1 +3.3 V 2 + 4.7 µ F VIN VB VOUT 4 R3 60 Ω UC385−ADJ GND ADJ 3 + 330 µ F OSCON +1.8 V Output F 2.2 µ Ceramic 5 R4 120 Ω UDG-00086 Figure 8. Typical UC385-ADJ Application POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 7 


 
 
 
 
  
        
 
   SLUS212E − NOVEMBER 1999 − REVISED FEBRUARY 2004 APPLICATION INFORMATION +5 V + 4.7 µ F Kelvin Sense Point 1 2 VIN VB VOUT + UC385−1 GND +1.5 V Output 4 ADJ 330 µ F OSCON 2.2 µF Ceramic 5 3 UDG-00087 Figure 9. Typical UC385-1, -2, or -3 Application 8 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 PACKAGE OPTION ADDENDUM www.ti.com 20-Feb-2004 PACKAGING INFORMATION ORDERABLE DEVICE STATUS(1) PACKAGE TYPE PACKAGE DRAWING PINS PACKAGE QTY UC285T-1 ACTIVE TO/SOT KC 5 50 UC285T-2 ACTIVE TO/SOT KC 5 50 UC285T-3 ACTIVE TO/SOT KC 5 50 UC285T-ADJ ACTIVE TO/SOT KC 5 50 UC285TD-1 OBSOLETE PFM KTT 5 UC285TD-2 OBSOLETE PFM KTT 5 UC285TD-3 OBSOLETE PFM KTT 5 UC285TD-ADJ OBSOLETE PFM KTT 5 UC285TDKTTT-1 ACTIVE PFM KTT 5 50 UC285TDKTTT-2 ACTIVE PFM KTT 5 50 50 UC285TDKTTT-3 ACTIVE PFM KTT 5 UC285TDKTTT-ADJ ACTIVE PFM KTT 5 50 UC285TDTR-1 ACTIVE PFM KTT 5 500 UC285TDTR-2 ACTIVE PFM KTT 5 500 UC285TDTR-3 ACTIVE PFM KTT 5 500 UC285TDTR-ADJ ACTIVE PFM KTT 5 500 UC385T-1 ACTIVE TO/SOT KC 5 50 UC385T-2 ACTIVE TO/SOT KC 5 50 UC385T-3 ACTIVE TO/SOT KC 5 50 UC385T-ADJ ACTIVE TO/SOT KC 5 50 UC385TD-1 OBSOLETE PFM KTT 5 UC385TD-2 OBSOLETE PFM KTT 5 UC385TD-3 OBSOLETE PFM KTT 5 UC385TD-ADJ OBSOLETE PFM KTT 5 UC385TDKTTT-1 ACTIVE PFM KTT 5 50 UC385TDKTTT-2 ACTIVE PFM KTT 5 50 50 UC385TDKTTT-3 ACTIVE PFM KTT 5 UC385TDKTTT-ADJ ACTIVE PFM KTT 5 50 UC385TDTR-1 ACTIVE PFM KTT 5 500 UC385TDTR-2 ACTIVE PFM KTT 5 500 UC385TDTR-3 ACTIVE PFM KTT 5 500 UC385TDTR-ADJ ACTIVE PFM KTT 5 500 UC385TH-ADJ OBSOLETE TO/SOT KC 5 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. MECHANICAL DATA MSOT008B – JANUARY 1995 – REVISED SEPTEMBER 2000 KC (R-PSFM-T5) PLASTIC FLANGE-MOUNT 0.113 (2,87) 0.103 (2,62) 0.420 (10,67) 0.380 (9,65) 0.156 (3,96) DIA 0.146 (3,71) 0.185 (4,70) 0.175 (4,46) 0.055 (1,40) 0.045 (1,14) 0.147 (3,73) 0.137 (3,48) 0.340 (8,64) 0.330 (8,38) 1.037 (26,34) 0.997 (25,32) 0.125 (3,18) (see Note C) 1 0.040 (1,02) 0.030 (0,76) 0.010 (0,25) M 5 0.067 (1,70) 0.268 (6,81) 0.122 (3,10) 0.102 (2,59) 0.025 (0,64) 0.012 (0,30) 4040208/E 09/00 NOTES: A. B. C. D. E. All linear dimensions are in inches (millimeters). This drawing is subject to change without notice. Lead dimensions are not controlled within this area. All lead dimensions apply before solder dip. The center lead is in electrical contact with the mounting tab. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. 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