UC182-1,-2,-3,-ADJ UC282-1,-2,-3,-ADJ UC382-1,-2,-3,-ADJ Fast LDO Linear Regulator FEATURES DESCRIPTION • Fast Transient Response The UC382 is a low dropout linear regulator providing a quick response to fast load changes. Combined with its precision on-board reference, the UC382 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. • 10mA to 3A Load Current • Short Circuit Protection • Maximum Dropout of 450mV at 3A Load Current • Separate Bias and VIN Pins • Available in Adjustable or Fixed Output Voltages • 5 Pin Package allows Kelvin Sensing of Load Voltage • Reverse Current Protection Dropout voltage (VIN to VOUT) is only 450mV maximum at 100°C and 350mV typical at 3A load. The on-board bandgap reference is stable with temperature and scaled for a 1.200V input to the internal power amplifier. The UC382 is available in fixed output voltages of 1.5V, 2.1V, or 2.5V. 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 1.2V. BLOCK DIAGRAM UDG-96037-1 SLUS317 - JANUARY 1999 Powered by ICminer.com Electronic-Library Service CopyRight 2003 UC182-1,-2,-3,-ADJ UC282-1,-2,-3,-ADJ UC382-1,-2,-3,-ADJ ABSOLUTE MAXIMUM RATINGS ORDERING INFORMATION VB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13V VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7.5V Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . +1.2V to 6.0V Storage Temperature . . . . . . . . . . . . . . . . . . . –65°C to +150°C Junction Temperature . . . . . . . . . . . . . . . . . . . –55°C to +150°C Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . . +300°C Temperature Range Package Output Voltage 1: –55°C to +125°C T: TO-220 1: 1.5V 2: –25°C to +100°C TD: TO-263 2: 2.1V 3: 0°C to +100°C 3: 2.5V ADJ: 1.2V or Adjustable Currents are positive into, negative out of the specified terminal. Consult Packaging Section of Databook for thermal limitations and considerations of packages. CONNECTION DIAGRAMS 5-Pin TO-220 (Top View) T Package 5-Pin TO-263 (Top View) TD Package Note: Tab tied to Pin 3. Note: Tab tied to Pin 3. ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these parameters apply for TA = –55°C to 125°C for the UC182-X series, –25°C to +100°C for the UC282-X series and 0°C to +100°C for the UC382-X, VB = 5V; VIN = 3.3V, VOUT = 2.5V for the UC382-ADJ, TA = TJ. PARAMETERS TEST CONDITIONS MIN TYP MAX UNITS UC382-3 2.475 2.500 2.525 UC282-3 and UC182-3 2.450 2.500 2.525 V 0.5 4 mV UC382-3 Fixed 2.5V, 3A Family Output Voltage (IVOUT = 100mA) Load Regulation IVOUT = 10mA to 3A V VIN PSSR 80 100 dB VB PSSR 50 60 dB VIN Dropout Voltage = VIN–VOUT VB Dropout = VB–VOUT IVOUT = 3A, TJ = 25°C 350 425 mV IVOUT = 3A, UC382-3 350 450 mV IVOUT = 3A, UC282-3 and UC182-3 350 500 mV IVOUT = 3A, UC382-3 1.8 2.10 V IVOUT = 3A, UC282-3 1.8 2.20 V IVOUT = 3A, UC182-3 1.8 2.35 V Short Circuit Current Limit VB Current VIN Current 4.5 A IVOUT = 10mA 3.3 6 9 mA IVOUT = 3A 18 60 mA IVOUT = 3A 2.94 2.97 A UC382-2 2.079 2.100 2.121 V UC282-2 and UC182-2 2.058 2.100 2.121 V 0.5 4 mV 80 100 UC382-2 Fixed 2.1V, 3A Family Output Voltage (IVOUT = 100mA) Load Regulation IVOUT = 10mA to 3A VIN PSSR Powered by ICminer.com Electronic-Library Service CopyRight 2003 2 dB UC182-1,-2,-3,-ADJ UC282-1,-2,-3,-ADJ UC382-1,-2,-3,-ADJ ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these parameters apply for TA = –55°C to 125°C for the UC182-X series, –25°C to +100°C for the UC282-X series and 0°C to +100°C for the UC382-X, VB = 5V; VIN = 3.3V, VOUT = 2.5V for the UC382-ADJ, TA = TJ. PARAMETERS TEST CONDITIONS MIN TYP 52 62 MAX UNITS UC382-2 Fixed 2.1V, 3A Family (cont.) VB PSSR VIN Dropout Voltage = VIN–VOUT VB Dropout = VB–VOUT IVOUT = 3A, TJ = 25°C 350 425 mV IVOUT = 3A, UC382-2 350 450 mV IVOUT = 3A, UC282-2 and UC182-2 350 500 mV IVOUT = 3A, UC382-2 1.8 2.10 V IVOUT = 3A, UC282-2 1.8 2.20 V 1.8 2.35 V 4.5 A IVOUT = 3A, UC182-2 Short Circuit Current Limit VB Current VIN Current dB 3.3 IVOUT = 10mA 6 9 mA IVOUT = 3A 18 60 mA IVOUT = 3A 2.94 2.97 A UC382-1 1.485 1.500 1.515 V UC282-1 and UC182-1 1.470 1.500 1.515 V 0.5 4 mV 80 100 UC382-1 Fixed 1.5V, 3A Family Output Voltage (IVOUT = 100mA) Load Regulation IVOUT = 10mA to 3A VIN PSSR VB PSSR VIN Dropout Voltage = VIN–VOUT VB Dropout = VB–VOUT 55 dB 350 425 mV IVOUT = 3A, UC282-1 350 450 mV IVOUT = 3A, UC282-2 and UC182-1 350 500 mV IVOUT = 3A, UC382-1 1.8 2.10 V IVOUT = 3A, UC282-1 1.8 2.20 V 1.8 2.35 V IVOUT = 3A, UC182-1 3.3 IVOUT = 10mA IVOUT = 3A VIN Current 65 IVOUT = 3A, TJ = 25°C Short Circuit Current Limit VB Current dB 4.5 A 6 9 mA 18 60 mA IVOUT = 3A 2.94 2.97 A UC382-ADJ 1.188 1.200 1.212 UC282-ADJ and UC182-ADJ 1.176 1.200 1.212 V 0.5 4 mV UC382-ADJ Adjustable, 3A Family ADJ Voltage (IVOUT = 100 mA) V Load Regulation IVOUT = 10mA to 3A VIN PSSR VOUT Programmed for 2.5V 80 100 dB VB PSSR VOUT Programmed for 2.5V 50 60 dB VIN Dropout Voltage = VIN–VOUT VB Dropout = VB–VOUT IVOUT = 3A, TJ = 25°C 350 425 mV IVOUT = 3A, UC382-ADJ 350 450 mV IVOUT = 3A, UC282-ADJ and UC182-ADJ 350 500 mV IVOUT = 3A, UC382-ADJ 1.8 2.10 V 1.8 2.20 V 4.5 A IVOUT = 3A, UC282-ADJ Short Circuit Current Limit VB Current VIN Current Powered by ICminer.com Electronic-Library Service CopyRight 2003 3.3 IVOUT = 10mA 6 9 mA IVOUT = 3A 18 60 mA IVOUT = 3A 2.94 3 2.97 A UC182-1,-2,-3,-ADJ UC282-1,-2,-3,-ADJ UC382-1,-2,-3,-ADJ PIN DESCRIPTIONS impedance and fast response. (Dropout is derated for junction temperatures below 0°C.) 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 non-inverting operational amplifier. The resistors should meet the criteria of R3 || R4 < 100Ω. Connect ADJ to VOUT for an output voltage of 1.2V. Note that the point at which the feedback network is connected to the output is the Kelvin sense point. VIN: Supplies the current to the collector of the output power transistor only. The dropout (VIN-VOUT) is under 100mV for light loads; maximum dropout is 450mV at 3A for TJ = 0°C to +110°C. (Dropout is derated for junction temperatures over 110°C.) At full load, the majority of the VB current is going to the load. GND: For accurate results, the GND pin should be referenced to the load ground. 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. VB: Supplies power to all circuits of the regulator except the collector of the output power transistor. The 2V headroom from VB to VOUT allows the use of a Darlington output stage for inherently low output 400 VDROPOUT (mV) VDROPOUT (V) 1.9 1.8 1.7 1 2 200 100 100mA 1.6 0 300 3 1A 2A 3A IL IL (A) Figure 2. Typical Dropout (VIN - VOUT), TJ = 27°C Figure 1. Typical Dropout (VB - VOUT), TJ = 27°C APPLICATION INFORMATION 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 UC382 is easy to use. The adjustable version requires two 0.1% resistors to set the output voltage. The fixed versions of the UC382 require no external resistors. All versions of the UC382 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 UC382 is further than 12 inches from the power supply, it is recommended to add local decoupling as close as possible to the linear regulator. The UC382 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 450mV is measured at the pins and does not include additional drops due to trace resistance. The minimum load current is 10mA. Decouple the output of the UC382 with at least 100µF of high quality tantalum or Sanyo OSCON capacitors close to the VOUT pin for maximum stability. Many applications involving ultra fast GTL or BTL applications require additional capacitance close to the load. The exact amount Powered by ICminer.com Electronic-Library Service CopyRight 2003 Two or more UC382’s may be used in parallel. While stable, this arrangement does degrade the transient response. 4 UC182-1,-2,-3,-ADJ UC282-1,-2,-3,-ADJ UC382-1,-2,-3,-ADJ APPLICATION INFORMATION (cont.) Figure 3. Open Loop Gain (100µF Output Capacitance, 1A Load). Figure 4. Open Loop Phase (100µF Output Capacitance, 1A Load). 60 50 dB 40 30 20 10 0 100 1k 10k 100k 1M 10M FREQUENCY (Hz) Figure 5. PSRR (VB) 2.5V Out. UDG-96038 Figure 6. Transient test circuit. Powered by ICminer.com Electronic-Library Service CopyRight 2003 5 UC182-1,-2,-3,-ADJ UC282-1,-2,-3,-ADJ UC382-1,-2,-3,-ADJ APPLICATION INFORMATION (cont.) ∆VO 10mV/DIV IL 1A/DIV 2µs/DIV Figure 7. 10mA to 3A/µs load transient response. UDG-96039 UDG-96040 Figure 8. Typical UC382-ADJ application Figure 9. Typical UC382-1, -2, or -3 application UNITRODE CORPORATION 7 CONTINENTAL BLVD. • MERRIMACK, NH 03054 TEL. (603) 424-2410 FAX (603) 424-3460 Powered by ICminer.com Electronic-Library Service CopyRight 2003 6