AS2840 4A Low Dropout Voltage Regulator Adjustable & Fixed 3.3V FEATURES APPLICATIONS • Adjustable Output Down To 1.25V Or Fixed 3.3V • Output Current Of 4A • Low Dropout Voltage • Extremely Tight Load And Line Regulation • Current & Thermal Limiting • Standard 3-Terminal Low Cost TO-220 • Powering Intel Pentium µP from +5V Supplies • Power PC Supplies • SMPS Post-Regulator • High Efficiency “Green” Computer Systems • High Efficiency Linear Power Supplies • Portable Instrumentation • Constant Current Regulators • Adjustable Power Supplies • Battery Charger PRODUCT DESCRIPTION The AS2840 is a low power 4A Adjustable Voltage Regulator that is very easy to use. It requires only 2 external resistors to set the output voltage. This device is an excellent choice for use in Powering Intel Microprocessor to convert from +5V to 3.3V supplies and as a post regulator for switching supplies applications. The AS2840 features low dropout of a maximum 1.3 volts. The AS2840 offers over-current limit and full protection against reversed input polarity, reversed load insertion, over temperature operation, and positive and negative transient voltage. On-Chip trimming adjusts the reference voltage to 1%. The IQ of this device flows in to the load, which increases the efficiency. The AS2840 is offered in a 3-pin TO-220 package compatible with other 3 terminal regulators. For a 3A low dropout regulator refer to the AS2830 data sheet. ORDERING INFORMATION TO-220 3-PIN AS2840AU Consult with factory for other fixed output voltages. PIN CONNECTIONS TO-220-3 (U) AS2840 1 2 3 ADJ/GND VOUT VIN Front View Rev. 10/11/00 AS2840 ABSOLUTE MAXIMUM RATINGS Power Dissipation..........................................Internally Limited Lead Temp. (Soldering, 10 Seconds) .............................. 300°C Storage Temperature Range ............................ -65° to +150°C Operating Junction Temperature Range AS2840 Control Section ............................0C° to +125°C AS2840 Power Transistor..........................0C° to +150°C Input Supply Voltage .................................................... +10V Input to Output Voltage Differential ............................. +10V ELECTRICAL CHARACTERISTICS.(NOTE 1) at IOUT = 10mA, TA=25°C, unless otherwise specified. Parameter Conditions AS2840 Reference Voltage Min. Load Current Line Regulation Load Regulation Dropout Voltage 10 mA ≤ IOUT ≤ IFULLLOAD 1.5V≤(VIN - VOUT ≤ 7V ( Over Temperature) (VIN-VOUT) + 25V Typ Max 1.238 1.250 1.262 V 1.225 1.250 5 1.270 10 V mA 0.015 0.035 0.05 0.1 0.2 1.1 0.2 0.2 0.5 0.3 0.4 1.3 % % % % % V 1.5V ≤VIN - VOUT ≤7V ILOAD = 10mA 15V ≤VIN - VOUT ≤7V 10 mA ≤ IOUT ≤ IFULLLOAD (VIN - VOUT)=3V IOUT=IFULLLOAD , ∆VREF=1% Current Limit VIN - VOUT=5V VIN - VOUT=25V Long Term Stability TA=125°C, 1000 Hrs. 0.3 Adjust Pin Current TA=25°C 55 5.5 0.3 Adjust Pin Current Change Thermal Regulation 30 ms pulse Temperature Stability Ripple Rejection Ratio VIN - VOUT=3V IOUT =3A, COUT = 25µF, CADJ = 25µF, f= 120Hz Output Noise, RMS 10Hz to 10kHz Units Min 60 A A 6.5 0.6 1 % 120 µA µA 0.2 5 µA 0.003 0.015 %/W 0.5 % 75 dB 0.003 % VO The Bold specifications apply to the full operating temperature range. Note 1: Changes in output voltage due to heating effects are covered under the specification for thermal regulation. Note 2: A 10µF output capacitor is required on AS2840. Rev. 10/11/00 AS2840 TYPICAL CHARACTERISTICS Rev. 10/11/00 AS2840 TYPICAL APPLICATIONS VIN IN AS2840 OUT VIN OUT C1 C1 Typical Adjustable Regulator 4A Current output Regulator IN AS2840 VCC OUT C2 C1 ADJ Intel 486TM 3.45V +5V C2 R1 R2 VOUT = VREF (1 + R2 ) + IADJ R2 R1 LOAD VIN VREF ADJ R1 ADJ VOUT AS2840 IN R1 R1 Powering Intel PentiumTM with AS2840 Pentium Processor is a trademark of Intel Corp. Power PC is a trademark of Motorola Corp. Rev. 10/11/00