LP3891ET-1.8

LP3891 0.8A Fast-Response Ultra Low Dropout Linear Regulators September 2003 LP3891 0.8A Fast-Response Ultra Low Dropout Linear Regulators General Description The LP3891 is a high current, fast response regulator which can maintain output voltage regulation with minimum input to output voltage drop. Fabricated on a CMOS process, the device operates from two input voltages: Vbias provides voltage to drive the gate of the N-MOS power transistor, while Vin is the input voltage which supplies power to the load. The use of an external bias rail allows the part to operate from ultra low Vin voltages. Unlike bipolar regulators, the CMOS architectutre consumes extremely low quiescent current at any output load current. The use of an N-MOS power transistor results in wide bandwidth, yet minimum external capacitance is required to maintain loop stability. The fast transient response of these devices makes them suitable for use in powering DSP, Microcontroller Core voltages and Switch Mode Power Supply post regulators. The parts are available in TO-220 and TO-263 packages. Dropout Voltage: 100 mV (typ) @ 0.8A load current. Ground Pin Current: 3 mA (typ) at full load. Shutdown Current: 60 nA (typ) when S/D pin is low. Precision Output Voltage: 1.5% room temperature accuracy. Features n n n n n n n n Ultra low dropout voltage (100mV @ 0.8A typ) Low ground pin current Load regulation of 0.04%/A 60 nA typical quiescent current in shutdown 1.5% output accuracy (25˚C) TO-220, TO-263 packages Over temperature/over current protection −40˚C to +125˚C junction temperature range Applications n n n n n n n DSP Power Supplies Server Core and I/O Supplies PC Add-in-Cards Local Regulators in Set-Top Boxes Microcontroller Power Supplies High Efficiency Power Supplies SMPS Post-Regulators Typical Application Circuit 20069501 At least 10 µF of input and output capacitance is required for stability. *Tantalum capacitors are recommended. Aluminum electrolytic capacitors may be used for restricted temperature range. See application hints. Connection Diagrams 20069502 20069503 TO-220, Top View TO-263, Top View © 2003 National Semiconductor Corporation DS200695 www.national.com LP3891 Ordering Information Order Number LP3891ES-1.2 LP3891ESX-1.2 LP3891ET-1.2 LP3891ES-1.5 LP3891ESX-1.5 LP3891ET-1.5 LP3891ES-1.8 LP3891ESX-1.8 LP3891ET-1.8 Package Type TO263-5 TO263-5 TO220-5 TO263-5 TO263-5 TO220-5 TO263-5 TO263-5 TO220-5 Package Drawing TS5B TS5B T05D TS5B TS5B T05D TS5B TS5B T05D Supplied As Rail Tape and Reel Rail Rail Tape and Reel Rail Rail Tape and Reel Rail Block Diagram 20069524 www.national.com 2 LP3891 Absolute Maximum Ratings (Note 1) Shutdown Input Voltage (Survival) IOUT (Survival) Output Voltage (Survival) Junction Temperature −0.3V to +7V Internally Limited −0.3V to +6V −40˚C to +150˚C If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Storage Temperature Range Lead Temp. (Soldering, 5 seconds) ESD Rating Human Body Model (Note 3) Machine Model (Note 10) Power Dissipation (Note 2) VIN Supply Voltage (Survival) VBIAS Supply Voltage (Survival) −65˚C to +150˚C 260˚C 2 kV 200V Internally Limited −0.3V to +6V −0.3V to +7V Operating Ratings VIN Shutdown IOUT Junction Temperature VBIAS (VOUT + VDO) to 5.5V 0 to +6V 0.8A −40˚C to +125˚C 4.5V to 6V Electrical Characteristics Limits in standard typeface are for TJ = 25˚C, and limits in boldface type apply over the full operating temperature range. Unless otherwise specified: VIN = VO(NOM) + 1V, VBIAS = 4.5V, IL = 10 mA, CIN = COUT = 10 µF, VS/D = VBIAS. Symbol VO Parameter Output Voltage Tolerance Conditions 10 mA ≤ IL ≤ 0.8A VO(NOM) + 1V ≤ VIN ≤ 5.5V 4.5V ≤ VBIAS ≤ 6V Typical (Note 4) MIN (Note 5) 1.198 1.216 1.186 1.478 1.5 1.455 1.773 1.8 1.746 ∆VO/∆VIN ∆VO/∆IL VDO IQ(VIN) Output Voltage Line Regulation (Note 7) Output Voltage Load Regulation (Note 8) Dropout Voltage (Note 9) Quiescent Current Drawn from VIN Supply VO(NOM) + 1V ≤ VIN ≤ 5.5V 10 mA ≤ IL ≤ 0.8A IL = 0.8A 10 mA ≤ IL ≤ 0.8A V IQ(VBIAS) Quiescent Current Drawn from VBIAS Supply S/D MAX (Note 5) 1.234 1.246 1.522 Units V 1.545 1.827 1.854 %/V %/A 300 400 7 8 1 30 2 3 1 30 mV mA µA mA µA A 1.3 0.3 0.01 0.04 0.06 100 3 0.03 1 0.03 1.8 0.7 0.7 20 15 1 −1 ≤ 0.3V L 10 mA ≤ V S/D ≤ 0.8A ≤ 0.3V ISC VSDT Td (OFF) Td (ON) IS/D Short-Circuit Current Output Turn-off Threshold Turn-OFF Delay Turn-ON Delay S/D Input Current VOUT = 0V Output = ON Output = OFF RLOAD X COUT