LP38851

LP38851 800 mA Fast-Response High-Accuracy LDO Linear Regulator with Enable and Soft-Start June 2007 LP38851 800 mA Fast-Response High-Accuracy Adjustable LDO Linear Regulator with Enable and Soft-Start General Description The LP38851-ADJ is a high current, fast response regulator which can maintain output voltage regulation with extremely low 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 architecture 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 this device makes it suitable for use in powering DSP, Microcontroller Core voltages and Switch Mode Power Supply post regulators. The part is available in PSOP 8–pin, TO-220 7–pin, and TO-263 7-pin packages. Dropout Voltage: 115 mV (typical) at 800 mA load current. Low Ground Pin Current: 10 mA (typical) at 800 mA load current. Soft-Start: Programmable Soft-Start time. Precision ADJ Voltage: ±1.5% for TJ = 25°C, and ±2.0% for 0°C ≤ TJ ≤ +125°C, across all line and load conditions Features ■ ■ ■ ■ ■ Adjustable VOUT range of 0.80V to 1.8V Wide VBIAS Supply operating range of 3.0V to 5.5V Stable with 10µF Ceramic capacitors Dropout voltage of 115 mV (typical) at 800 mA load current Precision VADJ across all line and load conditions: — ±1.5% VADJ for TJ = 25°C — ±2.0% VADJ for 0°C ≤ TJ ≤ +125°C — ±3.0% VADJ for -40°C ≤ TJ ≤ +125°C ■ Over-Temperature and Over-Current protection ■ Available in 8 lead PSOP, 7 lead TO-220 and 7 lead TO-263 packages ■ −40°C to +125°C Operating Junction Temperature Range Applications ■ ASIC Power Supplies in: - Desktops, Notebooks, and Graphics Cards, Servers - Gaming Set Top Boxes, Printers and Copiers ■ Server Core and I/O Supplies ■ DSP and FPGA Power Supplies ■ SMPS Post-Regulator Typical Application Circuit 30002501 © 2007 National Semiconductor Corporation 300025 www.national.com LP38851 Ordering Information VOUT Order Number LP38851S-ADJ LP38851SX-ADJ ADJ LP38851T-ADJ LP38851MR-ADJ LP38851MRX-ADJ Package Type TO263-7 TO263-7 TO220-7 PSOP-8 PSOP-8 Package Drawing TS7B TS7B TA07B MR08B MR08B Supplied As Rail of 45 Tape and Reel of 500 Rail of 45 Rail of 95 Tape and Reel of 2500 Connection Diagrams 30002502 30002503 TO263-7, Top View TO220-7, Top View 30002504 PSOP-8, Top View Pin Descriptions TO220-7 Pin # 1 2 3 4 5 6 7 TO263-7 Pin # 1 2 3 4 5 6 7 PSOP-8 Pin # 5 6 7 4 1 2 3 8 Pin Symbol SS EN IN GND ADJ OUT BIAS N/C Pin Description Soft-Start capacitor connection. Used to control the rise time of VOUT at turn-on. Device Enable, High = On, Low = Off. The unregulated voltage input Ground The feedback connection to set the output voltage The regulated output voltage The supply for the internal control and reference circuitry. No internal connection The TO220 and TO263 TAB is a thermal and electrical connection that is physically attached to the backside of the die, and used as a thermal heat-sink connection. See the Application Information section for details. The PSOP DAP is a thermal connection only that is physically attached to the backside of the die, and used as a thermal heatsink connection. See the Application Information section for details. TAB TAB - TAB - - DAP DAP www.national.com 2 LP38851 Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Storage Temperature Range Lead Temperature Soldering, 5 seconds ESD Rating Human Body Model (Note 2) Power Dissipation (Note 3) VIN Supply Voltage (Survival) VBIAS Supply Voltage (Survival) VSS SoftStart Voltage (Survival) −65°C to +150°C 260°C ±2 kV Internally Limited −0.3V to +6.0V −0.3V to +6.0V −0.3V to +6.0V VOUT Voltage (Survival) IOUT Current (Survival) Junction Temperature −0.3V to +6.0V Internally Limited −40°C to +150°C (Note 1) (VOUT + VDO) to VBIAS   3.0V to 5.5V 4.5V to 5.5V 0.0V to VBIAS 0 mA to 800 mA −40°C to +125°C Operating Ratings VIN Supply Voltage VBIAS Supply Voltage 0.8V ≤ VOUT ≤ 1.2V 1.2V < VOUT ≤ 1.8V VEN Voltage IOUT Junction Temperature Range (Note 3) Unless otherwise specified: VOUT = 0.80V, VIN = VOUT(NOM) + 1V, VBIAS = 3.0V, VEN = VBIAS, IOUT = 10 mA, CIN = COUT = 10 µF, CBIAS = 1 µF, CSS = open. Limits in standard type are for TJ = 25°C only; limits in boldface type apply over the junction temperature (TJ) range of -40°C to +125°C. Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only. Symbol Parameter Conditions VOUT(NOM)+1V ≤ VIN ≤ VBIAS ≤ 4.5V, See (Note 7) 3.0V ≤ VBIAS ≤ 5.5V, VADJ VADJ Accuracy 10 mA ≤ IOUT ≤ 800 mA mV 490.0 500. 510.0 MIN 492.5 485.0 TYP MAX 507.5 515.0 Units Electrical Characteristics 500. VOUT(NOM)+1V ≤ VIN ≤ VBIAS ≤ 4.5V, See (Note 7) 3.0V ≤ VBIAS ≤ 5.5V, 0°C ≤ TJ ≤ +125°C 10 mA ≤ IOUT ≤ 800 mA, 0.80 0.80 0.04 0.10 0.2 115 1.20 1.80 150 200 8.5 9.0 100 300 3.8 4.5 170 200 2.70 2.90 300 350 - VOUT ΔVOUT/ΔVIN ΔVOUT/ΔVBIAS ΔVOUT/ΔIOUT VDO VOUT Range Line Regulation, VIN (Note 4) Line Regulation, VBIAS (Note 4) Output Voltage Load Regulation (Note 5) Dropout Voltage (Note 6) 3.0V ≤ VBIAS ≤ 5.5V 4.5V ≤ VBIAS ≤ 5.5V VOUT(NOM)+1V ≤ VIN ≤ VBIAS 3.0V ≤ VBIAS ≤ 5.5V 10 mA ≤ IOUT ≤ 800 mA IOUT = 800 mA VOUT = 0.80V VBIAS = 3.0V VEN ≤ 0.5V V %/V %/V %/A mV IGND(IN) Quiescent Current Drawn from VIN Supply - 7.0 mA 10 mA ≤ IOUT ≤ 800 mA 1 3.0 100 2.20 2.00 60 50 2.45 150 2.5 μA mA μA V mV A IGND(BIAS) Quiescent Current Drawn from VBIAS Supply Under-Voltage Lock-Out Threshold Under-Voltage Lock-Out Hysteresis Output Short-Circuit Current 10 mA ≤ IOUT ≤ 800 mA VEN ≤ 0.5V VBIAS rising until device is functional VBIAS falling from UVLO threshold until device is non-functional VIN = VOUT(NOM) + 1V, VBIAS = 3.0V, VOUT = 0.0V UVLO UVLO(HYS) ISC 3 www.national.com LP38851 Symbol Soft-Start rSS tSS Enable Parameter Soft-Start internal resistance Soft-Start time tSS = CSS × rSS × 5 CSS = 10 nF Conditions MIN 11.0 - TYP 14.0 700 MAX 17.0 - Units kΩ μs VEN = VBIAS IEN ENABLE pin Current VEN = 0.0V, VBIAS = 5.5V VEN rising until Output = ON VEN falling from VEN(ON) until Output = OFF RLOAD x COUT