LP38855T-1.2

LP38855 1.5A Fast-Response High-Accuracy LDO Linear Regulator with Enable December 2006 LP38855 1.5A Fast-Response High-Accuracy LDO Linear Regulator with Enable General Description The LP38855 is a high-current, fast-response regulator which can maintain output voltage regulation with an extremely low input to output voltage drop. Fabricated on a CMOS process, the device operates from two input voltages: VBIAS provides power for the internal bias and control circuits, as well as drive for the gate of the N-MOS power transistor, while VIN 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 NMOS 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 LP38855 is available in TO-220 and TO-263 5-Lead packages. Dropout Voltage: 130 mV (typical) at 1.5A load current. Low Ground Pin Current: 14 mA (typical) at 1.5A load current. Shutdown Current: 1 µA (typical) IIN(GND) when EN pin is low. Precision Output Voltage: ±1.0% for TJ = 25°C and ±2.0% for 0°C ≤ TJ ≤ +125°C, across all line and load conditions Features ■ ■ ■ ■ ■ Standard VOUT values of 0.8V and 1.2V Wide VBIAS Supply operating range of 3.0V to 5.5V Stable with 10 µF ceramic capacitors Dropout voltage of 130 mV (typical) at 1.5A load current Precision Output Voltage across all line and load conditions: — ±1.0% for TJ = 25°C — ±2.0% for 0°C ≤ TJ ≤ +125°C — ±3.0% for -40°C ≤ TJ ≤ +125°C Over-Temperature and Over-Current protection Available in 5 lead TO-220 and TO-263 packages Custom VOUT values between 0.8V and 1.2V are available -40°C to +125°C Operating 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 20202601 © 2007 National Semiconductor Corporation 202026 www.national.com LP38855 Ordering Information VOUT * 0.8V Order Number LP38855S-0.8 LP38855SX-0.8 LP38855T-0.8 LP38855S-1.2 1.2V LP38855SX-1.2 LP38855T-1.2 Package Type TO263-5 TO263-5 TO220-5 TO263-5 TO263-5 TO220-5 Package Drawing TS5B TS5B T05D TS5B TS5B T05D Supplied As Rail of 45 Tape and Reel of 500 Rail of 45 Rail of 45 Tape and Reel of 500 Rail of 45 * For custom VOUT values between 0.8V and 1.2V please contact the National Semiconductor Sales Office. Connection Diagrams 20202602 20202603 TO-263, Top View TO-220, Top View Pin Descriptions TO220–5 and TO263–5 Packages Pin # 1 2 3 4 5 TAB Pin Symbol EN IN GND OUT BIAS TAB The device Enable pin. The unregulated input voltage pin Ground The regulated output voltage pin The supply for the internal control and reference circuitry The TAB is a thermal connection that is physically attached to the backside of the die, and is used as a thermal heat-sink connection. See the Application Information section for details Pin Description www.national.com 2 LP38855 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) −65°C to +150°C 260°C ±2 kV Internally Limited −0.3V to +6.0V −0.3V to +6.0V VEN Voltage (Survival) VOUT Voltage (Survival) IOUT Current (Survival) Junction Temperature −0.3V to +6.0V −0.3V to +6.0V Internally Limited −40°C to +150°C (Note 1) (VOUT + VDO) to VBIAS 3.0V to 5.5V 0.0V to VBIAS 0 mA to 1.5A −40°C to +125°C Operating Ratings VIN Supply Voltage VBIAS Supply Voltage VEN Enable Input Voltage IOUT Junction Temperature Range (Note 3) Unless otherwise specified: VIN = VOUT(NOM) + 1V, VBIAS = 3.0V, IOUT = 10 mA, CIN = COUT = 10 µF, CBIAS = 1µF, VEN = VBIAS. 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, 3.0V ≤ VBIAS ≤ 5.5V, 10 mA ≤ IOUT ≤ 1.5A MIN -1.0 -3.0 TYP 0 MAX +1.0 +3.0 % -2.0 0 +2.0 Units Electrical Characteristics VOUT Output Voltage Tolerance VOUT(NOM) + 1V ≤ VIN ≤ VBIAS, 3.0V ≤ VBIAS ≤ 5.5V, 0°C ≤ TJ ≤ 125°C 10 mA ≤ IOUT ≤ 1.5A, ΔVOUT/ΔVIN ΔVOUT/ΔVBIAS ΔVOUT/ΔIOUT VDO Line Regulation, VIN (Note 4) Line Regulation, VBIAS (Note 4) Output Voltage Load Regulation (Note 5) Dropout Voltage VIN − VOUT (Note 6) VOUT(NOM) + 1V ≤ VIN ≤ VBIAS 3.0V ≤ VBIAS ≤ 5.5V 10 mA ≤ IOUT ≤ 1.5A IOUT = 1.5A LP38855-0.8 10 mA ≤ IOUT ≤ 1.5A - 0.04 0.10 0.2 165 180 8.5 9.0 12 15 10 300 3.8 4.5 170 200 2.70 2.90 300 350 - %/V %/V %/A - 130 mV 2.20 2.00 60 50 - 7.0 11 1.0 3.0 100 2.45 150 4.5 IGND(IN) Ground Pin Current Drawn from VIN Supply LP38855-1.2 10 mA ≤ IOUT ≤ 1.5A VEN ≤ 0.5V mA µA mA µA V mV A IGND(BIAS) Ground Pin Current Drawn from VBIAS Supply Under-Voltage Lock-Out Threshold Under-Voltage Lock-Out Hysteresis Output Short-Circuit Current 10 mA ≤ IOUT ≤ 1.5A 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 LP38855 Symbol ENABLE Pin Parameter Conditions VEN = VBIAS MIN -19 -13 1.00 0.90 50 30 - TYP 0.01 -30 1.25 100 20 15 MAX -40 -51 1.50 1.55 150 200 - Units IEN ENABLE pin Current VEN = 0.0V, VBIAS = 5.5V VEN rising until Output = ON VEN falling from VEN(ON) until Output = OFF RLOAD × COUT