LMS5258

LMS5258 150mA, µCap, Low Dropout Voltage Regulator with Power Good February 2003 LMS5258 150mA, µCap, Low Dropout Voltage Regulator with Power Good General Description The LMS5258 is a µCap, precise CMOS voltage regulator with power good output. It provides up to 150mA and consumes a typical of 10nA in shutdown mode. The LMS5258 output stage is designed with a push pull output for faster transient response. The LMS5258 is optimized to work with low value, low cost ceramic capacitors. The output typically require only 1µF of output capacitance for stability. The enable pin can be tied to VIN for easy device layout. The LMS5258 is designed for portable, battery powered equipment applications with small space requirements. The LMS5258 is available in a 5-pin SOT-23 package. Performance is specified for the −40˚C to +125˚C temperature range and is available in a fixed 1.2V. For other output voltage options, please contact National Semiconductor. Features n n n n n n n n n n n Power good indicator Stability with low ESR capacitors Low ground current: 120µA 150mA output current "Zero" shutdown mode current Fast transient response Auto Discharge Thermal shutdown Current limiting TTL-Logic-controlled enable input Pin-to-pin replacement for Mic™ 5258 Applications n Processor power-up sequencing n Laptop, notebook and palm top computer n PCMCIA VCC and VPP regulation switching Typical Application 20042419 Pin Description Pin Number 1 2 3 Pin Name VIN GND EN Pin Function Input Voltage Ground Enable Input Logic, Logic High = Enabled Logic Low = Shutdown (Do not leave open) Power Good Output Output Voltage 4 5 PG VOUT © 2003 National Semiconductor Corporation DS200424 www.national.com LMS5258 Connection Diagram SOT23-5 20042421 Top View Ordering Information Package Part Number LMS5258MF-1.2 LMS5258MFX-1.2 Package Marking Transport Media 1k Units Tape and Reel 3k Units Tape and Reel NSC Drawing MF05A 5-Pin SOT-23 LF9B www.national.com 2 LMS5258 Absolute Maximum Ratings (Note 1) Operating Ratings Supply Voltages VIN VEN Junction Temp. Range (Note 3) Storage Temperature Range Package Themal Resistance SOT23-5 235˚C/W 2.7V to 6V 0V to VIN −40˚C to +125˚C −65˚C to 150˚C If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. ESD Tolerance (Note 2) Human Body Model Junction Temperature VIN, VOUT, VEN Soldering Information Infrared or Convection (20 sec) Wave Soldering (10 sec) 235˚C 260˚C (lead temp) 2000V 150˚C −0.3 TO 6.5V Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25˚C, VIN = 2.7V, IL = 100µA, COUT = 1µF, VEN ≥ 2.0V. Boldface limits apply over the entire operating temperature range, −40˚C to 125˚C. Symbol VO ∆VO/VO ∆VO/VO IQ IGND Parameter Output Voltage Accuracy Line Regulation Load Regulation Quiescent Current VIN = 2.7V to 6V IL = 0.1mA to 150mA (Note 6) VEN ≤ 0.4V (Shutdown), PG = NC Conditions Min (Note 5) -3 -4 −0.3 1 .01 120 160 62 160 350 150 Typ (Note 4) Max (Note 5) 3 4 0.3 4 1 180 225 dB mA ˚C Units % % % µA µA Ground Pin Current (Note 5) VEN ≥ 2.0V (active), VIN = 6V, IL = 0mA IL = 150mA, VEN ≥ 2.0V (active), VIN = 6V PSRR ILIMIT Power Supply Rejection Current Limit Thermal Shutdown Temperature f = 120HZ, COUT = 4.7µF, IL = 150mA VOUT = 0V Thermal Protection Enable Input VIL VIH IIL IIH Power Good VPG VOL IPG VPG Delay Low Threshold High Threshold PG Output Logic-Low Voltage Power Good Leakage Current Delay Time to Power Good % of VOUT (PG ON) % of VOUT (PG OFF) Ipowergood = 100µA, Fault Condition Power Good Off, VPG = 5.5V See Timing Diagram 1 0.02 0.01 5 89 97 0.1 % V µA ms Enable Input Current Enable Input Voltage Level Logic Low (off), VIN = 5.5V Logic High (on), VIN = 5.5V VIL ≤ 0.4V, VIN = 5.5V VIH ≥ 2.0V, VIN = 5.5V 2 0.01 0.01 0.4 V V µA µA Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics. Note 2: Human body model, 1.5kΩ in series with 100pF. Note 3: The maximum power dissipation is a function of TJ(MAX) , θJA, and TA. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(MAX)–T A)/θJA. All numbers apply for packages soldered directly into a PC board. Note 4: Typical Values represent the most likely parametric norm. Note 5: All limits are guaranteed by testing or statistical analysis. Note 6: Regulation is measured at constant junction temperature using low duty cycle pulse testing. Note 7: Ground pin current is the regulator quiescent current. The total current drawn from the supply is the sum of the load current plus the ground pin current. 3 www.national.com LMS5258 Timing Diagram 20042415 Block Diagram 20042420 www.national.com 4 LMS5258 Typical Performance Characteristics 25˚C and powergood pull up resistor = 47kΩ. Ground Current vs. Output Current Unless otherwise specified, VIN = 3.3V, COUT = 1µF, TA = Ground Current vs. Input Voltage 20042401 20042402 Ground Current vs. Temperature Short Circuit Current vs. Temperature (VIN = 3.3V) 20042403 20042404 Short Circuit Current vs. Input Voltage Power Good Delay vs. Input Voltage (IL = 100µA) 20042405 20042406 5 www.national.com LMS5258 Typical Performance Characteristics Unless otherwise specified, VIN = 3.3V, COUT = 1µF, TA = 25˚C and powergood pull up resistor = 47kΩ. (Continued) Power Good Delay vs. Temperature (VIN = 3.3V) Output Voltage vs. Temperature 20042407 20042408 Output Voltage vs. Input Voltage Output Voltage vs. Output Current 20042409 20042411 Enable Voltage vs. Input Voltage Enable Voltage vs. Temperature 20042422 20042423 www.national.com 6 LMS5258 Typical Performance Characteristics Unless otherwise specified, VIN = 3.3V, COUT = 1µF, TA = 25˚C and powergood pull up resistor = 47kΩ. (Continued) Power Good Pull-Up Resistor vs. Power Good Voltage Noise vs. Frequency 20042416 20042412 PSRR vs. Frequency Power On Reset Delay Time 20042414 20042413 7 www.national.com LMS5258 Application Notes LMS5258 is a linear regulator designed to be used with a low ESR, low cost ceramic capacitors. EXTERNAL CAPACITORS The LMS5258 regulator requires an output capacitor to maintain stability. The capacitor must be at least 1µF or greater. The capacitor can be low-ESR ceramic chip capacitor, however for improved capacitance over temperature, tantalum capacitors can be used. A 1µF input capacitor is recommended when the supply capacitance is more than 10 inches away from the device, or when the supply is a battery. X7R dielectric ceramic capacitors are recommended because of their temperature performance. X7R-type capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic capacitors. Z5U and Y5V dielectric capacitors change value by as much 50% and 60% respectively over their operating temperature range. To use a ceramic chip capacitor with Y5V dielectric, the value must be much higher than an X7R ceramic or a tantalum capacitor to ensure the same minimum capacitance value over the operating temperature range. Tantalum capacitors have a very stable dielectric (10% over their operating temperature range) and can also be used with this device. ENABLE/SHUTDOWN The LMS5258 has an active high enable pin that allows the regulator to be disabled. Applying a Logic Level low ( < 0.4 V) to the Shutdown pin will cause the output to turn off, in this state current consumed by the regulator goes nearly to zero. Applying a logic level high ( > 2.0) enables the output voltage. The enable/shutdown pin can’t be left floating; a floating enable pin may cause an indeterminate state on the output. ACTIVE SHUTDOWN The LMS5258 designed with a N-channel MOSFET that acts as a shutdown clamp. The N-channel turns on when the device is disabled to allow the output capacitor and load to discharge. POWER GOOD The power good output is an open-drain output. It is designed essentially to work as a power-on reset generator once the regulated voltage was up and/ or a fault condition. When a fault condition and an undervoltage detection occur, the output of the power good pin goes low. The power good output comes back up once the output has reached 97% of its nominal value and 1ms to 5ms delay has passed , see timing diagram. The LMS5258 internal circuit monitors overcurrent, temperature and falling output voltage. If one of these conditions is flaged that indicates a fault condition. The flaged condition output is fed into an onchip delay circuit that drives the open drain output transistor. TRANSIENT RESPONSE The LMS5258 implements a unique output stage to dramatically improve transient response recovery time. The output is a totem-pole configuration with a P-channel MOSFET pass device and a N-channel MOSFET clamp. The N-channel clamp is a significantly smaller device that prevents the output voltage from overshooting when a heavy load is removed. This feature helps to speed up the transient response by significantly decreasing transient response recovery time during the transition from heavy load to light load. THERMAL BEHAVIOR The LMS5258 regulator has internal thermal shutdown to protect the device from over heating. Under all operating conditions, the maximum junction temperature of the LMS5258 must be below 125˚C. Maximum power dissipation can be calculated based on the output current and the voltage drop across the part. The maximum power dissipation is PD(MAX) = (TJ(MAX)–TA)/θJA θJA is the junction-to-ambient thermal resistance, 235˚C/W for the LMS5258 in the SOT23-5 package. TA is the maximum ambient temperature T J(MAX) is the maximum junction temperature of the die, 125˚C. When operating the LMS5258 at room temperature, the maximum power dissipation is 425mW. The actual power dissipated by the regulator is PD = (VIN – VOUT) IL + VIN IGND Substituting PD(MAX), determined above, for PD and solving for the operating condition that are critical to the application will give the maximum operating conditions for the regulator circuit. To prevent the device from entering thermal shutdown, maximum power dissipation cannot be exceeded. www.national.com 8 LMS5258 150mA, µCap, Low Dropout Voltage Regulator with Power Good Physical Dimensions unless otherwise noted inches (millimeters) 5-Pin SOT23-5 NSC Package Number MF05A LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 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