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LP2980 Micropower SOT, 50 mA Ultra Low-Dropout Regulator
May 1999
LP2980 Micropower SOT, 50 mA Ultra Low-Dropout Regulator
General Description
The LP2980 is a 50 mA, fixed-output voltage regulator designed specifically to meet the requirements of battery-powered applications. Using an optimized VIPTM (Vertically Integrated PNP) process, the LP2980 delivers unequaled performance in all specifications critical to battery-powered designs: Dropout Voltage. Typically 120 mV @ 50 mA load, and 7 mV @ 1 mA load. Ground Pin Current. Typically 375 A @ 50 mA load, and 80 A @ 1 mA load. Sleep Mode. Less than 1 A quiescent current when ON/ OFF pin is pulled low. Smallest Possible Size. SOT-23 package uses an absolute minimum of board space. Minimum Part Count. Requires only 1 F of external capacitance on the regulator output. Precision Output. 0.5% tolerance output voltages available (A grade). 5.0V, 3.3V, and 3.0V versions available as standard products.
Features
n n n n n n n n n n n n n Ultra low dropout voltage Output voltage accuracy 0.5% (A Grade) Guaranteed 50 mA output current Smallest possible size (SOT-23 Package) Requires only 1 F external capacitance < 1 A quiescent current when shutdown Low ground pin current at all load currents High peak current capability (150 mA typical) Wide supply voltage range (16V max) Fast dynamic response to line and load Low ZOUT over wide frequency range Overtemperature/overcurrent protection -40C to +125C junction temperature range
Applications
n n n n Cellular Phone Palmtop/Laptop Computer Personal Digital Assistant (PDA) Camcorder, Personal Stereo, Camera
Block Diagram
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Connection Diagram and Ordering Information
5-Lead Small Outline Package (M5)
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Actual Size
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Top View For Ordering Information See Table 1 in this Datasheet See NS Package Number MA05B
VIPTM is a trademark of National Semiconductor Corporation.
(c) 1999 National Semiconductor Corporation
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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 Operating Junction Temperature Range Lead Temperature (Soldering, 5 sec.) -65C to +150C -40C to +125C 260C
ESD Rating (Note 2) Power Dissipation (Note 3) Input Supply Voltage (Survival) Input Supply Voltage (Operating) Shutdown Input Voltage (Survival) Output Voltage (Survival), (Note 4) IOUT (Survival) Input-Output Voltage (Survival), (Note 5)
2 kV Internally Limited -0.3V to +16V 2.1V to +16V -0.3V to +16V -0.3V to +9V Short Circuit Protected -0.3V to +16V
Electrical Characteristics
Limits in standard typeface are for TJ = 25C, and limits in boldface type apply over the full operating temperature range. Unless otherwise specified: VIN = VO(NOM) + 1V, IL = 1 mA, COUT = 1 F, VON/OFF = 2V. Symbol Parameter Conditions Typ LP2980AI-XX (Note 6) Min VO Output Voltage Tolerance IL = 1 mA 1 mA < IL < 50 mA Output Voltage Line Regulation VIN-VO Dropout Voltage (Note 7) IL = 1 mA IL = 10 mA IL = 50 mA IGND Ground Pin Current IL = 0 IL = 1 mA IL = 10 mA IL = 50 mA VON/OFF < 0.18V High = O/P ON Low = O/P OFF VON/OFF = 0 VON/OFF = 5V VOUT VO(NOM) - 5% BW = 300 Hz-50 kHz, COUT = 10 F f = 1 kHz COUT = 10 F IO(MAX) Short Circuit Current RL = 0 (Steady State) (Note 9)
Note 1: Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating the device outside of its rated operating conditions. Note 2: The ESD rating of pins 3 and 4 is 1 kV.
LP2980I-XX (Note 6) Min -1.0 -1.5 -3.5 Max 1.0 1.5 3.5 0.014 0.032 3 5 10 15 60 90 150 225 95 125 110 170 220 460 600 1200 1 1.6
Units
Max 0.50 0.75 2.5 0.014 0.032
-0.50 -0.75 -2.5 0.007
%VNOM
VO(NOM) + 1V VIN 16V IL = 0
%/V
1 7 40 120 65 80 140 375 0 1.4 0.55 0 5 150 160 63 150 100 1.6
3 5 10 15 60 90 150 225 95 125 110 170 220 460 600 1200 1 0.18 -1 15 100
mV
A
VON/OFF ION/OFF IO(PK) en
ON/OFF Input Voltage (Note 8) ON/OFF Input Current Peak Output Current Output Noise Voltage (RMS) Ripple Rejection
V 0.18 -1 15 mA V dB mA A
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Electrical Characteristics
(Continued)
Note 3: The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(MAX), the junction-to-ambient thermal resistance, JA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using:
The value of JA for the SOT-23 package is 220C/W. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Note 4: If used in a dual-supply system where the regulator load is returned to a negative supply, the LP2980 output must be diode-clamped to ground. Note 5: The output PNP structure contains a diode between the VIN and VOUT terminals that is normally reverse-biased. Reversing the polarity from VIN to VOUT will turn on this diode (see Application Hints). Note 6: Limits are 100% production tested at 25C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control (SQC) methods. The limits are used to calculate National's Averaging Outgoing Level (AOQL). Note 7: Dropout voltage is defined as the input to output differential at which the output voltage drops 100 mV below the value measured with a 1V differential. Note 8: The ON/OFF inputs must be properly driven to prevent misoperation. For details, refer to Application Hints. Note 9: See Typical Performance Characteristics curves.
Basic Application Circuit
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*ON/OFF input must be actively terminated. Tie to VIN if this function is not to be used. **Minimum Output Capacitance is 1 F to insure stability over full load current range. More capacitance provides superior dynamic performance and additional
stability margin (see Application Hints). ***Do not make connections to this pin.
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Ordering Information
TABLE 1. Package Marking and Order Information Output Voltage (V) 2.5 2.5 2.5 2.5 2.6 2.6 2.6 2.6 2.7 2.7 2.7 2.7 2.8 2.8 2.8 2.8 2.9 2.9 2.9 2.9 3.0 3.0 3.0 3.0 3.1 3.1 3.1 3.1 3.2 3.2 3.2 3.2 3.3 3.3 3.3 3.3 3.5 3.5 3.5 3.5 3.6 3.6 3.6 3.6 3.8
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Order Grade A A STD STD A A STD STD A A STD STD A A STD STD A A STD STD A A STD STD A A STD STD A A STD STD A A STD STD A A STD STD A A STD STD A Information LP2980AIM5X-2.5 LP2980AIM5-2.5 LP2980IM5X-2.5 LP2980IM5-2.5 LP2980AIM5X-2.6 LP2980AIM5-2.6 LP2980IM5X-2.6 LP2980IM5-2.6 LP2980AIM5X-2.7 LP2980AIM5-2.7 LP2980IM5X-2.7 LP2980IM5-2.7 LP2980AIM5X-2.8 LP2980AIM5-2.8 LP2980IM5X-2.8 LP2980IM5-2.8 LP2980AIM5X-2.9 LP2980AIM5-2.9 LP2980IM5X-2.9 LP2980IM5-2.9 LP2980AIM5X-3.0 LP2980AIM5-3.0 LP2980IM5X-3.0 LP2980IM5-3.0 LP2980AIM5X-3.1 LP2980AIM5-3.1 LP2980IM5X-3.1 LP2980IM5-3.1 LP2980AIM5X-3.2 LP2980AIM5-3.2 LP2980IM5X-3.2 LP2980IM5-3.2 LP2980AIM5X-3.3 LP2980AIM5-3.3 LP2980IM5X-3.3 LP2980IM5-3.3 LP2980AIM5X-3.5 LP2980AIM5-3.5 LP2980IM5X-3.5 LP2980IM5-3.5 LP2980AIM5X-3.6 LP2980AIM5-3.6 LP2980IM5X-3.6 LP2980IM5-3.6 LP2980AIM5X-3.8
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Package Marking L0NA L0NA L0NB L0NB L48A L48A L48B L48B L26A L26A L26B L26B L13A L13A L13B L13B L12A L12A L12B L12B L02A L02A L02B L02B L30A L30A L30B L30B L31A L31A L31B L31B L00A L00A L00B L00B L27A L27A L27B L27B L28A L28A L28B L28B L21A Supplied as: 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel
Ordering Information
Output Voltage (V) 3.8 3.8 3.8 4.0 4.0 4.0 4.0 4.5 4.5 4.5 4.5 4.7 4.7 4.7 4.7 5.0 5.0 5.0 5.0 A STD STD A A STD STD A A STD STD A A STD STD A A STD STD Grade
(Continued)
TABLE 1. Package Marking and Order Information (Continued) Order Information LP2980AIM5-3.8 LP2980IM5X-3.8 LP2980IM5-3.8 LP2980AIM5X-4.0 LP2980AIM5-4.0 LP2980IM5X-4.0 LP2980IM5-4.0 LP2980AIM5X-4.5 LP2980AIM5-4.5 LP2980IM5X-4.5 LP2980IM5-4.5 LP2980AIM5X-4.7 LP2980AIM5-4.7 LP2980IM5X-4.7 LP2980IM5-4.7 LP2980AIM5X-5.0 LP2980AIM5-5.0 LP2980IM5X-5.0 LP2980IM5-5.0 Package Marking L21A L21B L21B L25A L25A L25B L25B L0XA L0XA L0XB L0XB L37A L37A L37B L37B L01A L01A L01B L01B Supplied as: 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel 3k Units on Tape and Reel 250 Units on Tape and Reel
Connection Diagram
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Top View See NS Package Number MA05A
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Typical Performance Characteristics
COUT = 2.2 F, all voltage options, ON/OFF pin tied to VIN. Output Voltage vs Temperature
Unless otherwise specified: TA = 25C, VIN = VO(NOM) + 1V,
Output Voltage vs Temperature
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Output Voltage vs Temperature
Dropout Characteristics
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Dropout Characteristics
Dropout Characteristics
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Typical Performance Characteristics Unless otherwise specified: TA = 25C, VIN = VO(NOM) + 1V, COUT = 2.2 F, all voltage options, ON/OFF pin tied to VIN. (Continued)
Dropout Voltage vs Temperature Dropout Voltage vs Load Current
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Ground Pin Current vs Temperature
Ground Pin Current vs Load Current
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Input Current vs VIN
Input Current vs VIN
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Typical Performance Characteristics Unless otherwise specified: TA = 25C, VIN = VO(NOM) + 1V, COUT = 2.2 F, all voltage options, ON/OFF pin tied to VIN. (Continued)
Line Transient Response Line Transient Response
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Load Transient Response
Load Transient Response
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Load Transient Response
Load Transient Response
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Typical Performance Characteristics Unless otherwise specified: TA = 25C, VIN = VO(NOM) + 1V, COUT = 2.2 F, all voltage options, ON/OFF pin tied to VIN. (Continued)
Short Circuit Current Instantaneous Short Circuit Current vs Temperature
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Short Circuit Current
Instantaneous Short Circuit Current vs Output Voltage
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Output Impedance vs Frequency
Output Impedance vs Frequency
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Typical Performance Characteristics Unless otherwise specified: TA = 25C, VIN = VO(NOM) + 1V, COUT = 2.2 F, all voltage options, ON/OFF pin tied to VIN. (Continued)
Output Noise Density Ripple Rejection
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Input to Output Leakage vs Temperature
Output Reverse Leakage vs Temperature
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Turn-On Waveform
Turn-Off Waveform
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Typical Performance Characteristics Unless otherwise specified: TA = 25C, VIN = VO(NOM) + 1V, COUT = 2.2 F, all voltage options, ON/OFF pin tied to VIN. (Continued)
ON/OFF Pin Current vs VON/OFF
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Application Hints
OUTPUT CAPACITOR Like any low-dropout regulator, the LP2980 requires an output capacitor to maintain regulator loop stability. This capacitor must be selected to meet the requirements of minimum capacitance and equivalent series resistance (ESR) range. It is not difficult to find capacitors which meet the criteria of the LP2980, as the acceptable capacitance and ESR ranges are wider than for most other LDOs. In general, the capacitor value must be at least 1 F (over the actual ambient operating temperature), and the ESR must be within the range indicated in Figures 1, 2 and Figure 3. It should be noted that, although a maximum ESR is shown in these Figures, it is very unlikely to find a capacitor with ESR that high. Tantalum Capacitors Surface-mountable solid tantalum capacitors offer a good combination of small physical size for the capacitance value, and ESR in the range needed by the LP2980. The results of testing the LP2980 stability with surface-mount solid tantalum capacitors show good stability with values of at least 1 F. The value can be increased to 2.2 F (or more) for even better performance, including transient response and noise. Small value tantalum capacitors that have been verified as suitable for use with the LP2980 are shown in Table 2. Capacitance values can be increased without limit. Aluminum Electrolytic Capacitors Although probably not a good choice for a production design, because of relatively large physical size, an aluminum electrolytic capacitor can be used in the design prototype for an LP2980 regulator. A value of at least 1 F should be used, and the ESR must meet the conditions of Figures 1, 2 and Figure 3. If the operating temperature drops below 0C, the regulator may not remain stable, as the ESR of the aluminum electrolytic capacitor will increase, and may exceed the limits indicated in the Figures. TABLE 2. Surface-Mount Tantalum Capacitor Selection Guide 1 F Surface-Mount Tantalums Manufacturer Kemet NEC Siemens Nichicon Sprague Manufacturer Kemet NEC Siemens Nichicon Sprague Part Number T491A105M010AS NRU105M10 B45196-E3105-K F931C105MA 293D105X0016A2T 2.2 F Surface-Mount Tantalums Part Number T491A225M010AS NRU225M06 B45196/2.2/10/10 F930J225MA 293D225X0010A2T
times have ESR values lower than the minimum required by the LP2980, and relatively large capacitance change with temperature. The manufacturer's datasheet for the capacitor should be consulted before selecting a value. Test results of LP2980 stability using multilayer ceramic capacitors show that a minimum value of 2.2 F is usually needed for the 5V regulator. For the lower output voltages, or for better performance, a higher value should be used, such as 4.7 F. Multilayer ceramic capacitors that have been verified as suitable for use with the LP2980 are shown in Table 3. TABLE 3. Surface-Mount Multilayer Ceramic Capacitor Selection Guide 2.2 F Surface-Mount Ceramic Manufacturer Tokin Murata Manufacturer Tokin Part Number 1E225ZY5U-C203 GRM42-6Y5V225Z16 4.7 F Surface-Mount Ceramic Part Number 1E475ZY5U-C304
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FIGURE 1. 1 F ESR Range
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FIGURE 2. 2.2 F ESR Range
Multilayer Ceramic Capacitors Surface-mountable multilayer ceramic capacitors may be an attractive choice because of their relatively small physical size and excellent RF characteristics. However, they some-
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Application Hints
(Continued)
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FIGURE 3. 10 F ESR Range REVERSE CURRENT PATH The power transistor used in the LP2980 has an inherent diode connected between the regulator input and output (see below).
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FIGURE 4. LP2980 Reverse Current Path If the output is forced above the input by more than a VBE, this diode will become forward biased and current will flow from the VOUT terminal to VIN. No damage to the LP2980 will occur under these conditions as long as the current flowing into the output pin does not exceed 100 mA. ON/OFF INPUT OPERATION The LP2980 is shut off by pulling the ON/OFF input low, and turned on by driving the input high. If this feature is not to be used, the ON/OFF input should be tied to VIN to keep the regulator on at all times (the ON/OFF input must not be left floating). To ensure proper operation, the signal source used to drive the ON/OFF input must be able to swing above and below the specified turn-on/turn-off voltage thresholds which guarantee an ON or OFF state (see Electrical Characteristics). The ON/OFF signal may come from either a totem-pole output, or an open-collector output with pull-up resistor to the LP2980 input voltage or another logic supply. The high-level voltage may exceed the LP2980 input voltage, but must remain within the Absolute Maximum Ratings for the ON/OFF pin. It is also important that the turn-on/turn-off voltage signals applied to the ON/OFF input have a slew rate which is greater than 40 mV/s. Important: the regulator shutdown function will operate incorrectly if a slow-moving signal is applied to the ON/OFF input.
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Typical Applications
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FIGURE 5. 5V/400mA Regulator The LP2980 can be used to control higher-current regulators, by adding an external PNP pass device. With the PNP transistors shown in , the output current can be as high as 400 mA, as long as the input voltage is held within the Safe Operation Boundary Curves shown below in. To ensure regulation, the minimum input voltage of this regulator is 6V. This "headroom" is the sum of the VBE of the external transistor and the dropout voltage of the LP2980. Notes: A. Drive this input with a logic signal (see Application Hints). If the shutdown function is not to be used, tie the ON/OFF pin directly to the VIN pin. B. Recommended devices (other PNP transistors can be used if the current gain and voltage ratings are similar). C. Capacitor is required for regulator stability. Minimum size is shown, and may be increased without limit. D. Increasing the output capacitance improves transient response and increases phase margin. E. Maximum safe input voltage and load current are limited by power dissipation in the PNP pass transistor and the maximum ambient temperature for the specific application. If a TO-92 transistor such as the MPS2907A is used, the thermal resistance from junction-to-ambient is 180C/W in still air. Assuming a maximum allowable junction temperature of 150C for the MPS2907A device, the following curves show the maximum VIN and IL values that may be safely used for several ambient temperatures.
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FIGURE 6. Safe Operation Boundary Curves for Figure 5
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FIGURE 7. 5V to 3.3V @ 3A Converter With limited input voltage range, the LP2980 can control a 3.3V, 3A regulator with the use of a high current-gain external PNP pass transistorias shown in . If the regulator is to be loaded with the full 3A, heat sinking will be required on the pass transistor to keep it within its rated temperature range. Refer to the Heatsink Thermal Resistance Requirements,
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below. For best load regulation at the high load current, the LP2980 output voltage connection should be made as close to the load as possible. Although this regulator can handle a much higher load current than can the LP2980 alone, it can be shut down in the same manner as the LP2980. When the ON/OFF control is
Typical Applications
(Continued)
brought low, the converter will be in shutdown, and will draw less than 1 A from the source. Notes: A. Drive this input with a logic signal (see Application Hints). If the shutdown function is not to be used, tie the ON/OFF pin directly to the VIN pin. B. Capacitor is required for regulator stability. Minimum size is shown, and may be increased without limit. C. Increasing the output capacitance improves transient response and increases phase margin. D. A heatsink may be required for this transistor. The maximum allowable value for thermal resistance of the heatsink is dependent on ambient temperature and load current (see curves in ). Once the value is obtained from the graph, a heatsink must be selected which has a thermal resistance equal to or lower than this value. If the value is above 60C/W, no heatsink is required (the TO-220 package alone will safely dissipate this). For these curves, a maximum junction temperature of 150C is assumed for the pass transistor. The case-to-heatsink at-
tachment thermal resistance is assumed to be 1.5C/W. All calculations are for 5.5V input voltage (which is worst-case for power dissipation).
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FIGURE 8. Heatsink Thermal Resistance Requirements for Figure 7
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LP2980 Micropower SOT, 50 mA Ultra Low-Dropout Regulator
Physical Dimensions
inches (millimeters) unless otherwise noted
5-Lead Small Outline Package (M5) NS Package Number MA05B For Order Numbers, refer to Table 1 in the "Order Information" section of this document.
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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