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LP2982 Micropower SOT, 50 mA Ultra Low-Dropout Regulator
May 1999
LP2982 Micropower SOT, 50 mA Ultra Low-Dropout Regulator
General Description
The LP2982 is a 50 mA, fixed-output voltage regulator designed to provide ultra low dropout and lower noise in battery powered applications. Using an optimized VIPTM (Vertically Integrated PNP) process, the LP2982 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 absolute minimum of board space. Precision Output: 1.0% tolerance output voltages available (A grade). Low Noise: By adding an external bypass capacitor, output noise can be reduced to 30 V (typical). Ten output voltage versions, from 2.5V to 5.0V, are available as standard products.
Features
n n n n n n n n n n n n n n Ultra low dropout voltage Guaranteed 50 mA output current Typical dropout voltage 180 mV @ 80 mA Smallest possible size (SOT-23 Package) Requires minimum external components < 1 A quiescent current when shutdown Low ground pin current at all loads Output voltage accuracy 1.0% (A Grade) High peak current capability (150 mA typical) Wide supply voltage range (16V max) Low ZOUT 0.3 typical (10 Hz to 1 MHz) Overtemperature/overcurrent protection -40C to +125C junction temperature range Custom voltages available
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
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See NS Package Number MA05B
VIPTM is a trademark of National Semiconductor Corporation.
(c) 1999 National Semiconductor Corporation
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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 capacitance is shown to insure stability over full load current range. More capacitance provides superior dynamic performance (see Application
Hints).
***See Application Hints.
Ordering Information
TABLE 1. Package Marking and Ordering Information Output Voltage (V) 2.5 2.5 2.5 2.5 2.8 2.8 2.8 2.8 3.0 3.0 3.0 3.0 3.3 3.3 3.3 3.3 3.6 3.6 3.6 3.6 3.8 3.8 3.8 3.8 4.0 Package Marking L58A L58A L58B L58B L60A L60A L60B L60B L20A L20A L20B L20B L19A L19A L19B L19B L0BA L0BA L0BB L0BB L76A L76A L76B L76B L29A
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
Order Information LP2982AIM5X-2.5 LP2982AIM5-2.5 LP2982IM5X-2.5 LP2982IM5-2.5 LP2982AIM5X-2.8 LP2982AIM5-2.8 LP2982IM5X-2.8 LP2982IM5-2.8 LP2982AIM5X-3.0 LP2982AIM5-3.0 LP2982IM5X-3.0 LP2982IM5-3.0 LP2982AIM5X-3.3 LP2982AIM5-3.3 LP2982IM5X-3.3 LP2982IM5-3.3 LP2982AIM5X-3.6 LP2982AIM5-3.6 LP2982IM5X-3.6 LP2982IM5-3.6 LP2982AIM5X-3.8 LP2982AIM5-3.8 LP2982IM5X-3.8 LP2982IM5-3.8 LP2982AIM5X-4.0
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
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Ordering Information
Output Voltage (V) 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
(Continued)
TABLE 1. Package Marking and Ordering Information (Continued) Grade A STD STD A A STD STD A A STD STD A A STD STD Order Information LP2982AIM5-4.0 LP2982IM5X-4.0 LP2982IM5-4.0 LP2982AIM5X-4.5 LP2982AIM5-4.5 LP2982IM5X-4.5 LP2982IM5-4.5 LP2982AIM5X-4.7 LP2982AIM5-4.7 LP2982IM5X-4.7 LP2982IM5-4.7 LP2982AIM5X-5.0 LP2982AIM5-5.0 LP2982IM5X-5.0 LP2982IM5-5.0 Package Marking L29A L29B L29B LA8A LA8A LA8B LA8B L0HA L0HA L0HB L0HB L18A L18A L18B L18B 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
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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.) ESD Rating (Note 2) -65C to +150C -40C to +125C 260C 2 kV
Power Dissipation (Note 3) Internally Limited Input Supply Voltage (Survival) -0.3V to +16V Input Supply Voltage (Operating) 2.1V to +16V Shutdown Input Voltage (Survival) -0.3V to +16V Output Voltage (Survival, (Note 4)) -0.3V to +9V Short Circuit Protected IOUT (Survival) Input-Output Voltage (Survival, (Note 5)) -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, CIN = 1 F, COUT = 4.7 F, VON/OFF = 2V. Symbol Parameter Conditions Typ LP2982AI-X.X (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 < 0.3V VON/OFF ION/OFF IO(PK) VIN-VO IGND en ON/OFF Input Voltage (Note 8) ON/OFF Input Current Peak Output Current Dropout Voltage Ground Pin Current Output Noise Voltage (RMS) VON/OFF < 0.15V High = O/P ON Low = O/P OFF VON/OFF = 0 VON/OFF = 5V VOUT VO(NOM) - 5% IL = 80 mA IL = 80 mA BW = 300 Hz-50 kHz, COUT = 10 F CBYPASS = 0.01 F 7 40 120 65 80 140 375 0.01 0.10 1.4 0.55 0.01 5 150 180 525 100 225 325 750 1400 30 1.6 0.15 -2 15 100 225 325 750 1400 V A VO(NOM) + 1V VIN 16V IL = 0 0.007 -1.0 -1.5 -2.0 Max +1.0 +1.5 +2.0 0.014 0.032 1 3 5 10 15 60 90 150 225 95 125 110 170 220 460 600 1200 0.8 2.0 1.6 0.15 -2 15 LP2982I-X.X (Note 6) Min -1.5 -2.0 -3.5 Max +1.5 +2.0 +3.5 0.014 0.032 3 5 10 15 60 90 150 225 95 125 110 170 220 460 600 1200 0.8 2.0 V A mA mV A mV %/V %VNOM Units
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Electrical Characteristics
Symbol Parameter
(Continued)
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, CIN = 1 F, COUT = 4.7 F, VON/OFF = 2V. Conditions Typ LP2982AI-X.X (Note 6) Min Ripple Rejection f = 1 kHz COUT = 10 F RL = 0 (Steady State) (Note 9) 45 150 Max LP2982I-X.X (Note 6) Min Max dB mA Units
IO(MAX)
Short Circuit Current
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. 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 LP2982 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. 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 possible misoperation. For details, refer to Application Hints. Note 9: See Typical Performance Characteristics curves.
Typical Performance Characteristics Unless otherwise specified: TA = 25C, VIN = VO(NOM) + 1V, COUT = 4.7 F, CIN = 1 F, all voltage options, ON/OFF pin tied to VIN.
Output Voltage vs Temperature Output Voltage vs Temperature
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Typical Performance Characteristics Unless otherwise specified: TA = 25C, VIN = VO(NOM) + 1V, COUT = 4.7 F, CIN = 1 F, all voltage options, ON/OFF pin tied to VIN. (Continued)
Output Voltage vs Temparature Dropout Characteristics
DS012679-7 DS012679-6
Dropout Characteristics
Dropout Characteristics
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Dropout Voltage vs Temperature
Dropout Voltage vs Load Current
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Typical Performance Characteristics Unless otherwise specified: TA = 25C, VIN = VO(NOM) + 1V, COUT = 4.7 F, CIN = 1 F, all voltage options, ON/OFF pin tied to VIN. (Continued)
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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Line Transient Response
Line Transient Response
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Typical Performance Characteristics Unless otherwise specified: TA = 25C, VIN = VO(NOM) + 1V, COUT = 4.7 F, CIN = 1 F, all voltage options, ON/OFF pin tied to VIN. (Continued)
Load Transient Response Load Transient Response
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Load Transient Response
Load Transient Response
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Short Circuit Current
Instantaneous Short Circuit Current vs Temperature
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Typical Performance Characteristics Unless otherwise specified: TA = 25C, VIN = VO(NOM) + 1V, COUT = 4.7 F, CIN = 1 F, all voltage options, ON/OFF pin tied to VIN. (Continued)
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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ON/OFF Pin Current vs VON/OFF
ON/OFF Threshold vs Temperature
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Typical Performance Characteristics Unless otherwise specified: TA = 25C, VIN = VO(NOM) + 1V, COUT = 4.7 F, CIN = 1 F, all voltage options, ON/OFF pin tied to VIN. (Continued)
Input to Output Leakage vs Temperature Output Reverse Leakage vs Temperature
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Output Noise Density
Output Noise Density
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Output Noise Density
Ripple Rejection
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DS012679-41
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Typical Performance Characteristics Unless otherwise specified: TA = 25C, VIN = VO(NOM) + 1V, COUT = 4.7 F, CIN = 1 F, all voltage options, ON/OFF pin tied to VIN. (Continued)
Turn-ON Waveform Turn-ON Waveform
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Turn-ON Waveform
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Application Hints
EXTERNAL CAPACITORS Like any low-dropout regulator, the external capacitors used with the LP2982 must be carefully selected to assure regulator loop stability. INPUT CAPACITOR: An input capacitor whose value is 1 F is required with the LP2982 (amount of capacitance can be increased without limit). This capacitor must be located a distance of not more than 0.5" from the input pin of the LP2982 and returned to a clean analog ground. Any good quality ceramic or tantalum can be used for this capacitor. OUTPUT CAPACITOR: The output capacitor must meet both the requirement for minimum amount of capacitance and E.S.R. (equivalent series resistance) value. Curves are provided which show the allowable ESR range as a function of load current for various output voltages and capacitor values (refer to Figure 1, Figure 2). IMPORTANT: The output capacitor must maintain its ESR in the stable region over the full operating temperature to assure stability. Also, capacitor tolerance and variation with temperature must be considered to assure the minimum amount of capacitance is provided at all times. This capacitor should be located not more than 0.5" from the output pin of the LP2982 and returned to a clean analog ground. LOW-CURRENT OPERATION: In applications where the load current is < 1 mA, special consideration must be given to the output capacitor. Circuitry inside the LP2982 is specially designed to reduce operating (quiescent) current at light loads down to about 65 A. The mode of operation which yields this very low quiescent current also means that the output capacitor ESR is critical. For optimum stability and minimum output noise, it is recommended that a 10 resistor be placed in series with the output capacitor in any applications where IL < 1 mA. CAPACITOR CHARACTERISTICS TANTALUM: Tantalum capacitors are the best choice for use with the LP2982. Most good quality tantalums can be used with the LP2982, but check the manufacturer's data sheet to be sure the ESR is in range. It is important to remember that ESR increases sharply at lower temperatures (< 10C) and a capacitor that is near the upper limit for stability at room temperature can cause instability when it gets cold. In applications which must operate at very low temperatures, it may be necessary to parallel the output tantalum capacitor with a ceramic capacitor to prevent the ESR from going up too high (see next section for important information on ceramic capacitors). CERAMIC: Ceramic capacitors are not recommended for use at the output of the LP2982. This is because the ESR of a ceramic can be low enough to go below the minimum stable value for the LP2982. A good 2.2 F ceramic was measured and found to have an ESR of about 15 m, which is low enough to cause oscillations. If a ceramic capacitor is used on the output, a 1 resistor should be placed in series with the capacitor. ALUMINUM: Because of large physical size, aluminum electrolytics are not typically used with the LP2982. They must
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meet the same ESR requirements over the operating temperature range, which is more difficult because of their large increase in ESR at cold temperature. An aluminum electrolytic can exhibit an ESR increase of as much as 50X when going from 20C to -40C. Also, some aluminum electrolytics are not operational below -25C because the electrolyte can freeze.
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FIGURE 1.
5V/2.2 F ESR Curves
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FIGURE 2.
3V/4.7 F ESR Curves
BYPASS CAPACITOR The 0.01 F capacitor connected to the bypass pin to reduce noise must have very low leakage. The current flowing out of the bypass pin comes from the bandgap reference, which is used to set the output voltage. This capacitor leakage current causes the output voltage to decline by an amount proportional to the current. Typical values are -0.015%/nA @ -40C, -0.021%/nA @ 25C, and -0.035%/nA @ +125C. This data is valid up to a maximum leakage current of about 500 nA, beyond which the bandgap is so severly loaded that it can not function. Care must be taken to ensure that the capacitor selected will not have excessive leakage current over the operating temperature range of the application. A high quality ceramic capacitor which uses either NPO or COG type dielectric material will typically have very low leakage. Small surface mount polypropolene or polycarbonate film capacitors also have extremely low leakage, but are slightly larger than ceramics.
Application Hints
REVERSE CURRENT PATH
(Continued)
The power transistor used in the LP2982 has an inherent diode connected between the regulator input and output (see below).
DS012679-40
DS012679-39
As shown, the Schottky diode is connected in parallel with the internal parasitic diode and prevents it from being turned on by limiting the voltage drop across it to about 0.3V. ON/OFF INPUT OPERATION The LP2982 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 LP2982 input voltage or another logic supply. The high-level voltage may exceed the LP2982 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.
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. This current must be limited to < 100 mA to prevent damage to the part. The internal diode can also be turned on by abruptly stepping the input voltage to a value below the output voltage. To prevent regulator mis-operation, a Schottky diode should be used in any application where input/output voltage conditions can cause the internal diode to be turned on (see below).
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LP2982 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 I in the "Ordering Information" section of this document.
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2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.
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National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.

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