Datasheet LP2980AIM5X-2.8, LP2980AIM5X-2.5, LP2980AIM5-3.3, LP2980AIM5-2.5, LP2980IM5X-5.0 Datasheet (NSC)

LP2980
Micropower 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 VIP

™

(Vertically Integrated PNP) pro­cess, the LP2980 delivers unequaled performance in all
specifications critical to battery-powered designs:

Dropout Voltage. Typically 120mV

@

50 mAload, and7 mV

@

1 mA load.

Ground PinCurrent. Typically375 µA

@

50 mAload, and80

µA

@

1 mA load.

Sleep Mode. Less than 1 µA quiescent current when ON/
OFF pin is pulled low.

Smallest Possible Size. SOT-23 and micro SMD packages
use an absolute minimum board space.

Minimum Part Count. Requires only 1 µF 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 Ultra low dropout voltage
n Output voltage accuracy 0.5% (A Grade)
n Guaranteed 50 mA output current
n Smallest possible size (SOT-23, micro SMD package)
n Requires only 1 µF external capacitance

n

<

1 µA quiescent current when shutdown

n Low ground pin current at all load currents
n High peak current capability (150 mA typical)
n Wide supply voltage range (16V max)
n Fast dynamic response to line and load
n Low Z

OUT

over wide frequency range

n Overtemperature/overcurrent protection
n −40˚C to +125˚C junction temperature range

Applications

n Cellular Phone
n Palmtop/Laptop Computer
n Personal Digital Assistant (PDA)
n Camcorder, Personal Stereo, Camera

Block Diagram

Connection Diagram and Ordering Information

VIP™is a trademark of National Semiconductor Corporation.

DS012078-1

5-Lead Small Outline Package (M5)

DS012078-3

Top View

See NS Package Number MF05A

For ordering information see

Table 1

micro SMD, 5 Bump Package (BPA05)

DS012078-60

Bottom View

See NS Package Number BPA05

April 2000

LP2980 Micropower 50 mA Ultra Low-Dropout Regulator

© 2000 National Semiconductor Corporation DS012078 www.national.com

Ordering Information

TABLE 1. Package Marking and Order Information

Output Voltage

(V)

Grade Order Information Package

Marking

Supplied as:

5-Lead Small Outline Package (M5)
For output voltages ≤ 2V, refer to LP2980LV datasheet. If a non-standard voltage is required, see LP2980-ADJ.

2.5 A LP2980AIM5X-2.5 L0NA 3000 Units on Tape and Reel

2.5 A LP2980AIM5-2.5 L0NA 1000 Units on Tape and Reel

2.5 STD LP2980IM5X-2.5 L0NB 3000 Units on Tape and Reel

2.5 STD LP2980IM5-2.5 L0NB 1000 Units on Tape and Reel

2.6 A LP2980AIM5X-2.6 L48A 3000 Units on Tape and Reel

2.6 A LP2980AIM5-2.6 L48A 1000 Units on Tape and Reel

2.6 STD LP2980IM5X-2.6 L48B 3000 Units on Tape and Reel

2.6 STD LP2980IM5-2.6 L48B 1000 Units on Tape and Reel

2.7 A LP2980AIM5X-2.7 L26A 3000 Units on Tape and Reel

2.7 A LP2980AIM5-2.7 L26A 1000 Units on Tape and Reel

2.7 STD LP2980IM5X-2.7 L26B 3000 Units on Tape and Reel

2.7 STD LP2980IM5-2.7 L26B 1000 Units on Tape and Reel

2.8 A LP2980AIM5X-2.8 L13A 3000 Units on Tape and Reel

2.8 A LP2980AIM5-2.8 L13A 1000 Units on Tape and Reel

2.8 STD LP2980IM5X-2.8 L13B 3000 Units on Tape and Reel

2.8 STD LP2980IM5-2.8 L13B 1000 Units on Tape and Reel

2.9 A LP2980AIM5X-2.9 L12A 3000 Units on Tape and Reel

2.9 A LP2980AIM5-2.9 L12A 1000 Units on Tape and Reel

2.9 STD LP2980IM5X-2.9 L12B 3000 Units on Tape and Reel

2.9 STD LP2980IM5-2.9 L12B 1000 Units on Tape and Reel

3.0 A LP2980AIM5X-3.0 L02A 3000 Units on Tape and Reel

3.0 A LP2980AIM5-3.0 L02A 1000 Units on Tape and Reel

3.0 STD LP2980IM5X-3.0 L02B 3000 Units on Tape and Reel

3.0 STD LP2980IM5-3.0 L02B 1000 Units on Tape and Reel

3.1 A LP2980AIM5X-3.1 L30A 3000 Units on Tape and Reel

3.1 A LP2980AIM5-3.1 L30A 1000 Units on Tape and Reel

3.1 STD LP2980IM5X-3.1 L30B 3000 Units on Tape and Reel

3.1 STD LP2980IM5-3.1 L30B 1000 Units on Tape and Reel

3.2 A LP2980AIM5X-3.2 L31A 3000 Units on Tape and Reel

3.2 A LP2980AIM5-3.2 L31A 1000 Units on Tape and Reel

3.2 STD LP2980IM5X-3.2 L31B 3000 Units on Tape and Reel

3.2 STD LP2980IM5-3.2 L31B 1000 Units on Tape and Reel

3.3 A LP2980AIM5X-3.3 L00A 3000 Units on Tape and Reel

3.3 A LP2980AIM5-3.3 L00A 1000 Units on Tape and Reel

3.3 STD LP2980IM5X-3.3 L00B 3000 Units on Tape and Reel

3.3 STD LP2980IM5-3.3 L00B 1000 Units on Tape and Reel

3.5 A LP2980AIM5X-3.5 L27A 3000 Units on Tape and Reel

3.5 A LP2980AIM5-3.5 L27A 1000 Units on Tape and Reel

3.5 STD LP2980IM5X-3.5 L27B 3000 Units on Tape and Reel

3.5 STD LP2980IM5-3.5 L27B 1000 Units on Tape and Reel

3.6 A LP2980AIM5X-3.6 L28A 3000 Units on Tape and Reel

3.6 A LP2980AIM5-3.6 L28A 1000 Units on Tape and Reel

3.6 STD LP2980IM5X-3.6 L28B 3000 Units on Tape and Reel

3.6 STD LP2980IM5-3.6 L28B 1000 Units on Tape and Reel

LP2980

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Ordering Information (Continued)

TABLE 1. Package Marking and Order Information (Continued)

Output Voltage

(V)

Grade Order Information Package

Marking

Supplied as:

For output voltages ≤ 2V, refer to LP2980LV datasheet. If a non-standard voltage is required, see LP2980-ADJ.

3.8 A LP2980AIM5X-3.8 L21A 3000 Units on Tape and Reel

3.8 A LP2980AIM5-3.8 L21A 1000 Units on Tape and Reel

3.8 STD LP2980IM5X-3.8 L21B 3000 Units on Tape and Reel

3.8 STD LP2980IM5-3.8 L21B 1000 Units on Tape and Reel

4.0 A LP2980AIM5X-4.0 L25A 3000 Units on Tape and Reel

4.0 A LP2980AIM5-4.0 L25A 1000 Units on Tape and Reel

4.0 STD LP2980IM5X-4.0 L25B 3000 Units on Tape and Reel

4.0 STD LP2980IM5-4.0 L25B 1000 Units on Tape and Reel

4.5 A LP2980AIM5X-4.5 L0XA 3000 Units on Tape and Reel

4.5 A LP2980AIM5-4.5 L0XA 1000 Units on Tape and Reel

4.5 STD LP2980IM5X-4.5 L0XB 3000 Units on Tape and Reel

4.5 STD LP2980IM5-4.5 L0XB 1000 Units on Tape and Reel

4.7 A LP2980AIM5X-4.7 L37A 3000 Units on Tape and Reel

4.7 A LP2980AIM5-4.7 L37A 1000 Units on Tape and Reel

4.7 STD LP2980IM5X-4.7 L37B 3000 Units on Tape and Reel

4.7 STD LP2980IM5-4.7 L37B 1000 Units on Tape and Reel

5.0 A LP2980AIM5X-5.0 L01A 3000 Units on Tape and Reel

5.0 A LP2980AIM5-5.0 L01A 1000 Units on Tape and Reel

5.0 STD LP2980IM5X-5.0 L01B 3000 Units on Tape and Reel

5.0 STD LP2980IM5-5.0 L01B 1000 Units on Tape and Reel

micro SMD, 5 Bump Package (BPA05)

3.3 A LP2980AIBP-3.3 250 Units on Tape and Reel

3.3 A LP2980AIBPX-3.3 3000 Units on Tape and Reel

3.3 STD LP2980IBP-3.3 250 Units on Tape and Reel

3.3 STD LP2980IBPX-3.3 3000 Units on Tape and Reel

5.0 A LP2980AIBP-5.0 250 Units on Tape and Reel

5.0 A LP2980AIBPX-5.0 3000 Units on Tape and Reel

5.0 STD LP2980IBP-5.0 250 Units on Tape and Reel

5.0 STD LP2980IBPX-5.0 3000 Units on Tape and Reel

LP2980

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Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor SalesOffice/
Distributors for availability and specifications.

Storage Temperature Range −65˚C to +150˚C
Operating Junction Temperature

Range −40˚C to +125˚C

Lead Temperature

(Soldering, 5 sec.) 260˚C

ESD Rating (Note 2) 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
I

OUT

(Survival) Short Circuit Protected

Input-Output Voltage (Survival),

(Note 5) −0.3V to +16V

Electrical Characteristics

Limits in standard typeface are for TJ= 25˚C, and limits in boldface type apply over the full operating temperature range. Un­less otherwise specified: VIN=V

O(NOM)

+ 1V, IL= 1 mA, C

OUT

= 1 µF, V

ON/OFF

= 2V.

Symbol Parameter Conditions Typ LP2980AI-XX LP2980I-XX Units

(Note 6) (Note 6)

Min Max Min Max

∆V

O

Output Voltage
Tolerance

IL= 1 mA −0.50 0.50 −1.0 1.0

%V

NOM

1mA<I

L

<

50 mA −0.75 0.75 −1.5 1.5

−2.5 2.5 −3.5 3.5

Output Voltage V

O(NOM)

+1V

0.007

0.014 0.014

%/V

Line Regulation ≤ V

IN

≤ 16V 0.032 0.032

V

IN–VO

Dropout Voltage IL=0 133mV
(Note 7) 55

I

L

= 1 mA 7 10 10

15 15

I

L

=10mA 406060

90 90

I

L

= 50 mA 120 150 150

225 225

I

GND

Ground Pin Current IL= 0 65 95 95 µA

125 125

I

L

= 1 mA 80 110 110

170 170

I

L

= 10 mA 140 220 220

460 460

I

L

= 50 mA 375 600 600

1200 1200

V

ON/OFF

<

0.18V 0 11

V

ON/OFF

ON/OFF Input Voltage High = O/P ON 1.4 1.6 1.6 V
(Note 8) Low = O/P OFF 0.55 0.18 0.18

I

ON/OFF

ON/OFF Input Current V

ON/OFF

=0 0 −1 −1 µA

V

ON/OFF

=5V 5 15 15

I

O(PK)

Peak Output Current V

OUT

≥ V

O(NOM)

− 5% 150 100 100 mA

e

n

Output Noise BW = 300 Hz–50 kHz, 160 µV
Voltage (RMS) C

OUT

=10µF

Ripple Rejection f = 1 kHz

63 dB

C

OUT

=10µF

I

O(MAX)

Short Circuit Current RL= 0 (Steady State) 150 mA

(Note 9)

Note 1: Absolute maximum ratings indicate limits beyond which damageto the component may occur. Electrical specifications do notapply when operating the de­vice outside of its rated operating conditions.

Note 2: The ESD rating of pins 3 and 4 is 1 kV.

LP2980

www.national.com 4

Electrical Characteristics (Continued)

Note 3: The maximum allowablepower dissipationis a function of the maximum junction temperature, T

J(MAX)

, thejunction-to-ambient thermalresistance, θJA, and

the ambient temperature, T

A

. The maximum allowable power dissipation at any ambient temperature is calculated using:

The value of θJAfor the SOT-23 package is 220˚C/W and the micro SMD package is 320˚C/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 V

IN

and V

OUT

terminals that is normally reverse-biased. Reversing the polarity from VINto V

OUT

will turn on this diode (see Application Hints).
Note 6: Limits are 100%production testedat 25˚C. Limits over the operating temperature range are guaranteed throughcorrelation usingStatistical Quality Control

(SQC) methods. The limits are used to calculate National’s Average Outgoing Quality 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

DS012078-2

*

ON/OFF input must be actively terminated. Tie to VINif this function is not to be used.

**

Minimum Output Capacitance is 1 µF to insure stability over full load current range. More capacitance provides superior dynamic performance and additional

stability margin (seeApplication Hints).

***

Do not make connections to this pin.

LP2980

www.national.com5

Typical Performance Characteristics Unless otherwise specified: T

A

= 25˚C, VIN=V

O(NOM)

+1V,

C

OUT

= 2.2 µF, all voltage options, ON/OFF pin tied to VIN.

Output Voltage vs
Temperature

DS012078-9

Output Voltage vs
Temperature

DS012078-39

Output Voltage vs
Temperature

DS012078-40

Dropout Characteristics

DS012078-16

Dropout Characteristics

DS012078-15

Dropout Characteristics

DS012078-14

LP2980

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Typical Performance Characteristics Unless otherwise specified: T

A

= 25˚C, VIN=V

O(NOM)

+ 1V,

C

OUT

= 2.2 µF, all voltage options, ON/OFF pin tied to VIN. (Continued)

Dropout Voltage vs
Temperature

DS012078-11

Dropout Voltage vs
Load Current

DS012078-20

Ground Pin Current vs
Temperature

DS012078-10

Ground Pin Current vs
Load Current

DS012078-19

Input Current vs V

IN

DS012078-17

Input Current vs V

IN

DS012078-18

LP2980

www.national.com7

Typical Performance Characteristics Unless otherwise specified: T

A

= 25˚C, VIN=V

O(NOM)

+ 1V,

C

OUT

= 2.2 µF, all voltage options, ON/OFF pin tied to VIN. (Continued)

Line Transient Response

DS012078-21

Line Transient Response

DS012078-22

Load Transient Response

DS012078-41

Load Transient Response

DS012078-42

Load Transient Response

DS012078-23

Load Transient Response

DS012078-24

LP2980

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Typical Performance Characteristics Unless otherwise specified: T

A

= 25˚C, VIN=V

O(NOM)

+ 1V,

C

OUT

= 2.2 µF, all voltage options, ON/OFF pin tied to VIN. (Continued)

Short Circuit Current

DS012078-32

Instantaneous Short Circuit Current
vs Temperature

DS012078-12

Short Circuit Current

DS012078-33

Instantaneous Short Circuit Current
vs Output Voltage

DS012078-43

Output Impedance vs
Frequency

DS012078-44

Output Impedance vs
Frequency

DS012078-26

LP2980

www.national.com9

Typical Performance Characteristics Unless otherwise specified: T

A

= 25˚C, VIN=V

O(NOM)

+ 1V,

C

OUT

= 2.2 µF, all voltage options, ON/OFF pin tied to VIN. (Continued)

Output Noise Density

DS012078-27

Ripple Rejection

DS012078-25

Input to Output Leakage
vs Temperature

DS012078-28

Output Reverse Leakage vs
Temperature

DS012078-29

Turn-On Waveform

DS012078-30

Turn-Off Waveform

DS012078-31

LP2980

www.national.com 10

Typical Performance Characteristics Unless otherwise specified: T

A

= 25˚C, VIN=V

O(NOM)

+ 1V,

C

OUT

= 2.2 µF, all voltage options, ON/OFF pin tied to VIN. (Continued)

ON/OFF Pin Current vs V

ON/OFF

DS012078-45

LP2980

www.national.com11

Application Hints

OUTPUT CAPACITOR

Like any low-dropout regulator, the LP2980 requires an out­put capacitor tomaintain regulator loop stability. This capaci­tor must be selected to meet the requirements of minimum
capacitance andequivalent series resistance(ESR) range. It
is not difficult tofind capacitors which meet the criteria of the
LP2980, as the acceptable capacitance and ESRranges are
wider than for most other LDOs.

In general, the capacitor value must be at least 1 µF (over
the actual ambient operating temperature), and the ESR
must be withinthe 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 smallphysical size for the capacitancevalue,
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 µF. The value can be increased to

2.2 µF (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

. Ca-

pacitance values can be increased without limit.

Aluminum Electrolytic Capacitors

Although probablynot a goodchoice for aproduction 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 µF should be used,
and the ESR must meet the conditions of

Figures 1, 2

and

Figure 3

. If the operating temperature drops below 0˚C, 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 µF Surface-Mount Tantalums

Manufacturer Part Number

Kemet T491A105M010AS
NEC NRU105M10
Siemens B45196-E3105-K
Nichicon F931C105MA
Sprague 293D105X0016A2T

2.2 µF Surface-Mount Tantalums

Manufacturer Part Number

Kemet T491A225M010AS
NEC NRU225M06
Siemens B45196/2.2/10/10
Nichicon F930J225MA
Sprague 293D225X0010A2T

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-

times have ESR values lower than the minimum required by
the LP2980, and relatively large capacitance change with
temperature. The manufacturer’sdatasheet 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 µF is usually
needed forthe 5V regulator. Forthe lower outputvoltages, or
for better performance, a higher value should be used, such
as 4.7 µF.

Multilayer ceramic capacitors that have been verifiedas suit­able for use with the LP2980 are shown in

Table 3

.

TABLE 3. Surface-Mount Multilayer Ceramic Capacitor

Selection Guide

2.2 µF Surface-Mount Ceramic

Manufacturer Part Number

Tokin 1E225ZY5U-C203
Murata GRM42-6Y5V225Z16

4.7 µF Surface-Mount Ceramic

Manufacturer Part Number

Tokin 1E475ZY5U-C304

DS012078-48

FIGURE 1. 1 µF ESR Range

DS012078-49

FIGURE 2. 2.2 µF ESR Range

LP2980

www.national.com 12

Application Hints (Continued)

REVERSE CURRENT PATH

The power transistor used in the LP2980 has an inherent di­ode connected between the regulator input and output (see
below).

If the output is forced above the input by more than a V

BE

,
this diode will become forward biased and current will flow
from the V

OUT

terminal to VIN. No damageto 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 offby 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 V

IN

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/µs.

Important: theregulator shutdown functionwill operate incor­rectly if aslow-moving signal is applied tothe ON/OFF input.

Micro SMD Mounting

The micro SMD package requires specific mounting tech­niques which are detailed in National Semiconductor Appli­cation Note

#

1112. Referring to the section

Surface Mount

Technology (SMT) Assembly Considerations

, itshould be
noted that the pad style which must be used with the 5-pin
package is the NSMD (non-solder mask defined) type.

For best results during assembly, alignment ordinals on the
PC board may be used to facilitate placement of the micro
SMD device.

Micro SMD Light Sensitivity

Exposing the micro SMD device to direct sunlight will cause
misoperation of the device. Light sources such as Halogen
lamps can also affect electrical performance if brought near
to the device.

The wavelenghts which have the mostdetrimental effect are
reds and infra-reds, which means that the fluorescent light­ing used insidemost buildings has very littleeffect on perfor­mance. A micro SMD test board was brought to within 1 cm
of a fluorescent desk lamp and the effect on the regulated
output voltage was negligible, showing a deviation of less
than 0.1% from nominal.

DS012078-50

FIGURE 3. 10 µF ESR Range

DS012078-34

FIGURE 4. LP2980 Reverse Current Path

LP2980

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Typical Applications

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 voltageof this regu­lator is 6V. This “headroom” is the sum of the V

BE

of the ex-

ternal 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 V

IN

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 temperaturefor the specific application. If
a TO-92 transistor such as the MPS2907A is used, the ther­mal resistance from junction-to-ambient is 180˚C/W in still
air.

Assuming a maximum allowable junction temperature of
150˚C for the MPS2907A device, the following curves show
the maximum V

IN

and ILvalues that may be safely used for

several ambient temperatures.

With limited input voltage range, the LP2980 can control a

3.3V, 3A regulator with the use of a high current-gain exter­nal PNP passtransistorias 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,

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

DS012078-51

FIGURE 5. 5V/400mA Regulator

DS012078-52

FIGURE 6. Safe Operation Boundary Curves for

Figure

5

DS012078-53

FIGURE 7. 5V to 3.3V@3A Converter

LP2980

www.national.com 14

Typical Applications (Continued)

brought low, the converter will be in shutdown, and will draw
less than 1 µA 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 V

IN

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
60˚C/W, no heatsink is required (the TO-220 package alone
will safely dissipate this).

For these curves, amaximum junction temperature of 150˚C
is assumed for the pass transistor. The case-to-heatsink at-

tachment thermal resistance is assumed to be 1.5˚C/W. All
calculations are for 5.5V input voltage (which is worst-case
for power dissipation).

DS012078-54

FIGURE 8. Heatsink Thermal Resistance Requirements

for

Figure 7

LP2980

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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.

LP2980

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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

NOTES: UNLESS OTHERWISE SPECIFIED

1. EPOXY COATING

2. 63Sn/37Pb EUTECTIC BUMP

3. RECOMMEND NON-SOLDER MASK DEFINED LANDING PAD.

4. PIN 1 IS ESTABLISHED BY LOWER LEFT CORNER WITH RESPECT TO TEXT ORIENTATION. REMAINING PINS ARE
NUMBERED COUNTER CLOCKWISE.

5. XXX IN DRAWING NUMBER REPRESENTS PACKAGE SIZE VARIATION WHERE X1 IS PACKAGE WIDTH, X2 IS PACK­AGE LENGTH AND X3 IS PACKAGE HEIGHT.

6.NO JEDEC REGISTRATIONAS OF AUG.1999.

micro SMD, 5 Bump Package (BPA05)

NS Package Number BPA05A

For Order Numbers, refer to

Table 1

in the “Order Information” section of this document.

The dimensions for X1, X2 and X3 are as given:

X1 = 0.930 +/− 0.030mm
X2 = 1.107 +/− 0.030mm
X3 = 0.850 +/− 0.050mm

LP2980

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Notes

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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.

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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www.national.com

LP2980 Micropower 50 mA Ultra Low-Dropout Regulator

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.