Datasheet LP2987AIM-2.8 Datasheet (NSC)

Page 1

February 2002

LP2987/LP2988 Micropower, 200 mA Ultra Low-Dropout Voltage Regulator with Programmable Power-On Reset Delay; Low Noise Version Available (LP2988)

LP2987/LP2988 Micropower, 200 mA Ultra Low-Dropout Voltage Regulator with Programmable

Power-On Reset Delay

General Description

The LP2987/8 are fixed-output 200 mA precision LDO voltage regulators with power-ON reset delay which can be implemented using a single external capacitor.

The LP2988 is specifically designed for noise-critical applications. Asingleexternal capacitor connected to the Bypass pin reduces regulator output noise.

Using an optimized VIP cess, these regulators deliver superior performance:

Dropout Voltage: 180 mV load (typical).

Ground Pin Current: 1mA 10 mA load (typical).

Sleep Mode: The LP2987/8 draws less than 2 µA quiescent current when shutdown pin is held low.

Error Flag/Reset: The error flag goes low when the output drops approximately 5% below nominal. This pin also provides a power-ON reset signal if a capacitor is connected to the DELAY pin.

Precision Output: Standard product versions of the LP2987 and LP2988 are available with output voltages of 5.0V, 3.8V,

3.3V, 3.2V, 3.0V, or 2.8V, with guaranteed accuracy of 0.5% (“A” grade) and 1% (standard grade) at room temperature.

™

(Vertically Integrated PNP) pro-

200 mAload, and1 mV@1mA

200 mA load, and 200 µA

Block Diagrams

Features

n Ultra low dropout voltage n Power-ON reset delay requires only one component n Bypass pin for reduced output noise (LP2988) n Guaranteed continuous output current 200 mA n Guaranteed peak output current n SO-8 and mini SO-8 surface mount packages

2 µA quiescent current when shutdown

n Low ground pin current at all loads n 0.5% output voltage accuracy (“A” grade) n Wide supply voltage range (16V max)

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

250 mA

Applications

n Cellular Phone n Palmtop/Laptop Computer n Camcorder, Personal Stereo, Camera

10001701

10001702

VIP™is a trademark of National Semiconductor Corporation.

Page 2

Connection Diagram (LP2987)

Surface Mount Packages: 8-Lead LLP Surface Mount Package

LP2987/LP2988

Top View

SO-8/Mini SO-8 Package

See NS Package Drawing Number M08A/MUA08A

For ordering information, refer to

document.

10001703

Table 1

in this

Top View

See NS Package Drawing Number LDC08A

Ordering Information (LP2987)

TABLE 1. Package Marking and Ordering Information

Output Voltage Grade Order Information Package Marking Supplied as:

5 A LP2987AIMMX-5.0 L44A 3500 Units on Tape and

Reel

5 A LP2987AIMM-5.0 L44A 1000 Units on Tape and

Reel

5 STD LP2987IMMX-5.0 L44B 3500 Units on Tape and

Reel

5 STD LP2987IMM-5.0 L44B 1000 Units on Tape and

Reel

3.8 A LP2987AIMMX-3.8 L96A 3500 Units on Tape and Reel

3.8 A LP2987AIMM-3.8 L96A 1000 Units on Tape and Reel

3.8 STD LP2987IMMX-3.8 L96B 3500 Units on Tape and Reel

3.8 STD LP2987IMM-3.8 L96B 1000 Units on Tape and Reel

3.3 A LP2987AIMMX-3.3 L43A 3500 Units on Tape and Reel

3.3 A LP2987AIMM-3.3 L43A 1000 Units on Tape and Reel

3.3 STD LP2987IMMX-3.3 L43B 3500 Units on Tape and Reel

3.3 STD LP2987IMM-3.3 L43B 1000 Units on Tape and Reel

3.2 A LP2987AIMMX-3.2 L66A 3500 Units on Tape and Reel

3.2 A LP2987AIMM-3.2 L66A 1000 Units on Tape and Reel

3.2 STD LP2987IMMX-3.2 L66B 3500 Units on Tape and Reel

3.2 STD LP2987IMM-3.2 L66B 1000 Units on Tape and Reel

3.0 A LP2987AIMMX-3.0 L42A 3500 Units on Tape and Reel

10001757

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Page 3

Ordering Information (LP2987) (Continued)

TABLE 1. Package Marking and Ordering Information (Continued)

Output Voltage Grade Order Information Package Marking Supplied as:

3.0 A LP2987AIMM-3.0 L42A 1000 Units on Tape and Reel

3.0 STD LP2987IMMX-3.0 L42B 3500 Units on Tape and Reel

3.0 STD LP2987IMM-3.0 L42B 1000 Units on Tape and Reel

2.8 A LP2987AIMMX-2.8 L89A 3500 Units on Tape and Reel

2.8 A LP2987AIMM-2.8 L89A 1000 Units on Tape and Reel

2.8 STD LP2987IMMX-2.8 L89B 3500 Units on Tape and Reel

2.8 STD LP2987IMM-2.8 L89B 1000 Units on Tape and Reel

5 A LP2987AIMX-5.0 2987AIM5.0 2500 Units on Tape and

Reel

5 A LP2987AIM-5.0 2987AIM5.0 Shipped in Anti-Static

Rails

5 STD LP2987IMX-5.0 2987IM5.0 2500 Units on Tape and

Reel

5 STD LP2987IM-5.0 2987IM5.0 Shipped in Anti-Static

Rails

3.8 A LP2987AIMX-3.8 2987AIM3.8 2500 Units on Tape and Reel

3.8 A LP2987AIM-3.8 2987AIM3.8 Shipped in Anti-Static

Rails

3.8 STD LP2987IMX-3.8 2987IM3.8 2500 Units on Tape and Reel

3.8 STD LP2987IM-3.8 2987IM3.8 Shipped in Anti-Static

Rails

3.3 A LP2987AIMX-3.3 2987AIM3.3 2500 Units on Tape and Reel

3.3 A LP2987AIM-3.3 2987AIM3.3 Shipped in Anti-Static

Rails

3.3 STD LP2987IMX-3.3 2987IM3.3 2500 Units on Tape and Reel

3.3 STD LP2987IM-3.3 2987IM3.3 Shipped in Anti-Static

Rails

3.2 A LP2987AIMX-3.2 2987AIM3.2 2500 Units on Tape and Reel

3.2 A LP2987AIM-3.2 2987AIM3.2 Shipped in Anti-Static

Rails

3.2 STD LP2987IMX-3.2 2987IM3.2 2500 Units on Tape and Reel

3.2 STD LP2987AIM-3.2 2987IM3.2 Shipped in Anti-Static

Rails

3.0 A LP2987IMX-3.0 2987AIM3.0 2500 Units on Tape and Reel

3.0 A LP2987AIM-3.0 2987AIM3.0 Shipped in Anti-Static

Rails

LP2987/LP2988

www.national.com3

Page 4

Ordering Information (LP2987) (Continued)

TABLE 1. Package Marking and Ordering Information (Continued)

Output Voltage Grade Order Information Package Marking Supplied as:

3.0 STD LP2987IMX-3.0 2987IM3.0 2500 Units on Tape and

LP2987/LP2988

3.0 STD LP2987IM-3.0 2987IM3.0 Shipped in Anti-Static

2.8 A LP2987AIMX-2.8 2987AIM2.8 2500 Units on Tape and

2.8 A LP2987AIM-2.8 2987AIM2.8 Shipped in Anti-Static

2.8 STD LP2987IMX-2.8 2987IM2.8 2500 Units on Tape and

2.8 STD LP2987AIM-2.8 2987AIM2.8 Shipped in Anti-Static

8-Lead LLP

5 A LP2987AILD-5 L009A 1000 Units on Tape and

5 A LP2987AILDX-5 L009A 4500 Units on Tape and

5 STD LP2987ILD-5 L009AB 1000 Units on Tape and

5 STD LP2987ILDX-5 L009AB 4500 Units on Tape and

3.3 A LP2987AILD-3.3 L008A 1000 Units on Tape and

3.3 A LP2987AILDX-3.3 L008A 4500 Units on Tape and

3.3 STD LP2987ILD-3.3 L008AB 1000 Units on Tape and

3.3 STD LP2987ILDX-3.3 L008AB 4500 Units on Tape and

3.0 A LP2987AILD-3.0 L007A 1000 Units on Tape and

3.0 A LP2987AILDX-3.0 L007A 4500 Units on Tape and

3.0 STD LP2987ILD-3.0 L007AB 1000 Units on Tape and

3.0 STD LP2987ILDX-3.0 L007AB 4500 Units on Tape and

Reel

Rails

Reel

Rails

Reel

Rails

Reel

www.national.com 4

Page 5

Connection Diagram (LP2988)

Surface Mount Packages: 8-Lead LLP Surface Mount Package

LP2987/LP2988

Top View

SO-8/Mini SO-8 Package

See NS Package Drawing Number M08A/MUA08A

For ordering information, refer to

document.

10001703

Table 1

in this

Top View

10001758

See NS Package Drawing Number LDC08A

Ordering Information (LP2988)

TABLE 2. Package Marking and Ordering Information

Output Voltage Grade Order Information Package Marking Supplied as:

5.7 A LP2988AIMMX-5.7 LF2A 3500 Units on Tape and Reel

5.7 A LP2988AIMM-5.7 LF2A 1000 Units on Tape and Reel

5.7 STD LP2988IMMX-5.7 LF2B 3500 Units on Tape and Reel

5.7 STD LP2988IMM-5.7 LF2B 1000 Units on Tape and Reel

5.0 A LP2988AIMMX-5.0 L51A 3500 Units on Tape and Reel

5.0 A LP2988AIMM-5.0 L51A 1000 Units on Tape and Reel

5.0 STD LP2988IMMX-5.0 L51B 3500 Units on Tape and Reel

5.0 STD LP2988IMM-5.0 L51B 1000 Units on Tape and Reel

3.8 A LP2988AIMMX-3.8 L0AA 3500 Units on Tape and Reel

3.8 A LP2988AIMM-3.8 L0AA 1000 Units on Tape and Reel

3.8 STD LP2988IMMX-3.8 L0AB 3500 Units on Tape and Reel

3.8 STD LP2988IMM-3.8 L0AB 1000 Units on Tape and Reel

3.3 A LP2988AIMMX-3.3 L50A 3500 Units on Tape and Reel

3.3 A LP2988AIMM-3.3 L50A 1000 Units on Tape and Reel

3.3 STD LP2988IMMX-3.3 L50B 3500 Units on Tape and Reel

3.3 STD LP2988IMM-3.3 L50B 1000 Units on Tape and Reel

3.2 A LP2988AIMMX-3.2 L67A 3500 Units on Tape and Reel

3.2 A LP2988AIMM-3.2 L67A 1000 Units on Tape and Reel

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Page 6

Ordering Information (LP2988) (Continued)

TABLE 2. Package Marking and Ordering Information (Continued)

Output Voltage Grade Order Information Package Marking Supplied as:

3.2 STD LP2988IMMX-3.2 L67B 3500 Units on Tape and

LP2987/LP2988

3.2 STD LP2988IMM-3.2 L67B 1000 Units on Tape and

3.0 A LP2988AIMMX-3.0 L49A 3500 Units on Tape and

3.0 A LP2988AIMM-3.0 L49A 1000 Units on Tape and

3.0 STD LP2988IMMX-3.0 L49B 3500 Units on Tape and

3.0 STD LP2988IMM-3.0 L49B 1000 Units on Tape and

2.8 A LP2988AIMMX-2.8 L0IA 3500 Units on Tape and

2.8 A LP2988AIMM-2.8 L0IA 1000 Units on Tape and

2.8 STD LP2988IMMX-2.8 L0IB 3500 Units on Tape and

2.8 STD LP2988IMM-2.8 L0IB 1000 Units on Tape and

2.7 A LP2988AIMMX-2.7 LCVA 3500 Units on Tape and

2.7 A LP2988AIMM-2.7 LCVA 1000 Units on Tape and

2.7 STD LP2988IMMX-2.7 LCVB 3500 Units on Tape and

2.7 STD LP2988IMM-2.7 LCVB 1000 Units on Tape and

2.5 A LP2988AIMMX-2.5 L99A 3500 Units on Tape and

2.5 A LP2988AIMM-2.5 L99A 1000 Units on Tape and

2.5 STD LP2988IMMX-2.5 L99B 3500 Units on Tape and

2.5 STD LP2988IMM-2.5 L99B 1000 Units on Tape and

5.0 A LP2988AIMX-5.0 2988AIM5.0 2500 Units on Tape and

5.0 A LP2988AIM-5.0 2988AIM5.0 Shipped in Anti-Static

5.0 STD LP2988IMX-5.0 2988IM5.0 2500 Units on Tape and

5.0 STD LP2988IM-5.0 2988IM5.0 Shipped in Anti-Static

3.8 A LP2988AIMX-3.8 2988AIM3.8 2500 Units on Tape and

3.8 A LP2988AIM-3.8 2988AIM3.8 Shipped in Anti-Static

3.8 STD LP2988IMX-3.8 2988IM3.8 2500 Units on Tape and

Reel

Rails

Reel

Rails

Reel

Rails

Reel

www.national.com 6

Page 7

Ordering Information (LP2988) (Continued)

TABLE 2. Package Marking and Ordering Information (Continued)

Output Voltage Grade Order Information Package Marking Supplied as:

3.8 STD LP2988IM-3.8 2988IM3.8 Shipped in Anti-Static

Rails

3.3 A LP2988AIMX-3.3 2988AIM3.3 2500 Units on Tape and Reel

3.3 A LP2988AIM-3.3 2988AIM3.3 Shipped in Anti-Static

Rails

3.3 STD LP2988IMX-3.3 2988IM3.3 2.5k Units on Tape and Reel

3.3 STD LP2988IM-3.3 2988IM3.3 Shipped in Anti-Static

Rails

3.2 A LP2988AIMX-3.2 2988AIM3.2 2500 Units on Tape and Reel

3.2 A LP2988AIM-3.2 2988AIM3.2 Shipped in Anti-Static

Rails

3.2 STD LP2988IMX-3.2 2988IM3.2 2500 Units on Tape and Reel

3.2 STD LP2988IM-3.2 2988IM3.2 Shipped in Anti-Static

Rails

3.0 A LP2988AIMX-3.0 2988AIM3.0 2500 Units on Tape and Reel

3.0 A LP2988AIM-3.0 2988AIM3.0 Shipped in Anti-Static

Rails

3.0 STD LP2988IMX-3.0 2988IM3.0 2500 Units on Tape and Reel

3.0 STD LP2988IM-3.0 2988IM3.0 Shipped in Anti-Static

Rails

2.8 A LP2988AIMX-2.8 2988AIM2.8 2500 Units on Tape and Reel

2.8 A LP2988AIM-2.8 2988AIM2.8 Shipped in Anti-Static

Rails

2.8 STD LP2988IMX-2.8 2988IM2.8 2500 Units on Tape and Reel

2.8 STD LP2988IM-2.8 2988IM2.8 Shipped in Anti-Static

Rails

2.7 A LP2988AIMX-2.7 2988AIM2.7 2500 Units on Tape and Reel

2.7 A LP2988AIM-2.7 2988AIM2.7 Shipped in Anti-Static

Rails

2.7 STD LP2988IMX-2.7 2988IM2.7 2500 Units on Tape and Reel

2.7 STD LP2988IM-2.7 2988IM2.7 Shipped in Anti-Static

Rails

2.5 A LP2988AIMX-2.5 2988AIM2.5 2500 Units on Tape and Reel

2.5 A LP2988AIM-2.5 2988AIM2.5 Shipped in Anti-Static

Rails

2.5 STD LP2988IMX-2.5 2988IM2.5 2500 Units on Tape and Reel

2.5 STD LP2988IM-2.5 2988IM2.5 Shipped in Anti-Static

Rails

LP2987/LP2988

www.national.com7

Page 8

Ordering Information (LP2988) (Continued)

TABLE 2. Package Marking and Ordering Information (Continued)

Output Voltage Grade Order Information Package Marking Supplied as:

8-Lead LLP

LP2987/LP2988

5 A LP2988AILD-5 L01DA 1000 Units on Tape and

5 A LP2988AILDX-5 L01DA 4500 Units on Tape and

5 STD LP2988ILD-5 L01DAB 1000 Units on Tape and

5 STD LP2988ILDX-5 L01DAB 4500 Units on Tape and

3.3 A LP2988AILD-3.3 L01CA 1000 Units on Tape and

3.3 A LP2988AILDX-3.3 L01CA 4500 Units on Tape and

3.3 STD LP2988ILD-3.3 L01CAB 1000 Units on Tape and

3.3 STD LP2988ILDX-3.3 L01CAB 4500 Units on Tape and

3.0 A LP2988AILD-3.0 L01BA 1000 Units on Tape and

3.0 A LP2988AILDX-3.0 L01BA 4500 Units on Tape and

3.0 STD LP2988ILD-3.0 L01BAB 1000 Units on Tape and

3.0 STD LP2988ILDX-3.0 L01BAB 4500 Units on Tape and

2.5 A LP2988AILD-2.5 L01AA 1000 Units on Tape and

2.5 A LP2988AILDX-2.5 L01AA 4500 Units on Tape and

2.5 STD LP2988ILD-2.5 L01AAB 1000 Units on Tape and

2.5 STD LP2988ILDX-2.5 L01AAB 4500 Units on Tape and

Reel

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Page 9

LP2987/LP2988

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 −65˚C to +150˚C Operating Junction

Temperature Range −40˚C to +125˚C

Lead Temperature

(Soldering, 5 seconds) 260˚C

Input Supply Voltage

(Operating) 2.1V to +16V Shutdown Pin −0.3V to +16V Sense Pin −0.3V to +6V Output Voltage

(Survival) (Note 4) −0.3V to +16V I

(Survival) Short Circuit Protected

OUT

Input-Output Voltage

(Survival) (Note 5) −0.3V to +16V

ESD Rating (Note 2) 2 kV Power Dissipation (Note 3) Internally Limited Input Supply Voltage

(Survival) −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: V

Symbol Parameter Conditions Typical

∆V

Output Voltage Tolerance

Output Voltage Line Regulation

IN–VO

Dropout Voltage (Note 7)

GND

(PK) Peak Output Current V

(MAX) Short Circuit Current RL= 0 (Steady State)

Ground Pin Current IL= 100 µA

LP2987 Output Noise Voltage (RMS)

LP2988 Output Noise Voltage (RMS)

Ripple Rejection f = 1 kHz, C

(NOM) + 1V, IL= 1 mA, C

IN=VO

0.1 mA<I

VO(NOM) + 1V ≤ VIN≤ 16V

IL= 100 µA

=75mA

= 200 mA

=75mA

= 200 mA

S/D OUT

(Note 10) BW = 300 Hz to

50 kHz, V C

OUT

BW = 300 Hz to 50 kHz, V

OUT

BYPASS

BYP

= 4.7 µF, CIN= 2.2 µF, V

OUT

LM2987/8AI-X.X

(Note 6)

S/D

= 2V.

LM2987/8I-X.X

(Note 6)

Min Max Min Max

−0.5 0.5 −1.0 1.0

200 mA −0.8 0.8 −1.6 1.6

−1.8 1.8 −2.8 2.8

0.014 0.014

0.007

180

100

500

0.3V 0.05 1.5 1.5 µA

0.032 0.032

2.0 2.0

3.5 3.5

120 120

170 170

230 230

350 350

120 120

150 150

800 800

1400 1400

2.1 2.1

3.7 3.7

≥ VO(NOM) − 5% 400 250 250

400

OUT

= 3.3V

100

=10µF

= 3.3V =10µF

= .01 µF

=10µF

OUT

= 0 (LP2988)

65 dB

µV(RMS)

Units

NOM

%/V

µA

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Page 10

Electrical Characteristics (Continued)

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

Symbol Parameter Conditions Typical

LP2987/LP2988

Output Voltage Temperature Coefficient

(NOM) + 1V, IL= 1 mA, C

IN=VO

(Note 9)

= 4.7 µF, CIN= 2.2 µF, V

OUT

LM2987/8AI-X.X

20 ppm/˚C

= 2V.

S/D

LM2987/8I-X.X

(Note 6)

Min Max Min Max

Units

DELAY

Delay Pin Current Source

2.2

1.6 2.8 1.6 2.8

1.4 3.0 1.4 3.0

SHUTDOWN INPUT

S/D

S/D Input Voltage (Note 8)

S/D Input Current V

VH= O/P ON 1.4 1.6 1.6

= O/P OFF 0.55 0.18 0.18

=0 0 −1 −1

S/D

=5V 5 15 15

S/D

ERROR COMPARATOR

THR

(MAX) V

THR

(MIN)

Output “HIGH” Leakage VOH= 16V

Output “LOW” Voltage VIN=VO(NOM) − 0.5V,

(COMP) = 300 µA

Upper Threshold Voltage

Lower Threshold Voltage

0.01

150

−4.6

−6.6

220 220

350 350

−5.5 −3.5 −5.5 −3.5

−7.7 −2.5 −7.7 −2.5

−8.9 −4.9 −8.9 −4.9

−13.0 −3.3 −13.0 −3.3

HYST Hysteresis 2.0

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 the Bypass pin is 500V (LP2988 only.) Note 3: The maximum allowable power dissipation is a function of the maximum junction temperature, T

and the ambient temperature, T

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

(MAX), the junction-to-ambient thermal resistance, θ

µA

OUT

J−A

The value of θ dependent on PCB trace area, trace material, and the number of layers and thermal vias. For improved thermal resistance and power dissipation for the LLP package, refer toApplicationNoteAN-1187.Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulatorwillgo into thermal shutdown.

Note 4: If used in a dual-supply system where the regulator load is returned to a negative supply, the LM2987/8 output must be diode-clamped to ground. Note 5: The output PNP structure contains a diode between the V

on this diode and may induce a latch-up mode which can damage the part (see Application Hints). Note 6: Limits are 100% production tested at 25˚C. Limits over the operating temperature range are guaranteed through correlation using Statistical 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: To prevent mis-operation, the Shutdown input must be driven by a signal that swings above V

Application Hints).

Note 9: Temperature coefficient is defined as the maximum (worst-case) change divided by the total temperature range. Note 10: See Typical Performance Characteristics curves.

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for the SO-8 (M) package is 160˚C/W, and the mini SO-8 (MM) package is 200˚C/W. The value θ

J−A

and V

terminals that is normally reverse-biased. Forcing the output above the input will turn

OUT

and below VLwith a slew rate not less than 40 mV/µs (see

for the LLP (LD) package is specifically

J−A

Page 11

LP2987/LP2988

Typical Performance Characteristics Unless otherwise specified: T

= 2.2 µF, S/D is tied to VIN,VIN=VO(NOM) + 1V, IL= 1 mA.

vs Temperature Dropout Voltage vs Temperature

OUT

10001717

Dropout Voltage vs Load Current Dropout Characteristics

= 25˚C, C

OUT

= 4.7 µF,

10001718

Ground Pin Current vs Temperature and Load

10001719

10001721

10001720

Ground Pin Current vs

Load Current

10001722

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Page 12

Typical Performance Characteristics Unless otherwise specified: T

= 2.2 µF, S/D is tied to VIN,VIN=VO(NOM) + 1V, IL= 1 mA. (Continued)

= 25˚C, C

OUT

= 4.7 µF,

LP2987/LP2988

Input Current vs V

10001723

Input Current vs V

Load Transient Response Load Transient Response

10001724

10001725 10001726

Line Transient Response Line Transient Response

10001727 10001728

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Page 13

LP2987/LP2988

Typical Performance Characteristics Unless otherwise specified: T

= 2.2 µF, S/D is tied to VIN,VIN=VO(NOM) + 1V, IL= 1 mA. (Continued)

Turn-On Waveform Turn-On Waveform

10001729

Short Circuit Current Short Circuit Current

= 25˚C, C

OUT

= 4.7 µF,

10001730

Short Circuit Current

vs Output Voltage

10001731 10001732

Instantaneous Short Circuit Current

vs Temperature

10001733

10001734

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Page 14

Typical Performance Characteristics Unless otherwise specified: T

= 2.2 µF, S/D is tied to VIN,VIN=VO(NOM) + 1V, IL= 1 mA. (Continued)

LP2987/LP2988

DC Load Regulation

= 25˚C, C

OUT

Shutdown Pin Current vs

Shutdown Pin Voltage

= 4.7 µF,

Shutdown Voltage

vs Temperature

Delay Pin Current vs V

10001735

10001737

10001736

Input to Output Leakage

vs Temperature

10001738

Delay Pin Current vs

Delay Pin Voltage

10001745

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10001748

Page 15

LP2987/LP2988

Typical Performance Characteristics Unless otherwise specified: T

= 2.2 µF, S/D is tied to VIN,VIN=VO(NOM) + 1V, IL= 1 mA. (Continued)

Delay Sink Current

vs Temperature Delay Sink Current vs Temperature

10001747 10001746

Output Impedance vs Frequency Output Impedance vs Frequency

= 25˚C, C

OUT

= 4.7 µF,

10001740 10001741

Ripple Rejection (LP2987) Ripple Rejection (LP2988)

10001742

10001751

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Page 16

Typical Performance Characteristics Unless otherwise specified: T

= 2.2 µF, S/D is tied to VIN,VIN=VO(NOM) + 1V, IL= 1 mA. (Continued)

= 25˚C, C

OUT

= 4.7 µF,

LP2987/LP2988

Output Noise Density (LP2987) Output Noise Voltage (LP2988)

10001739

Output Noise Density (LP2988) Output Noise Density (LP2988)

10001744

10001752 10001753

Turn-On Time (LP2988) Turn-On Time (LP2988)

10001754

10001755

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Page 17

LP2987/LP2988

Typical Performance Characteristics Unless otherwise specified: T

= 2.2 µF, S/D is tied to VIN,VIN=VO(NOM) + 1V, IL= 1 mA. (Continued)

Turn-On Time (LP2988)

10001756

Basic Application Circuits

= 25˚C, C

OUT

= 4.7 µF,

10001705

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Page 18

Basic Application Circuits (Continued)

LP2987/LP2988

*Capacitance value shown is minimum required to assure stability, but may be increased without limit. Larger output capacitor provides improved dynamic

response. **Shutdown must be actively terminated (see Application Hints). Tie to INPUT (pin 4) if not used.

10001706

Application Hints

LLP Package Devices

The LP2987/LP2988 is offered in the 8 lead LLP surface mount package to allow for increased power dissipation compared to the SO-8 and Mini SO-8. For details on thermal performance as well as mounting and soldering specifications, refer to Application Note AN-1187.

EXTERNAL CAPACITORS

As with any low-dropout regulator, external capacitors are required to assure stability. These capacitors must be correctly selected for proper performance.

INPUT CAPACITOR: An input capacitor (≥ 2.2 µF) is re- quired between the LP2987/8 input and ground (amount of capacitance may be increased without limit).

This capacitor must be located a distance of not more than

0.5” from the input pin and returned to a clean analog ground. Any good quality ceramic or tantalum may be used for this capacitor.

OUTPUT CAPACITOR:The output capacitor must meet the requirement for minimum amount of capacitance and also have an appropriate E.S.R. (equivalent series resistance) value.

Curves are provided which show the allowable ESR range as a function of load current for 3V and 5V outputs.

ESR Curves For 5V Output

10001707

ESR Curves For 3V Output

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10001708

Page 19

Application Hints (Continued)

IMPORTANT: The output capacitor must maintain its ESR in

the stable region

the application

The minimum required amount of output capacitance is

4.7 µF. Output capacitor size can be increased without limit. It is important to remember that capacitor tolerance and

variation with temperature must be taken into consideration when selecting an output capacitor so that the minimum required amount of output capacitance is provided over the full operating temperature range. A good Tantalum capacitor will show very little variation with temperature, but a ceramic may not be as good (see next section).

The output capacitor should be located not more than 0.5” from the output pin and returned to a clean analog ground.

CAPACITOR CHARACTERISTICS TANTALUM: Asolid tantalum capacitor is the best choice for

the output capacitor on the LM2987/8. Available from many sources, their typical ESR is very close to the ideal value required on the output of many LDO regulators.

Tantalums also have good temperature stability: a 4.7 µF was tested and showed only a 10% decline in capacitance as the temperature was decreased from +125˚C to −40˚C. The ESR increased only about 2:1 over the same range of temperature.

However,it should be noted that the increasing ESR at lower temperatures present in all tantalums can cause oscillations when marginal quality capacitors are used (where the ESR of the capacitor is near the upper limit of the stability range at room temperature).

CERAMIC: The ESR of ceramic capacitor can be low enough to cause an LDO regulator to oscillate: a 2.2 µF ceramic was measured and found to have an ESR of 15 mΩ.

If a ceramic capacitor is to be used on the LP2987/8 output, a1Ωresistor should be placed in series with the capacitor to provide a minimum ESR for the regulator.

A disadvantage of ceramic capacitors is that their capacitance varies a lot with temperature: Large ceramic capacitors are typically manufactured with the Z5U temperature characteristic, which results in the capacitance dropping by 50% as the temperature goes from 25˚C to 80˚C.

This means you have to buy a capacitor with twice the minimum C

ALUMINUM: The large physical size of aluminum electrolytics makes them unsuitable for most applications. Their ESR characteristics are also not well suited to the requirements of LDO regulators. The ESR of a typical aluminum electrolytic is higher than a tantalum, and it also varies greatly with temperature.

A typical aluminum electrolytic can exhibit an ESR increase of 50X when going from 20˚C to −40˚C. Also, some aluminum electrolytics can not be used below −25˚C because the electrolyte will freeze.

over the full operating temperature range of

to assure stability.

to assure stable operation up to 80˚C.

OUT

POWER-ON RESET DELAY

A power-on reset function can be easily implemented using the LP2987/8 by adding a single external capacitor to the Delay pin. The Error output provides the power-on reset signal when input power is applied to the regulator.

The reset signal stays low for a pre-set time period after power is applied to the regulator, and then goes high (see Timing Diagram below).

Timing Diagram for Power-Up

10001709

The external capacitor c

sets the delay time (T

DLY

DELAY

The value of capacitor required for a given time delay may be calculated using the formula:

DLY=TDELAY

/(5.59 X 105)

To simplify design, a plot is provided below which shows values of C

versus delay time.

DLY

Plot of C

DLY

vs T

10001711

DELAY

LP2987/LP2988

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Page 20

Application Hints (Continued)

DETAILS OF ERR/RESET CIRCUIT OPERATION: (Refer

to LP2987/8 Equivalent Circuit).

LP2987/LP2988

LP2987/8 Equivalent Circuit

The output of comparator U2 is the ERR/RESET flag. Since it is an open-collector output, it requires the use of a pull-up resistor (R input of U2, which means that its output is controlled by the voltage applied to the non-inverting input.

The output of U1 (also an open-collector) will force the non-inverting input of U2 to go low whenever the LP2987/8 regulated output drops about 5% below nominal.

U1’s inverting input is also held at 1.23V. The other input samples the regulated output through a resistive divider (R and RB). When the regulated output is at nominal voltage, the voltage at the divider tap point will be 1.23V. If this voltage drops about 60 mV below 1.23V, the output of U1 will go low forcing the output of U2 low (which is the ERROR state).

Power-ON reset delay occurs when a capacitor (shown as C

DLY

tor is initially fully discharged (which means the voltage at the Delay pin is 0V). The output of U1 keeps C discharged (by sinking the 2.2 µA from the current source) until the regulator output voltage comes up to within about 5% of nominal. At this point, U1’s output stops sinking current and the 2.2 µA starts charging up C

When the voltage across C U2 will go high (note that D1 limits the maximum voltage to about 2V).

SELECTING C this capacitor is 1 µF. The capacitor must not have excessively high leakage current, since it is being charged from a

2.2 µA current source.

). The 1.23V reference is tied to the inverting

) is connected to the Delay pin. At turn-ON, this capaci-

DLY

reaches 1.23V, the output of

DLY

: The maximum recommended value for

DLY

10001710

fully

Aluminum electrolytics can not be used, but good-quality tantalum, ceremic, mica, or film types will work.

SHUTDOWN INPUT OPERATION

The LP2987/8 is shut off by driving the Shutdown input low, and turned on by pulling it high. If this feature is not to be used, the Shutdown input should be tied to V

to keep the

regulator output on at all times. To assure proper operation, the signal source used to drive

the Shutdown input must be able to swing above and below the specified turn-on/turn-off voltage thresholds listed as V

and VL, respectively (see Electrical Characteristics). It is also important that the turn-on (and turn-off) voltage

signals applied to the Shutdown input have a slew rate which is not less than 40 mV/µs.

CAUTION:

the regulator output state can not be guaranteed if a slow-moving AC (or DC) signal is applied that is in the range between V

and VL.

REVERSE INPUT-OUTPUT VOLTAGE

The PNP power transistor used as the pass element in the LP2987/8 has an inherent diode connected between the regulator output and input.

During normal operation (where the input voltage is higher than the output) this diode is reverse-biased.

However, if the output is pulled above the input, this diode will turn ON and current will flow into the regulator output.

In such cases, a parasitic SCR can latch which will allow a high current to flow into V

(and out the ground pin), which

can damage the part. In any application where the output may be pulled above the

input, an external Schottky diode must be connected from V

to V

(cathode on VIN, anode on V

OUT

), to limit the

OUT

reverse voltage across the LP2987/8 to 0.3V (see Absolute Maximum Ratings).

BYPASS CAPACITOR (LP2988)

The capacitor connected to the Bypass pin 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. Since the Bandgap circuit has only a few microamps flowing in it, loading effects due to leakage current will cause a change in the regulated output voltage.

Curves are provided which show the effect of loading the Bypass pin on the regulated output voltage.

Care must be taken to ensure that the capacitor selected for bypass will not have significant leakage current over the operating temperature range of the application.

A high quality ceramic capacitor which uses either NPO or COG type dielectiric material will typically have very low leakage. Small surface-mount polypropolene or polycarbonate film capacitors also have extremely low leakage, but are slightly larger in size than ceramics.

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Page 21

Application Hints (Continued)

LP2987/LP2988

10001749

10001750

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Page 22

Physical Dimensions inches (millimeters)

unless otherwise noted

LP2987/LP2988

Mini SO-8 Package Type MM

NS Package Number MUA08A

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Page 23

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

LP2987/LP2988

SO-8 Package Type M

NS Package Number M08A

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Page 24

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

Power-On Reset Delay

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.

National Semiconductor Corporation

Americas Email: support@nsc.com

LP2987/LP2988 Micropower, 200 mA Ultra Low-Dropout Voltage Regulator with Programmable

www.national.com

8-Lead LLP Surface Mount Package

NS Package Number LDC08A

National Semiconductor Europe

Fax: +49 (0) 180-530 85 86

Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790

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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Tel: 65-2544466 Fax: 65-2504466 Email: ap.support@nsc.com

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Tel: 81-3-5639-7560 Fax: 81-3-5639-7507

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.