LM2991 MDC - National Semiconductor

Original Creation Date: 09/06/95

Last Update Date: 09/22/00

Last Major Revision Date: 08/16/00

MNLM2991-X REV 1A1 MICROCIRCUIT DATA SHEET

NEGATIVE LOW DROPOUT ADJUSTABLE REGULATOR

General Description

The LM2991 is a low dropout adjustable negative regulator with a output voltage range

between -2V to -25V. The LM2991 provides up to 1A of load current and features a ON/Off

pin for remote shutdown capability.

The LM2991 uses new circuit design techniques to provide a low dropout voltage, low

quiescent current and low temperature coefficient precision reference. The dropout voltage

at 1A load current is typically 0.6V and a guaranteed worst-case maximum of 1V over the

entire operating temperature range. The quiescent current is typically 1mA with a 1A load

current and an input-output voltage differential greater than 3V. A unique circuit design

of the internal bias supply limits the quiescent current to only 9mA (typical) when the

regulator is in the dropout mode (Vout - Vin < 3V).

The LM2991 is short-circuit proof, and thermal shutdown includes hysteresis to enhance the

reliability of the device when inadvertently overloaded for extended periods.

NS Part Numbers

LM2991J-QML

LM2991J-QMLV

LM2991WG-QML

Industry Part Number

LM2991

Prime Die

LM2991

Controlling Document

SEE FEATURES SECTION

Processing

MIL-STD-883, Method 5004

Quality Conformance Inspection

MIL-STD-883, Method 5005

Subgrp Description Temp ( C)

1 Static tests at +25

2 Static tests at +125

3 Static tests at -55

4 Dynamic tests at +25

5 Dynamic tests at +125

6 Dynamic tests at -55

7 Functional tests at +25

8A Functional tests at +125

8B Functional tests at -55

9 Switching tests at +25

10 Switching tests at +125

11 Switching tests at -55

MICROCIRCUIT DATA SHEET

MNLM2991-X REV 1A1

Features

- Output voltage adjustable from -2V to -25V

- Output current in excess of 1A

- Dropout voltage typically 0.6V at 1A load

- Low quiescent current

- Internal short circuit current limit

- Internal thermal shutdown with hysteresis

- TTL, CMOS compatible ON/OFF switch

- Functional complement to the LM2941 series

CONTROLLING DOCUMENTS:

LM2991J-QML 5962-9650501QEA

LM2991J-QMLV 5962-9650501VEA

LM2991WG-QML 5962-9650501QXA

Applications

- Post switcher regulator

- Local, on-card, regulation

- Battery operated equipment

MICROCIRCUIT DATA SHEET

MNLM2991-X REV 1A1

(Absolute Maximum Ratings)

(Note 1)

Input Voltage -26V to +0.3V

Power Dissipation

(Note 2, 3) Internally Limited

Operating Temperature Range (Tj) -55 C to +125 C

Maximum Junction Temperature (Tjmax) 150 C

Storage Temperature Range -65 C < Ta < +150 C

Thermal Resistance

(Note 3)

ThetaJA 75 C/W CERAMIC DIP (Still Air @ 0.5 C/W) 35 C/W (500LF/Min Air flow @ 0.5 C/W) 119 C/W CERAMIC SOIC (Still Air @ 0.5 C/W) 73 C/W (500LF/Min Air flow @ 0.5 C/W)

ThetaJC 5 C/W CERAMIC DIP 3 C/W CERAMIC SOIC

Package Weight TBD(Typical)

Lead Temperature 260 C(Soldering, 10 seconds)

ESD Susceptibility

(Note 4) 1.5kV

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.

Operating Ratings indicate conditions for which the device is functional, but do not

guarantee specific performance limits. For guaranteed specifications and test

conditions, see the Electrical Characteristics. The guaranteed specification apply

only for the test conditions listed. Some performance characteristics may degrade

when the device is not operated under the listed test conditions.

Note 2: The maximum power dissipation must be derated at elevated temperatures and is

dictated by Tjmax (maximum junction temperature), ThetaJA (package junction to

ambient thermal resistance), and TA (ambient temperature). The maximum allowable

power dissipation at any temperature is Pdmax = (Tjmax -TA)/ThetaJA or the number

given in the Absolute Maximum Ratings, whichever is lower. If this dissipation is

exceeded, the die temperature will rise above 125 C and the LM2991 will go into

thermal shutdown.

Note 3: The package material for these devices allows much improved heat transfer over our

standard ceramic packages. In order to take full advantage of this improved heat

transfer, heat sinking must be provided between the package base (directly beneath

the die), and either metal traces on, or thermal vias through, the printed circuit

board. Without this additional heat sinking, device power dissipation must be

calculated using junction-to-ambient, rather than junction-to-case, thermal

resistance. It must not be assumed that the device leads will provide substantial

heat transfer out of the package, since the thermal resistance of the leadframe

material is very poor, relative to the material of the package base. The stated

junction-to-case thermal resistance is for the package material only, and does not

account for the additional thermal resistance between the package base and the

printed circuit board. The user must determine the value of the additional thermal

resistance and must combine this with the stated value for the package, to calculate

the total allowed power dissipation for the device.

Note 4: Human body model, 100pF discharge through a 1.5K Ohms resistor.

MICROCIRCUIT DATA SHEET

MNLM2991-X REV 1A1

Recommended Operating Conditions

(Note 1)

Maximum Input Voltage (Operational) -26V

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.

Operating Ratings indicate conditions for which the device is functional, but do not

guarantee specific performance limits. For guaranteed specifications and test

conditions, see the Electrical Characteristics. The guaranteed specifications apply

only for the test conditions listed. Some performance characteristics may degrade

when the device is not operated under the listed test conditions.

MNLM2991-X REV 1A1 MICROCIRCUIT DATA SHEET

Electrical Characteristics

DC PARAMETERS

(The following conditions apply to all the following parameters, unless otherwise specified.)

DC: Vin = -10V, Vo = -3V, Io = 1A, Co = 47uF, R1 = 2.7K, Tj = 25 C

SYMBOL PARAMETER CONDITIONS NOTES PIN-

NAME MIN MAX UNIT SUB-

GROUPS

Vref Reference Voltage 5mA < Io < 1A -1.234 -1.186 V 1

5mA < Io < 1A, Vo - 1V > Vin > -26V -1.27 -1.15 V 2, 3

Vout Output Voltage

Range -3 V 1

Vin = -26V -24 V 1

+25 V 2, 3

VRLN Line Regulation Io = 5mA, Vo - 1V > Vin > -26V -26 +26 mV 1, 2,

VRLD Load Regulation 50mA < Io < 1A -12 +12 mV 1

-15 +15 mV 2, 3

V DO Dropout Voltage Io = 0.1A, Delta Vo < 100mV 0.2 V 1

Io = 0.1A, Delta Vo < 100mV 0.3 V 2, 3

Io = 1A, Delta Vo < 100mV 0.8 V 1

Io = 1A, Delta Vo < 100mV 1 V 2, 3

I q Quiescent Current Io < 1A 5 mA 1, 2,

Dropout Quiescent

Current Vin = Vo, Io < 1A 50 mA 1, 2,

R R Ripple Rejection Vripple = 1Vrms, Fripple = 1KHz,

Io = 5mA 50 dB 1

V O N Output Noise 10Hz - 100KHz, Io = 5mA 450 uV 1

500 uV 2, 3

ON/OFF Input

Voltage (Vout:ON) 0.8 V 1, 2,

ON/OFF Input

Voltage (Vout:OFF) 2.4 V 1, 2,

ON/OFF Input

Current VON/OFF = 0.8V (Vout:ON) 10 uA 1

ON/OFF Input

Current VON/OFF = 0.8V (Vout:ON) 25 uA 2, 3

ON/OFF Input

Current VON/OFF = 2.4V (Vout:OFF) 100 uA 1

ON/OFF Input

Current VON/OFF = 2.4V (Vout:OFF) 150 uA 2, 3

I l Output Leakage

Current Vin = -26V, VON/OFF = 2.4V, Vout = 0V 250 uA 1

300 uA 2, 3

MNLM2991-X REV 1A1 MICROCIRCUIT DATA SHEET

Electrical Characteristics

DC PARAMETERS(Continued)

(The following conditions apply to all the following parameters, unless otherwise specified.)

DC: Vin = -10V, Vo = -3V, Io = 1A, Co = 47uF, R1 = 2.7K, Tj = 25 C

SYMBOL PARAMETER CONDITIONS NOTES PIN-

NAME MIN MAX UNIT SUB-

GROUPS

I Limit Current Limit Vout = 0V 1.5 2.5 A 1

1.0 4.0 A 2, 3

DC PARAMETERS: DRIFT VALUES

(The following conditions apply to all the following parameters, unless otherwise specified.)

DC: Vin = -10V, Vo = -3V, Io = 1A, Co = 47uF, R1 = 2.7K, Tj = 25 C "Deltas not required on B-Level product.

Deltas required for S-Level product ONLY as specified on Internal Processing Instructions (IPI)"

Vref Reference Voltage 5mA < Io < 1A + 20 mV 1

Graphics and Diagrams

GRAPHICS# DESCRIPTION

06323HRB3 CERDIP (J), 16 LEAD (B/I CKT)

06349HRA2 CERPACK (W), 16 LEAD (B/I CKT)

J16ARL CERDIP (J), 16 LEAD (P/P DWG)

P000384A CERAMIC SOIC (WG), 16 LEAD (PINOUT)

P000388A CERDIP (J), 16 LEAD (PINOUT)

WG16ARC CERAMIC SOIC (WG), 16 LEAD (P/P DWG)

See attached graphics following this page.

MIL/AEROSPACE OPERATIONS

2900 SEMICONDUCTOR DRIVE

SANTA CLARA, CA 95050

1 16

2 15

3 14

4 13

5 12

6 11

7 10

N/C

GROUND

N/C

OUTPUT

N/C

INPUT

16 - LEAD CERAMIC SOIC

LM2991WG

TOP VIEW

CONNECTION DIAGRAM

P000384A

8 9

N/C N/C

ADJUST

N/C N/C

N/C

ON/OFF

MIL/AEROSPACE OPERATIONS

2900 SEMICONDUCTOR DRIVE

SANTA CLARA, CA 95050

1 16

9 N/C

N/C

ADJ

N/C

INPUT

ON/OFF

N/C

GND

OUTPUT

LM2991J

16 - LEAD DIP

CONNECTION DIAGRAM

TOP VIEW

P000388A

MICROCIRCUIT DATA SHEET

MNLM2991-X REV 1A1

Revision History

Rev ECN # Rel Date Originator Changes

0B0 M0001490 05/19/98 Barbara Lopez Changed: MNLM2991-X Rev. 0A0 to MNLM2991-X Rev. 0B0.

Added power dissipation note for Aluminum Nitride

package.

0C1 M0002862 12/15/98 Barbara Lopez Updated MDS: MNLM2991-X Rev. 0B0 to MNLM2991-X Rev.

0C1. Added WG package to MDS. Updated B/I CKT and

Pinout for J package. Added WG package graphics. Added

Package Weight to Absolute section.

0D1 M0003138 09/22/00 Rose Malone Update MDS: MNLM2991-X, Rev. 0C1 to MNLM2991-X, Rev.

0D1.

1A1 M0003741 09/22/00 Rose Malone Updated MDS: MNLM2991-X, Rev. 0D1 to MNLM2991-X, Rev.

1A1. Re-format to Features Section, Absolute Section.

Added Drift Value Table to Electrical Section.