LM2991 - Negative Low Dropout Adjustable Regulator
Datasheet Packaging Samples & Pricing Reliability Knowledge Base

Features
Output voltage adjustable from -3V to -24V, typically -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

General Description


The LM2991 is a low dropout adjustable negative regulator with a output voltage range between -3V to -24V. More...


Applications


Post switcher regulator
Local, on-card, regulation
Battery operated equipment
  Typical Application
click for larger image


ParametersValues
Output Current 1000 mA
Output Min -24 Volt
Input Min Voltage -26 Volt
Input Max Voltage 0.3 Volt
Dropout Voltage 0.6 Volt
Adjustable Output Yes
Quiescent Current 0.7 mA
On/Off Pin Yes
Error Flag No
RegType LDO
Temperature Min -40 deg C
Temperature Max 125 deg C
Output Max -3 Volt
Output Voltage Undefined Volt


Typical Performance


click for larger image


  Connection Diagram
click for larger image



Datasheet
RoHS Compliance Information Size in KbytesDate Click link below to Download
LM2991 Negative Low Dropout Adjustable Regulator 346
Kbytes
14-Sep-00 Download
LM2991 Negative Low Dropout Adjustable Regulator (Japanese)
168 Kbytes   Download
LM2991QML Negative Low Dropout Adjustable Regulator 682
Kbytes
10-Mar-06 Download

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Package Availability, Models, Samples & Pricing
Part NumberPackageFactory Lead TimeModelsSamples &
Electronic
Orders
Budgetary PricingStd
Pack
Size
Package
Marking
Format
TypePinsSpec.MSL
Rating
Peak
Reflow
RoHS
Report
CAD
Symbols
WeeksQtyQty$US each
LM2991TTO-2205NOPB
STD
1
1
NA
NA
RoHS N/A Full productionN/A
Samples
Buy Now
1K+$1.35rail
of
45
NSUZXYTTE#
LM2991T
P+
6 weeks500
LM2991STO-2635NOPB
STD
3
3
245
235
RoHS N/A Full productionN/A
Samples
Buy Now
1K+$1.35rail
of
45
NSUZXYTTE#
LM2991S
P+
6 weeks1000
LM2991SXTO-2635NOPB
STD
3
3
245
235
RoHS N/A Full productionN/A
 
Buy Now
1K+$1.35reel
of
500
NSUZXYTTE#
LM2991S
P+
6 weeks1000
LM2991 MD8Unpackaged DieLifetime buyN/A
  CALLtray
of
N/A
-
6 weeks7500
5962-9650501QXA
(LM2991WG-QML)
CERPACK16RoHS N/A Full productionN/A
 
Buy Now
50+$72.00tray
of
42
NSZSSXXYYA
LM2991WG-
QML Q 5962-
9650501QXA
10 weeks100

Obsolete Versions

Obsolete PartAlternate Part or SupplierSourceLast Time Buy Date
LM2991J-QML
NONE
NATIONAL SEMICONDUCTOR
03 Dec 2008
LM2991J-QMLV
NONE
NATIONAL SEMICONDUCTOR
03 Dec 2008
LM2991T MWC
NONE
NONE
08 Sep 1999

General Description


The LM2991 is a low dropout adjustable negative regulator with a output voltage range between -3V to -24V. 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 1 mA 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 9 mA (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. The LM2991 is available in 5-lead TO-220 and TO-263 packages and is rated for operation over the automotive temperature range of -40°C to +125°C. Mil-Aero versions are also available.

Reliability Metrics


Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
LM2991SSLM04404600353250011002356520
LM2991SXSLM04404600353250011002356520
LM2991TSLM04404600353250011002356520

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

For more information on Reliability Metrics, please click here.


[Information as of 8-Nov-2009]