LM2991

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




Application

·Post switcher regulator
·Local, on-card, regulation
·Battery operated equipment




Pinout






Specifications

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
View Using Catalog

Input Voltage −26V to +0.3V
ESD Susceptibility (Note 2) 2kV
Power Dissipation (Note 3) Internally limited
Junction Temperature (T_Jmax) 125
Storage Temperature Range−65°C to +150
Lead Temperature (Soldering, 10 sec.) 230




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 (V_OUT - V_IN <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)
LM2991S	SLM	0	42786	0	0	3352500	2	951281028
LM2991SX	SLM	0	42786	0	0	3352500	2	951281028
LM2991T	SLM	0	42786	0	0	3352500	2	951281028

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.




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.