LM2991J-QMLV datasheet(6/12 Pages) NSC

No de pièce	LM2991J-QMLV

Description	Negative Low Dropout Adjustable Regulator

Download	12 Pages

Scroll/Zoom	100%

Fabricant	NSC [National Semiconductor (TI)]

Site Internet	http://www.national.com

Logo

6 / 12 page

Application Hints (Continued)

MINIMUM LOAD

A minimum load current of 500 µA is required for proper op-

eration. The external resistor divider can provide the mini-

mum load, with the resistor from the adjust pin to ground set

to 2.4 k

Ω.

SETTING THE OUTPUT VOLTAGE

The output voltage of the LM2991 is set externally by a resis-

tor divider using the following equation:

V

OUT =VREF x(1+R2/R1)−(IADJ xR2)

where V

REF

= −1.21V. The output voltage can be pro-

grammed within the range of −3V to −24V, typically an even

greater range of −2V to −25V. The adjust pin current is about

60 nA, causing a slight error in the output voltage. However,

using resistors lower than 100 k

Ω makes the adjust pin cur-

rent negligible. For example, neglecting the adjust pin cur-

rent, and setting R2 to 100 k

Ω and V

OUT to −5V, results in an

output voltage error of only 0.16%.

ON/OFF PIN

The LM2991 regulator can be turned off by applying a TTL or

CMOS level high signal to the ON/OFF pin (see Adjustable

Current Sink Application).

FORCING THE OUTPUT POSITIVE

Due to an internal clamp circuit, the LM2991 can withstand

positive voltages on its output. If the voltage source pulling

the output positive is DC, the current must be limited to 1.5A.

A current over 1.5A fed back into the LM2991 could damage

the device. The LM2991 output can also withstand fast posi-

tive voltage transients up to 26V, without any current limiting

of the source. However, if the transients have a duration of

over 1 ms, the output should be clamped with a Schottky di-

ode to ground.

Typical Applications

Output Capacitor ESR Range

DS011260-5

Fully Isolated Post-Switcher Regulator

DS011260-6

www.national.com

6

Numéro de pièce similaire - LM2991J-QMLV

Fabricant	No de pièce	Fiches technique	Description
National Semiconductor ...	LM2991J-QMLV	338Kb / 11P	Negative Low Dropout Adjustable Regulator
National Semiconductor ...	LM2991J-QMLV	688Kb / 13P	Negative Low Dropout Adjustable Regulator

More results

Description similaire - LM2991J-QMLV

Fabricant	No de pièce	Fiches technique	Description
Texas Instruments	LM2991	1Mb / 19P	[Old version datasheet] Negative Low Dropout Adjustable Regulator
Texas Instruments	LM2991QML	414Kb / 15P	[Old version datasheet] Negative Low Dropout Adjustable Regulator
National Semiconductor ...	LM2991QML	688Kb / 13P	Negative Low Dropout Adjustable Regulator
National Semiconductor ...	LM2991	338Kb / 11P	Negative Low Dropout Adjustable Regulator
Texas Instruments	LM2991GW-QML	391Kb / 15P	[Old version datasheet] LM2991QML Negative Low Dropout Adjustable Regulator
	LM2991S	1Mb / 19P	[Old version datasheet] LM2991 Negative Low Dropout Adjustable Regulator
	LM2991	1Mb / 19P	[Old version datasheet] LM2991 Negative Low Dropout Adjustable Regulator
	LM2991S	1Mb / 19P	[Old version datasheet] LM2991 Negative Low Dropout Adjustable Regulator
Intersil Corporation	ISL72991RH	210Kb / 3P	Radiation Hardened Negative Low Dropout Adjustable Voltage Regulator
Renesas Technology Corp	ISL72991RH	562Kb / 15P	Radiation Hardened Low Dropout Adjustable Negative Voltage Regulator Jun 16, 2022

More results

LM2991J-QMLV Fiches technique(PDF) 6 Page - National Semiconductor (TI)

LM2991J-QMLV Fiches technique(HTML) 6 Page - National Semiconductor (TI)

Numéro de pièce similaire - LM2991J-QMLV

Description similaire - LM2991J-QMLV

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12

Fiches technique Télécharger

Lien URL