L M September 2000 2 9 1 N e LM2991 g a Negative Low Dropout Adjustable Regulator i e General Description Features The LM2991 is a low dropout adjustable negative regulatorn Output voltage adjustable from −3V to −24V, typically o with
true LDO” current-limiting transistor Q 3 pos: LT1764A/LT1963 (BJT); TPS744xx (CMOS) neg: LT1175, LM2991 (BJT); TPS7A3xxx (CMOS) GND 3-term current reference pos: LT3080 V Z –Vout 9.3.2 Three-terminal fixed regulators Q 2 + The original (and often good enough) 3-terminal regula- – Q 1 tor is the 78xx series
