The is a three-terminal, low dropout, 1 ampere negative voltage regulator available with fixed output voltages -5.2, -12, and -15V. The LM2990 uses new circuit design techniques to provide low dropout and low quiescent current. 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 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). Output voltage accuracy is guaranteed ± 5% over load, and temperature extremes. The LM2990 is short-circuit proof, and thermal shutdown includes hysteresis to enhance the reliability of the device when overloaded for an extended period of time. The LM2990 is available 3-lead TO-220 package and is rated for operation over the automotive temperature range to +125°C.
5% output accuracy over entire operating range Output current in excess of 1A Dropout voltage typically at 1A load Low quiescent current Internal short circuit current limit Internal thermal shutdown with hysteresis Functional complement to the LM2940 series
n Post switcher regulator n Local, on-card, regulation n Battery operated equipment
*Required if the regulator is located further than 6 inches from the power supply filter capacitors. 1 µF solid tantalum 10 µF aluminum electrolytic capacitor is recommended. **Required for stability. Must be at least 10 µF aluminum electrolytic 1 µF solid tantalum to maintain stability. May be increased without bound to maintain regulation during transients. Locate the capacitor as close as possible to the regulator. The equivalent series resistance (ESR) is critical, and should be less than 10 over the same operating temperature range as the regulator.
Front View Order Number or LM2990T-15 See NS Package Number T03B
Side View Order Number or LM2990S-15 See NS Package Number TS3B
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Input Voltage ESD Susceptibility (Note 2) Power Dissipation (Note 3) Junction Temperature (TJmax) 2 kV Internally Limited 125°C
Storage Temperature Lead Temperature (Soldering, 10 sec.)
Junction Temperature Range (TJ) Maximum Input Voltage (Operational) +125°C -26V
VIN -5V + VO(NOM) (Note = 47 µF, unless otherwise specified. Boldface limits apply over the entire operating temperature range, TJ 125°C, all other limits apply for 25°C. LM2990-5.0 Parameter Output Voltage (VO) Conditions IO 1A Line Regulation Load Regulation Dropout Voltage Quiescent Current (Iq) Short Circuit Current Maximum Output Current Ripple Rejection Output Noise Voltage Long Term Stability = 5 mA, VO(NOM) -1V > VIN = 1A, VIN = VO(NOM) = 1 (Note 7) (Note 7) Vripple = 1 Vrms, ripple = 1 kHz, 10 Hz100 kHz, mA 1000 Hours mV (max) V (max) V (max) mA (max) mA (max) A (min) A (min) dB (min) µV (max) ppm Typ (Note 4) Limit (Note LM2990-5.2 Typ (Note 4) Limit (Note -5.30 V (max) mV (min) V (max) V (min) mV (max) Units (Limit)
VIN -5V + VO(NOM) (Note = 47 µF, unless otherwise specified. Boldface limits apply over the entire operating temperature range, TJ 125°C, all other limits apply for 25°C. LM2990-12 Parameter Output Voltage (VO) Conditions IO 1A Line Regulation Load Regulation Dropout Voltage Quiescent Current (Iq) = 5 mA, VO(NOM) -1V > VIN = 1A, VIN = VO(NOM) mV (max) V (max) V (max) mA (max) mA (max) Typ (Note 4) Limit (Note LM2990-15 Typ (Note 4) Limit (Note -15.30 V (max) V (min) V (max) V (min) mV (max) Units (Limit)