LM2990S-12/NOPB National Semiconductor, LM2990S-12/NOPB Datasheet - Page 9
![IC REGULATOR NEG LDO TO-263](/photos/12/65/126593/ts3b_sml.jpg)
LM2990S-12/NOPB
Manufacturer Part Number
LM2990S-12/NOPB
Description
IC REGULATOR NEG LDO TO-263
Manufacturer
National Semiconductor
Datasheet
1.LM2990S-5.0NOPB.pdf
(14 pages)
Specifications of LM2990S-12/NOPB
Regulator Topology
Negative Fixed
Voltage - Output
-12V
Voltage - Input
Down to -26V
Voltage - Dropout (typical)
0.6V @ 1A
Number Of Regulators
1
Current - Output
1.8A
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
TO-263-3, D²Pak (3 leads + Tab), TO-263AA
Number Of Outputs
1
Polarity
Negative
Input Voltage Max
0.3 V
Output Voltage
- 12 V
Output Type
Fixed
Dropout Voltage (max)
0.3 V at 100 mA
Output Current
1.8 A (Typ)
Line Regulation
60 mV
Load Regulation
50 mV
Voltage Regulation Accuracy
+/- 5 %
Maximum Operating Temperature
+ 125 C
Mounting Style
SMD/SMT
Minimum Operating Temperature
- 40 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Current - Limit (min)
-
Lead Free Status / Rohs Status
Details
Other names
*LM2990S-12
*LM2990S-12/NOPB
LM2990S-12
*LM2990S-12/NOPB
LM2990S-12
Application Hints
EXTERNAL CAPACITORS
The LM2990 regulator requires an output capacitor to main-
tain stability. The capacitor must be at least 10 μF aluminum
electrolytic or 1 μF solid tantalum. The output capacitor's ESR
must be less than 10Ω, or the zero added to the regulator
frequency response by the ESR could reduce the phase mar-
gin, creating oscillations (refer to the graph on the right). An
input capacitor, of at least 1 μF solid tantalum or 10 μF alu-
minum electrolytic, is also needed if the regulator is situated
more than 6 from the input power supply filter.
FORCING THE OUTPUT POSITIVE
Due to an internal clamp circuit, the LM2990 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 LM2990 could damage
the device. The LM2990 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
9
over 1 ms, the output should be clamped with a Schottky
diode to ground.
Output Capacitor ESR
1080109
www.national.com