LM2990S-12 National Semiconductor, LM2990S-12 Datasheet - Page 9
![Linear Voltage Regulator IC](/photos/19/7/190752/4243266_sml.jpg)
LM2990S-12
Manufacturer Part Number
LM2990S-12
Description
Linear Voltage Regulator IC
Manufacturer
National Semiconductor
Specifications of LM2990S-12
No. Of Pins
3
Output Current
1.5A
Termination Type
SMD
Mounting Type
Through Hole
Voltage Regulator Type
LDO Linear
Peak Reflow Compatible (260 C)
No
Supply Voltage
0.3V
Current Rating
1500A
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
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 margin, creating oscillations (refer to the graph on the
right). An input capacitor, of at least 1 µF solid tantalum or 10
µF aluminum 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
positive voltage transients up to 26V, without any current
limiting of the source. However, if the transients have a
9
duration of over 1 ms, the output should be clamped with a
Schottky diode to ground.
Output Capacitor ESR
01080109
www.national.com