LM3411AM5-5.0/NOPB National Semiconductor, LM3411AM5-5.0/NOPB Datasheet - Page 10

• Manufacturer Part Number: LM3411AM5-5.0/NOPB
• Description: IC REG/DRIVER SECONDARY SOT23-5
• Manufacturer: National Semiconductor

Specifications of LM3411AM5-5.0/NOPB

• Reference Type: Shunt
• Voltage - Output: 5V
• Tolerance: ±0.5%
• Number Of Channels: 1
• Current - Cathode: 110µA
• Current - Output: 15mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-5, SC-74A, SOT-25
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Input: -
• Temperature Coefficient: -
• Current - Quiescent: -
• Other names: LM3411AM5-5.0/NOPBTR

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Applications Information
The output of a switching regulator typically will contain a
small ripple voltage at the switching frequency and may also
contain voltage transients. These transient voltage spikes
can be sensed by the LM3411 and could give an incorrect
Improved output voltage tolerance and regulation specifica-
tions are possible by combining the LM3411A with one of the
SIMPLE SWITCHER buck regulator IC’s, such as the
LM2574, LM2575, or LM2576. The circuit shown in Figure 5
can provide a 5V,
temperature range) without using any trim-pots or precision
resistors. Typical line regulation numbers are a 1 mV change
on the output for a 8V–18V change on the input, and load
regulation of 1 mV with a load change from 100 mA–1A.
A DC-DC flyback converter that accepts a negative input
voltage, and delivers either a positive or negative output is
shown in Figure 6. The circuit utilizes a buck regulator (such
as the LM2574, LM2575, or LM2576, depending on how
much output current is needed) operating in a flyback con-
figuration. The LM3411 provides the reference and the re-
quired level shifting circuitry needed to make the circuit work
correctly.
A unique feature of this circuit is the ability to ground either
the high or low side of the output, thus generating either a
±
0.5% Output (1% over the operating
FIGURE 6. Negative Input, Negative or Positive Output Flyback Regulator
FIGURE 5. Precision 1A Buck Regulator
(Continued)
10
regulation voltage. An RC filter consisting of a 1Ω resistor
and a 100 nF capacitor will filter these transients and mini-
mize this problem. The 1Ω resistor should be located on the
ground side of the LM3411, and the capacitor should be
physically located near the package.
negative or a positive output voltage. Although no isolation is
provided, with the addition of an opto-isolator and related
components, this circuit could provide input/output isolation.
Combining a LM3411A-5.0 with a 1A low dropout linear
regulator results in a 5V
temperature range) regulator with excellent regulation speci-
fications, with no trimming or 1% resistors needed.
An added benefit of this circuit (and also true of many of the
other circuits shown here) is the high-side and low-side
remote output voltage sensing feature. Sensing the output
voltage at the load eliminates the voltage drops associated
with wire resistance, thus providing near perfect load regu-
lation.
A 5V, 1A regulator circuit featuring low dropout, very good
regulation specifications, self protection features and allows
output voltage sensing is shown in Figure 7. The regulator
used is a LM2941 adjustable low dropout positive regulator,
which also features an ON/OFF pin to provide a shutdown
feature.
±
0.5% (1% over the operating
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