LM1117IMPX-3.3 National Semiconductor, LM1117IMPX-3.3 Datasheet - Page 7

• Manufacturer Part Number: LM1117IMPX-3.3
• Description: IC,VOLT REGULATOR,FIXED,+3.3V,BIPOLAR,SOT-223,3PIN,PLASTIC
• Manufacturer: National Semiconductor

Specifications of LM1117IMPX-3.3

• Rohs Compliant: NO

Errors Caused by Adjust Pin Current
*Values of R2 greater than 1 MΩ may be inappropriate because of the difficultly associated with maintaining high impedances with surface mount resistors. In
particular, ionic PC board contaminants may limit the highest attainable on-board resistance figures that can be reliably maintained.
Conclusion
The presented method for calculating voltage tolerances in
adjustable regulators results in substantial improvements in
the available output voltage tolerance while maintaining tight
process control and a six sigma paradigm.
Complete understanding of the commonly used methods for
combining tolerances and sources of error is the only way to
get the most from any design.
I
I
I
adj
adj
adj
0.01
0.01
0.01
0.1
0.1
10
0.1
10
10
1
1
(µA)
1
(µA)
(µA)
1.8 MΩ*
900 kΩ
180 kΩ
1.8 kΩ
90 kΩ
900 Ω
18 kΩ
180 kΩ
1.8 V
1.8 V
1.8 kΩ
9 kΩ
18 kΩ
180 Ω
1.8 V
TABLE 3. Largest Sensible Values of R2 for Various I
For No More Than 0.5% Additional Error Select R
For No More Than 0.1% Additional Error Select R
For No More Than 1% Additional Error Select R
1.25 MΩ*
2.5 MΩ*
12.5 kΩ
1.25 kΩ
250 kΩ
125 kΩ
2.5 kΩ
25 kΩ
250 kΩ
2.5 V
2.5 kΩ
2.5 V
25 kΩ
250 Ω
2.5 V
3.3 MΩ*
330 kΩ
3.3 kΩ
1.65 MΩ*
33 kΩ
330 kΩ
3.3 V
3.3 kΩ
330 Ω
33 kΩ
16.5 kΩ
1.65 kΩ
3.3 V
165 kΩ
3.3 V
7
(Continued)
References
Mood, Alexander McFarlane, Franklin A. Graybill, and Duane
C. Boes, Introduction to the Theory of Statistics. n.p.:
McGraw-Hill, 1974.
Mathword,
mathworld.wolfram.com/topics/ContinuousDistributions.html
Cooper, George R. and Clare D. McGillem, Probabilistic
Methods of Signal and System Analysis. New York: Holt,
Rinehart and Winston, Inc., 1971.
Papoulis, Athanasios. Probability, Random Variables, and
Stochastic Processes. New York: McGraw-Hill, Inc., 1991
V
V
V
out
out
out
5.0 MΩ*
500 kΩ
500 kΩ
50 kΩ
5.0 V
50 kΩ
500 Ω
5 kΩ
5.0 V
5 kΩ
2.5 MΩ
250 kΩ
2.5 kΩ
25 kΩ
5.0 V
2
Continuous
2
2
Less Than:
Less Than:
Less Than:
adj
and V
12.0 MΩ*
1.2 MΩ*
1.2 MΩ*
120 kΩ
120 kΩ
12.0 V
12 kΩ
out
1.2 kΩ
12.0 V
12 kΩ
6.0 MΩ*
Distributions,
600 kΩ
12.0 V
60 kΩ
6 kΩ
2005,
15.0 MΩ*
1.5 MΩ*
1.5 MΩ*
7.5 MΩ*
150 kΩ
150 kΩ
15.0 V
15.0 V
1.5 kΩ
750 kΩ
15 kΩ
15 kΩ
15.0 V
7.5 kΩ
75 kΩ
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