LM is an adjustable voltage regulator IC used for shunt regulator, current regulator, and temperature controller. The LM LMC is a voltage regulator designed primar- ily for series regulator applications By itself it will supply output currents up to mA but external. Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. 2All trademarks are the property of their respective.
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Its comparing apples and oranges. People used to 3-terminal regulators are in for a culture shock caused by the amount of design aspects to consider. Relying on a buried Zener low noise reference, it can compete with a lot of newer chips when it comes to stability it does dagasheet a long term stability rating in the datasheet, few new chips have that.
Extended Temperature Range available. Tempco is also very good, also when compared to newer chips. They dont make this part anymore. The current limiting feature is implemented as a transistor that is turned on by the voltage drop on a current sensing resistor.
You can tailor the frequency response to your application but you also have to do that because there is no internal compensation. They see this lm7223 as an old-age part that has datashfet merits today. The dataeheet design of an LM looks like this: On a transistor level, you can see some design tricks by the legendary Bob Widlar: Provide enough voltage headroom.
First, ST went out of the LM business. If we pragmatically summarize the pros and cons of this methusalem, we end up with something like this: This is due to the 7. So, in case you have decided for an LM to make a good power supply, datasueet are some rules of thumb that will make your life easier:.
For getting an output voltage range from 2v to 7v you can use the circuit below, which is a Basic Voltage Regulator circuit using LM voltage regulator IC.
The LM values translate to about 0. This wastes some power, but speed, noise and other performance criteria are a lot better with a few volts across the pass transistor. This also acts as a soft start feature. The performance of an LM is not bad at all, especially for noise and long term stability. Leave a Reply Cancel reply Enter your comment here Current limiting sensitive to overload.
No microscopic SMD datasyeet available. The LM is a classic, now available for 50 continuous years and still going strong.
Email required Address never made public. Support for external pass transistorskeeping on-chip dissipation and therefore drift low.
Compensation by the user. From a power supply manufacturer I read some email correspondence with TI tech support where he also claimed more drift in recent parts.
If you want precision current control, dont try to do this with a pot sampling a fraction of voltage across a shunt measurement resistor. Can serve as positive, negative, shunt, pass, floating or switching regulator or as a temperature controller.
Which comparable ICs are so much better now? The LM is not discontinued at all, sold by TI in the millions, available from all electronic distributors and dirt cheap. As I found out and others did as well their consumer parts where a bit drifty within spec limitsprobably by a conversion to a new manufacturing process with not just improvements as a consequence. A lot of basic application circuits can be found in the LM datasheet.
LM Datasheet(PDF) – National Semiconductor (TI)
If you use current limiting, protect the base of the limiting transistor by a 1K, e. The superbeta bipolars in the error amp have a low, but nonzero bias current that can cause voltage shifts of a few millivolts across voltage divider or RC filter resistors. Naturally, it is frowned upon by a lot of designers that are just half as old.
The curves of the limiting transistors Pm723 voltages over temperature in datwsheet LM datasheet should make it absolutely clear that no precision can be expected here. There are only better ones with low voltage 10V and lessand they cost a lot more than a LM The way to go is either high side sensing with an op amp that can do that, or a floating design like the famous Elektor one from lm732 x LM, 2 x LM Pin configuration Pin No.
If you have a heavily overcompensated i. Minimum Output for Floating Regulators.