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 a self-heated reference. With less accurracy, you may go below that, but not by much. Reason one is the low noise buried Zener reference, reason two is the fact that the reference voltage can be noise filtered before going into the error amp.

Click here for a larger resolution picture … A lot of basic application circuits can be found in the LM datasheet. Extended Temperature Range available. For finding the value of output voltage for this circuit you can use the formula below:.

Which comparable ICs are so much better now? Error amp bias current. There is even an obsolete 80V version, the LCB. No wonder after 50 years, it is known what you may expect and what not. Compensation by the user. If we pragmatically summarize the pros and cons of this methusalem, we end up with something like this: A schematic with all suggestions implemented can be seen at the bottom of adtasheet page.

Silence or no reply. Also able to use as either linear or switching type regulator. This wastes some power, but speed, noise and other performance criteria are a lot better with a few volts across the pass transistor. Support for external pass transistorskeeping on-chip dissipation and therefore drift low.


National Semiconductor

The curves of the limiting transistors Vbe voltages over temperature in the Datashet datasheet should make it absolutely clear that no precision can be expected here.

Can serve as positive, negative, shunt, pass, floating or switching regulator or as a temperature controller. Pin configuration Pin No. The LM is not discontinued at all, sold by TI in the millions, available from all electronic distributors and dirt cheap. Email required Address never made public. Submitted by webmaster on 15 January They see this chip as an old-age part that has no merits today. You are commenting using your Twitter account.

The datasheet is not very instructive on this, but the floating regulator variants will fail to regulate when the load resistance becomes to high. Minimum dropout voltage is ca. It can able to provide a higher range of output voltage and current up to 10A by simply adding a series pass transistor with it, with having a wider range of operating temperature so the IC able to withstand for long.

Its comparing apples and oranges. A PNP pass transistor can further improve noise performance. Click here for a larger resolution picture …. They dont make this part anymore. I added a reference study that compares voltage regulator noise.

National Semiconductor – datasheet pdf

The current limiting feature is implemented as a transistor that is turned on by the voltage drop on a current sensing resistor. Gate parasitic suppression resistors of a few Ohms are also a good idea.

The load must be able to drain at least the supply current of the circuit without exhibiting a voltage higher than the desired output voltage. There are only better ones with low voltage 10V and less datawheet, and they cost a lot more than a LM Not a very high PSRR. Tempco is also very good, also when compared to newer chips. First, ST went out of the LM business. Current limiting sensitive to overload. The net and some manufacturers application notes are also a good source of information.


Intolerant to missing or misdesigned compensation. This cancels the error amps base bias currents.

A Collection of Proper Design Practices using the LM IC Regulator – Electronic Projects for Fun

When you ask for the same basic parameters 40V, mA, … there is simply no better IC today. The LM datasyeet translate to about 0. Notify me of new comments via email.

For your bread-and-butter PSU, they are still fine and noise is quite low. Before you specify a compensation cap, run a few tests using SPICE to see if gain and phase margins are in order.

Dayasheet interior design of an LM looks like this: If you use current limiting, protect the base of the limiting transistor by a 1K, e. Yes, it will oscillate if you forget or undercompensate. Take all datashheet into account, and make sure that the reference divider and the output sampling network present the same impedance to the error amplifier inputs. On a transistor level, you can see some design tricks by the legendary Bob Widlar: Naturally, it is frowned upon by a lot of designers that are just half as old.

One of the best low noise regulators even today when hooked up properly. This terminal is directly supplied from the supply when datasheeet connected to series pass transistor.