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.
|Published (Last):||15 July 2018|
|PDF File Size:||5.58 Mb|
|ePub File Size:||13.59 Mb|
|Price:||Free* [*Free Regsitration Required]|
A Collection of Proper Design Practices using the LM723 IC Regulator
This is due to the 7. The curves of the limiting transistors Vbe voltages over temperature in the LM datasheet should make it absolutely clear that no precision can be expected here.
The net and some manufacturers application notes are also a good source of information. TL — Programmable Reference Voltage.
Current limiting sensitive to overload. First, ST went out of the LM business. Input voltage goes up tp 40V constant, with 50V pulses allowed. You can tailor the frequency response to your application but you also have to do that because there is no internal compensation.
They dont make this part anymore. Especially when driving MOSFETs, you might need a bleeder resistor to make the falling edges fast enough for your needs. It can be found here. If you have a heavily overcompensated i. This terminal is directly supplied from the datasheeh when not connected to series pass transistor.
National Semiconductor – datasheet pdf
A schematic where all this has been implemented can be see below: No microscopic SMD cases available. For your bread-and-butter PSU, they are still fine and noise is quite low. No wonder after 50 years, it is known what lj723 may expect and what not. A PNP pass transistor can further improve noise performance. Fill in your details below or click an icon to log in: Submitted by webmaster on 15 January Which comparable ICs are so much better now?
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. From a power supply manufacturer I read some email correspondence with TI tech support where he also datasneet more drift in recent parts.
If you use current dztasheet, protect the base of the limiting transistor by a 1K, e. So, in case you have decided for an LM to make a good power supply, there are some rules of thumb that will make your life easier:.
If you need to regulate lower voltages, the LM chip itself needs a separate power input at 10V minimum. We have only a factor of ca. The LM values translate to about 0. Its comparing apples and oranges. Pin configuration Pin No. After some ping-pong TI recommended the MIL-spec part and guaranteed that this would be free from drift. Although the LM can dissipate a few mW and deliver up to mA, better use an external pass transistor to do the hard work and keep the regulator chip cool.
With less accurracy, you may go below that, but not by much. 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.
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. Before you specify a compensation cap, run a few tests using SPICE to see if gain and phase margins are in order.
Provide enough voltage headroom. Silence or no reply. Click here for a larger resolution picture …. I added a reference study that compares voltage regulator noise. Minimum Output for Floating Regulators. The LM is a classic, now available for 50 continuous years and still going strong. Both have been making s for decades, and after the sale TI took over the National Semiconductor designation of LM and used their own of uA Error amp bias current.
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. They see this chip as an old-age part that has no merits today. Minimum regulated output voltage is ca.
A schematic with all suggestions implemented can be seen at the bottom of this page.