LMT/NOPB Texas Instruments Switching Voltage Regulators 3A STEP- DOWN VLTG REG datasheet, inventory, & pricing. High-Efficiency 3A Battery Chargers Use LM Regulators (Rev. B) · Link · Input and Output Capacitor. LMWU Microchip Technology / Micrel Switching Voltage Regulators 3A Step-Down SMPS Regulator datasheet, inventory, & pricing. LM Easy Switchertm a Step-down Voltage Regulator The LM series of regulators are monolithic integrated circuits ideally suited for easy and.
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Written by Lim Siong Boon, last dated Dec LMTO package. Suitable only for very low power application. This is a very simple and useful adjustable voltage regulator. Suitable for application that requires low noise. Suitable for application that requires high power. Schematic, PCB layout and component list are available on this page.
LM2576M1K-5.0 Datasheet PDF
LM circuits perform same function as the commonly known voltage regulator LM from National Semiconductor. The voltage regulator dissipates a lot heat. The higher input voltage, the more heat is generated. The extra input energy is converted to heat, keeping the output voltage regulated at 5V.
LM78XX series is available to regulate 5, 6, 8, 9, 12, 15, 18, 24V. If you want the output voltage adjustable, there is also a adj model. For -negative voltage supply, you can use LM79xx series. These regulator is able to support up to a maximum of 1A current rating. LM IC requires input voltage to be higher than output in order to regulate the output voltage.
Input voltage needs to be at least 7V up to a maximum of 20V in order for LM to regulate at an output of 5V. It is advisable to supply a voltage input range from 7.
A switching mode power supply such as LM dc-dc converter, uses switching control to reduce the input dc voltage on average. This is equivalent to a lower input voltage resulting in minimum heat dissipated. The control results in better regulated output, less energy wasted through heat and the use for high current application.
Nowadays dc-dc converter are getting smaller and comes in the TO package too. You can simply change your LM to dc-dc converter without any change in your design.
It is very good and easy to use.
LM Datasheet(PDF) – Motorola, Inc
However it is very big and bulky. If size is a constraint, you might consider the model SDM However it generates a lot of heat through its metal casing. It is by far the most compact smaller than SDM and most efficient dc-dc.
Heat is also dissipated through it ceramic package, however it does not scalded your finger as much as SDM do. The IC package is surface mount however soldering is relatively easy because the IC leads are quite broad.
It is rated at output 5Vdc 16A and generate far less heat. Through some research, I get to learn about commercial standard dc-dc IC that perform with only a few external components.
There are also various brand of dc-dc regulator IC available.
The interfacing of most dc-dc IC requires the use of inductor. This is the case for LM too. Try sourcing your local electronics shop for one if possible. I am not stopping you to make your own inductor. Just that making your own inductor takes up time and it is very likely to cost you more than what a shop might be selling. If you are interested in making your own coil, you might interested in this website, http: The aurthor Jeff Mucha had demonstrated a simple and creative way to make inductive.
One Long screw, 2 board flat washer, 2 nut, 1 ring spacer, glue, and XXX is all the tools that is require to make your own air core inductor. It is really interesting. Jens Moller has contributed a program which generate a table of information for building air core inductor.
Simply input the inductance value you need, the program will display a table containing the wire coil height radius and number of turns required. You need not have to understand formula to make your own inductor. Take a look at the following website, http: A greenhorn when I first attempt to use inductor.
It is a tough job building circuits using inductor. I do not have proper equipment to measure the inductor on hand. Never able to find out the inductance value I have. Fortunately, there is this inductance measurement product selling at an affordable price. It also function as a multi-meter, and can be used to measure voltage, current, etc Even with an inductance meter, it is not a easy task to measure inductance accurately.
Typical LED requires about 2V to operate. This ciruict is able to drive the LED from a 1. The transistor forms the oscillating circuit generating pulsing output. Although the output is pulsing, we can’t actually see it on the LED, as the switching is quite fast. There a variety of capacitors out there in the market. Capacitance, voltage rating, dielectric material, etc Choose a suitable voltage rating across the capacitor.
The circuits deals with high current, therefore it will be better to choose a low ESR equivalent series resistance Aluminum electrolytic capacitor. As a general guide, a higher voltage rating has lower ESR rating. The inductor coil use should be able to handle the current passing through the inductor coil. If the wire is too thin, the coil may be burn or just fail. My previous circuit uses small wattage inductor package like a big resistor. The circuit couldn’t work and was later found to be IC problem.
I have not yet do a test to check on the possibility of the inductor contributing to the failure.
LM2576-5.0 Datasheet PDF
Using a inductor meter to measure the inductance will be easier. Inductance value can be observe immediately for any modification to the coil of wire. Lm5276-5.0 inductance value can also be calculated, depend on the coil size, number of turns, wire size lm256-5.0, dielectric of the core etc Dataxheet 1N is a high current, high speed, schottky diode and is suitable for this digital switching circuit.
Schottky diode Schottky Barrier Rectifiermeans that the forward voltage drop is low. For this application, a low forward voltage diode is necessary. Failure, my first prototype circuit to test out the performance of LM, LM Some of the various sizes of inductor tested and seems to be working with LM Initially I thought that I had use the wrong type of inductor, resulting in the circuit malfunction.
Initially I had used a smaller type of inductor looks dafasheet a resistor. Realizing that this circuit drive high current load, I should use a thicker inductor coil. That’s why I modified the circuit with an inductor enamelled wire, wound around the ferrite core.
LMWT – Microchip – PCB Footprint & Symbol Download
Still it doesn’t work. The capacitor used is suspected because the datasheet call for low ESR capacitor.
It is very difficult to find these in the local shops, therefore I use a normal capacitor instead. One day, I visited a shop selling ready made inductors and brought LM at the same time. The circuit was rebuild and it finally works.
My deduction at that time was either the inductor or the capacitor is giving me the problem. After further testing, I find out that ordinary capacitor works as well. There is hardly any difference in performance. Various type of inductor were tested except the resistor like type. All inductor works too, big or small. Quite weird actually, and I couldn’t figure it out the actual problem I had in my previous attempt.
The mystery is resolve finally. One fine day I went back to the shop where I first purchase my LM and brought 2 additional LM for more testing. A new circuit was build and the familiar failure was observed. The output voltage of 5V cannot be sustain and eventually drop when more than 1A of current is draw by the load. The lab power supply display a current loading limit warning. IC becomes very hot. Both brand new IC are tested to have the same problem.
This is weird, as the same inductor and capacitor previously tested do not result in this same old problem. However the circuit shows the same failure symptom.