Prices are subject to change without notice. Our expert team have over 25 years experience solving problems and providing expert advice. Adk answer for both topic is yes. The Intertek calibration certificates include: The Intertek calibration service provides the assurance that your instruments perform as stated in the datasheet. If the detected deviation is too large in relation to factory specification, adjustment of your data logger or measuring instrument will be required.

Author:Fenribei Kizragore
Language:English (Spanish)
Published (Last):11 November 2018
PDF File Size:11.85 Mb
ePub File Size:4.57 Mb
Price:Free* [*Free Regsitration Required]

The LM is available in four fixed voltage, 1. Additionally it is also available in adjustable version. Current limit is also trimmed to ensure specified output current and controlled short-circuit current. Output 3.

VOUT 1. C Figure 2. Temperature Stability Frequency Hz Figure 3. Minimum Load Current Adjustable Temperature? C Figure 5. Dropout V oltage vs. Output Current Ambient Temperature? C Figure 7. Temperature April. AC Load Current 0. Load Transient Response Figure 9. This bypass capacitor prevents ripple from being amplified as the output voltage is increased.

Output Capacitor The output capacitor is critical in maintaining regulator stability, and must meet the required conditions for both minimum amount of capacitance and ESR Equivalent Series Resistance. Any increase of the output capacitance will merely improve the loop stability and transient response. The ESR of the output capacitor should be less than 0. Output Voltage The LM adjustable version develops a 1.

As shown in Figure 10, this voltage is applied across resistor R1 to generate a constant current I1. The current IADJ from the adjust terminal could introduce error to the output.

The constant current I1 then flows through the output set resistor R2 and sets the output voltage to the desired level. For fixed voltage devices, R1 and R2 are integrated inside the devices. Basic Adjustable Regulator Load Regulation The LM regulates the voltage that appears between its output and ground pins, or between its output and adjust pins. In some cases, line resistances can introduce errors to the voltage across the load. To obtain the best load regulation, a few precautions are needed.

Figure 11, shows a typical application using a fixed output regulator. The Rt1 and Rt2 are the line resistances. In this case, the load regulation seen at the RLOAD would be degraded from the data sheet specification. To improve this, the load should be tied directly to the output terminal on the positive side and directly tied to the ground terminal on the negative side. Typical Application using Fixed Output Regulator When the adjustable regulator is used Figure 12 , the best performance is obtained with the positive side of the resistor R1 tied directly to the output terminal of the regulator rather than near the load.

This eliminates line drops from appearing effectively in series with the reference and degrading regulation. For example, a 5V regulator with 0. In addition, the ground side of the resistor R2 can be returned near the ground of the load to provide remote ground sensing and improve load regulation.

With the adjustable device, the internal resistance between the adjust and output terminals limits the current. No diode is needed to divert the current around the regulator even with capacitor on the adjust terminal. When an output capacitor is connected to a regulator and the input is shorted to ground, the output capacitor will discharge into the output of the regulator. The discharge current depends on the value of the capacitor, the output voltage of the regulator, and rate of decrease of VIN.

In the LM regulators, the internal diode between the output and input pins can withstand microsecond surge currents of 10A to 20A. In this case, an external diode is recommended between the output and input pins to protect the regulator, as shown in Figure Regulator With Protection Diode Heat sink Requirements When an integrated circuit operates with an appreciable current, its junction temperature is elevated.

It is important to quantify its thermal limits in order to achieve acceptable performance and reliability. This limit is determined by summing the individual parts consisting of a series of temperature rises from the semiconductor junction to the operating environment. A one-dimensional steady-state model of conduction heat transfer is demonstrated in Figure The heat generated at the device junction flows through the die to the die attach pad, through the lead frame to the surrounding case material, to the printed circuit board, and eventually to the ambient environment.

Below is a list of variables that may affect the thermal resistance and in turn the need for a heat sink. Cross-sectional view of integrated circuit mounted on a printed circuit board.

Note that the case temperature is measured at the point where the leads contact with the mounting pad surface The LM regulators have internal thermal shutdown to protect the device from overheating. A heat sink may be required depending on the maximum power dissipation and maximum ambient temperature of the application. Top Side in? Figure Adjustable- Voltage Model April. TYP 3?









Related Articles