Protection features include cycle-by-cycle current limit, thermal shutdown, and frequency fold back at short circuit. Connect a 10nF between this pin and SW. Input Supply. Bypass this pin to G with a low ESR capacitor. See Input Capacitor in Application Information section. Switch Output.
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Protection features include cycle-bycycle current limit, thermal shutdown, and frequency foldback at short circuit. Active Solutions. Input Supply. Bypass this pin to G with a low ESR capacitor. See Input Capacitor in the Application Information section. Switch Output. Connect this pin to the switching end of the inductor. Feedback Input. The voltage at this pin is regulated to 1. Connect to the resistor divider between output and ground to set output voltage.
Compensation Pin. See Stability Compensation in the Application Information section. Enable Input. When higher than 1. When lower than 0. Output voltage is discharged when the IC is off. When left unconnected, EN is pulled up to 4. A pull-up current. Not Connected. Exposure to absolute maximum rating conditions for long periods may affect device reliability. The converter operates as follows: A switching cycle starts when the rising edge of the Oscillator clock output causes the High-Side Power Switch to turn on and the Low-Side Power Switch to turn off.
With the SW side of the inductor now connected to IN, the inductor current ramps up to store energy in the magnetic field. The inductor current level is measured by the Current Sense Amplifier and added to the Oscillator ramp signal. At this point, the SW side of the inductor swings to a diode voltage below ground, causing the inductor current to decrease and magnetic energy to be transferred to output. This state continues until the cycle starts again. Current limit happens when COMP reaches its maximum clamp value of 2.
The Oscillator normally switches at kHz. However, if FB voltage is less than 0. When EN is less than 0. When EN is higher than 1. Note that EN is a low voltage input with a maximum voltage of 6V, it should never be directly connected to IN. Innovative Products. A low ESR capacitor is highly recommended.
Since large current flows in and out of this capacitor during switching, its ESR also affects efficiency. The input capacitance needs to be higher than 10? The input capacitor should be placed close to the IN and G pins of the IC, with the shortest traces possible.
In the case of tantalum or electrolytic types, they can be further away if a small parallel 0. F ceramic capacitor is placed right next to the IC. R FB1? This inductor current has a ripple that is dependent on the inductance value: higher inductance reduces the peak-to-peak ripple current. The trade off for high inductance value is the increase in inductor core size and series resistance, and the reduction in current handling capability.
In general, select an inductance value L based on ripple current requirement:? VIN 28? Make sure that this peak inductor current is less that the 3A current limit. Finally, select the inductor core size so that it does not saturate at 3A. Typical inductor values for various output voltages are shown in Table 1. In the case of ceramic output capacitors, RESR is very small and does not contribute to the ripple.
Therefore, a lower capacitance value can be used for ceramic type. In the case of tantalum or electrolytic capacitors, the ripple is dominated by RESR multiplied by the ripple current. In that case, the output capacitor is chosen to have sufficiently low ESR. For ceramic output capacitor, typically choose a capacitance of about 22? The Schottky diode must have current rating higher than the maximum output current and a reverse voltage rating higher than the maximum input voltage.
Table 2 shows some calculated results based on the compensation method above. The SP-Cap is based on aluminum electrolytic capacitor technology, but uses a solid polymer electrolyte and has very stable capacitance characteristics in both operating temperature and frequency compared to ceramic, polymer, and low ESR tantalum capacitors. Feedback Voltage vs. Junction Temperature 1. Users should evaluate each product to make sure that it is suitable for their applications. Active-Semi products are not intended or authorized for use as critical components in life-support devices or systems.
Active-Semi, Inc. Active-Semi and its logo are trademarks of Active-Semi, Inc. For more information on this and other products, contact sales active-semi.
LM350K DATASHEET PDF
Protection features include cycle-bycycle current limit, thermal shutdown, and frequency foldback at short circuit. Active Solutions. Input Supply. Bypass this pin to G with a low ESR capacitor. See Input Capacitor in the Application Information section. Switch Output.
Consuming only 8? Protection features include cycle-by-cycle current limit, thermal shutdown, and frequency fold back at short circuit. Connect a 10nF between this pin and SW. Input Supply.