Electronic Components Datasheet Search |
|
MIC4417BM4 Datasheet(PDF) 9 Page - Micrel Semiconductor |
|
MIC4417BM4 Datasheet(HTML) 9 Page - Micrel Semiconductor |
9 / 10 page May 2005 9 MIC4416/4417 MIC4416/4417 Micrel, Inc. Power Dissipation The maximum power dissipation must not be exceeded to prevent die meltdown or deterioration. Power dissipation in on/off switch applications is negligible. Fast repetitive switching applications, such as SMPS (switch- mode power supplies), cause a significant increase in power dissipation with frequency. Power is dissipated each time current passes through the internal output MOSFETs when charging or discharging the external MOSFET. Power is also dissipated during each transition when some current momen- tarily passes from VS to GND through both internal MOSFETs. Power dissipation is the product of supply voltage and supply current: 1) P D = VS × IS where: P D = power dissipation (W) V S = supply voltage (V) I S = supply current (A) [see paragraph below] Supply current is a function of supply voltage, switching frequency, and load capacitance. Determine this value from the “Typical Characteristics: Supply Current vs. Frequency” graph or measure it in the actual application. Do not allow P D to exceed PD (max), below. T J (junction temperature) is the sum of TA (ambient tempera- ture) and the temperature rise across the thermal resistance of the package. In another form: 2) P 150 T 220 D A ≤ − where: P D (max) = maximum power dissipation (W) 150 = absolute maximum junction temperature (°C) T A = ambient temperature (°C) [68°F = 20°C] 220 = package thermal resistance (°C/W) Maximum power dissipation at 20°C with the driver soldered to a 0.25in2 ground plane is approximately 600mW. CTL G VS GND PCB heat sink/ ground plane PCB traces Figure 4. Heat-Sink Plane The SOT-143 package θJA (junction-to-ambient thermal re- sistance) can be improved by using a heat sink larger than the specified 0.25in2 ground plane. Significant heat transfer occurs through the large (GND) lead. This lead is an extension of the paddle to which the die is attached. High-Frequency Operation Although the MIC4416/7 driver will operate at frequencies greater than 1MHz, the MOSFET’s capacitance and the load will affect the output waveform (at the MOSFET’s drain). For example, an MIC4416/IRL3103 test circuit using a 47Ω 5W load resistor will produce an output waveform that closely matches the input signal shape up to about 500kHz. The same test circuit with a 1kΩ load resistor operates only up to about 25kHz before the MOSFET source waveform shows significant change. VS CTL G GND MIC4416 +4.5V to 18V 1 32 4 Logic Input +5V Logic-Level MOSFET IRL3103* * International Rectifier 14m Ω, 30V MOSFET, logic-level, VGS = ±20V max. 4.7µF 0.1µF Compare 47k Ω, 5W to 1k Ω, 1/4W loads G D S Slower rise time observed at MOSFET’s drain Figure 5. MOSFET Capacitance Effects at High Switching Frequency When the MOSFET is driven off, the slower rise occurs because the MOSFET’s output capacitance recharges through the load resistance (RC circuit). A lower load resistance allows the output to rise faster. For the fastest driver opera- tion, choose the smallest power MOSFET that will safely handle the desired voltage, current, and safety margin. The smallest MOSFETs generally have the lowest capacitance. |
Similar Part No. - MIC4417BM4 |
|
Similar Description - MIC4417BM4 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |