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ward ayat

Prodigy 35 points

Other Parts Discussed in Thread: CSD15380F3, SN74AUC1G07, SN74AUC1G66

Looking for a transistor that works as a switch at 25 MHz, the pulse that gives a very small cycle time

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 313920 points

25 MHz = 1 / 40 ns

How fast you can make a MOSFET switch depends on how fast you can charge/discharge its gate. Assuming that your gate driving circuit is fast enough, choose a device with a small gate capacitance, e.g., the CSD15380F3.

Discrete transistors are designed for larger loads. For small loads at low voltages, it might make sense to use a logic gate like the SN74AUC1G07 or an analog switch like the SN74AUC1G66.

0 John Wallace1 over 4 years ago

TI__Mastermind 36980 points

Hello Ward,

Thanks for your interest in TI FETs. Most of our power MOSFETs are optimized for switching in the kHz to low MHz frequencies. Some of our smaller FemtoFET and other similar devices have been used in applications switching up to 80MHz driving VCSEL lasers. What are the voltage and current requirements for your application? How are you driving the MOSFET gate and what is the gate drive voltage?

Best Regards,

John Wallace

TI FET Applications

0 ward ayat over 4 years ago in reply to John Wallace1

Prodigy 35 points

Small Vgs voltage 1.5 and Vds voltage 2.5, I gate gets a really narrow pulse and at a frequency of 25 MHz

0 ward ayat over 4 years ago in reply to Clemens Ladisch

Prodigy 35 points

CSD15380F3 no have legs (BGA) is not good.

0 kai klaas69 over 4 years ago in reply to ward ayat

Guru 140200 points

Hi Ward,

are your leds that fast?

Kai

0 John Wallace1 over 4 years ago in reply to ward ayat

TI__Mastermind 36980 points

Hi Ward,

TI has no N-channel FETs with on resistance specified at VGS = 1.5V. We have a few devices rated down to VGS = 1.8V and all of those are in chip scale packages similar to the CSD15380F3. The only leaded devices are in TO220 packages and those FETs are optimized for high current/mid-voltage switching up to a few hundred kHz. I am going to close this thread and we can continue this discussion via private message.

Thanks,

John

0 ward ayat over 4 years ago in reply to kai klaas69

Prodigy 35 points

YES. DATASHEET

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