# Increasing current of a digital signal

#### Saurabh.30

Joined Apr 27, 2021
6
Hi,
I am working on a project which require to increase the current of a 5v high speed digital signal from 20ma to 100-150ma. can someone help me how to achieve that

Thanks

#### andrewmm

Joined Feb 25, 2011
1,757
Easy answer is you need a buffer,

to point you in right direction,
what voltage out , what is the edge speed you need ( bandwidth )
Relay, led , laser , resistor or what ?

#### Ian0

Joined Aug 7, 2020
3,280
Try a low side MOSFET driver such as MCP1401

#### andrewmm

Joined Feb 25, 2011
1,757
Try a low side MOSFET driver such as MCP1401
great part @Saurabh.30 if your Ok with 30 ns rise / fall time and under 18v

#### BobTPH

Joined Jun 5, 2013
3,690
What is the load and what is high speed?

Does it have to sink current or source it or both?

It could be as simple as a BJT or MOSFET used as switch.

Bob

#### Yaakov

Joined Jan 27, 2019
3,522
Can you describe the project and application for the signal?

#### AnalogKid

Joined Aug 1, 2013
9,361
How high speed? <duh>

ak

#### Ian0

Joined Aug 7, 2020
3,280
If you just need more current, but only 5V, then all 4 sections of a 74AC125 would do 100mA and still have the speedy rise/fall times.
A 74AC541 won‘t gain much more, as you reach the supply pin limits.

Last edited:

#### Saurabh.30

Joined Apr 27, 2021
6
Easy answer is you need a buffer,

to point you in right direction,
what voltage out , what is the edge speed you need ( bandwidth )
Relay, led , laser , resistor or what ?
output is from Arduino so it'll have variety of loads

#### Ian0

Joined Aug 7, 2020
3,280
output is from Arduino so it'll have variety of loads
for push-pull 3.3V or 5V logic up to 100mA at full speed = paralleled sections of 75AC125
for push-pull up to 18V with 30ns rise-time = MPC1401
for single ended with load connected to a higher voltage = single MOSFET - choose MOSFET Vds/Id to suit load
for single ended with load connected to a higher voltage but slower = bipolar transistor.

#### Saurabh.30

Joined Apr 27, 2021
6
for push-pull 3.3V or 5V logic up to 100mA at full speed = paralleled sections of 75AC125
for push-pull up to 18V with 30ns rise-time = MPC1401
for single ended with load connected to a higher voltage = single MOSFET - choose MOSFET Vds/Id to suit load
for single ended with load connected to a higher voltage but slower = bipolar transistor.
cannot find anything for "75AC125" can you please elaborate

#### Ian0

Joined Aug 7, 2020
3,280
cannot find anything for "75AC125" can you please elaborate
See post #8 (mistyped 75 for 74)

#### andrewmm

Joined Feb 25, 2011
1,757
To select a driver, you need to know,

Just what are you aiming to drive , at what sort of edge speed ?

One size does NOT fit all.

#### BobTPH

Joined Jun 5, 2013
3,690

Bob

#### Saurabh.30

Joined Apr 27, 2021
6

Bob
what is?

#### AnalogKid

Joined Aug 1, 2013
9,361

#### BobTPH

Joined Jun 5, 2013
3,690

Bob

#### Papabravo

Joined Feb 24, 2006
16,832

#### Saurabh.30

Joined Apr 27, 2021
6

Bob
they gave me a solution why to continue the discussion and waste everyone's time