SN7407: What's the SN7407 maximum sink current per buffer?

Dave Hunson

Expert 1720 points

Part Number: SN7407
Other Parts Discussed in Thread: SN74LVC07A

What's the SN7407 maximum sink current per buffer?

The 7407 or 74LS07 Datasheet puts: "The maximum sink current is 40 mA for the SN7407". So,

1.Does it means each buffer can sink up to 40 mA or the whole chip can sink up to 40 mA?

2.if it is for each buffer ,would it be possible to sink (40mA x 6 chanel) 240mA form one 7407?

Regards.

Dave.

over 5 years ago

0 Emrys Maier over 5 years ago

TI__Guru* 96681 points

Hi Dave,

In general, I would recommend against exceeding 100mA total current from a logic device (unless the datasheet specifies otherwise).

0 Dave Hunson over 5 years ago in reply to Emrys Maier

Expert 1720 points

hi dear .

again I did not get my answer!!!

Let's say we want to drive HCPL3120 (IGBT Driver) ,the sink for each driver is 12mA ,if all drivers are OFF then (12x6) =72mA

I want to know should I use 2 chips to drive 6 LED For IGBT Driver or One is enough?

Please Tell me if each buffer can sink up to 40 mA or the whole chip can sink up to 40 mA?

Regards.

Dave.

0 Clemens Ladisch over 5 years ago in reply to Dave Hunson

Guru 269850 points

The 40 mA is for each channel.

Please note that there are other buffers that use less power. And the SN74LVC07A specifies the limits of both the per-pin current and the overall current (when using all outputs at the same time, each could drive 100 mA / 6 ≈ 16 mA).

0 Emrys Maier over 5 years ago in reply to Dave Hunson

TI__Guru* 96681 points

Hey Dave,

My apologies for misunderstanding your question -- you were very clear and I guess I was just in a hurry.

Clemens is correct - the value there is per channel, but you shouldn't exceed 100mA total for the device -- which is what I meant by my first answer.

0 Dave Hunson over 5 years ago in reply to Emrys Maier

Expert 1720 points

dear Emrys

you said :

but you shouldn't exceed 100mA total for the device

my question here is that ,that is the ABSOLUTE MAXIMUM RATINGS or it is the RECOMMENDED OPERATING CONDITIONS?

0 Clemens Ladisch over 5 years ago in reply to Dave Hunson

Guru 269850 points

There is no specified Recommended Operating Condition value for the overall current, so it's the same as the Absolute Maximum Rating value.

0 Emrys Maier over 5 years ago in reply to Dave Hunson

TI__Guru* 96681 points

Hey Dave,

There's no limitation in the datasheet, so there's no limitation. This is just my recommendation from my experience with these parts.

This part is ~60 years old -- I believe the original intent was for it to only drive 1 or 2 stages of additional logic, not to supply power to other circuits.

0 Dave Hunson over 5 years ago in reply to Clemens Ladisch

Expert 1720 points

Thank dear

what is the difference between these chips?

74LS07,

74F07 ,

74LVC07,

74HC07 ,

7407

please explain it ,thanks!

Regards

Dave.

0 Clemens Ladisch over 5 years ago in reply to Dave Hunson

Guru 269850 points

The difference is the logic family, i.e., the technology with which the chip was made.

The TTL family (SN7407) is the oldest one; it uses only NPN transistors, which means that the power consumption is comparatively high,

The later LS family adds Schottky diodes, which allows reduced power consumption at about the same speed as TTL.

LVC is a modern CMOS family; the static (when not switching) power consumption is approximately zero, at much higher speeds.

(TI never made a SN74F07 or SN74HC07, and those families have no benefits for your circuit.)

0 Dave Hunson over 5 years ago in reply to Clemens Ladisch

Expert 1720 points

Thanks Dear Clemens

your explain was perfect , good job!

Best wishes,

Dave.

Logic

Logic forum

SN7407: What's the SN7407 maximum sink current per buffer?

What's the SN7407 maximum sink current per buffer?