5-volt output usb-8451 vs 8452

[mysticfree]

I'm trying to clarify the specs for the 5-volt out on the usb-8452.  The 845x hardware/software manual says the module can only supply up to 20 mA.  Yet, the USB-8451 has a maximum of 230 mA. 

Is there a mistake in the 8452 manual or did NI cut the available current to 1/10 of the original SPI module? 

I ask because we have several 8451 in our testers using the +5v out with a draw of under 100 mA.  Future testers and replacements of the 8451 would mean adding another power supply to the system.

Just thought I'd better check.  Thanks!

[JB · Accepted solution]

On pages 3-11 and 3-21 of this  manual, compare the "+5 V Power Source" indications for both modules.

The 20mA limitation of the USB-8452 is unfortunately not a mistake.

[Ashok31]

Hi,

I’m currently using the NI USB-8452 for SPI communication, which operates at a 3.3V logic level. However, the peripheral device I’m interfacing with requires 5V logic for proper SPI signaling.

Is there any way to configure or modify the USB-8452 to output 5V I/O levels directly, without using an external level shifter or voltage translator?

Thanks
Ashok G

[santo_13]

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@Ashok31 wrote:

Hi,

I’m currently using the NI USB-8452 for SPI communication, which operates at a 3.3V logic level. However, the peripheral device I’m interfacing with requires 5V logic for proper SPI signaling.

Is there any way to configure or modify the USB-8452 to output 5V I/O levels directly, without using an external level shifter or voltage translator?

Thanks
Ashok G

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What is your device spec and why a 5V TTL logic device not happy with a 3.1V VOH from USB-8542 SPI?

Unfortunately, you need to work with 5V CMOS, then you need external level shifter, no other option.