AMC1301: AMC1301 power dissipation too high.

Hi there,

The high side of the AMC1301 will draw up to 8.3 mA so with 5 devices , that is 41.5 mA total. Are you trying to say that each of the 5 devices are drawing 50 mA or that your total current draw is 50 mA?

Hi Tom

each of the 5 devices 50ma,my LOO is 150ma，it's can not work.

Check your grounding and ensure you are getting proper connections to the AMC1301 devices and that you are not exceeding the common mode input voltage limits. Under normal circumstances, the AMC1301 should not draw anywhere near 50mA.

Hi Tom

this is my schematic.high side and low side is both 5VDC power supply.

I got a test .  VINP is 30mv，VINN is 0mv，VOUTP is 1.6V VOUTN is 1.3V，AMC1301 is gain 8.2  so I think it is work OK

but the high side near 7ma, the low side 41ma, so total 50ma.

when I cut off high side power ,I think the amc1301 is Fail-Safe Output,the low side is 28ma now.

whatever the power is higher than the datasheet.

please help!

thank you

Hi There,

the ~7mA sounds normal for the AMC1301 high side, but the 41/28mA on the low side is not. What are you driving into with AN20 and AN21?

hi tom.
you mean high side input?
It is a shunt voltage，but now it no current ，you can check my schematic.

whatever the AMC1301 is working no problem,input 30mv,output 280mv

Hi tom
the low side output is suspend Now,because this is a test.
practical application is going to ADC ADS7263.
what's your means "I suspect you cleared the issue with the large current draw"??
how can I fix that ? because I want used one LDO for cost down,Now I had to used two LDO.

thanks for your help

Hi,

When you said earlier "whatever the AMC1301 is working no problem,input 30mv,output 280mv" I took that to mean that you resolved the high current issue. Where are you measuring the current? In your schematic, I see a net named '+5V' which is tied to the AMC1301 and what appears to be an isolated DC/DC converter. How are you breaking the connection between the two devices to measure only the AMC1301 low side supply current?

Hi tom

I used two DCDC replace the isolated DCDC，so I measure the two DCDC current with digital multimeter.

The two DCDC is not common ground.

Still confused...

If you are measuring the +5V current that feeds the DC/DC as well as the AMC1301, then you are not measuring the current consumed by the AMC1301 on its own. Are you somehow lifting the AMC1301 AVDD pin from the +5V node and measuring the current there?

Hi tom
I used two DCDC,so U3 is empty. one for high side,one for low side,and I measuring the current.

I think the current is the AMC1301 on its own.