I have searched and looked through the data sheet and I can't find the information I am looking for.

I am designing a circuit that uses an ATtiny45-20PU operating at 5V. I will be using three digital (high/low) inputs and driving one output that will draw 22mA when driven high (a PLC relay, APAN3105).

I am trying to figure out how to calculate the power consumption both when the output is low and when the output is high.

The datasheet I am looking at is here: http://www.mouser.com/ds/2/268/Atmel-2586-AVR-8-bit-Microcontroller-ATtiny25-ATti-1065586.pdf

The power consumption when the output is low is important because the power supply is a battery.

The power consumption when the output is high is important so I can chose an appropriately rated voltage regulator.

I do understand that the operating speed chosen during programming will effect power consumption. High speed operation is not critical here as all of the inputs are electromechanical in nature and require a physical (human interface) input, so I plan to use as low of a speed as possible.

I don't want anyone to spoon feed me the answer here. I just need help figuring out how to get to the answer. Is there a more detailed datasheet that I am not finding? I searched the Atmel website and got lost in a web of links for hours and didn't find anything helpful.


marked as duplicate by Voltage Spike, PeterJ, uint128_t, Dmitry Grigoryev, Brian Carlton Aug 7 '17 at 22:20

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Just go to www.atmel.com and type in ATtiny45-20PU in their search bar. There you will find the ATtiny "Complete" datasheet instead of the "summary" you found at Mouser.

The complete datasheet of an MCU or CPU is of course not a paper you read from start to beginning.

Hint: Go to the DC Characteristics at page 161, 162 and see if you can sort out the current consumption from there.

  • \$\begingroup\$ Thank you. IDK how I kept getting redirected elsewhere while searching yestedray. I found it now: atmel.com/images/… \$\endgroup\$ – LsD Aug 4 '17 at 14:35
  • \$\begingroup\$ Have I lost my mind or is it saying that the absolute maximum power consumption of the MC from the power supply with maximum usage of the outputs would be 260mA? \$\endgroup\$ – LsD Aug 4 '17 at 14:55
  • \$\begingroup\$ You have slightly lost your mind. Power would be in mW, not mA. Your datasheet page 162 says "Although each I/O port can sink more than the test conditions (10 mA at Vcc = 5V, 5 mA at Vcc = 3V) under steady state conditions (non-transient), the following must be observed: 1] The sum of all IOL, for all ports, should not exceed 60 mA". \$\endgroup\$ – Transistor Aug 4 '17 at 15:17
  • \$\begingroup\$ @LsD. You are misreading the data, The maximum active current is about 13 mA @ 5.5 V (this does not include an I/O external current flows). The supply current can vary from 0.1 uA to the maximum of 13 mA depending on supply voltage, freq, and enabled functions. If you want the lowest power supply consumption then investigate firstly the Modes and PRR functions ( Section 7). If you need ultra low power consumption investigate deep sleep interrupt and timer functions. \$\endgroup\$ – Jack Creasey Aug 4 '17 at 15:17
  • \$\begingroup\$ Thank you everybody for your help. I have a lot more reading and calculating to do, but I have the correct documentation now! :) \$\endgroup\$ – LsD Aug 4 '17 at 18:05

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