AT25XE081D Ultra Deep Power Mode

Question

Hello,

I am working with a AT25XE081D-MAHN-T via this schematic (note the MX25U8035FZUI is our second choice as this is a low power application).

The issue I am seeing is that the device is not entering ultra deep power mode.

I can see on the oscilloscope/multimeter that nHOLD, nWP are being held high. I can, also, see that the proper command 0x79 is being sent on the MOSI line.

Before the ultra deep power mode command, the ID command, 0x9f, returns the correct ID - after the command, the device returns zeros (expected).

The problem is that I am not seeing a reduction in current draw from the device. Before and after the command, the current draw is 90uA.

The current is being measured via this circuit:

This is my command line log via UART:

flash id gets the ID (0x9f).
flash write does a dummy write (0x02).
flash erase performs a chip erase (0x60).
flash read does a read back for the dummy write (0x0b).
flash sleep puts the device into ultra deep power mode (0x7f).
flash wake takes the device out of UDPM (0xab).

Again, I can see my uC sending and receiving properly over the SPI interface.

Sarpa_REN · Answer

Hi Tom, Please check if you meet the following conditions: 1) The complete opcode must be clocked in before the CS pin is de-asserted, and the CS pin must be de-asserted on a byte boundary (multiples of eight bits); otherwise, the device aborts the operation and returns to the Standby Mode once the CS pin is de-asserted. 2) Also, the device defaults to the Standby Mode after a power-cycle. 3) The Deep Power-Down command is ignored if an internally self-timed operation, such as a program or erase cycle, is in progress. The Deep Power-Down command must be reissued after the internally self-timed operation has been completed in order for the device to enter the Deep Power-Down mode. Confirm that the erase operation in your step "flash erase performs a chip erase (0x60)" was completed before sending the ultra-deep power mode. 
 In fact, I suggest that you should simply try the ultra-deep power mode right after a normal power RESET (without any other commands or operations). Check to see what the current draw is. 
 Also, I see you say the following in your screenshot number 2 => AT25XE081D: Current stand by 50 uA and Current power down 250 nA: what is this about? Best regards Renesas Electronics Online Support

AT25XE081D Ultra Deep Power Mode

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