How much current supply is needed for i.MX6 eFuse blowing?

[satoshishimoda]

Hi community,

I have a question about i.MX6SDL eFuse blowing.

Actually, our customer failed eFuse blowing on thier custom board. even though they used PlatformSDK.

The written data was 0x3F3F3F3F though they wrote 0xFFFFFFFF.

But the failure was not occurred on all thier board, a part of their boards were succeeded.

So we doubt current supply for i.MX6.

How much current supply is needed for i.MX6 eFuse blowing?

(e.g. xx mA on VDD_SOC_IN)

Best Regards,

Satoshi Shimoda

[igorpadykov · Accepted solution]

Hi Satoshi

I am afraid for i.MX6 eFuse blowing current is not specified, but as estimation one can look

i.MX53 data Table 9. Maximal Supply Currents 120mA Fuse Write Mode operation

http://cache.freescale.com/files/32bit/doc/data_sheet/IMX53CEC.pdf

In i.MX6 voltage provided from VDD_HIGH_IN, as described in sect.4.3.2.2 LDO_2P5

http://cache.freescale.com/files/32bit/doc/data_sheet/IMX6DQCEC.pdf

The LDO_2P5 module implements a programmable linear-regulator function from VDD_HIGH_IN

(see Table 6 for min and max input requirements). Typical Programming Operating Range is 2.25 V to 2.75 V

with the nominal default setting as 2.5 V. The LDO_2P5 supplies the SATA PHY, USB PHY, LVDS PHY,

HDMI PHY, MIPI PHY, E-fuse module and PLLs.

Best regards

igor

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[satoshishimoda]

Hi Igor,

Thank you for your reply.

I understood approximately 120mA on VDDHIGH_IN may be needed to program eFuse.

SABRE-SDP design seems to not satisfies this requirement (VGEN5 = max 100mA), so if customer designed same as SABRE-SDP, I think the eFuse programming issue might be occurred by current insufficient.

Beest Regards,

Satoshi Shimoda

[igorpadykov]

Hi Satoshi

1. according to Table 8. Maximum Supply Currents

http://cache.freescale.com/files/32bit/doc/data_sheet/IMX6DQCEC.pdf

The actual maximum current drawn from VDD_HIGH_IN will be as shown

plus any additional current drawn from the VDD_HIGH_CAP outputs, depending

upon actual application configuration (for example, NVCC_LVDS_2P5, NVCC_MIPI,

or HDMI, PCIe, and SATA VPH supplies).

2. i.MX53 data 120mA is worst case, blowing 8 fuses simultaneously,

blowing 1 fuse bit will require 120/8=15mA (max)

Best regards

igor