SSHD,, e-fuse?

[ddd123]

Hi guys,

i have defect pcb on this SSHD
we removed TVS diode (was shorted), but the drive doesnt start

is this E-FUse marked on the picture?

Thanks

Attachments

[Lardman]

What are the markings ? Can't see anything from that image.

[ddd123]

7167B
1434D
MSC

[Lardman]

My Google-fu is weak today, taken from a working board.

Pin
1 NC
2 NC
3 0.9v
4 NC
5 NC
6 1.8v
7 NC
8 4.8v
9 0.9v
10 4.8v
11 0.9v
12 4.8v

[fzabkar]

LX7167A, Microsemi, 3MHz, 2.4A, Vin = 3V - 5.5V, Constant Frequency Hysteretic Synchronous Buck Regulator, marking 67A, DFN-8:
https://www.microsemi.com/document-portal/doc_view/132266-lx716a-datasheet
https://www.microsemi.com/document-portal/doc_download/132564-lx7167-datasheet

http://www.users.on.net/~fzabkar/Datasheets/DATAURLS.HTM

[fzabkar]

I just realised that the pin counts of the LX7167 and LX7167A are wrong. I still think the chip is made by Microsemi, and I know it is a stepdown switchmode converter, but I'm wondering if it could indeed be an LX7167B, with a different pin count to the LX7167/A versions. The other possibility is NX7167B, but I haven't been able to find either.

I think the other number is probably a YYWW (Year/Week) date code. This could be confirmed by comparing the date codes on the other chips.

Edit: It's an LX7157B.

LX7157B, Microsemi (MSC), step-down PWM regulator IC with integrated high side P-Ch MOSFET and low side N-CH MOSFET, 2.2MHz, 3V to 5.5V:
http://www.microsemi.com/document-portal/doc_download/124259-lx7157bds

https://upload.wikimedia.org/wikipedia/commons/d/d7/Seagate_ST1000LM014_-_controller-8425.jpg

[Lardman]

The board I tested had a 7169-1443B-MSC on it. AFAICS it matches the LX7169 (Id read the pin left to right rather than down then up as shown on the data sheet.

[fzabkar]

LX7169, Microsemi, 3A Step-Down Converter, 3V - 5.5V input, DFN-12:
http://www.electronicsdatasheets.com/download/93262.pdf?format=pdf