Need help to identify supervisor IC

Oct 05, 2008 6 Replies
F

I'm trying to identify two 6-pin SMT supervisor ICs in a D-Link DSL-302G ADSL modem.



They are U7 and U12, to the left of the Atmel EEPROM in this photo:

formatting link



The markings are ... _ 1KXW -



The pinouts appear to be as follows



U7-1 NC (?) 2 ground 3 RST* to GS8120 CPU pin 53, VIA VT6103 pin 48, JP2-3 - pulled up to CPU Vcc by R51 (4K7) 4 CPU Vcc 5 NC (?) 6 CPU Vcc



U12-1 NC (?) 2 ground 3 RST* to GS8120 CPU pin 68 - pulled up to CPU Vcc by R30 (4K7) 4 ground 5 NC (?) 6 unregulated 12VDC from bridge rectifier



I suspect that the reset output is open collector or open drain, as it is bussed to connector JP2 which is provided for EEPROM programming via an external jig. I'm guessing that the NC pins may be manual reset pins, and/or RC time constant pins.



The CPU/DSP, GS8120, is from a Globespan Virata Viking chipset. Does anyone have a datasheet for this chip?


- Franc Zabkar


Please remove one \'i\' from my address when replying by email.
Vote
Twitter Facebook LinkedIn
E

Can you do more of a macro pic ?

Graham

Vote
Twitter Facebook LinkedIn
F

On Sun, 05 Oct 2008 03:05:37 +0100, Eeyore put finger to keyboard and composed:

The other photos are here:

formatting link

This is the entire PCB:

formatting link

- Franc Zabkar

Please remove one \'i\' from my address when replying by email.
Vote
Twitter Facebook LinkedIn
F

On Sun, 05 Oct 2008 14:05:22 +1000, Franc Zabkar put finger to keyboard and composed:

I tried getting a better close-up, but the image just blurs.

- Franc Zabkar

Please remove one \'i\' from my address when replying by email.
Vote
Twitter Facebook LinkedIn
F

On Sun, 05 Oct 2008 10:58:17 +1000, Franc Zabkar put finger to keyboard and composed:

This is a similar PCB with U12 unpopulated:

formatting link

It shows that pins 4 & 6 are linked at the resistor pads, which suggests that the two resistors form a potential divider, and that U12 lets the CPU know when the +12V input is low.

- Franc Zabkar

Please remove one \'i\' from my address when replying by email.
Vote
Twitter Facebook LinkedIn
J

I can't help you with identifying those parts, but with a few mods (removing R65 for one) I bet you could use a couple of LM3724IM5-4.63 devices.

Vote
Twitter Facebook LinkedIn
F

On Mon, 06 Oct 2008 08:06:05 -0400, JW put finger to keyboard and composed:

Thanks, but I should have explained that I'm not trying to repair a fault. I'm just trying to add a manual reset switch with the least amount of effort. If the NC pins are internally debounced manual reset inputs, then all I have to do is to add the switch. Otherwise I plan to add a debounced reset input via JP2, without disturbing the PCB (my eyesight isn't as good as it used to be).

- Franc Zabkar

Please remove one \'i\' from my address when replying by email.
Vote
Twitter Facebook LinkedIn

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required