Need help finding an IC Chip

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Shane Vadnais

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May 27, 2023, 3:01:21 PM5/27/23
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Looking for a little help, I am trying to find a replacement for this chip and I'm not having much luck. Hoping some of you might now some tricks that could help me track it down.

349573121_1691078784662627_5620070010544724245_n.jpg

John Norman

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May 27, 2023, 3:21:43 PM5/27/23
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It's in a Lexus stereo that won't power on.  It was the only obvious defect I could find on taking it apart and examining.  It's probably some type of power IC - buck converter, soft  power-on circuit or similar.

On Sat, May 27, 2023, 12:01 PM Shane Vadnais <seva...@gmail.com> wrote:
Looking for a little help, I am trying to find a replacement for this chip and I'm not having much luck. Hoping some of you might now some tricks that could help me track it down.

349573121_1691078784662627_5620070010544724245_n.jpg

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Jim Tulenko

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May 27, 2023, 4:14:59 PM5/27/23
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Might be one of these. The Vishay part is a typical FET, while the Broadcom part is an optocoupled solid state relay.

The difference between the two is that a solid state relay is bi-directional, it is built with two N-ch FETs connected in series, back to back 

The bi-directional FET switch, aka Solid State Relay (SSR) is typically used as a bi-directional power switch to flow power in to, and out, of a battery. Any product with a rechargeable battery will use at least one of them.
Schematic drawings:

Vishay SI4128DY
30V 10A N-ch FET
Datasheet
In stock at Mouser

Broadcom  ASSR-4128-002E
Standard, 2 Form A, Solid State Relay (Photo MOSFET), 400V/0.1A/35Ω



Steve Wong

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May 27, 2023, 6:00:19 PM5/27/23
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JW logo is likely joulwatt and they make voltage step down chips in 8 pin packages

On Sat, May 27, 2023, 12:01 PM Shane Vadnais <seva...@gmail.com> wrote:
Looking for a little help, I am trying to find a replacement for this chip and I'm not having much luck. Hoping some of you might now some tricks that could help me track it down.

349573121_1691078784662627_5620070010544724245_n.jpg

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Jim Tulenko

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May 28, 2023, 1:28:17 PM5/28/23
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If the black component just visible at 6-o'clock is an inductor, then the pinouts of these two parts match what's visible in the board layout.
And 'JW4128' is close to the package marking.

New Japan Radio NJW4128 Switching Regulator Buck Converter

Nisshinbo Micro Devices NJW4128 Switching Regulator Buck Converter
https://www.nisshinbo-microdevices.co.jp/en/products/dc-dc-switching-regulator/spec/?product=njw4128

Octopart shows stock at a couple of Asian distributors.
NJW4128GM1-A-TE2
NJW4128GM1-B-TE2

.

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