Reason for gold lines on old ICs?
up vote
17
down vote
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A lot of older (ceramic) ICs have a gold-plated line extending from the die cover to the edge of the package. Did this serve a practical purpose or was it just bling?
I suspect that it might be what's left of the lead frame leading to the pad under the soldered die cover. It would hold the pad in position while the package was molded. Similarly, the gold plating on the pin-1 notch in the photo below is part of the trimmed lead frame. This is just a hypothesis; can anyone confirm?
Source: Wikipedia/Arnold Reinhold (CC/A-SA)
hardware chip
asked Nov 19 at 9:04
Alex Hajnal
3,43531432
add a comment |
up vote
17
down vote
favorite
A lot of older (ceramic) ICs have a gold-plated line extending from the die cover to the edge of the package. Did this serve a practical purpose or was it just bling?
I suspect that it might be what's left of the lead frame leading to the pad under the soldered die cover. It would hold the pad in position while the package was molded. Similarly, the gold plating on the pin-1 notch in the photo below is part of the trimmed lead frame. This is just a hypothesis; can anyone confirm?
Source: Wikipedia/Arnold Reinhold (CC/A-SA)
hardware chip
asked Nov 19 at 9:04
Alex Hajnal
3,43531432
add a comment |
up vote
17
down vote
favorite
up vote
17
down vote
favorite
A lot of older (ceramic) ICs have a gold-plated line extending from the die cover to the edge of the package. Did this serve a practical purpose or was it just bling?
I suspect that it might be what's left of the lead frame leading to the pad under the soldered die cover. It would hold the pad in position while the package was molded. Similarly, the gold plating on the pin-1 notch in the photo below is part of the trimmed lead frame. This is just a hypothesis; can anyone confirm?
Source: Wikipedia/Arnold Reinhold (CC/A-SA)
hardware chip
asked Nov 19 at 9:04
Alex Hajnal
3,43531432
A lot of older (ceramic) ICs have a gold-plated line extending from the die cover to the edge of the package. Did this serve a practical purpose or was it just bling?
I suspect that it might be what's left of the lead frame leading to the pad under the soldered die cover. It would hold the pad in position while the package was molded. Similarly, the gold plating on the pin-1 notch in the photo below is part of the trimmed lead frame. This is just a hypothesis; can anyone confirm?
Source: Wikipedia/Arnold Reinhold (CC/A-SA)
hardware chip
hardware chip
asked Nov 19 at 9:04
Alex Hajnal
3,43531432
asked Nov 19 at 9:04
Alex Hajnal
3,43531432
edited Nov 19 at 12:59
asked Nov 19 at 9:04
Alex Hajnal
3,43531432
asked Nov 19 at 9:04
Alex Hajnal
3,43531432
asked Nov 19 at 9:04
Alex Hajnal
3,43531432
3,43531432
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
up vote
19
down vote
accepted
It's a ground wire. The way ICs were manufactured back then had the metal cover placed over the die as the last step, and grounding it helps protect the die from static shock and interference.
If you look closely you can see the solder that bonds the strip to the die cover. If you check continuity you will find that both are connected to the IC's ground plane and ground pin(s).
answered Nov 19 at 9:21
user
2,632414
When would it be grounded though? The line doesn't connect to any pin.
– Alex Hajnal
Nov 19 at 9:27
3
It connects to the exposed ground plane on the side of the IC.
– user
Nov 19 at 9:29
2
I guess they don't have to be, there is a cost to it so if it wasn't necessary for that particular part they might skip it. It depends how sensitive it is, what the application is, that kind of thing. Manufacturers quickly moved to plastic packages once they became practical.
– user
Nov 19 at 10:33
1
MBA810 is a high power (up to 10W depending on manufacturer) amplifier. The 'wings' aren't ment as ground (although they are connected), but for cooling. They do not go over the IC (like the cap) but below to transfer heat.
– Raffzahn
Nov 19 at 15:07
2
Also, the metal cap is never atatched to the die inside, as the upper side of a die contains circuitry and a metal cap will carry a high chance of shortcuting. Heat for dissapation is taken from the lower side. That's why modern CPUs are flip mounted, so heat transfer can be aproved ( also it allows more connections, as now pins may also connect to pads inside the chip, not just aroudn the border.
– Raffzahn
Nov 19 at 15:13
|
show 8 more comments
up vote
0
down vote
Definitely not "bling". Since gold is (obviously) expensive, there is only one reason it's used in electrical circuits: it's because it doesn't corrode (oxidize), and therefore it makes for the best interconnects. There are better conductors out there, such as silver (the best), but they all have issues with corrosion to some extent or another. Think of the "tarnish" that quickly builds-up on any silver that gets exposed to oxygen. But you can drop a piece of gold in the ocean and come back a year later and it still won't have any oxidation on it whatsoever.
answered Nov 20 at 8:44
ColdCold
101
New contributor
ColdCold is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Welcome to Retrocomputing.SE! This doesn’t answer the question, which is specifically about the gold line extending along the top of the IC’s package, not the use of gold in general.
– Stephen Kitt
Nov 20 at 11:43
Thanks. Sorry, I thought my answer was implied. As several people mentioned the connections made to this chip (whether electrical, or for thermal dispersion), gold will always maximize connection quality over the life of a product.
– ColdCold
Nov 20 at 21:20
add a comment |
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
19
down vote
accepted
It's a ground wire. The way ICs were manufactured back then had the metal cover placed over the die as the last step, and grounding it helps protect the die from static shock and interference.
If you look closely you can see the solder that bonds the strip to the die cover. If you check continuity you will find that both are connected to the IC's ground plane and ground pin(s).
answered Nov 19 at 9:21
user
2,632414
When would it be grounded though? The line doesn't connect to any pin.
– Alex Hajnal
Nov 19 at 9:27
3
It connects to the exposed ground plane on the side of the IC.
– user
Nov 19 at 9:29
2
I guess they don't have to be, there is a cost to it so if it wasn't necessary for that particular part they might skip it. It depends how sensitive it is, what the application is, that kind of thing. Manufacturers quickly moved to plastic packages once they became practical.
– user
Nov 19 at 10:33
1
MBA810 is a high power (up to 10W depending on manufacturer) amplifier. The 'wings' aren't ment as ground (although they are connected), but for cooling. They do not go over the IC (like the cap) but below to transfer heat.
– Raffzahn
Nov 19 at 15:07
2
Also, the metal cap is never atatched to the die inside, as the upper side of a die contains circuitry and a metal cap will carry a high chance of shortcuting. Heat for dissapation is taken from the lower side. That's why modern CPUs are flip mounted, so heat transfer can be aproved ( also it allows more connections, as now pins may also connect to pads inside the chip, not just aroudn the border.
– Raffzahn
Nov 19 at 15:13
|
show 8 more comments
up vote
19
down vote
accepted
It's a ground wire. The way ICs were manufactured back then had the metal cover placed over the die as the last step, and grounding it helps protect the die from static shock and interference.
If you look closely you can see the solder that bonds the strip to the die cover. If you check continuity you will find that both are connected to the IC's ground plane and ground pin(s).
answered Nov 19 at 9:21
user
2,632414
When would it be grounded though? The line doesn't connect to any pin.
– Alex Hajnal
Nov 19 at 9:27
3
It connects to the exposed ground plane on the side of the IC.
– user
Nov 19 at 9:29
2
I guess they don't have to be, there is a cost to it so if it wasn't necessary for that particular part they might skip it. It depends how sensitive it is, what the application is, that kind of thing. Manufacturers quickly moved to plastic packages once they became practical.
– user
Nov 19 at 10:33
1
MBA810 is a high power (up to 10W depending on manufacturer) amplifier. The 'wings' aren't ment as ground (although they are connected), but for cooling. They do not go over the IC (like the cap) but below to transfer heat.
– Raffzahn
Nov 19 at 15:07
2
Also, the metal cap is never atatched to the die inside, as the upper side of a die contains circuitry and a metal cap will carry a high chance of shortcuting. Heat for dissapation is taken from the lower side. That's why modern CPUs are flip mounted, so heat transfer can be aproved ( also it allows more connections, as now pins may also connect to pads inside the chip, not just aroudn the border.
– Raffzahn
Nov 19 at 15:13
|
show 8 more comments
up vote
19
down vote
accepted
up vote
19
down vote
accepted
It's a ground wire. The way ICs were manufactured back then had the metal cover placed over the die as the last step, and grounding it helps protect the die from static shock and interference.
If you look closely you can see the solder that bonds the strip to the die cover. If you check continuity you will find that both are connected to the IC's ground plane and ground pin(s).
answered Nov 19 at 9:21
user
2,632414
It's a ground wire. The way ICs were manufactured back then had the metal cover placed over the die as the last step, and grounding it helps protect the die from static shock and interference.
If you look closely you can see the solder that bonds the strip to the die cover. If you check continuity you will find that both are connected to the IC's ground plane and ground pin(s).
answered Nov 19 at 9:21
user
2,632414
answered Nov 19 at 9:21
user
2,632414
answered Nov 19 at 9:21
user
2,632414
answered Nov 19 at 9:21
user
2,632414
2,632414
When would it be grounded though? The line doesn't connect to any pin.
– Alex Hajnal
Nov 19 at 9:27
3
It connects to the exposed ground plane on the side of the IC.
– user
Nov 19 at 9:29
2
I guess they don't have to be, there is a cost to it so if it wasn't necessary for that particular part they might skip it. It depends how sensitive it is, what the application is, that kind of thing. Manufacturers quickly moved to plastic packages once they became practical.
– user
Nov 19 at 10:33
1
MBA810 is a high power (up to 10W depending on manufacturer) amplifier. The 'wings' aren't ment as ground (although they are connected), but for cooling. They do not go over the IC (like the cap) but below to transfer heat.
– Raffzahn
Nov 19 at 15:07
2
Also, the metal cap is never atatched to the die inside, as the upper side of a die contains circuitry and a metal cap will carry a high chance of shortcuting. Heat for dissapation is taken from the lower side. That's why modern CPUs are flip mounted, so heat transfer can be aproved ( also it allows more connections, as now pins may also connect to pads inside the chip, not just aroudn the border.
– Raffzahn
Nov 19 at 15:13
|
show 8 more comments
When would it be grounded though? The line doesn't connect to any pin.
– Alex Hajnal
Nov 19 at 9:27
3
It connects to the exposed ground plane on the side of the IC.
– user
Nov 19 at 9:29
2
I guess they don't have to be, there is a cost to it so if it wasn't necessary for that particular part they might skip it. It depends how sensitive it is, what the application is, that kind of thing. Manufacturers quickly moved to plastic packages once they became practical.
– user
Nov 19 at 10:33
1
MBA810 is a high power (up to 10W depending on manufacturer) amplifier. The 'wings' aren't ment as ground (although they are connected), but for cooling. They do not go over the IC (like the cap) but below to transfer heat.
– Raffzahn
Nov 19 at 15:07
2
Also, the metal cap is never atatched to the die inside, as the upper side of a die contains circuitry and a metal cap will carry a high chance of shortcuting. Heat for dissapation is taken from the lower side. That's why modern CPUs are flip mounted, so heat transfer can be aproved ( also it allows more connections, as now pins may also connect to pads inside the chip, not just aroudn the border.
– Raffzahn
Nov 19 at 15:13
When would it be grounded though? The line doesn't connect to any pin.
– Alex Hajnal
Nov 19 at 9:27
When would it be grounded though? The line doesn't connect to any pin.
– Alex Hajnal
Nov 19 at 9:27
3
3
It connects to the exposed ground plane on the side of the IC.
– user
Nov 19 at 9:29
It connects to the exposed ground plane on the side of the IC.
– user
Nov 19 at 9:29
2
2
I guess they don't have to be, there is a cost to it so if it wasn't necessary for that particular part they might skip it. It depends how sensitive it is, what the application is, that kind of thing. Manufacturers quickly moved to plastic packages once they became practical.
– user
Nov 19 at 10:33
I guess they don't have to be, there is a cost to it so if it wasn't necessary for that particular part they might skip it. It depends how sensitive it is, what the application is, that kind of thing. Manufacturers quickly moved to plastic packages once they became practical.
– user
Nov 19 at 10:33
1
1
MBA810 is a high power (up to 10W depending on manufacturer) amplifier. The 'wings' aren't ment as ground (although they are connected), but for cooling. They do not go over the IC (like the cap) but below to transfer heat.
– Raffzahn
Nov 19 at 15:07
MBA810 is a high power (up to 10W depending on manufacturer) amplifier. The 'wings' aren't ment as ground (although they are connected), but for cooling. They do not go over the IC (like the cap) but below to transfer heat.
– Raffzahn
Nov 19 at 15:07
2
2
Also, the metal cap is never atatched to the die inside, as the upper side of a die contains circuitry and a metal cap will carry a high chance of shortcuting. Heat for dissapation is taken from the lower side. That's why modern CPUs are flip mounted, so heat transfer can be aproved ( also it allows more connections, as now pins may also connect to pads inside the chip, not just aroudn the border.
– Raffzahn
Nov 19 at 15:13
Also, the metal cap is never atatched to the die inside, as the upper side of a die contains circuitry and a metal cap will carry a high chance of shortcuting. Heat for dissapation is taken from the lower side. That's why modern CPUs are flip mounted, so heat transfer can be aproved ( also it allows more connections, as now pins may also connect to pads inside the chip, not just aroudn the border.
– Raffzahn
Nov 19 at 15:13
|
show 8 more comments
up vote
0
down vote
Definitely not "bling". Since gold is (obviously) expensive, there is only one reason it's used in electrical circuits: it's because it doesn't corrode (oxidize), and therefore it makes for the best interconnects. There are better conductors out there, such as silver (the best), but they all have issues with corrosion to some extent or another. Think of the "tarnish" that quickly builds-up on any silver that gets exposed to oxygen. But you can drop a piece of gold in the ocean and come back a year later and it still won't have any oxidation on it whatsoever.
answered Nov 20 at 8:44
ColdCold
101
New contributor
ColdCold is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Welcome to Retrocomputing.SE! This doesn’t answer the question, which is specifically about the gold line extending along the top of the IC’s package, not the use of gold in general.
– Stephen Kitt
Nov 20 at 11:43
Thanks. Sorry, I thought my answer was implied. As several people mentioned the connections made to this chip (whether electrical, or for thermal dispersion), gold will always maximize connection quality over the life of a product.
– ColdCold
Nov 20 at 21:20
add a comment |
up vote
0
down vote
Definitely not "bling". Since gold is (obviously) expensive, there is only one reason it's used in electrical circuits: it's because it doesn't corrode (oxidize), and therefore it makes for the best interconnects. There are better conductors out there, such as silver (the best), but they all have issues with corrosion to some extent or another. Think of the "tarnish" that quickly builds-up on any silver that gets exposed to oxygen. But you can drop a piece of gold in the ocean and come back a year later and it still won't have any oxidation on it whatsoever.
answered Nov 20 at 8:44
ColdCold
101
New contributor
ColdCold is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Welcome to Retrocomputing.SE! This doesn’t answer the question, which is specifically about the gold line extending along the top of the IC’s package, not the use of gold in general.
– Stephen Kitt
Nov 20 at 11:43
Thanks. Sorry, I thought my answer was implied. As several people mentioned the connections made to this chip (whether electrical, or for thermal dispersion), gold will always maximize connection quality over the life of a product.
– ColdCold
Nov 20 at 21:20
add a comment |
up vote
0
down vote
up vote
0
down vote
Definitely not "bling". Since gold is (obviously) expensive, there is only one reason it's used in electrical circuits: it's because it doesn't corrode (oxidize), and therefore it makes for the best interconnects. There are better conductors out there, such as silver (the best), but they all have issues with corrosion to some extent or another. Think of the "tarnish" that quickly builds-up on any silver that gets exposed to oxygen. But you can drop a piece of gold in the ocean and come back a year later and it still won't have any oxidation on it whatsoever.
answered Nov 20 at 8:44
ColdCold
101
New contributor
ColdCold is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Definitely not "bling". Since gold is (obviously) expensive, there is only one reason it's used in electrical circuits: it's because it doesn't corrode (oxidize), and therefore it makes for the best interconnects. There are better conductors out there, such as silver (the best), but they all have issues with corrosion to some extent or another. Think of the "tarnish" that quickly builds-up on any silver that gets exposed to oxygen. But you can drop a piece of gold in the ocean and come back a year later and it still won't have any oxidation on it whatsoever.
answered Nov 20 at 8:44
ColdCold
101
New contributor
ColdCold is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered Nov 20 at 8:44
ColdCold
101
New contributor
ColdCold is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered Nov 20 at 8:44
ColdCold
101
answered Nov 20 at 8:44
ColdCold
101
101
New contributor
ColdCold is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
ColdCold is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
ColdCold is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Welcome to Retrocomputing.SE! This doesn’t answer the question, which is specifically about the gold line extending along the top of the IC’s package, not the use of gold in general.
– Stephen Kitt
Nov 20 at 11:43
Thanks. Sorry, I thought my answer was implied. As several people mentioned the connections made to this chip (whether electrical, or for thermal dispersion), gold will always maximize connection quality over the life of a product.
– ColdCold
Nov 20 at 21:20
add a comment |
Welcome to Retrocomputing.SE! This doesn’t answer the question, which is specifically about the gold line extending along the top of the IC’s package, not the use of gold in general.
– Stephen Kitt
Nov 20 at 11:43
Thanks. Sorry, I thought my answer was implied. As several people mentioned the connections made to this chip (whether electrical, or for thermal dispersion), gold will always maximize connection quality over the life of a product.
– ColdCold
Nov 20 at 21:20
Welcome to Retrocomputing.SE! This doesn’t answer the question, which is specifically about the gold line extending along the top of the IC’s package, not the use of gold in general.
– Stephen Kitt
Nov 20 at 11:43
Welcome to Retrocomputing.SE! This doesn’t answer the question, which is specifically about the gold line extending along the top of the IC’s package, not the use of gold in general.
– Stephen Kitt
Nov 20 at 11:43
Thanks. Sorry, I thought my answer was implied. As several people mentioned the connections made to this chip (whether electrical, or for thermal dispersion), gold will always maximize connection quality over the life of a product.
– ColdCold
Nov 20 at 21:20
Thanks. Sorry, I thought my answer was implied. As several people mentioned the connections made to this chip (whether electrical, or for thermal dispersion), gold will always maximize connection quality over the life of a product.
– ColdCold
Nov 20 at 21:20
add a comment |
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