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young
Joined: 24 Jun 2004
Posts: 285
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| How to tell the difference of the Microchip by name? |
 Posted: Fri Jul 30, 2004 7:02 am |
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THere is a bunch of microchips, like 16c73, 16f73, 16LC84, , 16CR83,16HV540, 16f877, 16f877a, 12f675, what does
Chip name
16 f 877 a
1 2 3 4
these parts in the name means |
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Ttelmah
Guest
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| Re: How to tell the difference of the Microchip by name? |
| Posted: Fri Jul 30, 2004 7:23 am |
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| young wrote: | THere is a bunch of microchips, like 16c73, 16f73, 16LC84, , 16CR83,16HV540, 16f877, 16f877a, 12f675, what does
Chip name
16 f 877 a
1 2 3 4
these parts in the name means |
The '12', or '16', are supposed to mean they are using the 12bit, or 14bit 'core' (unfortunately, the 12F675, is one of only a couple of chips that 'breaks the rules', and is a 14bit core chip, though it is sold as part of the smaller family - go figure!...).
The 'F', shows if is a 'flash' part. Again though, there are exceptions, wth the old 16C84, being flash, yet using a 'C' number. This one was corrected latter with the chip 'relaunched' as the 16F84.
Then the 'L', implies a low power variant.
CR, says it is a ROM based chip (usually cheaper for mass production).
The 'HV' letters, imply it supports more than 5v (has a voltage regulator).
The '877', is just a model 'number'. A bit like saying a car is an [spam], or a Fiesta. The only 'meaning', is by looking the number up on the MicroChip site.
The 'A', implies it is a revised version. The meaning of this is indeterminate. For some chips, the 'A', versions just support higher speed, or lower power. However there are a couple of models where the 'A' variants has sigificant feature changes...
The numbers afterwards, are the manufacturing date code.
The only real way to know what a chip does is to look it up.
Best Wishes |
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young
Joined: 24 Jun 2004
Posts: 285
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| Posted: Fri Jul 30, 2004 7:43 am |
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| thanks a lot. |
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valemike
Guest
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| Re: How to tell the difference of the Microchip by name? |
| Posted: Fri Jul 30, 2004 8:10 am |
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| Quote: | | The 'A', implies it is a revised version. The meaning of this is indeterminate. For some chips, the 'A', versions just support higher speed, or lower power. However there are a couple of models where the 'A' variants has sigificant feature changes... |
I'm no VLSI designer, but I noticed that the 'A' version is usually cheaper than the predecessor. In the past I was told that there are die shrinks involved, so Microchip gets more yield for less material. I guess that is why characteristics can change. Usually they are benign and transparent to most applications, but some circuits may behave a bit more erratic with newer chips. That's why it's best to re-do your test procedure than simply upgrading to the 'A' chip and then shipping w/o testing. |
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Ttelmah
Guest
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| Re: How to tell the difference of the Microchip by name? |
| Posted: Fri Jul 30, 2004 2:42 pm |
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| valemike wrote: | | Quote: | | The 'A', implies it is a revised version. The meaning of this is indeterminate. For some chips, the 'A', versions just support higher speed, or lower power. However there are a couple of models where the 'A' variants has sigificant feature changes... |
I'm no VLSI designer, but I noticed that the 'A' version is usually cheaper than the predecessor. In the past I was told that there are die shrinks involved, so Microchip gets more yield for less material. I guess that is why characteristics can change. Usually they are benign and transparent to most applications, but some circuits may behave a bit more erratic with newer chips. That's why it's best to re-do your test procedure than simply upgrading to the 'A' chip and then shipping w/o testing. |
Yes. Historically, 90% of the 'A' variants are exactly as you describe. Latter, slight smaller cores, usually faster, and often cheaper. Unfortunately, a while ago, a couple of 'A' variants appeared, which are significantly different from their 'ancestors', with extra features (these normally warrant a different chip number), in a couple of cases, the loss of another feature (same comment), and in several cases, different programming requirements. These latter 'A' variants, probably do still use smaller dies, but in all honesty, have to be treated as seperate chips...
Best Wishes |
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falleaf
Joined: 23 May 2004
Posts: 48
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| Re: How to tell the difference of the Microchip by name? |
| Posted: Sun Aug 01, 2004 11:04 am |
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| Ttelmah wrote: | | young wrote: | THere is a bunch of microchips, like 16c73, 16f73, 16LC84, , 16CR83,16HV540, 16f877, 16f877a, 12f675, what does
Chip name
16 f 877 a
1 2 3 4
these parts in the name means |
The '12', or '16', are supposed to mean they are using the 12bit, or 14bit 'core' (unfortunately, the 12F675, is one of only a couple of chips that 'breaks the rules', and is a 14bit core chip, though it is sold as part of the smaller family - go figure!...).
The 'F', shows if is a 'flash' part. Again though, there are exceptions, wth the old 16C84, being flash, yet using a 'C' number. This one was corrected latter with the chip 'relaunched' as the 16F84.
Then the 'L', implies a low power variant.
CR, says it is a ROM based chip (usually cheaper for mass production).
The 'HV' letters, imply it supports more than 5v (has a voltage regulator).
The '877', is just a model 'number'. A bit like saying a car is an [spam], or a Fiesta. The only 'meaning', is by looking the number up on the MicroChip site.
The 'A', implies it is a revised version. The meaning of this is indeterminate. For some chips, the 'A', versions just support higher speed, or lower power. However there are a couple of models where the 'A' variants has sigificant feature changes...
The numbers afterwards, are the manufacturing date code.
The only real way to know what a chip does is to look it up.
Best Wishes |
Note:
1) F is not Flash. It's only EEPROM. The end with A is really Flash! Why? Because the Flash is first called by Atmel, and Microchip need to call their chip Flash too. But it's really EEPROM only. 16F877 is an example.
2) 16F877A is really Flash chip. And it's cheaper because microchip add more functions on it. But these functions are not quite necessary! So, if they sell it at higher prices, people will choose old version unless they need newer functions. But with designed products, they don't wanna change to 16F877A if the price is equa or higher. So, at first, microchip need people to play with new version, after that, I don't know !!!
3) 16C84 is not Flash, it's EEPROM. 16F84A is a flash one. |
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