Datasheet or info for Fairchild uA3656D?

[Dwight K. Elvey]

Hi
 There is a good chance it is an interface part.
Remember the 8008 bus is not TTL.
Dwight


>From: "Brent Hilpert" <hilpert at cs.ubc.ca>
>
>I (too) can not find a reference for the uA3656 in the Fairchild Full Line 
Condensed Catalog (1975).
>
>However, I believe Fairchild's naming convention is that "uA..." would indicate 
analog or interface functionality.
>
>Speculation #1:
>  If there are some connections from the uA3656 to the 1101s (or 1702s) (but 
not pin-for-pin parallelling) it may be a TTL<->MOS 
sense-amplifier/driver/level-converter. Early MOS memory chips used external 
drivers/sense amplifiers, and specialised ICs were produced for those functions.
>
>  For example, I found Motorola refs for DS3645/75 (hex 3S latch driver for MOS 
mem), DS3647/77 (quad 3S MOS mem IO reg), MC3461 (dual NMOS Memory Sense Amp) 
(from Motorola Linear 1976).
>
>  Perhaps it is from the Motorola DS36.. line, but second-sourced from 
Fairchild.
>
>Speculation #2:
>  An A/D or D/A converter (perhaps connected to the nearby D connector?).
>
>
>BTW & FWIW:
>  On your web page about the AMI S6800 
(http://www.classiccmp.org/hp/ami/ami.htm), you wonder what the FCM7002 IC is.
>It is a clock/calendar chip, like those used in the 1970s for constructing 
digital clocks: the FCM7001 (aka CT7001) was a clock/calendar chip with 
multiplexed 6-digit 7-segment display outputs. If I have it correctly, on the 
FCM7002 the 7-segment outputs are replaced with BCD outputs. (... built a clock 
using the 7001, and saw the 7002 on a real-time-clock I/O board for the TI-990 
in the late 1970s, must have been rather awkward for the board designers to 
interface.)
>
>
>"Joe R." wrote:
>> 
>>   Does anyone have any information about this IC? I have two of them. I
>> found them in the memory section of an Intel 8008 based computer. The other
>> RAMs are Intel 1101s so I'm guessing that these are equivelent parts but I
>> want to be sure. The date code on these is 7114 and they're white ceramic
>> with gold lids and faint grey traces to each leg. Here
>> <http://www.classiccmp.org/hp/i8008-1/close-up.jpg> is a picture of the
>> board with the two ICs installed. The ICs in the top row are 1702 EPROMs.
>> The 1101 RAMs are in the second row. These two parts are the 2nd and 3rd
>> parts from the RH end. FWIW I have a 1970 and a 1973 Fairchild catalogs but
>> neigher one lists any uA36xx parts.
>> 
>>     Joe
>