COM8046 Datasheet | Standard Microsystems Corporation

FEATURES o On chip crystal oscillator or external frequency input o Single + 5v power supply o Choice of 32 output frequencies o 32 asynchronousl synchronous baud rates o Direct UARTIUSRTI ASTRO/USYNRT patibility ORe-programmable ROM via CLASp® technology allows generation of other frequencies o TTL, MOS patible o 1X Clock via fol 16 output o Crystal frequency output via fx and fxl 4 outputs o Output disable via FENA PIN CONFIGURATION XTALl EXT1 1 I XTALl EXT2 2 +5v 3 fx 4 GND 51 fo/16 61 FENA 71 E 81 ..J )16 fo 15 A 14 B 13 C 12 D 11 ST 10 fx/4 9 NC ST~--' A B C D E BLOCK DIAGRAM REPROGRAM MABLE FREQUENCY SELECT DIVIDER ROM XTALl EXT1 XTALl EXT2 DIVIDER FENA~------------------------------4------------------------------------------------------------------~----------~ A ,l +5v GND 10 10/16 fx fx/4 General Description The Standard Microsystems 8046 is an enhanced version of the 5046 Baud Rate Generator. It is fabricated using SMC's patented COPLAMOS® and CLASp® technologies and employs depletion mode loads, allowing operation - from a single +5v supply. The standard 8046 is specifically dedicated to generating the full spectrum of 16 asynchronousl synchronous data munication frequencies for 1X, 16X and 32X UARTI USRTI ASTRal USYNRT devices. The 8046 features an internal crystal oscillator which may be used to provide the master reference frequency. Alternatively, an external reference may be supplied by applying plementary TTL level signals to pins 1 and 2. Parts suitable for use only with an external TTL reference are marked 8046T. TTL outputs used to drive the 8046 or 8046T should not be used to drive other TTL inputs, as noise immunity may be promised due to excessive loading. The reference frequency (fx) is used to provide two high frequency outputs: one at fx and the other at fx/4. The fx/4 output will drive one standard 7400 load, while the fx output will drive two 74LS loads. The output of the oscillatorlbuffer is applied to the divider...