SLLS041E - OCTOBER 1988 - REVISED MARCH 1997
The SN75C189 and SN75C189A are low-power bipolar quadruple line receivers that are used to interface data terminal equipment (DTE) with data circuit-terminating equipment (DCE). These devices have been designed to conform with ANSI Standard EIA/TIA-232-E.
The SN75C189 has a 0.33 V typical hysteresis compared with 0.97 V for the SN75C189A. Each receiver has provision for adjustment of the overall input threshold levels. This is achieved by choosing external series resistors and voltages to provide bias levels for the response control pins. The output is in the high logic state if the input is left open circuited or shorted to ground.
These devices have an on-chip filter that rejects input pulses of shorter than 1-us minimum duration. An external capacitor may be connected from the control pins to ground to provide further input noise filtering for each receiver.
The SN75C189 and SN75C189A have been designed using low-power techniques in a bipolar technology. In most applications, these receivers will interface to single inputs of peripheral devices such as UARTs, ACEs, or microprocessors. By using sampling, such peripheral devices are usually insensitive to the transition times of the input signals. If this is not the case or for other uses, it is recommended that the SN75C189 and SN75C189A outputs be buffered by single Schmitt input gates or single gates of the HCMOS, ALS, or 74F logic families.
The SN75C189 and SN75C189A are characterized for operation from 0°C to 70°C.
View more information about generic part numbers:SN75C189, SN75C189A
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