DM74S257N

DM74S257N Datasheet

DM74S257 3-STATE Quad 1-of-2 Data Selector/Multiplexer

Part	Datasheet
DM74S257N	DM74S257N (pdf)

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DM74S257 3-STATE Quad 1-of-2 Data Selector/Multiplexer DM74S257 3-STATE Quad 1-of-2 Data Selector/Multiplexer These Schottky-clamped high-performance multiplexers feature 3-STATE outputs that can interface directly with data lines of bus-organized systems. With all but one of the common outputs disabled at a high impedance state , the low impedance of the single enabled output will drive the bus line to a HIGH or LOW logic level. To minimize the possibility that two outputs will attempt to take a common bus to opposite logic levels, the output enable circuitry is designed such that the output disable times are shorter than the output enable times. This 3-STATE output feature means that n-bit paralleled data selectors with up to 258 sources can be implemented for data buses. It also permits the use of standard TTL registers for data retention throughout the system. s 3-STATE versions S157, S158, with same pin-outs s Schottky-clamped for significant improvement in A-C performance s Provides bus interface from multiple sources in high-per- formance systems s Average propagation delay from data input ns s Typical power dissipation 320 mW Ordering Code: Order Number Package Number Package Description DM74S257N N16E 16-Lead Plastic Dual-In-Line Package PDIP , JEDEC MS-001, Wide Connection Diagram Function Table Inputs Output Select Control H = HIGH Level L = LOW Level X = Don’t Care Z = High Impedance OFF Output 2000 Fairchild Semiconductor Corporation DS006482 DM74S257 Logic Diagram DM74S257 Absolute Maximum Ratings Note 1 Supply Voltage Input Voltage 5.5V Operating Free Air Temperature Range 0°C to +70°C Storage Temperature Range −65°C to +150°C Note 1 The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The “Recommended Operating Conditions” table will define the conditions for actual device operation. Recommended Operating Conditions VCC VIH VIL IOH IOL TA Parameter Supply Voltage HIGH Level Input Voltage LOW Level Input Voltage HIGH Level Output Current LOW Level Output Current Free Air Operating Temperature Electrical Characteristics over recommended operating free air temperature unless otherwise noted Parameter Conditions Typ Min Note 2 Input Clamp Voltage VCC = Min, II = −18 mA HIGH Level VCC = Min, IOH = Max Output Voltage VIL = Max, VIH = Min LOW Level

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DM74S257 3-STATE Quad 1-of-2 Data Selector/Multiplexer

DM74S257 3-STATE Quad 1-of-2 Data Selector/Multiplexer

These Schottky-clamped high-performance multiplexers feature 3-STATE outputs that can interface directly with data lines of bus-organized systems. With all but one of the common outputs disabled at a high impedance state , the low impedance of the single enabled output will drive the bus line to a HIGH or LOW logic level. To minimize the possibility that two outputs will attempt to take a common bus to opposite logic levels, the output enable circuitry is designed such that the output disable times are shorter than the output enable times.

This 3-STATE output feature means that n-bit paralleled data selectors with up to 258 sources can be implemented for data buses. It also permits the use of standard TTL registers for data retention throughout the system.
s 3-STATE versions S157, S158, with same pin-outs
s Schottky-clamped for significant improvement in A-C performance
s Provides bus interface from multiple sources in high-per-
formance systems
s Average propagation delay from data input ns
s Typical power dissipation
320 mW
Ordering Code:

Order Number Package Number

Package Description

DM74S257N

N16E
16-Lead Plastic Dual-In-Line Package PDIP , JEDEC MS-001, Wide

Connection Diagram

Function Table

Inputs

Output Select

Control

H = HIGH Level L = LOW Level X = Don’t Care Z = High Impedance OFF

Output
2000 Fairchild Semiconductor Corporation DS006482

DM74S257

Logic Diagram

DM74S257

Absolute Maximum Ratings Note 1

Supply Voltage

Input Voltage
5.5V

Operating Free Air Temperature Range 0°C to +70°C

Storage Temperature Range
−65°C to +150°C

Note 1 The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The “Recommended Operating Conditions” table will define the conditions for actual device operation.

Recommended Operating Conditions

VCC VIH VIL IOH IOL TA

Parameter Supply Voltage HIGH Level Input Voltage LOW Level Input Voltage HIGH Level Output Current LOW Level Output Current Free Air Operating Temperature

Electrical Characteristics
over recommended operating free air temperature unless otherwise noted

Parameter

Conditions

Typ Min

Note 2

Input Clamp Voltage

VCC = Min, II = −18 mA

HIGH Level

VCC = Min, IOH = Max

Output Voltage

VIL = Max, VIH = Min

LOW Level

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Datasheet ID: DM74S257N 513839