NSC JM38510-30906BE, JD54LS257SEA, JM38510-30906BF Datasheet

0 (0)

June 1989

54LS257A/DM54LS257B/DM74LS257B,

54LS258A/DM54LS258B/DM74LS258B TRI-STATEÉ Quad 2-Data Selectors/Multiplexers

General Description

These Schottky-clamped high-performance multiplexers feature TRI-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 TRI-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.

Features

Y TRI-STATE versions LS157 and LS158 with same pinouts

Y Schottky-clamped for significant improvement in A-C performance

Y Provides bus interface from multiple sources in highperformance systems

YAverage propagation delay from data input 12 ns

YTypical power dissipation

LS257B	50 mW
LS258B	35 mW
Y Alternate	military/aerospace devices (54LS257A/

54LS258A) are available. Contact a National Semiconductor Sales Office/Distributor for specifications.

Connection Diagrams

Dual-In-Line Package

TL/F/6417 ± 1	TL/F/6417 ± 2
Order Number 54LS257ADMQB, 54LS257AFMQB,	Order Number 54LS258ADMQB, 54LS258AFMQB,
54LS257ALMQB, DM54LS257BJ, DM54LS257BW,	54LS258ALMQB, DM54LS258BJ, DM54LS258BW,
DM74LS257BM or DM74LS257BN	DM74LS258BM or DM74LS258BN
See NS Package Number E20A, J16A,	See NS Package Number E20A, J16A,
M16A, N16E or W16A	M16A, N16E or W16A

Function Table

	Inputs			Output Y

Output	Select	A B		LS257	LS258
Control	Select	A B		LS257	LS258
Control

H	X	X	X	Z		Z
L	L	L	X	L		H
L	L	H	X	H		L
L	H	X	L	L		H
L	H	X	H	H		L

H e High Level, L e Low Level, X e Don't Care,

Z e High Impedance (off)

TRI-STATEÉ is a registered trademark of National Semiconductor Corporation.

C1995 National Semiconductor Corporation

TL/F/6417

RRD-B30M105/Printed in U. S. A.

54LS258A/DM54LS258B/DM74LS258B 54LS257A/DM54LS257B/DM74LS257B, Selectors/Multiplexers Data-2 Quad STATE-TRI

Absolute Maximum Ratings (Note)

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications.

Supply Voltage	7V
Input Voltage	7V
Operating Free Air Temperature Range	b55§C to a125§C
DM54LS and 54LS	b55§C to a125§C
DM74LS	0§C to a70§C
Storage Temperature Range	b65§C to a150§C

Note: 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'' table are not guaranteed at the absolute maximum ratings. The ``Recommended Operating Conditions'' table will define the conditions for actual device operation.

Recommended Operating Conditions

Symbol

Parameter

DM54LS257B

DM74LS257B

Units

Min

Nom

Max

Min

Nom

Max

VCC

Supply Voltage

4.5

5.5

4.75

5.25

VIH

High Level Input Voltage

VIL

Low Level Input Voltage

0.7

0.8

IOH

High Level Output Current

b2.6

IOL

Low Level Output Current

Free Air Operating Temperature

b55

125

§C

'LS257B Electrical Characteristics

over recommended operating free air temperature range (unless otherwise noted)

Symbol	Parameter	Conditions		Min	Typ	Max	Units
Symbol	Parameter	Conditions		Min	(Note 1)	Max	Units
					(Note 1)
VI	Input Clamp Voltage	VCC e Min, II e b18 mA				b1.5	V
VOH	High Level Output	VCC e Min, IOH e Max	DM54	2.4	3.4		V
	Voltage	VIL e Max, VIH e Min	DM74	2.4	3.1		V
	Voltage	VIL e Max, VIH e Min

VOL	Low Level Output	VCC e Min, IOL e Max	DM54		0.25	0.4
	Voltage	VIL e Max, VIH e Min	DM74		0.35	0.5	V
			DM74		0.35	0.5	V
		IOL e 12 mA, VCC e Min	DM74		0.25	0.4
II	Input Current @ Max	VCC e Max,	Select			0.2	mA
	Input Voltage	VI e 7V	Other			0.1	mA
	Input Voltage	VI e 7V

IIH	High Level Input	VCC e Max,	Select			40	mA
	Current	VI e 2.7V	Other			20	mA
	Current	VI e 2.7V

IIL	Low Level Input	VCC e Max,	Select			b0.8	mA
	Current	VI e 0.4V	Other			b0.4	mA
	Current	VI e 0.4V

IOZH	Off-State Output Current	VCC e Max, VO e 2.7V
	with High Level Output	VIH e Min, VIL e Max				20	mA
	Voltage Applied
IOZL	Off-State Output Current	VCC e Max, VO e 0.4V
	with Low Level Output	VIH e Min, VIL e Max				b20	mA
	Voltage Applied
IOS	Short Circuit	VCC e Max	DM54	b20		b100	mA
	Output Current	(Note 2)	DM74	b20		b100	mA
	Output Current	(Note 2)

ICCH	Supply Current with	VCC e Max (Note 3)			5.9	10	mA
	Outputs High				5.9	10	mA
	Outputs High
ICCL	Supply Current with	VCC e Max (Note 3)			9.2	16	mA
	Outputs Low				9.2	16	mA
	Outputs Low
ICCZ	Supply Current with	VCC e Max (Note 3)			12	19	mA
	Outputs Disabled				12	19	mA
	Outputs Disabled
Note 1: All typicals are at VCC e 5V, TA e 25§C.

Note 2: Not more than one output should be shorted at a time, and the duration should not exceed one second.

Note 3: ICC is measured with all outputs open and all possible inputs grounded, while achieving the stated output conditions.

'LS257B Switching Characteristics

at VCC e 5V and TA e 25§C (See Section 1 for Test Waveforms and Output Load)

From (Input)

RL e

667X

Symbol

Parameter

To (Output)

CL e 45 pF

CL e 150 pF

Units

Min

Max

Min

Max

tPLH

Propagation Delay Time

Data to

Low to High Level Output

Output

tPHL

Propagation Delay Time

Data to

High to Low Level Output

Output

tPLH

Propagation Delay Time

Select to

Low to High Level Output

Output

tPHL

Propagation Delay Time

Select to

High to Low Level Output

Output

tPZH

Output Enable Time

Output

to High Level Output

Control to Y

tPZL

Output Enable Time

Output

to Low Level Output

Control to Y

tPHZ

Output Disable Time from

Output

High Level Output (Note 1)

Control to Y

tPLZ

Output Disable Time from

Output

Low Level Output (Note 1)

Control to Y

Note 1: CL e 5 pF.

Recommended Operating Conditions

Symbol

Parameter

DM54LS258B

DM74LS258B

Units

Min

Nom

Max

Min

Nom

Max

VCC

Supply Voltage

4.5

5.5

4.75

5.25

VIH

High Level Input Voltage

VIL

Low Level Input Voltage

0.7

0.8

IOH

High Level Output Current

b2.6

IOL

Low Level Output Current

Free Air Operating Temperature

b55

125

§C

'LS258B Electrical Characteristics

over recommended operating free air temperature range (unless otherwise noted)

Symbol	Parameter	Conditions		Min	Typ	Max	Units
Symbol	Parameter	Conditions		Min	(Note 1)	Max	Units
					(Note 1)

VI	Input Clamp Voltage	VCC e Min, II e b18 mA				b1.5	V
VOH	High Level Output	VCC e Min, IOH e Max	DM54	2.4	3.4		V
	Voltage	VIL e Max, VIH e Min	DM74	2.4	3.1		V
	Voltage	VIL e Max, VIH e Min


VOL	Low Level Output	VCC e Min, IOL e Max	DM54		0.25	0.4
	Voltage	VIL e Max, VIH e Min	DM74		0.35	0.5	V
			DM74		0.35	0.5	V

		IOL e 12 mA, VCC e Min	DM74		0.25	0.4
II	Input Current @ Max	VCC e Max,	Select			0.2	mA
	Input Voltage	VI e 7V	Other			0.1	mA
	Input Voltage	VI e 7V


IIH	High Level Input	VCC e Max,	Select			40	mA
	Current	VI e 2.7V	Other			20	mA
	Current	VI e 2.7V

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