Fairchild Semiconductor DM74LS243WM, DM74LS243N, DM74LS243MX, DM74LS243M, DM74LS243WMX Datasheet

August 1986

Revised January 2000

DM74LS243

Quadruple Bus Transceiver

General Description

This four data line transceiver is designed for asynchronous two-way communications between data buses. It can be used to drive terminated lines down to 133Ω.

Features

■Two-way asynchronous communication between data buses

■PNP inputs reduce DC loading on bus line

■Hysteresis at data inputs improves noise margin

Ordering Code:

Order Number	Package Number	Package Description
DM74LS243M	M14A	14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-120, 0.150 Narrow
DM74LS243N	N14A	14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide

Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.

Connection Diagram	Function Table
		Control		Data Port
		Inputs		Status
		G AB	GBA	A	B
		H	H	O	I
		L	H	(Note 1)	(Note 1)
		H	L	ISOLATED
		L	L	I	O
	I =	Input
	O = Output
	H = HIGH Logic Level
	L = LOW Logic Level
	Note 1: Possibly destructive oscillation may occur if the transceivers are
	enabled in both directions at once.

Transceiver Bus Quadruple DM74LS243

© 2000 Fairchild Semiconductor Corporation

DS006412

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DM74LS243

Absolute Maximum Ratings(Note 2)

Supply Voltage	7V
Input Voltage
Any G	7V
A or B	5.5V
Operating Free Air Temperature Range	0°C to +70°C
Storage Temperature Range	−65°C to +150°C

Note 2: 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

Symbol	Parameter	Min	Nom	Max	Units
VCC	Supply Voltage	4.75	5	5.25	V
VIH	HIGH Level Input Voltage	2			V
VIL	LOW Level Input Voltage			0.8	V
IOH	HIGH Level Output Current			−15	mA
IOL	LOW Level Output Current			24	mA
TA	Free Air Operating Temperature	0		70	°C

Electrical Characteristics

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

Symbol	Parameter		Conditions			Min	Typ	Max	Units
							(Note 3)
VI	Input Clamp Voltage	VCC = Min, II = −18 mA						−1.5	V
HYS	Hysteresis (VT+ − VT−)	VCC = Min				0.2	0.4		V
	(Data Inputs Only)
VOH	HIGH Level Output Voltage	VCC = Min, VIH = Min				2.7
		VIL = Max, IOH = −1 mA
		VCC = Min, VIH = Min				2.4	3.4		V
		VIL = Max, IOH = −3 mA
		VCC = Min, VIH = Min				2
		VIL = 0.5V, IOH = Max
VOL	LOW Level Output Voltage	VCC = Min		IOL = 12 mA				0.4
		VIL = Max		IOL = Max					V
		VIH = Min						0.5
IOZH	Off-State Output Current,	VCC = Max		VO = 2.7V				40	μA
	HIGH Level Voltage Applied	VIL = Max
IOZL	Off-State Output Current,	VIH = Min		VO = 0.4V				−200	μA
	LOW Level Voltage Applied
II	Input Current at Maximum	VCC = Max		VI = 5.5V	A or B			0.1	mA
	Input Voltage			VI = 7V	Any G			0.1	mA
IIH	HIGH Level Input Current	VCC = Max, VI =		2.7V				20	μA
IIL	LOW Level Input Current	VCC = Max, VI = 0.4V						−0.2	mA
IOS	Short Circuit Output Current	VCC = Max (Note 4)				−40		−225	mA
ICC	Supply Current	VCC = Max		Outputs HIGH			22	38
		Outputs		Outputs LOW			29	50	mA
		OPEN		Outputs Disabled			32	54
Note 3: All	typicals are at VCC = 5V, TA = 25°C.

Note 4: Not more than one output should be shorted at a time, and the duration should not exceed one second.

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