Fairchild Semiconductor DM74ALS244AWMX, DM74ALS244AWM, DM74ALS244ASJX, DM74ALS244ASJ, DM74ALS244AN Datasheet

September 1986

Revised February 2000

DM74ALS244A

Octal 3-STATE Bus Driver

General Description

This octal 3-STATE bus driver is designed to provide the designer with flexibility in implementing a bus interface with memory, microprocessor, or communication systems. This device offers 64-extended temperature Grade product guaranteeing performance from −40°C to +85°C. The output 3-STATE gating control is organized into two separate groups of four buffers, and both control inputs enable the respective outputs when set logic LOW. The 3-STATE circuitry contains a feature that maintains the buffer outputs in 3-STATE (high impedance state) during power supply ramp-up or ramp-down. This eliminates bus glitching problems that arise during power-up and power-down.

Features

■Advanced low power oxide-isolated ion-implanted Schottky TTL process

■Functional and pin compatible with the 74LS counterpart

■Improved switching performance with less power dissipation compared with the 74LS counterpart

■Switching response specified into 500Ω and 50 pF load

■Switching response specifications guaranteed over full temperature and VCC supply range

■PNP input design reduces input loading

Ordering Code:

Order Number	Package Number	Package Description
DM74ALS244AWM	M20B	20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
DM74ALS244ASJ	M20D	20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
DM74ALS244AMSA	MSA20	20-Lead Shrink Small Outline Package (SSOP), EIAJ TYPE II, 5.3mm Wide
DM74ALS244AN	N20A	20-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

Logic Diagram

Function Table

			Input	Output
			A	Y
G
	L		L	L
	L		H	H
	H		X	Z

H = HIGH Level Logic State

L = LOW Level Logic State

X = Don't Care (Either LOW or HIGH Level Logic State)

Z = High Impedance (OFF) State

Driver Bus STATE-3 Octal DM74ALS244A

© 2000 Fairchild Semiconductor Corporation

DS006212

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DM74ALS244A

Absolute Maximum Ratings(Note 1)

Supply Voltage, VCC	7V
Input Voltage	7V
Voltage Applied to Disabled Output	5.5V
Operating Free Air Temperature Range	0°C to +70°C
Storage Temperature Range	−65°C to +150°C
Typical θJA
N Package	60.5°C/W
M Package	79.8°C/W

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

Symbol	Parameter	Min	Typ	Max	Units
VCC	Supply Voltage	4.5	5	5.5	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	Operating Free-Air Temperature	0		70	°C

Electrical Characteristics

over recommended operating free air temperature (unless otherwise specified)

Symbol	Parameter	Conditions		Min	Typ	Max	Units
VIK	Input Clamp Voltage	VCC = 4.5V, II = −18 mA				−1.5	V
VOH	HIGH Level	VCC = 4.5V to 5.5V	IOH = −0.4 mA	VCC−2			V
	Output Voltage	VCC = 4.5V	IOH = −3 mA	2.4			V
			IOH = Max	2			V
VOL	LOW Level	VCC = 4.5V			0.35	0.5	V
	Output Voltage	IOL = 24 mA
II	Input Current at Maximum Input Voltage	VCC = 5.5V, VI = 7V				0.1	mA
IIH	HIGH Level Input Current	VCC = 5.5V, VI = 2.7V				20	μA
IIL	LOW Level Input Current	VCC = 5.5V, VIL = 0.4V				−0.1	mA
IO	Output Drive Current	VCC = 5.5V, VO = 2.25V		−30		−112	mA
IOZH	HIGH Level 3-STATE Output Current	VCC = 5.5V, VO = 2.7V				20	μA
IOZL	LOW Level 3-STATE Output Current	VCC = 5.5V, VO = 0.4V				−20	μA
ICC	Supply Current	VCC = 5.5V			9	15	mA
		Outputs HIGH
		Outputs LOW			15	24	mA
		Outputs 3-STATE			17	27	mA

Switching Characteristics

over recommended operating free-air temperature range

	Symbol	Parameter	Conditions	From				To	Min	Max	Units
				(Input)				(Output)
	tPLH	Propagation Delay Time	VCC = 4.5V to 5.5V,			A		Y	3	10	ns
		LOW-to-HIGH Level Output	CL = 50 pF,
	tPHL	Propagation Delay Time	R1 = 500Ω,			A		Y	3	10	ns
		HIGH-to-LOW Level Output	R2 = 500Ω,
			TA = Min to Max
	tPZH	Output Enable Time to HIGH Level Output				G		Y	3	20	ns
	tPZL	Output Enable Time to LOW Level Output						Y	3	20	ns
						G
	tPHZ	Output Disable Time from HIGH Level Output						Y	2	10	ns
					G
	tPLZ	Output Disable Time from LOW Level Output			G			Y	1	13	ns

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