Philips N74ALS240A-1D, N74ALS240A-1N, N74ALS240AD, N74ALS240ADB Datasheet

INTEGRATED CIRCUITS

74ALS240A/74ALS240A±1

Octal inverter buffer (3±State)

Product specification	1991 Feb 08
IC05 Data Handbook

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	Philips Semiconductors	Product specification
	Octal inverter buffer (3-State)	74ALS240A/
		74ALS240A-1

FEATURES

•Octal bus interface

•3-State buffer outputs sink 24mA and source 15mA

•The -1 version sinks 48 mA

DESCRIPTION

The 74ALS240A is an octal buffer that is ideal for driving bus lines or buffer memory address registers. The outputs are all capable of sinking 24mA and sourcing up to 15mA, producing very good capacitive drive characteristics. The device features two output

enables, OEa and OEb, each controlling four of the 3-State outputs.

The 74ALS240A-1 sinks 48 mA IOL if the VCC is limited to 5.0V ±0.25V.

	TYPICAL	TYPICAL
TYPE	PROPAGATION	SUPPLY CURRENT
	DELAY	(TOTAL)
74ALS240A	4.5ns	15mA
74ALS240A-1	4.5ns	15mA

PIN CONFIGURATION

					VCC
OEa			1	20
	Ia0		2	19
					OEb
			3	18
	Yb0				Ya0
	Ia1		4	17	Ib0
			5	16
	Yb1				Ya1
	Ia2		6	15	Ib1
			7	14
	Yb2				Ya2
	Ia3		8	13	Ib2
			9	12
	Yb3				Ya3
GND			10	11	Ib3

SF00320

ORDERING INFORMATION

		ORDER CODE
			DRAWING
		COMMERCIAL RANGE
			NUMBER
	DESCRIPTION	VCC = 5V ±10%,
		Tamb = 0°C to +70°C
	20-pin plastic DIP	74ALS240AN,	SOT146-1
		74ALS240A-1N
	20-pin plastic SOL	74ALS240AD,	SOT163-1
		74ALS240A-1D
	20-pin plastic SSOP	74ALS240ADB,	SOT339-1
	Type II	74ALS240A-1DB

INPUT AND OUTPUT LOADING AND FAN-OUT TABLE

			PINS																		DESCRIPTION							74ALS (U.L.)								LOAD VALUE
																														HIGH/LOW						HIGH/LOW
		Ian, Ibn										Data inputs																1.0/1.0								20μA/0.1mA
												Output Enable inputs (active-Low)																1.0/1.0								20μA/0.1mA
	OEa, OEb
												Data outputs																750/240								15mA/24mA
		Yan, Ybn
												Data outputs (-1 version)																750/480								15mA/48mA
		Yan, Ybn
NOTE: One (1.0) ALS unit load is defined as: 20μA in the High state and 0.1mA in the Low state.
LOGIC SYMBOL																											IEC/IEEE SYMBOL
																														1
									2		4		6		8		17		15		13		11									EN1
																											19
																																EN2
									Ia0		Ia1		Ia2		Ia3		Ib0		Ib1		Ib2		Ib3				2									18
1									OEa																					4		2D		1		16
19									OEb																					6						14
																											8									12
									Ya0 Ya1				Ya2		Ya3		Yb0		Yb1		Yb2		Yb3
																														17						3
																																		2
									18		16		14		12		3		5		7		9				15									5
																																				7
																											13
																																				9
VCC = Pin 20																											11
GND = Pin 10																									SF00321													SF00322

1991 Feb 08

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853±1244 01670

Philips Semiconductors	Product specification

Octal inverter buffer (3-State)

74ALS240A/ 74ALS240A-1

LOGIC DIAGRAM

2	18	Ya0	17	3
Ia0			Ib0	Yb0
4	16	Ya1	15	5
Ia1			Ib1	Yb1
6	14	Ya2	13	7
Ia2			Ib2	Yb2
8	12	Ya3	11	9
Ia3			Ib3	Yb3
OEa 1			OEb 10

VCC = Pin 20

GND = Pin 10

SF00323

FUNCTION TABLE

INPUTS

OUTPUTS

Ia

Ib

OEa

OEb

Ya

Yb

L

L

L

L

H

H

L

H

L

H

L

L

H

X

H

X

Z

Z

H

=

High voltage level

L

=

Low voltage level

X

=

Don't care

Z

=

High impedance ªoffº state

ABSOLUTE MAXIMUM RATINGS

(Operation beyond the limit set forth in this table may impair the useful life of the device. Unless otherwise noted these limits are over the operating free air temperature range.)

	SYMBOL	PARAMETER		RATING	UNIT
	VCC	Supply voltage		±0.5 to +7.0	V
	VIN	Input voltage		±0.5 to +7.0	V
	IIN	Input current		±30 to +5	mA
	VOUT	Voltage applied to output in High output state		±0.5 to VCC	V
	IOUT	Current applied to output in Low output state	All versions	48	mA
			-1 version	96	mA
	Tamb	Operating free-air temperature range		0 to +70	°C
	Tstg	Storage temperature range		±65 to +150	°C

RECOMMENDED OPERATING CONDITIONS

SYMBOL	PARAMETER			LIMITS		UNIT
			MIN	NOM	MAX
VCC	Supply voltage		4.5	5.0	5.5	V
VIH	High-level input voltage		2.0			V
VIL	Low-level input voltage				0.8	V
IIK	Input clamp current				±18	mA
IOH	High-level output current				±15	mA
IOL	Low-level output current	All versions			24	mA
		-1 version			48 1	mA
Tamb	Operating free-air temperature range		0		+70	°C

NOTE:

1. The 48mA limit applies only under the condition of VCC = 5.0V ±5%.

1991 Feb 08

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