Texas Instruments SN74ALS639ADW, SN74ALS639ADWR, SN74ALS639AN, SN74ALS638A-1DW, SN74ALS638A-1DWR Datasheet

SN74ALS638A, SN74ALS639A, SN74AS638A, SN74AS639

OCTAL BUS TRANSCEIVERS

SDAS123A ± DECEMBER 1983 ± REVISED JANUARY 1995

• Bidirectional Bus Transceivers in				DW OR N PACKAGE
High-Density 20-Pin Packages					(TOP VIEW)
• Choice of True or Inverting Logic				DIR						VCC
						1	20
• A-Bus Outputs Are Open Collector;
				A1		2	19			OE
B-Bus Outputs Are 3 State
				A2		3	18			B1
• Package Options Include Plastic
				A3		4	17			B2
Small-Outline (DW) Packages and				A4		5	16			B3
Standard Plastic (N) 300-mil DIPs				A5		6	15			B4
				A6		7	14			B5
DEVICE	A	B	LOGIC	A7		8	13			B6
	OUTPUT	OUTPUT		A8		9	12			B7
SN74ALS638A, SN74AS638A	Open collector	3 state	Inverting	GND		10	11			B8
SN74ALS639A, SN74AS639	Open collector	3 state	True

description

These octal bus transceivers are designed for asynchronous two-way communication between open-collector and 3-state buses. The devices transmit data from the A bus (open-collector) to the B bus (3 state) or from the B bus to the A bus, depending on the logic level at the direction-control (DIR) input. The output-enable (OE) input can be used to disable the device so the buses are isolated.

The -1 version of SN74ALS638A is identical to the standard version, except that the recommended maximum IOL is increased to 48 mA.

The SN74ALS638A, SN74ALS639A, SN74AS638A, and SN74AS639 are characterized for operation from 0°C to 70°C.

FUNCTION TABLE

	INPUTS						OPERATION
			SN74ALS638A					SN74ALS639A
	OE	DIR
					SN74AS638A			SN74AS639
	L	L					data to A bus	B data to A bus
					B
	L	H						A data to B bus
				A			data to B bus
	H	X					Isolation	Isolation

PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters.

Copyright 1995, Texas Instruments Incorporated

POST OFFICE BOX 655303 •DALLAS, TEXAS 75265

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SN74ALS638A, SN74ALS639A, SN74AS638A, SN74AS639

OCTAL BUS TRANSCEIVERS

SDAS123A ± DECEMBER 1983 ± REVISED JANUARY 1995

logic symbols²

SN74ALS638A, SN74AS638A

SN74ALS639A, SN74AS639

19

19

G3

G3

OE

OE

1

1

DIR

3 EN1 [BA]

DIR

3 EN1 [BA]

3 EN2 [AB]

3 EN2 [AB]

A1	2	18	A1	2	18
	1	B1		1	B1
	2				2
A2	3	17	A2	3	17
		B2			B2
A3	4	16	A3	4	16
		B3			B3
A4	5	15	A4	5	15
		B4			B4
A5	6	14	A5	6	14
		B5			B5
A6	7	13	A6	7	13
		B6			B6
A7	8	12	A7	8	12
		B7			B7
A8	9	11	A8	9	11
		B8			B8

² These symbols are in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.

logic diagrams (positive logic)

SN74ALS638A, SN74AS638A

SN74ALS639A, SN74AS639

OE	19
DIR	1
A1	2	18
		B1

OE	19
DIR	1
A1	2	18
		B1

To Seven Other Transceivers

To Seven Other Transceivers

absolute maximum ratings over operating free-air temperature range (unless otherwise noted)³

Supply voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . . . . . . . . . 7	V
Input voltage, VI: All inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . . . . . . . . 7	V
A-bus I/O ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . . . . . . . . 7	V
B-bus I/O ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . . . . . . 5.5	V
Operating free-air temperature range, TA: SN74ALS638A, SN74ALS639A . . . . . . . . . . . . . . .	. . 0°C to 70°C
Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	±65°C to 150°C

³Stresses beyond those listed under ªabsolute maximum ratingsº may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under ªrecommended operating conditionsº is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

2	POST OFFICE BOX 655303 •DALLAS, TEXAS 75265

SN74ALS638A, SN74ALS639A, SN74AS638A, SN74AS639

OCTAL BUS TRANSCEIVERS

SDAS123A ± DECEMBER 1983 ± REVISED JANUARY 1995

recommended operating conditions

			SN74ALS638A
			SN74ALS639A			UNIT
			MIN	NOM	MAX
VCC	Supply voltage		4.5	5	5.5	V
VIH	High-level input voltage		2			V
VIL	Low-level input voltage				0.8	V
VOH	High-level output voltage	A ports			5.5	V
IOH	High-level output current	B ports			± 15	mA
IOL	Low-level output current	A or B ports			24	mA
					48²
TA	Operating free-air temperature		0		70	°C
² Applies only to the SN74ALS638A-1 version and only if VCC is between 4.75 V and 5.25 V

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

					SN74ALS638A
	PARAMETER		TEST CONDITIONS		SN74ALS639A			UNIT
					MIN	TYP³	MAX
VIK			VCC = 4.5 V,	II = ± 18 mA			± 1.5	V
IOH		A ports	VCC = 4.5 V,	VOH = 5.5 V			0.1	mA
			VCC = 4.5 V to 5.5 V,	IOH = ± 0.4 mA	VCC ± 2
VOH		B ports	VCC = 4.5 V	IOH = ± 3 mA	2.4	3.2		V
				IOH = ± 15 mA	2
				IOL = 12 mA		0.25	0.4
VOL		A or B ports	VCC = 4.5 V	IOL = 24 mA		0.35	0.5	V
				IOL = 48 mA²		0.35	0.5
II		Control inputs	VCC = 5.5 V	VI = 7 V			0.1	mA
		A or B ports		VI = 5.5 V			0.1
IIH		Control inputs	VCC = 5.5 V,	VI = 2.7 V			20	μA
		A or B ports§					20
IIL		Control inputs	VCC = 5.5 V,	VI = 0.4 V			± 0.1	mA
		A or B ports§					± 0.1
I ¶		B ports	V = 5.5 V,	V = 2.25 V	± 30		± 112	mA
O			CC	O
				Outputs high		18	30
		SN74ALS638A	VCC = 5.5 V
				Outputs low		26	41
ICC				Outputs disabled		16	30	mA
				Outputs high		25	40
		SN74ALS639A	VCC = 5.5 V
				Outputs low		30	50
				Outputs disabled		33	54

² Applies only to the SN74ALS638A-1 version and only if VCC is between 4.75 V and 5.25 V ³ All typical values are at VCC = 5 V, TA = 25°C.

§For I/O ports, the parameters IIH and IIL include the off-state output current.

¶The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, IOS.

POST OFFICE BOX 655303 •DALLAS, TEXAS 75265

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