Texas Instruments SN74ACT2235-20FN, SN74ACT2235-20PAG, SN74ACT2235-20PM, SN74ACT2235-30FN, SN74ACT2235-30FNR Datasheet

SN74ACT2235 1024 ×9 ×2

ASYNCHRONOUS BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY

		SCAS148E ± DECEMBER 1990 ± REVISED APRIL 1998
D Independent Asynchronous Inputs and		D Access Times of 25 ns With a 50-pF Load
	Outputs	D Data Rates up to 50 MHz
D Low-Power Advanced CMOS Technology		D Fall-Through Times of 22 ns Maximum
D	Bidirectional	D High Output Drive for Direct Bus Interface
D Dual 1024 by 9 Bits		D Package Options Include 44-Pin Plastic
D	Programmable Almost-Full/Almost-Empty	Leaded Chip Carriers (FN) and 64-Pin Thin
	Flag	Quad Flat (PAG, PM) Packages

DEmpty, Full, and Half-Full Flags

description

A FIFO memory is a storage device that allows data to be written into and read from its array at independent data rates. The SN74ACT2235 is arranged as two 1024 by 9-bit FIFOs for high speed and fast access times. It processes data at rates up to 50 MHz, with access times of 25 ns in a bit-parallel format.

The SN74ACT2235 consists of bus-transceiver circuits, two 1024 ×9 FIFOs, and control circuitry arranged for multiplexed transmission of data directly from the data bus or from the internal FIFO memories. Enable (GAB and GBA) inputs are provided to control the transceiver functions. The select-control (SAB and SBA) inputs are provided to select whether real-time or stored data is transferred. The circuitry used for select control eliminates the typical decoding glitch that occurs in a multiplexer during the transition between stored and real-time data. Figure 2 shows the eight fundamental bus-management functions that can be performed with the SN74ACT2235.

For more information on this device family, see the application report, 1K × 9 × 2 Asynchronous FIFO SN74ACT2235, literature number SCAA010.

The SN74ACT2235 is characterized for operation from 0°C to 70°C.

FN PACKAGE (TOP VIEW)

			A2		A1		A0		GND		GBA		SBA		SAB GAB GND B0										B1
A3		6		5		4		3		2		1		44 43 42 41 40														B2
		7																						39
A4		8																						38				B3
VCC		9																						37				B4
A5		10																						36				VCC
A6		11																						35				B5
A7		12																						34				B6
A8		13																						33				B7
GND		14																						32				B8
AF/AEA																								31				GND
		15
HFA																								30				AF/AEB
		16
LDCKA																								29				HFB
		17
		18 19 20 21 22 23 24 25 26 27 28
			FULLA		UNCKB		EMPTYB		DAF		RSTA		RSTB		DBF			EMPTYA UNCKA					FULLB		LDCKB

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

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 1998, Texas Instruments Incorporated

POST OFFICE BOX 655303 •DALLAS, TEXAS 75265

1

SN74ACT2235 1024 ×9 ×2

ASYNCHRONOUS BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY

SCAS148E ± DECEMBER 1990 ± REVISED APRIL 1998

PAG OR PM PACKAGE

(TOP VIEW)

						V			A2		A1		A0 GND GND GBA SBA SAB GAB GND GND B0																									B1		B2	V
							CC																																			CC
				64 63 62 61 60 59 58 57 56 55 54 53 52																																	51 50 49
VCC																																									48						NC
						1
A3				2																																					47						VCC
A4
																																															B3
				3																																					46
VCC																																															B4
				4																																					45
GND																																															GND
				5																																					44
GND																																															GND
				6																																					43
A5				7																																					42						VCC
A6				8																																					41						B5
VCC				9																																					40						B6
VCC				10																																					39						VCC
A7																																															B7
				11																																					38
A8																																															B8
				12																																					37
GND				13																																					36						GND
GND				14																																					35						GND
AF/AEA				15																																					34						AF/AEB
HFA				16																																					33						HFB
				17 18 19 20 21 22 23 24 25 26 27 28 29																																	30 31 32
							NC		LDCKA		FULLA		UNCKB		EMPTYB			DAF			RSTA NC					RSTB		DBF			EMPTYA NC UNCKA							FULLB		LDCKB		NC

NC ± No internal connection

2	POST OFFICE BOX 655303 •DALLAS, TEXAS 75265

SN74ACT2235 1024 ×9 ×2

ASYNCHRONOUS BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY

SCAS148E ± DECEMBER 1990 ± REVISED APRIL 1998

logic symbol²

44

SAB

1

SBA

43

GAB

2

GBA

22

RSTA

21

DAF

17

LDCKA

26

UNCKA

18

FULLA

25

EMPTYA

15

AF/AEA

16

HFA

4

A0

5

A1

6

A2

7

A3

8

A4

10

A5

11

A6

12

A7

13

A8

F

FIFO

1024 × 9 × 2

1

MODE SN74ACT2235

0

EN1

EN2

RESET B

23

Reset A

RSTB

24

DEF A FLAG

DEF B FLAG

DBF

28

LDCKA

LDCKB

LDCKB

19

UNCKA

UNCKB

UNCKB

27

FULL B

FULLA

FULLB

20

EMPTYB

EMPTYA

EMPTYB

30

ALMOST-FULL/

ALMOST-FULL/

AF/AEB

ALMOST-EMPTY A ALMOST-EMPTY A

29

HALF-FULL A

HALF-FULL B

HFB

41

0

0

B0

40

B1

39

B2

38

B3

A Data

B Data

37

B4

35

B5

34

B6

33

B7

8

32

8

B8

² This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.

Pin numbers shown are for the FN package.

POST OFFICE BOX 655303 •DALLAS, TEXAS 75265

3

SN74ACT2235 1024 ×9 ×2

ASYNCHRONOUS BIDIRECTIONAL FIRST-IN, FIRST-OUT MEMORY

SCAS148E ± DECEMBER 1990 ± REVISED APRIL 1998

logic diagram (positive logic)

SAB
SBA
			F
HFB			FIFO B	RSTB
			1024 × 9
AF/AEB				DBF
EMPTYB				FULLB
UNCKB				LDCKB
GBA		Q	D	B0
	One of Nine Channels
	To Other Channels
GAB
	F
RSTA	FIFO A			HFA
	1024	× 9
DAF				AF/AEA
FULLA				EMPTYA
LDCKA				UNCKA
A0	D	Q
		One of Nine Channels
		To Other Channels

4	POST OFFICE BOX 655303 •DALLAS, TEXAS 75265