Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsLogic ICsLogic IC - FIFO memory Asynchronous Unidirectional Width SSOP 56

SN74ALVC7804

512 × 18

FIRST-IN, FIRST-OUT MEMORY

SCAS432 – JANUARY 1995

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

• Operates at 3-V to 3.6-V V

• Load Clock and Unload Clock Can Be

Asynchronous or Coincident

• Low-Power Advanced CMOS Technology

• Full, Empty, and Half-Full Flags

• Programmable Almost-Full/Almost-Empty

Flag

• Fast Access Times of 18 ns With a 50-pF

Load and All Data Outputs Switching

Simultaneously

• Data Rates From 0 to 40 MHz

• 3-State Outputs

• Pin Compatible With SN74ACT7804

• Packaged in Shrink Small-Outline 300-mil

Package (DL) Using 25-mil Center-to-Center

Spacing

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 SN74ALVC7804 is

an 18-bit FIFO with high speed and fast access

times. Data is processed at rates up to 40 MHz

with access times of 18 ns in a bit-parallel format.

The SN74ALVC7804 is designed for 3-V to 3.6-V

operation.

Data is written into memory on a low-to-high

transition of the load clock (LDCK) and is read out

on a low-to-high transition of the unload clock

(UNCK). The memory is full when the number of

words clocked in exceeds the number of words clocked out by 512. When the memory is full, LDCK has no effect

on the data residing in memory. When the memory is empty, UNCK has no effect.

Status of the FIFO memory is monitored by the full (FULL

), empty (EMPTY), half-full (HF), and almost-

full/almost-empty (AF/AE) flags. The FULL

output is low when the memory is full and high when the memory

is not full. The EMPTY

output is low when the memory is empty and high when it is not empty. The HF output

is high whenever the FIFO contains 256 or more words and is low when it contains 255 or less words. The AF/AE

status flag is a programmable flag. The first one or two low-to-high transitions of LDCK after reset are used to

program the almost-empty offset value (X) and the almost-full offset value (Y), if program enable (PEN

) is low.

The AF/AE flag is high when the FIFO contains X or less words or (512 minus Y) or more words. The AF/AE

flag is low when the FIFO contains between (X plus 1) and (511 minus Y) words.

A low level on the reset (RESET

) resets the internal stack pointers and sets FULL high, AF/AE high, HF low,

and EMPTY

low. The Q outputs are not reset to any specific logic level. The FIFO must be reset upon power

up. The first word loaded into empty memory causes EMPTY

to go high and the data to appear on the Q outputs.

The data outputs are in the high-impedance state when the output-enable (OE

) is high.

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.

RESET

D17

D16

D15

D14

D13

D12

D11

D10

GND

PEN

AF/AE

LDCK

FULL

Q17

Q16

Q15

GND

Q14

Q13

Q12

Q11

Q10

GND

UNCK

EMPTY

DL PACKAGE

(TOP VIEW)

Summary of content (13 pages)

PAGE 1
SN74ALVC7804 512 × 18 FIRST-IN, FIRST-OUT MEMORY SCAS432 – JANUARY 1995 • • • • • • • • • • Operates at 3-V to 3.
PAGE 2
SN74ALVC7804 512 × 18 FIRST-IN, FIRST-OUT MEMORY SCAS432 – JANUARY 1995 logic symbol† Φ FIFO 512 × 18 1 RESET LDCK UNCK OE D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 D16 D17 23 21 Full LDCK 32 56 PEN RESET 25 Half-Full UNCK Almost Full/Empty EN1 Empty 22 24 FULL HF AF/AE 29 EMPTY Program Enable 0 0 33 20 34 19 36 18 37 17 38 16 40 15 41 14 42 12 43 11 45 Data Data 1 9 46 8 47 7 48 6 49 5 51 4 53 3 54 2 55 17 17 † This symbol is in accor
PAGE 3
SN74ALVC7804 512 × 18 FIRST-IN, FIRST-OUT MEMORY SCAS432 – JANUARY 1995 functional block diagram OE D0 – D17 RAM Read Pointer UNCK 512 × 18 Write Pointer LDCK Q0 – Q17 EMPTY Reset Logic RESET StatusFlag Logic PEN FULL HF AF/AE Terminal Functions TERMINAL NAME NO. I/O DESCRIPTION AF/AE 24 O Almost full/almost empty flag. Depth offset values can be programmed for AF/AE, or the default value of 64 can be used for both the almost empty offset (X) and the almost full offset (Y).
PAGE 4
0 ÉÉ ÉÉ ÉÉÉÉ ÉÉÉÉ ÉÉÉÉ ÉÉ ÉÉ ÉÉÉÉ ÉÉÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ ÉÉ LDCK D0–D17 W1 W2 W (X+1) A B Don’t Care C 1 OE W1 W2 W (Y+1) W (Y+2) D E F EMPTY AF/AE HF FULL Define the AF/AE Flag Using the Default Value of X and Y Figure 1.
PAGE 5
SN74ALVC7804 512 × 18 FIRST-IN, FIRST-OUT MEMORY SCAS432 – JANUARY 1995 DATA WORD NUMBERS FOR FLAG TRANSITIONS DEVICE SN74ALVC7804 TRANSITION WORD A B C D E F G H I W256 W(512 – Y) W512 W257 W258 W(512 – X) W(513 – X) W511 W512 offset values for AF/AE The AF/AE flag has two programmable limits: the almost-empty offset value (X) and the almost-full offset value (Y). They can be programmed after the FIFO is reset and before the first word is written to memory.
PAGE 6
SN74ALVC7804 512 × 18 FIRST-IN, FIRST-OUT MEMORY SCAS432 – JANUARY 1995 absolute maximum ratings over operating free-air temperature range (unless otherwise noted)† Supply voltage range, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to 4.6 V Input voltage range, VI (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 4.
PAGE 7
SN74ALVC7804 512 × 18 FIRST-IN, FIRST-OUT MEMORY SCAS432 – JANUARY 1995 electrical characteristics over recommended operating free-air temperature range (unless otherwise noted) TEST CONDITIONS† PARAMETER TYP‡ MIN MAX UNIT VCC = MIN to MAX, VCC = 3 V, IOH = – 100 µA IOH = – 8 mA VCC = MIN to MAX, VCC = 3 V, IOL = 100 µA IOL = 8 mA VCC = 3 V, VCC = 3.6 V, IOL = 16 mA VI =VCC or GND 0.55 ±5 µA VCC = 3.6 V, VCC = 3.6 V, VO =VCC or GND VI = VCC or GND and IO = 0 ±10 µA 40 µA ∆ICC§ VCC = 3.
PAGE 8
SN74ALVC7804 512 × 18 FIRST-IN, FIRST-OUT MEMORY SCAS432 – JANUARY 1995 APPLICATION INFORMATION ′ALVC78xx LDCK LDCK UNCK UNCK EMPTY FULL EMPTY FULL OE D18 – D35 D0 – D17 OE Q18 – Q35 Q0 – Q17 ′ALVC78xx LDCK FULL UNCK EMPTY OE D0 – D17 D0 – D17 Q0 – Q17 Figure 3.
PAGE 9
SN74ALVC7804 512 × 18 FIRST-IN, FIRST-OUT MEMORY SCAS432 – JANUARY 1995 TYPICAL CHARACTERISTICS SUPPLY CURRENT vs CLOCK FREQUENCY 140 fdata = 1/2 fclock TA = 75°C CL = 0 pF I CC(f) – Supply Current – mA 120 VCC = 3.6 V 100 VCC = 3.
PAGE 10
SN74ALVC7804 512 × 18 FIRST-IN, FIRST-OUT MEMORY SCAS432 – JANUARY 1995 PARAMETER MEASUREMENT INFORMATION 6V S1 500 Ω From Output Under Test Open GND CL = 50 pF (see Note A) 500 Ω LOAD CIRCUIT FOR OUTPUTS tw 3V 3V Timing Input Input 1.5 V tsu 0V VOLTAGE WAVEFORMS PULSE DURATION th 1.5 V 1.5 V 1.5 V 0V tPLH tPHL Output Waveform 2 S1 at GND (see Note B) VOH 1.5 V tPLZ 3V Output Waveform 1 S1 at 6 V (see Note B) 1.5 V 1.5 V VOL 1.5 V 0V tPZL 3V 1.
PAGE 11
PACKAGE OPTION ADDENDUM www.ti.com 28-Aug-2008 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty SN74ALVC7804-25DL ACTIVE SSOP DL 56 20 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM SN74ALVC7804-40DL ACTIVE SSOP DL 56 20 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM Lead/Ball Finish MSL Peak Temp (3) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs.
PAGE 12
MECHANICAL DATA MSSO001C – JANUARY 1995 – REVISED DECEMBER 2001 DL (R-PDSO-G**) PLASTIC SMALL-OUTLINE PACKAGE 48 PINS SHOWN 0.025 (0,635) 0.0135 (0,343) 0.008 (0,203) 48 0.005 (0,13) M 25 0.010 (0,25) 0.005 (0,13) 0.299 (7,59) 0.291 (7,39) 0.420 (10,67) 0.395 (10,03) Gage Plane 0.010 (0,25) 1 0°–ā8° 24 0.040 (1,02) A 0.020 (0,51) Seating Plane 0.110 (2,79) MAX 0.004 (0,10) 0.008 (0,20) MIN PINS ** 28 48 56 A MAX 0.380 (9,65) 0.630 (16,00) 0.730 (18,54) A MIN 0.370 (9,40) 0.
PAGE 13
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