74F764-1 Datasheet, PDF (2/3 Pages) NXP Semiconductors – DRAM dual-ported controllers

Philips Semiconductors
DRAM dual-ported controllers
Product specification
74F764-1/74F765-1
FEATURES
• Allows two microprocessors to access the same bank of dynamic
RAM
• Performs arbitration, signal timing, address multiplexing and
refresh
• 9 Address output pins allow direct control of up to 256K dynamic
RAMs
• External address multiplexing enables control of 1Mbit (or greater)
dynamic RAMs
• Separate refresh clock allows adjustable refresh timing
• 74F764-1 has an on-chip 18-bit address input latch
• 74F764-1/765-1 allow control of dynamic RAMs with row access
times down to 40ns
• 74F764-1/765-1 output drivers designed for first reflected wave
switching
ORDERING INFORMATION
DESCRIPTION
40-Pin Plastic Dual In-line Package
44-Pin Plastic Leaded Chip Carrier
DESCRIPTION
The 74F764-1/765-1 DRAM Dual-ported Controller is a high-speed
synchronous dual-port arbiter and timing generator that allows two
microprocessors, microcontrollers, or any other memory accessing
device to share the same block of DRAM. The device performs
arbitration, signal timing, address multiplexing, and refresh address
generation, replacing up to 25 discrete devices.
74F764-1 vs. 74F765-1
The 74F764-1, though functionally and pin-to-pin compatible with
the 74F765-1, differs from the later in that it has an on-chip address
input latch. This is useful in systems that have unlatched or
multiplexed address and data bus.
The specialized outputs eliminate the need for signal terminations in
essentially all applications.
Both devices are available in 40-pin plastic DIP or 44-pin PLCC with
pinouts designed to allow convenient placement of microprocessors,
DRAMs, and other support chips.
COMMERCIAL RANGE
V_CC = 5V±10%,
T_amb = 0°C to 70°C
74F764-1N, 74F765-1N
74F764-1A, 74F765-1A
DRAWING NUMBER
SOT129–1
SOT187–2
PIN CONFIGURATIONS
N Package
A1 1
40 RCP
A10 ²
A2 ³
A11 4
39 WG
38 GNT
37 CASEN
A3 5
36 _DTACK
A12 6
A4 7
35 _RAS
34 MA0
A13 ⁸
A5 9
A14 10
VCC 11
33 _MA1
32 _MA2
31 GND
30 MA3
A6 12
29 MA4
A15 ¹³
A7 ¹⁴
A16 15
A8 16
A17 17
28 MA5
27 _MA6
26 _MA7
25 _MA8
24 CP
A9 18
23 SEL2
A18 19
22 REQ2
SEL1 20
21 _REQ1
SF00703
A Package
CASEN
A12 A3 A11 A2 A10 A1 RCP WG GNT DTACK
6 5 4 3 2 1 44 43 42 41 40
A4 ⁷
A13 ⁸
A5 ⁹
A14 10
VCC ¹¹
A6 12
A15 13
A7 14
A16 15
A8 16
A17 17
39 RAS
38 MA0
37 MA1
36 MA2
35 GND
34 GND
33 _MA3
32 MA4
31 MA5
30 MA6
29 _MA7
18 19 20 21 22 23 24 25 26 27 28
A9 A18 NC NC SEL1 REQ2 CP NC MA8
REQ1 SEL2
SF00685
1992 Aug 10
2
853-0878 07412