Philips Semiconductors
Product specification
74F764-1/74F765-1
DRAM dual-ported controllers
2
1992 Aug 10
853-0878 07412
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
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.
ORDERING INFORMATION
DESCRIPTION
COMMERCIAL RANGE
V
CC
= 5V
10%,
T
amb
= 0
C to 70
C
DRAWING NUMBER
40-Pin Plastic Dual In-line Package
74F764-1N, 74F765-1N
SOT1291
44-Pin Plastic Leaded Chip Carrier
74F764-1A, 74F765-1A
SOT1872
PIN CONFIGURATIONS
N Package
24
23
22
21
20
19
18
17
16
15
28
27
12
10
11
9
8
7
6
5
4
3
2
1
14
13
26
25
29
30
31
32
33
34
35
36
37
38
39
40 RCP
WG
GNT
CASEN
DTACK
RAS
MA0
MA1
MA2
GND
MA3
MA4
MA5
MA6
MA7
MA8
CP
SEL2
REQ2
REQ1
A1
A10
A2
A11
A3
A12
A4
A13
A5
A14
VCC
A6
A15
A7
A16
A8
A17
A9
A18
SEL1
SF00703
6
5
4
3
2
1
44 43 42 41 40
39
38
37
36
35
34
33
32
31
30
29
7
8
9
10
11
12
13
14
15
16
17
18 19 20 21 22
23 24 25 26 27 28
A Package
RAS
MA0
MA1
MA2
GND
GND
MA3
MA4
MA5
MA6
MA7
MA8
CP NC
SEL2
REQ2
REQ1
SEL1
NC
A18
A9
NC
A6
A15
A7
A16
A8
A17
A4
A13
A5
A14
VCC
A1
A10
A2
A11
A3
A12
RCP WG GNT
CASEN
DTACK
SF00685
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