DP8419N-70 National Semiconductor, DP8419N-70 Datasheet - Page 20

• Manufacturer Part Number: DP8419N-70
• Description: IC CTRLR 256K DRAM 48-DIP
• Manufacturer: National Semiconductor

Specifications of DP8419N-70

• Controller Type: Dynamic RAM (DRAM) Controller, Drivers
• Voltage - Supply: 4.5 V ~ 5.5 V
• Current - Supply: 150mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 48-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Interface: -
• Other names: *DP8419N-70

Switching Characteristics
All AC parameters are specified with the equivalent load
capacitances including traces of 88 DRAMs organized as 4
banks of 22 DRAMs each Maximums are based on worst-
case conditions including all outputs switching simulta-
neously This in many cases results in the AC values
shown in the DP84XX DRAM controller data sheet being
much looser than true worst case (maximum) AC delays
The system designer should estimate the DP8419 load in
his her application and modify the appropriate AC parame-
ters using the graph in Figure 10 Two example calculations
are provided below
2 Examples
Other parameters are adjusted in a similar manner
A C parameters should be adjusted as follows
1) A mode 4 user driving 2 16-bit banks of DRAM has the
2) A mode 5 user driving one 16-bit bank of DRAM has
CAS
Q0-Q8 - 250 pF
RAS
following approximate ‘‘true’’ loading conditions
max t
ing is the same as that which is spec’ed)
max t
max t
max t
min t
involve an output transition
the following approximate ‘‘true’’ loading conditions
CAS - 120 pF
Q0-Q8 - 100 pF
RAS - 120 pF
with RAHS
max t
max t
(the
is due to lighter CAS loading)
min t
Relative to ‘‘True’’ (Application) Load Minus
FIGURE 10 Change in Propagation Delay
a
RAH
RHA
RPDL
CPDL
CCAS
RCC
RICL
RCDL
1 ns is due to lighter RAS loading the
- 300 pF
- 150 pF
AC Specified Data Sheet Load
is not significantly effected since it does not
e
e
e
e
e
e
e
e
15 ns
41 ns
70 ns
20 ns
32 ns
55 ns
46 ns
‘‘1’’
a
b
b
b
b
b
a
1 ns
6 ns
11 ns
0 ns
7 ns
7 ns
1 ns
e
e
e
e
e
b
e
16 ns
35 ns
20 ns (since RAS load-
25 ns
39 ns
11 ns
59 ns
e
45 ns
TL F 8396– 22
b
11 ns
20
Absolute Maximum Ratings
If Military Aerospace specified devices are required
please contact the National Semiconductor Sales
Office Distributors for availability and specifications
Supply voltage V
Storage Temperature Range
Input Voltage
Output Current
Lead Temp (Soldering 10 seconds)
Operating Conditions
V
T
CC
A
The additional 1 ns is due to the fact that the RAS line
is driving less (switching faster) than the load to which
the 15 ns spec applies The row address will remain
valid for about the same time irregardless of address
loading since it is considered to be not valid at the
beginning of its transition
FIGURE 11b DP8417 TRI-STATE Waveforms
Supply Voltage
Ambient
Temperature
FIGURE 11a Output Load Circuit
CC
4 50
Min
0
b
a
Max
5 50
65 C to
70
(Note 1)
TL F 8396– 23
TL F 8396– 34
a
150 mA
150 C
300 C
Units
7 0V
5 5V
V
C