MCM32257B View Datasheet(PDF) - Motorola => Freescale
Part Name
Description
Manufacturer
MCM32257B Datasheet PDF : 8 Pages
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AC OPERATING CONDITIONS AND CHARACTERISTICS
(VCC = 5.0 V ± 10%, TA = 0 to + 70°C, Unless Otherwise Noted)
Input Timing Measurement Reference Level . . . . . . . . . . . . . . . 1.5 V
Output Timing Reference Level . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 V
Input Pulse Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to 3.0 V
Output Load . . . . . . . . . . . . See Figure 1A Unless Otherwise Noted
Input Rise/Fall Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 ns
READ CYCLE TIMING (See Notes 1 and 2)
MCM32257B–15 MCM32257B–20 MCM32257B–25
Parameter
Symbol Min
Max
Min
Max
Min
Max Unit Notes
Read Cycle Time
tAVAV
15
—
20
—
25
—
ns
3
Address Access Time
tAVQV
—
15
—
20
—
25
ns
Enable Access Time
tELQV
—
15
—
20
—
25
ns
Output Enable Access Time
tGLQV
—
8
—
9
—
10
ns
Output Hold from Address Change
tAXQX
5
—
5
—
5
—
ns
Enable Low to Output Active
tELQX
5
—
5
—
5
—
ns 4,5,6
Output Enable to Output Active
tGLQX
0
—
0
—
0
—
ns 4,5,6
Enable High to Output High–Z
tEHQZ
0
6
0
7
0
8
ns 4,5,6
Output Enable High to Output High–Z
tGHQZ
0
6
0
7
0
8
ns 4,5,6
Power Up Time
tELICCH
0
—
0
—
0
—
ns
Power Down Time
tEHICCL —
15
—
20
—
25
ns
NOTES:
1. W is high for read cycle.
2. E1 – E4 are represented by E in these timing specifications, any combination of Exs may be asserted.
3. All read cycle timing is referenced from the last valid address to the first transitioning address.
4. At any given voltage and temperature, tEHQZ max is less than tELQX min, and tGHQZ max is less than tGLQX min, both for a given
device and from device to device.
5. Transition is measured ± 500 mV from steady–state voltage with load of Figure 1B.
6. This parameter is sampled and not 100% tested.
7. Device is continuously selected (E = VIL, G = VIL). See Read Cycle 1.
OUTPUT
AC TEST LOADS
Z0 = 50 Ω
RL = 50 Ω
VL = 1.5 V
OUTPUT
255 Ω
+5V
480 Ω
5 pF
Figure 1A
Figure 1B
TIMING LIMITS
The table of timing values shows either a
minimum or a maximum limit for each param-
eter. Input requirements are specified from
the external system point of view. Thus, ad-
dress setup time is shown as a minimum
since the system must supply at least that
much time (even though most devices do not
require it). On the other hand, responses from
the memory are specified from the device
point of view. Thus, the access time is shown
as a maximum since the device never pro-
vides data later than that time.
MCM32257B
6–4
MOTOROLA FAST SRAM
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