
Enhanced Am486 Microprocessor
AMD
59
PRELIMINARY
The AC specifications, provided in the AC characteris-
tics table, consists of output delays, input setup require-
ments,
and
input
hold
requirements.
All
AC
specifications are relative to the rising edge of the CLK
signal. AC specifications measurement is defined by
Figure 36. All timings are referenced to 1.5 V unless
otherwise specified. Enhanced Am486 microprocessor
output delays are specified with minimum and maximum
limits, measured as shown. The minimum microproces-
sor delay times are hold times provided to external cir-
cuitry. Input setup and hold times are specified as
minimums, defining the smallest acceptable sampling
window. Within the sampling window, a synchronous
input signal must be stable for correct microprocessor
operation.
SWITCHING CHARACTERISTICS over COMMERCIAL operating ranges
Switching Characteristics for 33 MHz bus (66 MHz or 100 MHz operating frequency)
VCC = 3.3 V ±0.3 V; TCASE = 0°C to + 85°C; CL = 50 pF unless otherwise specified
Symbol
Parameter
Min
Max
Unit
Figure
Notes
Frequency
8
33
MHz
Note 2
t1
CLK Period
30
125
ns
39
t1a
CLK Period Stability
0.1%
Adjacent Clocks
Notes 3 and 4
t2
CLK High Time at 2 V
11
ns
39
Note 3
t3
CLK Low Time at 0.8 V
11
ns
39
Note 3
t4
CLK Fall Time (2 V–0.8 V)
3
ns
39
Note 3
t5
CLK Rise Time (0.8 V–2 V)
3
ns
39
Note 3
t6
A31–A2, PWT, PCD, BE3–BE0, M/IO, D/C, CACHE,
W/R, ADS, LOCK, FERR, BREQ, HLDA,
SMIACT, HITM Valid Delay
3
14
ns
40
Note 5
t7
A31–A2, PWT, PCD, BE3–BE0, M/IO, D/C, CACHE,
W/R, ADS, LOCK Float Delay
3
20
ns
41
Note 3
t8
PCHK Valid Delay
3
14
ns
42
t8a
BLAST, PLOCK, Valid Delay
3
14
ns
40
t9
BLAST, PLOCK, Float Delay
3
20
ns
41
Note 3
t10
D31–D0, DP3–DP0 Write Data Valid Delay
3
14
ns
40
t11
D31–D0, DP3–DP0 Write Data Float Delay
3
20
ns
41
Note 3
t12
EADS, INV, WB/WT Setup Time
5
ns
43
t13
EADS, INV, WB/WT Hold Time
3
ns
43
t14
KEN, BS16, BS8 Setup Time
5
ns
43
t15
KEN, BS16, BS8 Hold Time
3
ns
43
t16
RDY, BRDY Setup Time
5
ns
44
t17
RDY, BRDY Hold Time
3
ns
44
t18
HOLD, AHOLD Setup Time
6
ns
43
t18a
BOFF Setup Time
7
ns
43
t19
HOLD, AHOLD, BOFF Hold Time
3
ns
43
t20
RESET, FLUSH, A20M, NMI, INTR, IGNNE,
STPCLK, SRESET, SMI Setup Time
5
ns
43
Note 5
t21
RESET, FLUSH, A20M, NMI, INTR, IGNNE,
STPCLK, SRESET, SMI Hold Time
3
ns
43
Note 5
t22
D31–D0, DP3–DP0, A31–A4 Read Setup Time
5
ns
43, 44
t23
D32–D0, DP3–DP0, A31–A4 Read Hold Time
3
ns
43, 44
Notes:
1.
Specifications assume CL = 50 pF. I/O Buffer model must be used to determine delays due to loading (trace and
component). First Order I/O buffer models for the processor are available.
2.
0 MHz operation guaranteed during stop clock operation.
3.
Not 100% tested. Guaranteed by design characterization.
4.
For faster transitions (>0.1% between adjacent clocks), use the Stop Clock protocol to switch operating frequency.
5.
All timings are referenced at 1.5 V (as illustrated in the listed figures) unless otherwise noted.