27C256
TABLE 1-4:
PROGRAMMING DC CHARACTERISTICS
Ambient Temperature: Tamb = 25°C ± 5°C
VCC = 6.5V ± 0.25V, VPP = VH = 13.0V ± 0.25V
Parameter
Status
Symbol
Min
Max.
Units
Conditions
Input Voltages
Logic”1”
Logic”0”
VIH
VIL
2.0
-0.1
VCC+1
0.8
V
V
Input Leakage
—
ILI
-10
2.4
10
µA
VIN = 0V to VCC
Output Voltages
Logic”1”
Logic”0”
VOH
VOL
V
V
IOH = -400 µA
IOL = 2.1 mA
0.45
20
VCC Current, program & verify
VPP Current, program
—
—
—
ICC2
IPP2
VH
—
—
mA
mA
V
Note 1
Note 1
25
A9 Product Identification
11.5
12.5
Note 1: VCC must be applied simultaneously or before VPP and removed simultaneously or after VPP
TABLE 1-5:
PROGRAMMING AC CHARACTERISTICS
for Program, Program Verify
and Program Inhibit Modes
AC Testing Waveform: VIH=2.4V and VIL=0.45V; VOH=2.0V; VOL=0.8V
Output Load: 1 TTL Load + 100pF
Ambient Temperature: Tamb=25°C ± 5°C
VCC= 6.5V ± 0.25V, VPP = VH = 13.0V ± 0.25V
Parameter
Symbol
Min. Max. Units
Remarks
Address Set-Up Time
Data Set-Up Time
Data Hold Time
tAS
tDS
2
2
—
—
µs
µs
µs
µs
ns
µs
µs
µs
µs
µs
ns
tDH
2
—
Address Hold Time
Float Delay (2)
tAH
0
—
tDF
0
130
—
VCC Set-Up Time
Program Pulse Width (1)
CE Set-Up Time
tVCS
tPW
tCES
tOES
tVPS
tOE
2
95
2
105
—
100 µs typical
OE Set-Up Time
2
—
VPP Set-Up Time
Data Valid from OE
2
—
—
100
Note 1: For express algorithm, initial programming width tolerance is 100 µs ±5%.
2: This parameter is only sampled and not 100% tested. Output float is defined as the point where data is no
longer driven (see timing diagram).
DS11001M-page 4
1998 Microchip Technology Inc.