AT27C020
1
Features
Fast Read Access Time - 55 ns
Low Power CMOS Operation
100
A max. Standby
25 mA max. Active at 5 MHz
JEDEC Standard Packages
32-Lead 600-mil PDIP
32-Lead PLCC
32-Lead TSOP
5V
10% Supply
High-Reliability CMOS Technology
2,000V ESD Protection
200 mA Latchup Immunity
Rapid
TM
Programming Algorithm - 100
s/byte (typical)
CMOS and TTL Compatible Inputs and Outputs
Integrated Product Identification Code
Commercial and Industrial Temperature Ranges
Description
The AT27C020 is a low-power, high performance 2,097,152-bit one-time programma-
ble read only memory (OTP EPROM) organized as 256K by 8 bits. It requires only
one 5V power supply in normal read mode operation. Any byte can be accessed in
less than 55 ns, eliminating the need for speed reducing WAIT states on high perfor-
mance microprocessor systems.
In read mode, the AT27C020 typically consumes 8 mA. Standby mode supply current
is typically less than 10
A.
Rev. 0570C-B12/97
2-Megabit
(256K x 8)
OTP EPROM
AT27C020
PDIP Top View
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
VPP
A16
A15
A12
A7
A6
A5
A4
A3
A2
A1
A0
O0
O1
O2
GND
VCC
PGM
A17
A14
A13
A8
A9
A11
OE
A10
CE
07
06
05
04
03
TSOP Top View
Type 1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
A11
A9
A8
A13
A14
A17
PGM
VCC
VPP
A16
A15
A12
A7
A6
A5
A4
OE
A10
CE
07
06
05
04
03
GND
02
01
O0
A0
A1
A2
A3
PLCC Top View
5
6
7
8
9
10
11
12
13
29
28
27
26
25
24
23
22
21
A7
A6
A5
A4
A3
A2
A1
A0
O0
A14
A13
A8
A9
A11
OE
A10
CE
07
4
3
2
1
32
31
30
14
15
16
17
18
19
20
01
02
GND
03
04
05
06
A12
A15
A16
VPP
VCC
PGM
A17
Pin Configurations
Pin Name
Function
A0 - A17
Addresses
O0 - O7
Outputs
CE
Chip Enable
OE
Output Enable
PGM
Program Strobe
AT27C020
2
The AT27C020 is available in a choice of industry standard
JEDEC-approved one-time programmable (OTP) plastic
PDIP, PLCC, and TSOP packages. All devices feature two-
line control (CE, OE) to give designers the flexibility to pre-
vent bus contention.
With 256K byte storage capability, the AT27C020 allows
firmware to be stored reliably and to be accessed by the
system without the delays of mass storage media.
Atmel's 27C020 have additional features to ensure high
quality and efficient production use. The Rapid
TM
Program-
ming Algorithm reduces the time required to program the
part and guarantees reliable programming. Programming
time is typically only 100
s/byte. The Integrated Product
Identification Code electronically identifies the device and
manufacturer. This feature is used by industry standard
programming equipment to select the proper programming
algorithms and voltages.
System Considerations
Switching between active and standby conditions via the
Chip Enable pin may produce transient voltage excursions.
Unless accommodated by the system design, these tran-
sients may exceed data sheet limits, resulting in device
non-conformance. At a minimum, a 0.1
F high frequency,
low inherent inductance, ceramic capacitor should be uti-
lized for each device. This capacitor should be connected
between the V
CC
and Ground terminals of the device, as
close to the device as possible. Additionally, to stabilize the
supply voltage level on printed circuit boards with large
EPROM arrays, a 4.7
F bulk electrolytic capacitor should
be utilized, again connected between the V
CC
and Ground
terminals. This capacitor should be positioned as close as
possible to the point where the power supply is connected
to the array.
Block Diagram
AT27C020
3
Absolute Maximum Ratings*
Temperature Under Bias.......................-55C to +125C
*NOTICE:
Stresses beyond those listed under "Absolute
Maximum Ratings" may cause permanent
damage to the device. This is a stress rating
only and functional operation of the device at
these or any other conditions beyond those
indicated in the operational sections of this
specification is not implied. Exposure to abso-
lute maximum rating conditions for extended
periods may affect device reliability.
Note:
1.
Minimum voltage is -0.6V DC which may
undershoot to -2.0V for pulses of less than 20
ns. Maximum output pin voltage is V
CC
+
0.75V DC which may overshoot to +7.0V for
pulses of less than 20 ns.
Storage Temperature............................-65C to +150C
Voltage on Any Pin with
Respect to Ground ............................... -2.0V to +7.0V
(1)
Voltage on A9 with
Respect to Ground ............................ -2.0V to +14.0V
(1)
V
PP
Supply Voltage with
Respect to Ground ............................. -2.0V to +14.0V
(1)
Operating Modes
Notes:
1. X can be V
IL
or V
IH.
2. Refer to Programming Characteristics.
3. V
H
= 12.0
0.5V.
4. Two identifier bytes may be selected. All Ai inputs are held low (V
IL
), except A9 which is set to V
H
and A0 which is toggled
low (V
IL
) to select the Manufacturer's Identification byte and high (V
IH
) to select the Device Code byte.
Mode/Pin
CE
OE
PGM
Ai
V
PP
Outputs
Read
V
IL
V
IL
X
(1)
Ai
X
D
OUT
Output Disable
X
V
IH
X
X
X
High Z
Standby
V
IH
X
X
X
X
High Z
Rapid Program
(2)
V
IL
V
IH
V
IL
Ai
V
PP
D
IN
PGM Verify
V
IL
V
IL
V
IH
Ai
V
PP
D
OUT
PGM Inhibit
V
IH
X
X
X
V
PP
High Z
Product Identification
(4)
V
IL
V
IL
X
A9 = V
H
(3)
A0 = V
IH
or V
IL
A1 - A17 = V
IL
X
Identification Code
AT27C020
4
AC Characteristics for Read Operation
Note:
1. 2, 3, 4, 5. See AC Waveforms for Read Operation diagram.
Symbol
Parameter
AT27C020
Units
-55
-70
-90
-12
-15
Condition
Min
Max
Min
Max
Min
Max
Min
Max
Min
Max
t
ACC
(3)
Address to Output Delay
CE = OE
= V
IL
55
70
90
120
150
ns
t
CE
(2)
CE to Output Delay
OE = V
IL
55
70
90
120
150
ns
t
OE
(2)(3)
OE to Output Delay
CE = V
IL
20
30
35
35
40
ns
t
DF
(4)(5)
OE or CE High
to Output Float,
whichever occurred first
18
20
20
30
40
ns
t
OH
Output Hold
from Address, CE
or OE,whichever
occurred first
7
7
0
0
0
ns
DC and AC Operating Conditions for Read Operation
AT27C020
-55
-70
-90
-12
-15
Operating Temperature
(Case)
Com.
0C - 70C
0C - 70C
0C - 70C
0C - 70C
0C - 70C
Ind.
-40
C - 85C
-40
C - 85C
-40
C - 85C
-40
C - 85C
-40
C - 85C
V
CC
Power Supply
5V
10%
5V
10%
5V
10%
5V
10%
5V
10%
DC and Operating Characteristics for Read Operation
Notes:
1. V
CC
must be applied simultaneously or before V
PP
, and removed simultaneously or after V
PP
.
2. V
PP
may be connected directly to V
CC
except during programming. The supply current would then be the sum of I
CC
and I
PP
.
Symbol
Parameter
Condition
Min
Max
Units
I
LI
Input Load Current
V
IN
= 0V to V
CC
(Com., Ind.)
1.0
A
I
LO
Output Leakage Current
V
OUT
= 0V to V
CC
(Com., Ind.)
5.0
A
I
PP
(2)
V
PP
(1)
Read/Standby Current
V
PP
= V
CC
10
A
I
SB
V
CC
(1)
Standby Current
I
SB1
(CMOS), CE = V
CC
0.3V
100
A
I
SB2
(TTL), CE = 2.0 to V
CC
+ 0.5V
1.0
mA
I
CC
V
CC
Active Current
f = 5 MHz, I
OUT
= 0 mA, CE = V
IL
25
mA
V
IL
Input Low Voltage
-0.6
0.8
V
V
IH
Input High Voltage
2.0
V
CC
+ 0.5
V
V
OL
Output Low Voltage
I
OL
= 2.1 mA
0.4
V
V
OH
Output High Voltage
I
OH
= -400
A
2.4
V
AT27C020
5
AC Waveforms for Read Operation
(1)
Notes:
1.
Timing measurement references are 0.8V and 2.0V. Input AC drive levels are 0.45V and 2.4V, unless otherwise specified.
2.
OE may be delayed up to t
CE
- t
OE
after the falling edge of CE without impact on t
CE.
3.
OE may be delayed up to t
ACC
- t
OE
after the address is valid without impact on t
ACC
.
4.
This parameter is only sampled and is not 100% tested.
5.
Output float is defined as the point when data is no longer driven.
Input Test Waveforms and Measurement Levels
For -55 devices only:
t
R
, t
F
< 5 ns (10% to 90%)
For -70,-90,-12,-15 devices only:
t
R
, t
F
< 20 ns (10% to 90%)
0.0V
3.0V
1.5V
AC
DRIVING
LEVELS
AC
MEASUREMENT
LEVEL
Pin Capacitance
f = 1 MHz, T = 25
C
(1)
Note:
1. Typical values for nominal supply voltage. This parameter is only sampled and is not 100% tested.
Typ
Max
Units Conditions
C
IN
4
8
pF
V
IN
= 0V
C
OUT
8
12
pF
V
OUT
= 0V
Output Test Load
(1)
Note:
1.
CL = 100 pF including jig
capacitance except -55
devices where CL = 30 pF.
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