1
512K (64K x 8)
Multiplexed
Addresses/
Outputs
OTP EPROM
AT27C520
Features
8-Bit Multiplexed Addresses/Outputs
Fast Read Access Time - 70 ns
Low Power CMOS Operation
20 mA max. Active at 5 MHz
20-Lead TSSOP Package
20-Lead SOIC Package
28-Lead TSOP Package
5V
10% Supply
High Reliability CMOS Technology
2,000V ESD Protection
200 mA Latchup Immunity
Rapid
TM
Programming Algorithm - 50
s/byte (typical)
CMOS and TTL Compatible Inputs and Outputs
Integrated Product Identification Code
Commercial and Industrial Temperature Range
Description
The AT27C520 is a low-power, high performance 524,288 bit one-time programmable
read only memory (OTP EPROM) organized 64K by 8 bits. It incorporates latches for
the 8 lower order address bits to multiplex with the 8 data bits. This minimizes system
chip count, reduces cost, and simplifies the design of multiplexed bus systems. It
requires only one 5V power supply in normal read mode operation. Any byte can be
accessed in less than 70 ns, eliminating the need for speed reducing WAIT states on
high performance microprocessor systems.
Atmel's scaled CMOS technology provides high speed, lower active power consump-
tion, and significantly faster programming. Power consumption is typically only 8 mA
in Active Mode.
The AT27C520 is available in 173 mil, 20-pin TSSOP; 300 mil, 20-pin SOIC; and 28-
pin TSOP, one-time programmable (OTP) plastic packages.
Rev. 0752C-C01/98
Pin Configurations
Pin Name
Function
A8 - A15
Addresses
AD0 - AD7
Addresses/Outputs
OE /V
PP
Output Enable/V
PP
ALE
Address Latch Enable
SOIC Top View
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
OE/VPP
A15
A13
A11
A9
AD0
AD2
AD4
AD6
GND
VCC
ALE
A14
A12
A10
A8
AD1
AD3
AD5
AD7
(continued)
TSOP Top View
22
23
24
25
26
27
2
3
4
5
6
7
21
20
19
18
17
16
15
14
13
12
11
10
9
8
A10
NC
NC
A12
A14
ALE
VCC
OE/VPP
A15
A13
A11
NC
NC
A9
A8
NC
NC
AD1
AD3
AD5
AD7
GND
AD6
AD4
AD2
NC
NC
AD0
28
1
TSSOP Top View
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
A10
A12
A14
ALE
VCC
OE/VPP
A15
A13
A11
A9
A8
AD1
AD3
AD5
AD7
GND
AD6
AD4
AD2
AD0
AT27C520
2
With 64K byte storage capability, the AT27C520 allows
firmware to be stored reliably and to be accessed by the
system without the delays of mass storage media.
Atmel's 27C520 has 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 50
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 under active conditions may produce transient
voltage excursions. Unless accommodated by the system
design, these transients 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 utilized for each device. This capacitor
should be connected between the V
CC
and Ground termi-
nals of the device, as close to the device as possible. Addi-
tionally, to stabilize the supply voltage level on printed cir-
cuit boards with large EPROM arrays, a 4.7
F bulk elec-
trolytic 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
OE, ALE, AND
PROGRAM LOGIC
Y DECODER
X DECODER
Y-GATING
CELL MATRIX
IDENTIFICATION
OUTPUT
BUFFERS
V
CC
GND
OE/VPP
LATCHES
ALE
AD7 - AD0
A15 - A8
8
8
AT27C520
3
Absolute Maximum Ratings*
Temperature Under Bias ................................ -55C to +125C
*NOTICE:
Stresses beyond those listed under "Absolute
Maximum Ratings" may cause permanent dam-
age 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 absolute maximum rating
conditions for extended periods may affect device
reliability.
Note:
1.
Minimum voltage is -0.6V DC which may under-
shoot to -2.0V for pulses of less than 20 ns. Max-
imum 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 A8 - A15 inputs are held low (V
IL
), except A9 which is set to V
H
and A8 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
ALE
OE/V
PP
A8 - A15
AD0 - AD7
Read
V
IL
V
IL
Ai
D
OUT
Output Disable
V
IL
/V
IH
V
IH
X
(1)
High Z/A0 - A7
Address Latch Enable
V
IH
V
IH
X
A0 - A7
Rapid Program
(2)
V
IH
V
PP
Ai
D
IN
Product Identification
(3)
V
IL
V
IL
A9 = V
H
(4)
A8 = V
IH
or V
IL
A10 - A15 = V
IL
Identification Code
AT27C520
4
DC and AC Operating Conditions for Read Operation
AT27C520
-70
-90
Operating Temp.(Case)
Com.
0C - 70C
0C - 70C
Ind.
-40C - 85C
-40C - 85C
V
CC
Supply
5V
10%
5V
10%
DC and Operating Characteristics for Read Operation
Note:
1. For address input A13 only.
Symbol
Parameter
Condition
Min
Max
Units
I
LI
Input Load Current
V
IN
= 0V to V
CC
1
A
I
LI2
(1)
Input Load Current A13
V
IN
= 0V to V
CC
100
A
I
LO
Output Leakage Current
V
OUT
= 0V to V
CC
5
A
I
CC
V
CC
Active Current
f = 5 MHz, I
OUT
= 0 mA
20
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
AC Characteristics for Read Operation
Notes:
1. 2, 3, 4 -- see AC Waveforms for Read Operation
Symbol
Parameter
Condition
AT27C520
Units
-70
-90
Min
Max
Min
Max
t
ACC
(2)
Address to Output Delay
ALE = OE/V
PP
= V
IL
70
90
ns
t
AS
Address Setup Time
OE/V
PP
= V
IH
12
15
ns
t
AH
Address Hold Time
OE/V
PP
= V
IH
12
15
ns
t
ALE
Address Latch Enable Width
OE/V
PP
= V
IH
40
45
ns
t
OE
(2)
OE/V
PP
to Output Delay
ALE = V
IL
30
35
ns
t
DF
(3)(4)
OE/V
PP
High to Output Float
ALE = V
IL
25
25
ns
t
OH
Output Hold from Address or
OE/V
PP
, whichever occurred first
ALE = V
IL
7
0
ns
AT27C520
5
Output Test Load
Note:
C
L
= 100 pF including jig
capacitance.
Input Test Waveforms and Measurement Levels
For -70 and -90 devices:
t
R
, t
F
< 20 ns (10% to 90%)
AC Waveforms for Read Operation
(1)
Notes:
1.
Timing measurement reference levels for all speed grades are V
OL
= 0.8V and V
OH
= 2.0V. Input AC drive levels are V
IL
=
0.45V and V
IH
= 2.4V.
2.
OE/V
PP
may be delayed up to t
ACC
- t
OE
after the address is valid without impact on t
ACC
.
3.
This parameter is only sampled and is not 100% tested.
4.
Output float is defined as the point when data is no longer driven.
ALE
OE/V
PP
AD7 - AD0
A15 - A8
tALE
ADDRESS IN
tAS
tAH
DATA OUT
tOE
tACC
tDF
tOH
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
6
pF
V
IN
= 0V
C
OUT
8
12
pF
V
OUT
= 0V
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