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
™
Programming Algorithm - 50
µ
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.
(continued)
512K (64K x 8)
Multiplexed
Addresses/
Outputs
OTP EPROM
AT27C520
Pin Configurations
Pin Name
A8 - A15
AD0 - AD7
OE /V
PP
ALE
Function
Addresses
Addresses/Outputs
Output Enable/V
PP
Address Latch Enable
TSOP Top View
A10
NC
NC
A12
A14
ALE
VCC
OE/VPP
A15
A13
A11
NC
NC
A9
22
23
24
25
26
27
28
1
2
3
4
5
6
7
21
20
19
18
17
16
15
14
13
12
11
10
9
8
A8
NC
NC
AD1
AD3
AD5
AD7
GND
AD6
AD4
AD2
NC
NC
AD0
TSSOP Top View
A10
A12
A14
ALE
VCC
OE/VPP
A15
A13
A11
A9
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
A8
AD1
AD3
AD5
AD7
GND
AD6
AD4
AD2
AD0
SOIC Top View
OE/VPP
A15
A13
A11
A9
AD0
AD2
AD4
AD6
GND
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
VCC
ALE
A14
A12
A10
A8
AD1
AD3
AD5
AD7
Rev. 0752C-C–01/98
1
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
™
Program-
ming Algorithm reduces the time required to program the
part and guarantees reliable programming. Programming
time is typically only 50
µs/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
µF
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
µF
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
V
CC
GND
OE/VPP
ALE
OE, ALE, AND
PROGRAM LOGIC
OUTPUT
BUFFERS
8
LATCHES
Y DECODER
Y-GATING
AD7 - AD0
A15 - A8
8
X DECODER
CELL MATRIX
IDENTIFICATION
2
AT27C520
AT27C520
Absolute Maximum Ratings*
Temperature Under Bias................................ -55°C to +125°C
Storage Temperature ..................................... -65°C to +150°C
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)
Note:
V
PP
Supply Voltage with
Respect to Ground .......................................-2.0V to +14.0V
(1)
1.
*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.
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.
Operating Modes
Mode/Pin
Read
Output Disable
Address Latch Enable
Rapid Program
(2)
Product Identification
(3)
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.
ALE
V
IL
V
IL
/V
IH
V
IH
V
IH
V
IL
OE/V
PP
V
IL
V
IH
V
IH
V
PP
V
IL
A8 - A15
Ai
X
(1)
X
Ai
A9 = V
H(4)
A8 = V
IH
or V
IL
A10 - A15 = V
IL
AD0 - AD7
D
OUT
High Z/A0 - A7
A0 - A7
D
IN
Identification Code
3
DC and AC Operating Conditions for Read Operation
AT27C520
-70
Operating Temp.(Case)
V
CC
Supply
Com.
Ind.
0°C - 70°C
-40°C - 85°C
5V
±
10%
-90
0°C - 70°C
-40°C - 85°C
5V
±
10%
DC and Operating Characteristics for Read Operation
Symbol
I
LI
I
LI2(1)
I
LO
I
CC
V
IL
V
IH
V
OL
V
OH
Note:
Parameter
Input Load Current
Input Load Current A13
Output Leakage Current
V
CC
Active Current
Input Low Voltage
Input High Voltage
Output Low Voltage
Output High Voltage
Condition
V
IN
= 0V to V
CC
V
IN
= 0V to V
CC
V
OUT
= 0V to V
CC
f = 5 MHz, I
OUT
= 0 mA
Min
Max
±1
±100
±5
20
Units
µA
µA
µA
mA
V
V
V
V
-0.6
2.0
I
OL
= 2.1 mA
I
OH
= -400
µA
2.4
0.8
V
CC
+ 0.5
0.4
1. For address input A13 only.
AC Characteristics for Read Operation
AT27C520
-70
Symbol
t
ACC(2)
t
AS
t
AH
t
ALE
t
OE(2)
t
DF(3)(4)
t
OH
Notes:
Parameter
Address to Output Delay
Address Setup Time
Address Hold Time
Address Latch Enable Width
OE/V
PP
to Output Delay
OE/V
PP
High to Output Float
Output Hold from Address or
OE/V
PP
, whichever occurred first
Condition
ALE = OE/V
PP
= V
IL
OE/V
PP
= V
IH
OE/V
PP
= V
IH
OE/V
PP
= V
IH
ALE = V
IL
ALE = V
IL
ALE = V
IL
7
12
12
40
30
25
0
Min
Max
Min
-90
Max
Units
ns
ns
ns
ns
70
15
15
45
90
35
25
ns
ns
ns
1. 2, 3, 4 — see AC Waveforms for Read Operation
4
AT27C520
AT27C520
AC Waveforms for Read Operation
(1)
tALE
ALE
OE/V
PP
tDF
tAS
AD7 - AD0
ADDRESS IN
tACC
A15 - A8
Notes:
1.
2.
3.
4.
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.
OE/V
PP
may be delayed up to t
ACC
- t
OE
after the address is valid without impact on t
ACC
.
This parameter is only sampled and is not 100% tested.
Output float is defined as the point when data is no longer driven.
tAH
tOE
tOH
DATA OUT
Input Test Waveforms and Measurement Levels
For -70 and -90 devices:
Output Test Load
t
R
, t
F
< 20 ns (10% to 90%)
Note:
C
L
= 100 pF including jig
capacitance.
Pin Capacitance
(f = 1 MHz, T = 25°C)
(1)
Typ
C
IN
C
OUT
Note:
Max
6
12
Units
pF
pF
Conditions
V
IN
= 0V
V
OUT
= 0V
4
8
1. Typical values for nominal supply voltage. This parameter is only sampled and is not 100% tested.
5
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