Features
•
Fast read access time – 70ns
•
Dual voltage range operation
•
•
•
•
•
•
•
•
•
– Unregulated battery power supply range, 2.7V to 3.6V, or
– Standard power supply range, 5V
10%
Pin compatible with JEDEC standard Atmel
®
AT27C256R
Low-power CMOS operation
– 20µA max standby (less than 1µA, typical) for V
CC
= 3.6V
– 29mW max active at 5MHz for V
CC
= 3.6V
JEDEC standard surface mount package
– 32-lead PLCC
High-reliability CMOS technology
– 2,000V ESD protection
– 200mA latchup immunity
Rapid programming algorithm – 100µs/byte (typical)
CMOS- and TTL-compatible inputs and outputs
– JEDEC standard for LVTTL and LVBO
Integrated product identification code
Industrial temperature range
Green (Pb/halide-free) packaging option
256K (32K x 8)
Unregulated Battery
Voltage, High-
speed, One-time
Programmable,
Read-only Memory
Atmel AT27BV256
1.
Description
The Atmel AT27BV256 is a high-performance, low-power, low-voltage, 262,144-bit, one-
time programmable, read-only memory (OTP EPROM) organized as 32K by 8 bits. It
requires only one supply in the range of 2.7V to 3.6V in normal read mode operation, mak-
ing it ideal for fast, portable systems using either regulated or unregulated battery power.
The Atmel innovative design techniques provide fast speeds that rival 5V parts, while keep-
ing the low power consumption of a 3V supply. At V
CC
= 2.7V, any word can be accessed in
less than 70ns. With a typical power dissipation of only 18mW at 5 MHz and V
CC
= 3V, the
AT27BV256 consumes less than one-fifth the power of a standard, 5V EPROM.
Standby mode supply current is typically less than 1µA at 3V. The AT27BV256 simplifies
system design and stretches battery lifetime even further by eliminating the need for power
supply regulation.
The AT27BV256 is available in an industry-standard, JEDEC-approved ,one-time program-
mable (OTP) PLCC package. All devices feature two-line control (CE, OE) to give
designers the flexibility to prevent bus contention.
The AT27BV256 operating with V
CC
at 3.0V produces TTL-level outputs that are compatible
with standard TTL logic devices operating at V
CC
= 5.0V. At V
CC
= 2.7V, the part is compati-
ble with JEDEC-approved, low-voltage battery operation (LVBO) interface specifications.
The device is also capable of standard, 5V operation, making it ideally suited for dual supply
range systems or card products that are pluggable in both 3V and 5V hosts.
The AT27BV256 has additional features to ensure high quality and efficient production use.
The rapid programming algorithm reduces the time required to program the part and guar-
antees reliable programming. Programming time is typically only 100µs/byte. The
integrated product identification code electronically identifies the device and manufacturer.
0601F–EPROM–4/11
This feature is used by industry-standard programming equipment to select the proper programming algorithms and
voltages. The AT27BV256 programs in exactly the same way as a standard, 5V Atmel AT27C256R, and uses the same
programming equipment.
2.
Pin configurations
Pin name
A0 - A14
O0 - O7
CE
OE
NC
Function
Addresses
Outputs
Chip enable
Output enable
No connect
A6
A5
A4
A3
A2
A1
A0
NC
O0
32-lead PLCC
Top view
A7
A12
VPP
NC
VCC
A14
A13
Note:
PLCC package pins 1 and 17 are “don’t connect.”
3.
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 transients may exceed datasheet limits, resulting in device non-conformance.
At a minimum, a 0.1µF, high-frequency, low inherent inductance, ceramic capacitor should be utilized 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 4.7µF 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.
Figure 3-1.
Block diagram
2
Atmel AT27BV256
0601F–EPROM–4/11
O1
O2
GND
NC
O3
O4
O5
14
15
16
17
18
19
20
5
6
7
8
9
10
11
12
13
4
3
2
1
32
31
30
29
28
27
26
25
24
23
22
21
A8
A9
A11
NC
OE
A10
CE
O7
O6
Atmel AT27BV256
4.
Absolute maximum ratings*
Temperature under bias . . . . . . . . . . . . . . . -40°C to +85°C
Storage temperature . . . . . . . . . . . . . . . . .-65°C to +125°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)
V
PP
supply voltage with
respect to ground . . . . . . . . . . . . . . . . . . -2.0V to +14.0V
(1)
Note:
1. Minimum voltage is -0.6V DC, which may undershoot to -2.0V for pulses of less than 20ns. Maximum output pin voltage is
V
CC
+ 0.75V DC, which may be exceeded if certain precautions are observed (consult application notes), and which may
overshoot to +7.0V for pulses of less than 20ns.
*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
absolute maximum rating conditions for extended
periods may affect device reliability.
5.
DC and AC characterisitcs
Table 5-1.
Mode/Pin
Read
(2)
Output disable
(2)
Standby
(2)
Rapid program
(3)
PGM verify
(3)
Optional PGM verify
(3)
PGM inhibit
(3)
Product identification
(3)(5)
Note:
1. X can be V
IL
or V
IH
.
2. Read, output disable, and standby modes require 2.7V
V
CC
3.6V or 4.5V
V
CC
5.5V.
3. Refer to programming characteristics. Programming modes require V
CC
= 6.5V.
4. V
H
= 12.0 ± 0.5V.
5. 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 tog-
gled low (V
IL
) to select the manufacturers’ identification byte and high (V
IH
) to select the device code byte.
Table 5-2.
DC and AC operating conditions for read operation
Atmel AT27BV256-70
Industrial operating temperature (case)
V
CC
power supply
-40°C - 85°C
2.7V to 3.6V
5V
10%
Operating modes
CE
V
IL
V
IL
V
IH
V
IL
X
V
IL
V
IH
V
IL
OE
V
IL
V
IH
X
V
IH
V
IL
V
IL
V
IH
V
IL
Ai
Ai
X
(1)
X
Ai
Ai
Ai
X
A9 = V
H
(4)
A0 = V
IH
or V
IL
A1 - A14 = V
IL
V
PP
V
CC
V
CC
V
CC
V
PP
V
PP
V
CC
V
PP
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
Outputs
D
OUT
High Z
High Z
D
IN
D
OUT
D
OUT
High Z
Identification code
3
0601F–EPROM–4/11
Table 5-3.
Symbol
DC and operating characteristics for read operation
Parameter
Condition
Min
Max
Units
V
CC
= 2.7V to 3.6V
I
LI
I
LO
I
PP1
(2)
I
SB
I
CC
V
IL
Input load current
Output leakage current
V
PP
(1)
read/standby current
V
CC
(1)
standby current
V
CC
active current
Input low voltage
V
IN
= 0V to V
CC
V
OUT
= 0V to V
CC
V
PP
= V
CC
I
SB1
(CMOS), CE = V
CC
0.3V
I
SB2
(TTL), CE = 2.0 to V
CC
+ 0.5V
f = 5MHz, I
OUT
= 0mA, CE = V
IL
, V
CC
= 3.6V
V
CC
= 3.0 to 3.6V
V
CC
= 2.7 to 3.6V
Input high voltage
V
CC
= 3.0 to 3.6V
V
CC
= 2.7 to 3.6V
I
OL
= 2.0mA
V
OL
Output low voltage
I
OL
= 100µA
I
OL
= 20µA
I
OH
= -2.0mA
V
OH
Output high voltage
I
OH
= -100µA
I
OH
= -20µA
V
CC
= 4.5V to 5.5V
I
LI
I
LO
I
PP1
(2)
I
SB
I
CC
V
IL
V
IH
V
OL
V
OH
Notes:
Input load current
Output leakage current
V
PP
(1)
read/standby current
V
CC
(1)
standby current
V
CC
active current
Input low voltage
Input high voltage
Output low voltage
Output high voltage
I
OL
= 2.1mA
I
OH
= -400µA
2.4
V
IN
= 0V to V
CC
V
OUT
= 0V to V
CC
V
PP
= V
CC
I
SB1
(CMOS), CE = V
CC
0.3V
I
SB2
(TTL), CE = 2.0 to V
CC
+ 0.5V
f = 5MHz, I
OUT
= 0mA, CE = V
IL
-0.6
2.0
1
5
10
100
1
20
0.8
V
CC
+ 0.5
0.4
µA
µA
µA
µA
mA
mA
V
V
V
V
2.4
V
CC
- 0.2
V
CC
- 0.1
-0.6
-0.6
2.0
0.7 x V
CC
1
5
10
20
100
8
0.8
0.2 x V
CC
V
CC
+ 0.5
V
CC
+ 0.5
0.4
0.2
0.1
µA
µA
µA
µA
µA
mA
V
V
V
V
V
V
V
V
V
V
V
IH
1. V
CC
must be applied simultaneously with or before V
PP
, and removed simultaneously with 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
.
4
Atmel AT27BV256
0601F–EPROM–4/11
Atmel AT27BV256
Table 5-4.
AC characteristics for read operation
V
CC
= 2.7V to 3.6V and 4.5V to 5.5V
Atmel AT27BV256-70
Symbol
t
ACC
(3)
t
CE
(2)
t
OE
(2)(3)
t
DF
(4)(5)
t
OH
Figure 5-1.
Parameter
Address to output delay
CE to output delay
OE to output delay
OE or CE High to output float,
whichever occurred first
Output hold from address, CE or OE,
whichever occurred first
AC waveforms for read operation
(1)
0
Condition
CE = OE = V
IL
OE = V
IL
CE = V
IL
Min
Max
70
70
50
40
Units
ns
ns
ns
ns
ns
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.
6. When reading an Atmel AT27BV256, a 0.1µF capacitor is required across V
CC
and ground to suppress spurious voltage
transients.
Figure 5-2.
Input test waveform and measurement level
t
R
, t
F
< 20ns (10% to 90%)
5
0601F–EPROM–4/11
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