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
20A max standby (less than 1A, typical) for V = 3.6V
CC
29mW max active at 5MHz for V = 3.6V
CC 256K (32K x 8)
JEDEC standard surface mount package
Unregulated Battery
32-lead PLCC
High-reliability CMOS technology
Voltage, High-
2,000V ESD protection
speed, One-time
200mA latchup immunity
Programmable,
Rapid programming algorithm 100s/byte (typical)
CMOS- and TTL-compatible inputs and outputs
Read-only Memory
JEDEC standard for LVTTL and LVBO
Integrated product identification code
Industrial temperature range
Atmel AT27BV256
Green (Pb/halide-free) packaging option
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 = 2.7V, any word can be accessed in
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less than 70ns. With a typical power dissipation of only 18mW at 5 MHz and V = 3V, the
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AT27BV256 consumes less than one-fifth the power of a standard, 5V EPROM.
Standby mode supply current is typically less than 1A 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 at 3.0V produces TTL-level outputs that are compatible
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with standard TTL logic devices operating at V = 5.0V. At V = 2.7V, the part is compati-
CC CC
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 100s/byte. The
0601FEPROM4/11
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. The AT27BV256 programs in exactly the same way as a standard, 5V Atmel AT27C256R, and uses the same
programming equipment.
2. Pin configurations
32-lead PLCC
Pin name Function
Top view
A0 - A14 Addresses
O0 - O7 Outputs
A6 5 29 A8
CE Chip enable
A5 6 28 A9
OE Output enable
A4 7 27 A11
A3 8 26 NC
NC No connect
A2 9 25 OE
A1 10 24 A10
A0 11 23 CE
NC 12 22 O7
O0 13 21 O6
Note: PLCC package pins 1 and 17 are dont 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 0.1F, high-frequency, low inherent inductance, ceramic capacitor should be utilized for each device. This
capacitor should be connected between the V and ground terminals of the device, as close to the device as possible.
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Additionally, to stabilize the supply voltage level on printed circuit boards with large EPROM arrays, a 4.7F bulk electrolytic
capacitor should be utilized, again connected between the V and ground terminals. This capacitor should be positioned as
CC
close as possible to the point where the power supply is connected to the array.
Figure 3-1. Block diagram
2 Atmel AT27BV256
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O1 14 4 A7
O2 15 3 A12
GND 16 2 VPP
NC 17 1 NC
O3 18 32 VCC
O4 19 31 A14
O5 20 30 A13