W29C040P-90 Winbond Electronics, W29C040P-90 Datasheet - Page 5

• Manufacturer Part Number: W29C040P-90
• Manufacturer: Winbond Electronics

Specifications of W29C040P-90

• Density: 4Mb
• Access Time (max): 90ns
• Interface Type: Parallel
• Boot Type: Bottom/Top
• Address Bus: 19b
• Operating Supply Voltage (typ): 5V
• Operating Temp Range: 0C to 70C
• Package Type: PLCC
• Program/erase Volt (typ): 5V
• Sync/async: Asynchronous
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (max): 5.5V
• Word Size: 8b
• Number Of Words: 512K
• Supply Current: 50mA
• Mounting: Surface Mount
• Pin Count: 32
• Lead Free Status / Rohs Status: Not Compliant

software data protection feature. To reset the device to unprotected mode, a six-byte command
sequence is required. For information about specific codes, see the Command Codes for Software
Data Protection in the Table of Operating Modes. For information about timing waveforms, see the
timing diagrams below.
6.4
The integrity of the data stored in the W29C040 is also hardware protected in the following ways:
(1) Noise/Glitch Protection: A #WE pulse of less than 15 nS in duration will not initiate a write cycle.
(2) V
(3) Write Inhibit Mode: Forcing #OE low, #CE high, or #WE high will inhibit the write operation. This
(4) V
6.5
The entire device can be erased by using a six-byte software command code. See the Software Chip
Erase Timing Diagram.
6.6
There are two boot blocks (16K bytes each) in this device, which can be used to store boot code. One
of them is located in the first 16K bytes and the other is located in the last 16K bytes of the memory.
The first 16K or last 16K of the memory can be set as a boot block by using a seven-byte command
sequence.
See Command Codes for Boot Block Lockout Enable for the specific code. Once this feature is set the
data for the designated block cannot be erased or programmed (programming lockout); a regular
programming method can change other memory locations. Once the boot block programming lockout
feature is activated, the chip erase function will be disabled. In order to detect whether the boot block
feature is set on the two 16K blocks, users can perform a six-byte command sequence: enter the
product identification mode (see Command Codes for Identification/Boot Block Lockout Detection for
specific code), and then read from address "00002 hex" (for the first 16K bytes) or "7FFF2 hex" (for
the last 16K bytes). If the output data is "FF hex," the boot block programming lockout feature is
activated; if the output data is "FE hex," the lockout feature is inactivated and the block can be
programmed.
To return to normal operation, perform a three-byte command sequence to exit the identification
mode. For the specific code, see Command Codes for Identification/Boot Block Lockout Detection.
prevents inadvertent writes during power-up or power-down periods.
mS before any write (erase/program) operation.
2.5V.
DD
DD
Hardware Data Protection
Chip Erase Modes
Boot Block Operation
power-on delay: When V
Power Up/Down Detection: The write and read operation are inhibited when V
DD
has reach its sense level, the device will automatically time-out 10
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Publication Release Date: Aug. 14, 2006
W29C040
DD
Revision A11
is less than