ST52T440F3M6 STMicroelectronics, ST52T440F3M6 Datasheet - Page 36

• Manufacturer Part Number: ST52T440F3M6
• Description: MCU 8-Bit ST52 CISC 8KB EPROM 5V 20-Pin SO
• Manufacturer: STMicroelectronics

Specifications of ST52T440F3M6

• Package: 20SO
• Family Name: ST52
• Maximum Speed: 20 MHz
• Ram Size: 256 Byte
• Program Memory Size: 8 KB
• Operating Supply Voltage: 5 V
• Data Bus Width: 8 Bit
• Program Memory Type: EPROM
• Number Of Programmable I/os: 13
• On-chip Adc: 6-chx12-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 1

ST52T400/T440/E440/T441
3.1.5 Stand by Mode. EPROM has a standby
mode which reduces the active current from 10mA
(Programming mode) to less than 100 A. Mem-
ory is placed in standby mode by setting PHASE
signal at high level or when the EPROM Control
Register value is 0 and PHASE signal is low.
3.1.6 ID code. A software identification code,
called ID code may be written to distinguish which
software version is stored in the memory.
64 Bytes are dedicated to store this code by using
the address values from 0 to 63.
The ID Code may be read or verified even if the
Memory Lock Status is “0".
The signals timing is the same as that of a normal
operation.
3.2 Eprom Erasure
Thanks to the transparent window available in the
CDIP28W package, its memory contents may be
erased by exposure to UV light.
Erasure begins when the device is exposed to
light with a wavelength shorter than 4000Å. It
should be noted that sunlight, as well as some
types of artificial light, includes wavelengths in the
3000-4000Å range which, on prolonged exposure,
can cause erasure of memory contents. It is thus
recommended that EPROM devices be fitted with
an opaque label over the window area in order to
prevent unintentional erasure.
The recommended erasure procedure for EPROM
devices consists of exposure to short wave UV
light having a wavelength of 2537Å. The minimum
recommended integrated dose (intensity x expo-
2
sure time) for complete erasure is 15Wsec/cm
.
This is equivalent to an erasure time of 5-10 min-
utes using a UV source having an intensity of
2
12mW/cm
at a distance of 25mm (1 inch) from
the device window.
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