參數(shù)資料
型號： HD407A4384
廠商： Hitachi,Ltd.
英文描述： Low-Voltage AS Microcomputers with On-Chip A/D Converter(帶片上A/D轉(zhuǎn)換器的低壓微計算機)
中文描述： 低電壓如同在微機芯片的A / D轉(zhuǎn)換器（帶片上的A / D轉(zhuǎn)換器的低壓微計算機）
文件頁數(shù)： 122/162頁
文件大?。?/td> 482K
代理商： HD407A4384
HD404374/HD404384/HD404389/HD404082/HD404084 Series
122
Notes on PROM Programming
Principles of Programming/Erasure:
A memory cell in a ZTAT microcomputer is the same as an
EPROM cell; it is programmed by applying a high voltage between its control gate and drain to inject hot
electrons into its floating gate. These electrons are stable, surrounded by an energy barrier formed by an
SiO
2
film. The change in threshold voltage of a memory cell with a charged floating gate makes the
corresponding bit appear as 0; a cell whose floating gate is not charged appears as a 1 bit (figure 73).
The charge in a memory cell may decrease with time. This decrease is usually due to one of the following
causes:
Ultraviolet light excites electrons, allowing them to escape. This effect is the basis of the erasure
principle.
Heat excites trapped electrons, allowing them to escape.
High voltages between the control gate and drain may erase electrons.
If the oxide film covering a floating gate is defective, the electron erasure rate will be greater. However,
electron erasure does not often occur because defective devices are detected and removed at the testing
stage.
Control gate
Floating gate
Drain
SiO
2
Source
N
N
+
+
Control gate
Floating gate
Drain
SiO
2
Source
N
N
+
+
Erasure (1)
Write (0)
Figure 73 Cross-Sections of a PROM Cell
PROM Programming:
PROM memory cells must be programmed under specific voltage and timing
conditions. The higher the programming voltage V
PP
and the longer the programming pulse t
PW
is applied,
the more electrons are injected into the floating gates. However, if V
PP
exceeds specifications, the pn
junctions may be permanently damaged. Pay particular attention to overshooting in the PROM
programmer. In addition, note that negative voltage noise will produce a parasitic transistor effect that may
reduce breakdown voltages.
The ZTAT microcomputer is electrically connected to the PROM programmer by a socket adapter.
Therefore, note the following points:
Check that the socket adapter is firmly mounted on the PROM programmer.
Do not touch the socket adapter or the LSI during the programming. Touching them may affect the
quality of the contacts, which will cause programming errors.
相關(guān)PDF資料
PDF描述
HD407A4389 Low-Voltage AS Microcomputers with On-Chip A/D Converter(帶片上A/D轉(zhuǎn)換器的低壓微計算機)
HD407C4374 Low-Voltage AS Microcomputers with On-Chip A/D Converter(帶片上A/D轉(zhuǎn)換器的低壓微計算機)
HD407C4384 Low-Voltage AS Microcomputers with On-Chip A/D Converter(帶片上A/D轉(zhuǎn)換器的低壓微計算機)
HD407C4389 Low-Voltage AS Microcomputers with On-Chip A/D Converter(帶片上A/D轉(zhuǎn)換器的低壓微計算機)
HD40A4082 Low-Voltage AS Microcomputers with On-Chip A/D Converter(帶片上A/D轉(zhuǎn)換器的低壓微計算機)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
HD407A4384FT 制造商:未知廠家 制造商全稱:未知廠家 功能描述:4-Bit Microcontroller
HD407A4384S 制造商:未知廠家 制造商全稱:未知廠家 功能描述:4-Bit Microcontroller
HD407A4389FT 制造商:未知廠家 制造商全稱:未知廠家 功能描述:4-Bit Microcontroller
HD407A4639R 制造商:RENESAS 制造商全稱:Renesas Technology Corp 功能描述:4-Bit Single-Chip Microcomputer
HD407A4639RF 制造商:未知廠家 制造商全稱:未知廠家 功能描述:4-Bit Microcontroller
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