參數(shù)資料
型號(hào): HD4046612
廠商: Hitachi,Ltd.
英文描述: Low-Voltage AS Microcomputers with On-Chip DTMF Generation Circuit(帶雙音多頻電路的低電壓微計(jì)算機(jī))
中文描述: 低電壓如同在微機(jī)芯片的DTMF產(chǎn)生電路(帶雙音多頻電路的低電壓微計(jì)算機(jī))
文件頁數(shù): 111/142頁
文件大?。?/td> 894K
代理商: HD4046612
HD404669 Series
111
ZTAT
TM
Microcomputer Usage Notes
ZTAT
TM
Microcomputer On-Chip Programmable ROM Characteristics and Useage Notes
Principles of Programming/Erasure:
A memory cell in a ZTAT
TM
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.
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 83 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
TM
microcomputer is electrically connected to the PROM programmer by a socket adapter.
Therefore, note the following points:
相關(guān)PDF資料
PDF描述
HD40A46612 Low-Voltage AS Microcomputers with On-Chip DTMF Generation Circuit(帶雙音多頻電路的低電壓微計(jì)算機(jī))
HD40A4668 Low-Voltage AS Microcomputers with On-Chip DTMF Generation Circuit(帶雙音多頻電路的低電壓微計(jì)算機(jī))
HD40A4669 Low-Voltage AS Microcomputers with On-Chip DTMF Generation Circuit(帶雙音多頻電路的低電壓微計(jì)算機(jī))
HD404668 Low-Voltage AS Microcomputers with On-Chip DTMF Generation Circuit(帶雙音多頻電路的低電壓微計(jì)算機(jī))
HD404669 Low-Voltage AS Microcomputers with On-Chip DTMF Generation Circuit(帶雙音多頻電路的低電壓微計(jì)算機(jī))
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
HD4046612H 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:Low-Voltage AS Microcomputers with On-Chip DTMF Generation Circuit
HD404668 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:Low-Voltage AS Microcomputers with On-Chip DTMF Generation Circuit
HD404668H 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:Low-Voltage AS Microcomputers with On-Chip DTMF Generation Circuit
HD404669 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:Low-Voltage AS Microcomputers with On-Chip DTMF Generation Circuit
HD404669H 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:Low-Voltage AS Microcomputers with On-Chip DTMF Generation Circuit