LM1881M-X

更新时间： 2024-02-12 05:50:01

品牌	Logo	应用领域
美国国家半导体 - NSC		商用集成电路光电二极管
页数	文件大小	规格书
12页	302K
描述
LM1881 Video Sync Separator

阅读下载

获取价格

技术参数
数据手册

如果您发现信息不准确，欢迎纠错

LM1881M-X 技术参数

是否无铅：	不含铅	是否Rohs认证：	符合
生命周期：	Obsolete	零件包装代码：	DIP
包装说明：	DIP, DIP8,.3	针数：	8
Reach Compliance Code：	compliant	风险等级：	5.66
商用集成电路类型：	SYNC SEPARATOR IC	JESD-30 代码：	R-PDIP-T8
JESD-609代码：	e3	长度：	9.817 mm
湿度敏感等级：	1	功能数量：	1
端子数量：	8	最高工作温度：	70 °C
最低工作温度：		封装主体材料：	PLASTIC/EPOXY
封装代码：	DIP	封装等效代码：	DIP8,.3
封装形状：	RECTANGULAR	封装形式：	IN-LINE
峰值回流温度（摄氏度）：	260	电源：	5/12 V
认证状态：	Not Qualified	座面最大高度：	5.08 mm
子类别：	Other Consumer ICs	最大压摆率：	12 mA
最大供电电压 (Vsup)：	12 V	最小供电电压 (Vsup)：	5 V
表面贴装：	NO	技术：	BIPOLAR
温度等级：	COMMERCIAL	端子面层：	Matte Tin (Sn)
端子形式：	THROUGH-HOLE	端子节距：	2.54 mm
端子位置：	DUAL	处于峰值回流温度下的最长时间：	40
宽度：	7.62 mm	Base Number Matches：	1

LM1881M-X 数据手册

Application Notes (Continued)

00915004

*Components Optional, See Text

FIGURE 2.

ODD/EVEN FIELD PULSE

integration time between equalizing pulses prevents this

threshold from being reached and the Q output of the flip-flop

is toggled with each equalizing pulse. Since the half line

period at the end of the odd field will have the same effect as

an equalizing pulse period, the Q output will have a different

polarity on successive fields. Thus by comparing the Q

polarity with the vertical output pulse, an odd/even field index

is generated. Pin 7 remains low during the even field and

high during the odd field.

An unusual feature of LM1881 is an output level from Pin 7

that identifies the video field present at the input to the

LM1881. This can be useful in frame memory storage appli-

cations or in extracting test signals that occur in alternate

fields. For a composite video signal that is interlaced, one of

the two fields that make up each video frame or picture must

have a half horizontal scan line period at the end of the

vertical scan—i.e., at the bottom of the picture. This is called

the “odd field” or “even field”. The “even field” or “field 2” has

a complete horizontal scan line at the end of the field. An odd

field starts on the leading edge of the first equalizing pulse,

whereas the even field starts on the leading edge of the

second equalizing pulse of the vertical retrace interval. Fig-

ure 1(a) shows the end of the even field and the start of the

odd field.

BURST/BACKPORCH OUTPUT PULSE

In a composite video signal, the chroma burst is located on

the backporch of the horizontal blanking period. This period,

approximately 4.8 µs long, is also the black level reference

for the subsequent video scan line. The LM1881 generates a

pulse at Pin 5 that can be used either to retrieve the chroma

burst from the composite video signal (thus providing a

subcarrier synchronizing signal) or as a clamp for the DC

restoration of the video waveform. This output is obtained

simply by charging an internal capacitor starting on the

trailing edge of the horizontal sync pulses. Simultaneously

the output of Pin 5 is pulled low and held until the capacitor

charge circuit times out—4 µs later. A shorter output burst

gate pulse can be derived by differentiating the burst output

To detect the odd/even fields the LM1881 again integrates

the composite sync waveform (Figure 2). A capacitor is

charged during the period between sync pulses and dis-

charged when the sync pulse is present. The period between

normal horizontal sync pulses is enough to allow the capaci-

tor voltage to reach a threshold level of a comparator that

clears a flip-flop which is also being clocked by the sync

waveform. When the vertical interval is reached, the shorter

www.national.com

1...4 5 678 9 10...12

下载PDF

与LM1881M-X相关器件

型号	品牌	描述	获取价格	数据表
LM1881MX/NOPB	TI	Video Sync Separator	获取价格
LM1881M-X/NOPB	NSC	IC SYNC SEPARATOR IC, PDSO8, PLASTIC, SO-8, Signal Separator IC	获取价格
LM1881MX-X/NOPB	TI	SYNC SEPARATOR IC, PDSO8, PLASTIC, SO-8	获取价格
LM1881N	TI	Video Sync Separator	获取价格
LM1881N	NSC	LM1881 Video Sync Separator	获取价格
LM1881N/NOPB	TI	Video Sync Separator	获取价格

与LM1881M-X相关文章

深入解析CS8416引脚说明、参数、技术特点
2024-06-03

1
TPA3116D2功放芯片参数详解、引脚说明
2024-06-03

2
移位寄存器74HC165引脚说明、驱动程序示例解读
2024-06-03

2
深入解析AD9833：DDS频率合成器的卓越性能与广泛应用
2024-06-03

2

产品中心

服务支持

精选活动

关于我们

帮助中心

LM1881M-X

LM1881M-X 技术参数

LM1881M-X 数据手册

与LM1881M-X相关器件

与LM1881M-X相关文章

您还可以找

产品中心

服务支持

精选活动

关于我们

帮助中心

LM1881M-X

LM1881M-X 技术参数

LM1881M-X 数据手册

与LM1881M-X相关器件

与LM1881M-X相关文章

您还可以找

您在本页遇到什么问题？