参数资料
型号: MM5451BN
厂商: MICREL INC
元件分类: 显示驱动器
英文描述: LED Display Driver
中文描述: LED DISPLAY DRIVER, PDIP40
封装: PLASTIC, DIP-40
文件页数: 4/8页
文件大小: 125K
代理商: MM5451BN
Functional Description
Both the MM5450 and the MM5451 are specifically de-
signed to operate 4- or 5-digit alphanumeric displays with
minimal interface with the display and the data source Seri-
al data transfer from the data source to the display driver is
accomplished with 2 signals serial data and clock Using a
format of a leading ‘‘1’’ followed by the 35 data bits allows
data transfer without an additional load signal The 35 data
bits are latched after the 36th bit is complete thus providing
non-multiplexed direct drive to the display Outputs change
only if the serial data bits differ from the previous time Dis-
play brightness is determined by control of the output cur-
rent for LED displays A 0001 capacitor should be connect-
ed to brightness control pin 19 to prevent possible oscilla-
tions
A block diagram is shown in Figure 1 For the MM5450 a
DATA ENABLE is used instead of the 35th output The
DATA ENABLE input is a metal option for the MM5450 The
output current is typically 20 times greater than the current
into pin 19 which is set by an external variable resistor
There is an internal limiting resistor of 400
X
nominal value
Figure 4 shows the input data format A start bit of logical
‘‘1’’ precedes the 35 bits of data At the 36th clock a LOAD
signal is generated synchronously with the high state of the
clock which loads the 35 bits of the shift registers into the
latches At the low state of the clock a RESET signal is
generated which clears all the shift registers for the next set
of data The shift registers are static master-slave configura-
tion There is no clear for the master portion of the first shift
register thus allowing continuous operation
There must be a complete set of 36 clocks or the shift regis-
ters will not clear
When the chip first powers ON an internal power ON reset
signal is generated which resets all registers and all latches
The START bit and the first clock return the chip to its nor-
mal operation
Figure 2 shows the pin-out of the MM5450 and MM5451 Bit
1 is the first bit following the start bit and it will appear on pin
18 A logical ‘‘1’’ at the input will turn on the appropriate
LED
Figure 3 shows the timing relationships between data clock
and DATA ENABLE A max clock frequency of 05 MHz is
assumed
For applications where a lesser number of outputs are used
it is possible to either increase the current per output or
operate the part at higher than 1V V
OUT
The following
equation can be used for calculations
T
j
e
(V
OUT
) (I
LED
) (No of segments)(
i
JA
)
a
T
A
where
T
j
e
junction temperature 150 C max
V
OUT
e
the voltage at the LED driver outputs
I
LED
e
the LED current
i
JA
e
thermal coefficient of the package
T
A
e
ambient temperature
i
JA
(Socket Mount)
e
54 CW
i
JA
(Board Mount)
e
49 CW
The above equation was used to plotFigure 5 Figure 6 and
Figure 7
TLF6136–4
FIGURE 3
4
相关PDF资料
PDF描述
MM5451BV LED Display Driver
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参数描述
MM5451BV 功能描述:LED显示驱动器 LED Display Driver RoHS:否 制造商:Micrel 数位数量:5 片段数量: 安装风格:SMD/SMT 封装 / 箱体:PLCC-44 工作电源电压:4.75 V to 11 V 最大电源电流:10 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Tube
MM5451BV TR 功能描述:LED显示驱动器 LED Display Driver RoHS:否 制造商:Micrel 数位数量:5 片段数量: 安装风格:SMD/SMT 封装 / 箱体:PLCC-44 工作电源电压:4.75 V to 11 V 最大电源电流:10 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Tube
MM5451N 制造商:NSC 制造商全称:National Semiconductor 功能描述:LED Display Drivers
MM5451V 制造商:Texas Instruments 功能描述:LED DISPLAY DRIVER 5451 PLCC44
MM5451YN 功能描述:LED显示驱动器 LED Display Driver - Lead Free RoHS:否 制造商:Micrel 数位数量:5 片段数量: 安装风格:SMD/SMT 封装 / 箱体:PLCC-44 工作电源电压:4.75 V to 11 V 最大电源电流:10 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Tube