DataSheet8.cn


PDF ( 数据手册 , 数据表 ) MM5451

零件编号 MM5451
描述 LED Display Driver
制造商 Microchip
LOGO Microchip LOGO 


1 Page

No Preview Available !

MM5451 数据手册, 描述, 功能
MM5450/51
LED Display Driver
Features
• Continuous Brightness Control
• Serial Data Input
• No Load Signal Requirement
• Enable (MM5450 Only)
• Wide Power Supply Operation
• TTL Compatibility
• 34 or 35 Outputs, 15 mA Capability
• Alphanumeric Capability
Applications
• Industrial Control Indicator
• Relay Driver
• Digital Clock, Thermometer, Counter, Voltmeter
• Instrumentation Readouts
General Description
The MM5450 and MM5451 LED display drivers are
monolithic MOS IC’s fabricated in an N-Channel,
metal-gate process. The technology produces
low-threshold, enhancement-mode, and ion-implanted
depletion-mode devices.
A single pin controls the LED display brightness by
setting a reference current through a variable resistor
connected to the supply.
Block Diagram
BRIGHTNESS
CONTROL
OUT 34
VDD
20 24
OUT 1
18
19
35 OUTPUT BUFFERS
DATA ENABLE/OUT 35
(See Note 1)
SERIAL DATA
23
22
21
CLOCK
35 LATCHES
LOAD
35-BIT SHIFT
REGISTER
RESET
Note 1: Pin in Data Enable in MM5450
Pin in Output 25 in MM5451
RESET
(only available
1 in die form)
2016 Microchip Technology Inc.
DS20005651A-page 1







MM5451 pdf, 数据表
MM5450/51
3.0 FUNCTIONAL DESCRIPTION
The MM5450 and MM5451 are designed to drive either
4- or 5-digit alphanumeric LED displays with the added
benefit of requiring minimal interface with the display or
data source.
Data is transferred serially via two signals: clock and
serial data. Data transfer without the added
inconvenience of an external load signal is
accomplished by using a format of a leading “1”
followed by the allowed 35 data bits. These 35 data bits
are latched after the 36th has been transferred. This
scheme provides non-multiplexed, direct drive to the
LED display. Characters currently displayed (thus, data
output) changes only if the serial data bits differ from
those previously transferred.
Control of the output current for LED displays provides
for the display brightness. To prevent oscillations, a
1 nF capacitor should be connected to pin 19,
brightness control.
The Block Diagram is shown on page 1. For the
MIC5450, the /DATA ENABLE is a metal option and is
used instead of the 35th output. 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 external reset connection shown which is
available on unpackaged (die) only. Connection
Diagram: Die illustrates the die pad locations for
bonding in “chip on board” applications.
Figure 3-1 shows the input data format. A leading “1” is
followed by 35 bits of data. After the 36th had been
transferred, a LOAD signal is generated synchronously
with the clock high state. This loads the 35 bits of data
into the latches. The low side of the clock is used to
generate a RESET signal which clears all shift registers
for the next set of data. All shift registers are static
master-slave, with no clear for the master portion of the
first register, allowing continuous operation.
CLOCK
DATA
LOAD
(INTERNAL)
RESET
(INTERNAL)
1
START BIT 1
FIGURE 3-1:
36 37
BIT 35 BIT 36
Input Data Format.
There must be a complete set of 36 clocks or the shift
registers will not clear.
When the chip first powers ON, an internal power ON
reset signal is generated that resets all registers and all
latches. The START bit and the first clock return the
chip to its normal operation.
The Connection Diagram: Dual-Inline Package (DIP)
and Connection Diagram: Plastic-Leaded Chip Carrier
(PLCC) show the pinout of the MIC5450 and MIC5451.
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 3-2 shows the timing relationships between
data, clock and /DATA ENABLE. A maximum clock
frequency of 0.5 MHz is assumed.
CLOCK
DATA
300 nS MIN
DATA ENABLE
100 nS MIN
FIGURE 3-2:
Timing Diagram.
For applications where a lesser number of outputs is
used, it is possible to either increase the current per
output, or operate the part at higher than 1V VOUT. The
following equation can be used for calculations.
EQUATION 3-1:
TJ = VOUT ILED No of segments 124oC/W + TA
Where:
TJ Junction Temperature (+150°C max.)
VOUT Voltage at the LED driver outputs
ILED LED current
124°C/W Thermal resistance of the package
TA Ambient temperature
Equation 3-1 is used to plot Figure 2-1, Figure 2-2, and
Figure 2-3.
DS20005651A-page 8
2016 Microchip Technology Inc.







MM5451 equivalent, schematic
MM5450/51
NOTES:
DS20005651A-page 16
2016 Microchip Technology Inc.










页数 20 页
下载[ MM5451.PDF 数据手册 ]


分享链接

Link :

推荐数据表

零件编号描述制造商
MM5450LED Display DriverMicrochip
Microchip
MM5450LED Display DriversNational
National
MM5450LED Display DriverMicrel
Micrel
MM5451LED Display DriverMicrel
Micrel

零件编号描述制造商
STK15C88256-Kbit (32 K x 8) PowerStore nvSRAMCypress Semiconductor
Cypress Semiconductor
NJM4556DUAL HIGH CURRENT OPERATIONAL AMPLIFIERNew Japan Radio
New Japan Radio
EL1118-G5 PIN LONG CREEPAGE SOP PHOTOTRANSISTOR PHOTOCOUPLEREverlight
Everlight


DataSheet8.cn    |   2020   |  联系我们   |   搜索  |  Simemap