參數(shù)資料
型號(hào): ICM7211AM
廠商: Intersil Corporation
英文描述: 4-Digit, LCD Display Driver(4位, LCD顯示驅(qū)動(dòng)器)
中文描述: 4位,液晶顯示驅(qū)動(dòng)程序(4位,液晶顯示驅(qū)動(dòng)器)
文件頁數(shù): 6/8頁
文件大小: 204K
代理商: ICM7211AM
6
FN3158.7
April 17, 2006
Description of Operation
Device
The ICM7211AM provides outputs suitable for driving
conventional four-digit, seven-segment LCD displays. These
devices include 28 individual segment drivers, backplane
driver, and a self-contained oscillator and divider chain to
generate the backplane frequency.
The segment and backplane drivers each consist of a
CMOS inverter, with the N-Channel and P-Channel devices
ratioed to provide identical on resistances, and thus equal
rise and fall times. This eliminates any DC component, which
could arise from differing rise and fall times, and ensures
maximum display life.
The backplane output devices can be disabled by
connecting the OSCillator input (pin 36) to V
SS
. This allows
the 28 segment outputs to be synchronized directly to a
signal input at the BP terminal (pin 5). In this manner,
several slave devices may be cascaded to the backplane
output of one master device, or the backplane may be
derived from an external source. This allows the use of
displays with characters in multiples of four and a single
backplane. A slave device represents a load of
approximately 200pF (comparable to one additional
segment). Thus the limitation of the number of devices that
can be slaved to one master device backplane driver is the
additional load represented by the larger backplane of
displays of more than four digits. A good rule of thumb to
observe in order to minimize power consumption is to keep
the backplane rise and fall times less than about 5
μ
s. The
backplane output driver should handle the backplane to a
display of 16 one-half inch characters. It is recommended, if
more than four devices are to be slaved together, the
backplane signal be derived externally and all the
ICM7211AM devices be slaved to it. This external signal
should be capable of driving very large capacitive loads with
short (1 - 2
μ
s) rise and fall times. The maximum frequency
for a backplane signal should be about 150Hz although this
may be too fast for optimum display response at lower
display temperatures, depending on the display type.
The onboard oscillator is designed to free run at
approximately 19kHz at microampere current levels. The
oscillator frequency is divided by 128 to provide the
backplane frequency, which will be approximately 150Hz
with the oscillator free-running; the oscillator frequency may
be reduced by connecting an external capacitor between the
OSCillator terminal and V
DD
.
The oscillator may also be overdriven if desired, although care
must be taken to ensure that the backplane driver is not
disabled during the negative portion of the overdriving signal
(which could cause a DC component to the display). This can
be done by driving the OSCillator input between the positive
supply and a level out of the range where the backplane disable
is sensed (about one fifth of the supply voltage above V
SS
).
Another technique for overdriving the oscillator (with a signal
swinging the full supply) is to skew the duty cycle of the
overdriving signal such that the negative portion has a duration
shorter than about one microsecond. The backplane disable
sensing circuit will not respond to signals of this duration.
Input Configurations and Output Codes
The ICM7211AM accepts a four-bit true binary (i.e., positive
level = logical one) input at pins 27 thru 30, least significant
bit at pin 27 ascending to the most significant bit at pin 30. It
decodes the binary input into seven-segment alphanumeric
“Code B” output, i.e., 0-9, dash, E, H, L, P, blank. These
codes are shown explicitly in Table 1. It will correctly decode
true BCD to a seven-segment decimal output.
TABLE 1. OUTPUT CODES
BlNARY
CODE B
ICM7211AM
B3
B2
B1
BO
0
0
0
0
0
0
0
1
0
0
1
0
0
0
1
1
0
1
0
0
0
1
0
1
0
1
1
0
0
1
1
1
1
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
OSCILLATOR
FREQUENCY
BACKPLANE
INPUT/OUTPUT
OFF
ON
64 CYCLES
64 CYCLES
128 CYCLES
SEGMENTS
SEGMENTS
FIGURE 4. DISPLAY WAVEFORMS
ICM7211AM
相關(guān)PDF資料
PDF描述
ICM7216B 8-Digit, Multi-Function, Frequency Counters/Timers
ICM7216DIPI 8-Digit, Multi-Function, Frequency Counters/Timers
ICM7218AIJIR5254 8-Digit LED Microprocessor-Compatible Multiplexed Display Decoder Driver
ICM7218BIJIR5254 8-Digit LED Microprocessor-Compatible Multiplexed Display Decoder Driver
ICM7218CIJIR5254 8-Digit LED Microprocessor-Compatible Multiplexed Display Decoder Driver
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ICM7211AM_06 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:4-Digit, LCD Display Driver
ICM7211AMI/D+ 功能描述:LCD 驅(qū)動(dòng)器 RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時(shí)鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube
ICM7211AMIJ 制造商:Maxim Integrated Products 功能描述:
ICM7211AMIJL 功能描述:LCD 驅(qū)動(dòng)器 4 DIGIT DISPLAY DECODER/DRVRS RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時(shí)鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube
ICM7211AMIM44 制造商:Intersil Corporation 功能描述:LCD DRVR 4DIGIT 5V 44MQFP - Trays