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| 型号： | MAX7221CWG+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 10/17页 |
| 文件大小： | 0K |
| 描述： | IC DRVR DSPLY LED 8DIG 24SOIC |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1,000 |
| 显示器类型： | LED |
| 配置： | 7 段 + DP |
| 接口： | 4 线串行 |
| 数字或字符： | 8 位数字 |
| 电流 - 电源： | 330mA |
| 电源电压： | 4 V ~ 5.5 V |
| 工作温度： | 0°C ~ 70°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-SOIC（0.295"，7.50mm 宽） |
| 供应商设备封装： | 24-SOIC W |
| 包装： | 带卷 (TR) |
MAX7219/MAX7221
Serially Interfaced, 8-Digit LED Display Drivers
If the scan-limit register is set for three digits or less,
individual digit drivers will dissipate excessive amounts
of power. Consequently, the value of the R SET resistor
must be adjusted according to the number of digits dis-
played, to limit individual digit driver power dissipation.
Table 9 lists the number of digits displayed and the
corresponding maximum recommended segment cur-
rent when the digit drivers are used.
Display-Test Register
The display-test register operates in two modes: normal
and display test. Display-test mode turns all LEDs on
by overriding, but not altering, all controls and digit reg-
isters (including the shutdown register). In display-test
mode, 8 digits are scanned and the duty cycle is 31/32
(15/16 for MAX7221). Table 10 lists the display-test reg-
ister format.
Table 9. Maximum Segment Current for
1-, 2-, or 3-Digit Displays
fourth chip, sent the desired 16-bit word, followed by
three no-op codes (hex 0xXX0X, see Table 2). When
LOAD/ CS goes high, data is latched in all devices. The
first three chips receive no-op commands, and the
fourth receives the intended data.
Applications Information
Supply Bypassing and Wiring
To minimize power-supply ripple due to the peak digit
driver currents, connect a 10μF electrolytic and a 0.1μF
ceramic capacitor between V+ and GND as close to
the device as possible. The MAX7219/MAX7221 should
be placed in close proximity to the LED display, and
connections should be kept as short as possible to
minimize the effects of wiring inductance and electro-
magnetic interference. Also, both GND pins must be
connected to ground.
Selecting R SET Resistor and
Using External Drivers
NUMBER OF DIGITS
DISPLAYED
1
2
3
MAXIMUM SEGMENT
CURRENT
(mA)
10
20
30
The current per segment is approximately 100 times
the current in ISET. To select R SET , see Table 11. The
MAX7219/MAX7221’s maximum recommended seg-
ment current is 40mA. For segment current levels
above these levels, external digit drivers will be need-
ed. In this application, the MAX7219/MAX7221 serve
only as controllers for other high-current drivers or tran-
sistors. Therefore, to conserve power, use R SET = 47k Ω
when using external current sources as segment dri-
Table 10. Display-Test Register Format
(Address (Hex) = 0xXF)
vers.
The example in Figure 2 uses the MAX7219/MAX7221’s
segment drivers, a MAX394 single-pole double-throw
MODE
Normal
Operation
D7
X
D6
X
REGISTER DATA
D5 D4 D3 D2
X X X X
D1
X
D0
0
analog switch, and external transistors to drive 2.3”
AND2307SLC common-cathode displays. The 5.6V
zener diode has been added in series with the decimal
point LED because the decimal point LED forward volt-
age is typically 4.2V. For all other segments the LED
Display Test
Mode
X
X
X
X
X
X
X
1
forward voltage is typically 8V. Since external transis-
tors are used to sink current (DIG 0 and DIG 1 are used
Note: The MAX7219/MAX7221 remain in display-test mode
(all LEDs on) until the display-test register is reconfigured
for normal operation.
No-Op Register
The no-op register is used when cascading MAX7219s
or MAX7221s. Connect all devices’ LOAD/ CS inputs
together and connect DOUT to DIN on adjacent
devices. DOUT is a CMOS logic-level output that easily
drives DIN of successively cascaded parts. (Refer to
the Serial Addressing Modes section for detailed infor-
mation on serial input/output timing.) For example, if
four MAX7219s are cascaded, then to write to the
10
as logic switches), peak segment currents of 45mA are
allowed even though only two digits are displayed. In
applications where the MAX7219/MAX7221’s digit dri-
vers are used to sink current and fewer than four digits
are displayed, Table 9 specifies the maximum allow-
able segment current. R SET must be selected accord-
ingly (Table 11).
Refer to the Continuous Power Dissipation section of
the Absolute Maximum Ratings to calculate acceptable
limits for ambient temperature, segment current, and
the LED forward-voltage drop.
Maxim Integrated
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX7221ENG | 功能描述:LED显示驱动器 8-Digit 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 |
| MAX7221ENG+ | 功能描述:LED显示驱动器 8-Digit 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 |
| MAX7221ERG | 功能描述:LED显示驱动器 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 |
| MAX7221EWG | 功能描述:LED显示驱动器 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 |
| MAX7221EWG+ | 功能描述:LED显示驱动器 8-Digit 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 |
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