收藏本站
24-Output PWM LED Drivers
for Message Boards
When the MAX6974/MAX6975 send individual-intensity
PWM data, the data segment bit length is large due to
the 12-bit or 14-bit PWM data for each of the 24 outputs
(see Figure 11). The various data segment bit lengths
for each of the four commands and different operating
modes is shown in Table 4. Data capturing is the same
as described above with the header segment outputs
and data being delayed by the full length of the data bit
stream being captured plus one clock cycle.
header and new counter value out DOUT. Regardless
of the number of open-circuit outputs on a device, the
counter increment is 1.
The MAX6974/MAX6975 detect die temperatures above
T DIE = +165°C and disable all output drivers by setting
all PWM data to zero. During an overtemperature event,
the MAX6974/MAX6975 increment the counter segment
data, CNTR[9:0], received on DIN by 1 before transmitting
a header and new counter value out DOUT. The output
D0
H1 DATA 1 PWM 288 BITS
DATA 2 PWM 288 BITS DATA 3 PWM 288 BITS T
drivers are allowed to be on when the die temperature
falls below T DIE = +150°C.
D1
289 CLOCKS
H2 DATA 2 PWM 288 BITS DATA 3 PWM 288 BITS T
When there is no fault detected, the counter data is
D2
289 CLOCKS
H3 DATA 3 PWM 288 BITS T
passed directly to DOUT unaltered.
D3
289 CLOCKS
H4 T
Applications Information
Terminations and PCB Layout
Figure 11. Long (288 Bits) PWM Data Cascading Shown for
MAX6974 in Nonmultiplexed Mode
LED Open-Circuit and
Overtemperature Detection Counter
The MAX6974/MAX6975 feature LED open-circuit
detection and overtemperature detection that use the
counter section of the header segment to record
detected faults. Using commands 01 or 11 force the
counter to record LED open-circuit detection faults.
Using commands 00 or 10 force the counter to record
overtemperature faults.
The MAX6974/MAX6975 detect an open circuit on a driver
output by monitoring for output voltages below 200mV.
When an open circuit is detected, the MAX6974/
MAX6975 increment the counter segment data,
CNTR[9:0], received on DIN by 1 before transmitting a
The MAX6974/MAX6975’s layout simplifies cascading
multiple devices, as the interface signals flow through
from each device. The synchronous and buffered
nature of the interface simplifies the board design, but
pay attention to signal routing and termination, as with
other high-speed logic circuits.
Terminate the differential input pairs, CLKI+ and CLKI-,
as well as DIN+ and DIN-, with a termination resistor as
close as possible to the package. When using the
MAX6974/MAX6975 as the signal source, use a 200 Ω
termination resistor. When using a level translator or clock
retimer as the signal source, use a 110 Ω termination
resistor. Route each differential input pair as close
parallel tracks with spacing or a GND trace between
the track pair and the next signal track to minimize
cross-coupling. Track lengths up to a few inches do not
require termination-matched tracks (transmission lines).
n MORE DEVICES WITH
200 Ω TERMINATION
LOAD
LOADI
LOADO
LOADI
LOADO
DIN
DIN1
DO1+
DIN+
DOUT+
DIN+
DOUT+
HOST
110 Ω
200 Ω
MAX9112
MAX6974
MAX6974
CLK
DIN2
DO1-
DO2+
DIN-
CLKI+
DOUT-
CLKO+
DIN-
CLKI+
DOUT-
CLKO+
110 Ω
200 Ω
DO2-
CLKI-
CLKO-
CLKI-
CLKO-
Figure 12. Typical Cascaded Serial-Interface Termination Circuit
n-1
n-2
20
______________________________________________________________________________________
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
MAX6977AAE+ IC LED DRIVER LINEAR 16-SSOP
MAX6978AUE+ IC LED DVR CONST-CURR 16TSSOP
MAX6979AUG+ IC LED DRIVER LINEAR 24-TSSOP
MAX6983AUG+T IC LED DRIVER LINEAR 24-TSSOP
MAX71020AEUI+ IC ENERGY METER 1PH 28TSSOP
MAX7302ATE+ IC LED DRIVER LINEAR 16-TQFN
MAX7307AUB+T IC LED DRIVER LINEAR 10-UMAX
MAX831EVKIT-SO EVAL KIT FOR MAX831
相关代理商/技术参数
MAX6974ATL+T 功能描述:LED照明驱动器 24-Output PWM LED Driver RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N
MAX6974ATL-T 制造商:Maxim Integrated Products 功能描述:24-OUTPUT PWM LED DRIVERS FOR MESSA - Tape and Reel
MAX6974EVKIT 功能描述:LED 照明开发工具 MAX6974 Evaluation Kit RoHS:否 制造商:Fairchild Semiconductor 产品:Evaluation Kits 用于:FL7732 核心: 电源电压:120V 系列: 封装:
MAX6974EVKIT+ 功能描述:LED 照明开发工具 MAX6974 Evaluation Kit RoHS:否 制造商:Fairchild Semiconductor 产品:Evaluation Kits 用于:FL7732 核心: 电源电压:120V 系列: 封装:
MAX6975ATL 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
MAX6975ATL+ 功能描述:LED照明驱动器 24-Output PWM LED Driver RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N
MAX6975ATL+T 功能描述:LED照明驱动器 24-Output PWM LED Driver RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N
MAX6975ATL-T 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