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参数资料
| 型号： | MAX6947ATE+ |
| 厂商： | Maxim Integrated |
| 文件页数： | 19/24页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVER LINEAR 16-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 100 |
| 恒定电流： | 是 |
| 拓扑： | 开路漏极，PWM |
| 输出数： | 10 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 背光 |
| 类型 - 次要： | RGB，白色 LED |
| 频率： | 400kHz |
| 电源电压： | 2.25 V ~ 3.6 V |
| 输出电压： | 7V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WFQFN 裸露焊盘 |
| 供应商设备封装： | 16-TQFN（3x3） |
| 包装： | 管件 |
| 工作温度： | -40°C ~ 125°C |
10-Port, Constant-Current LED Driver and
I/O Expander with PWM Intensity Control
Hot Insertion
The RST , SCL, and AD0 inputs and SDA remain high
impedance with up to +6V asserted on them when the
MAX6946/MAX6947 power down (V DD = 0V). I/O ports
P0 to P9 remain high impedance with up to +8V asserted
on them when the MAX6946/MAX6947 power down. Use
the MAX6946/MAX6947 in hot-swap applications.
Differences Between
the MAX6946 and MAX6947
The MAX6946 features the OSC input, allowing the
device to use an external clock as the PWM clock
source. The MAX6946 features a fixed I 2 C slave
address of 0100000. The MAX6947 features an AD0
input, allowing two unique I 2 C addresses (Table 10).
The MAX6947 always uses the internal 32kHz oscillator
as the PWM clock source.
Driving LEDs into Brownout
The MAX6946/MAX6947 correctly regulate the con-
stant-current outputs, provided there is a minimum volt-
age drop across the port output. This port output
voltage is the difference between the load (typically
LED) supply and the load voltage drop (LED forward
voltage). If the LED supply drops so that the minimum
port output voltage is not maintained, the driver output
stages brownout and the load current falls. The mini-
mum port voltage is approximately 0.5V at 10mA sink
current and approximately 1V at 20mA sink current.
Operating the LEDs directly from a battery supply can
cause brownouts. For example, the LED supply voltage
is a single rechargeable lithium-ion battery with a maxi-
mum terminal voltage of 4.2V on charge, 3.4V to 3.7V
V LED vs. V LED SUPPLY
3.05
3.00
2.95
2.90
2.85
2.80
2.75
2.70
2.65
2.60
2.55
2.50
2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0
V LED SUPPLY (V)
Figure 15. LED Brownout
most of the time, and down to 3V when discharged. In
this scenario, the LED supply falls significantly below
the brownout point when the battery is at end-of-life
voltage (3V).
Figure 15 shows the typical current sink by a LITEON
LTST-C170TBKT 3.0V blue LED as the LED supply volt-
age is varied from 2.5V to 7V. The LED currents shown
are for ports programmed for 10mA and 20mA constant
current, swept over a 2.5V to 7V LED supply voltage
range. It can be seen that the LED forward voltage falls
with current, allowing the LED current to fall gracefully,
not abruptly, in brownout. In practice, the LED current
drops to 6mA to 7mA at a 3V LED supply voltage, this
is acceptable performance at end-of-life in many back-
light applications.
Output-Level Translation
The open-drain output architecture allows the ports to
level translate the outputs to higher or lower voltages
than the MAX6946/MAX6947 supply. Use an external
pullup resistor on any output to convert the high-imped-
ance, logic-high condition to a positive voltage level.
Connect the resistor to any voltage up to 7V. When
using a pullup on a constant-current output, select the
resistor value to sink no more than a few hundred
micramps in logic-low condition. This ensures that the
current sink output saturates close to GND. For inter-
facing CMOS inputs, a pullup resistor value of 220k Ω is
a good starting point. Use a lower resistance to
improve noise immunity in applications where power
consumption is less critical, or where a faster rise time
is needed for a given capacitive load.
I LED vs. V LED SUPPLY
20
18
16
14
12
10
8
6
4
2
0
2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0
V LED SUPPLY (V)
______________________________________________________________________________________
19
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX6947ATE+ | 功能描述:LED照明驱动器 10-Port Constant Current 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 |
| MAX6947ATE+T | 功能描述:LED照明驱动器 10-Port Constant Current 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 |
| MAX6948BGWA+ | 制造商:Maxim Integrated Products 功能描述:- Rail/Tube |
| MAX6948BGWA+T | 功能描述:LED照明驱动器 High-Efficiency 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 |
| MAX694C/D | 功能描述:监控电路 RoHS:否 制造商:STMicroelectronics 监测电压数: 监测电压: 欠电压阈值: 过电压阈值: 输出类型:Active Low, Open Drain 人工复位:Resettable 监视器:No Watchdog 电池备用开关:No Backup 上电复位延迟（典型值）:10 s 电源电压-最大:5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UDFN-6 封装:Reel |
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