MAX6948B
High-Efficiency PWM LED Driver with Boost
Converter and Five Constant-Current GPIO Ports
Serial Interface
Figure 8 shows the 2-wire serial-interface timing details.
Serial Addressing
The MAX6948B operates as a slave that sends and
receives data through an I 2 C-compatible 2-wire inter-
face. The interface uses a serial-data line (SDA) and
a serial-clock line (SCL) to achieve bidirectional com-
munication between master(s) and slave(s). A master
(typically a microcontroller) initiates all data transfers to
and from the MAX6948B and generates the SCL clock
that synchronizes the data transfer.
The MAX6948B’s SDA line operates as both an input and
an open-drain output. A pullup resistor, typically 4.7k I , is
required on SDA. The MAX6948B’s SCL line operates only
as an input. A pullup resistor is required on SCL if there are
multiple masters on the 2-wire interface, or if the master in a
single-master system has an open-drain SCL output.
SDA
Each transmission consists of a START condition (Figure
9) sent by a master, followed by the MAX6948B 7-bit
slave address plus R/ W bit, a register address byte, 1 or
more data bytes, and finally a STOP condition.
START and STOP Conditions
Both SCL and SDA remain high when the interface is not
busy. A master signals the beginning of a transmission
with a START (S) condition by transitioning SDA from high
to low while SCL is high. When the master has finished
communicating with the slave, it issues a STOP (P) con-
dition by transitioning SDA from low to high while SCL is
high. The bus is then free for another transmission.
Bit Transfer
One data bit is transferred during each clock pulse
(Figure 10). The data on SDA must remain stable while
SCL is high.
t LOW
t SU, DAT
t HD, DAT
t SU, STA
t HD, STA
t SU, STO
t BUF
SCL
t HIGH
t HD,STA
t R
t F
START CONDITION
REPEATED START CONDITION
STOP
CONDITION
START
CONDITION
Figure 8. 2-Wire Serial-Interface Timing Details
SDA
SDA
SCL
S
START
P
STOP
SCL
CONDITION
Figure 9. START and STOP Conditions
22
CONDITION
DATA LINE STABLE; CHANGE OF DATA
DATA VALID
ALLOWED
Figure 10. Bit Transfer
Maxim Integrated
相关PDF资料
MAX6964ATG+T IC LED DRIVER LINEAR 24-TQFN
MAX6965ATE+T IC LED DRIVER LINEAR 16-TQFN
MAX6967ATE+ IC LED DRIVER LINEAR 16-TQFN
MAX6968AAE+ IC LED DRIVER LINEAR 16-SSOP
MAX6970AUE+ IC LED DRIVER LINEAR 16-TSSOP
MAX6971AUG+T IC LED DRIVER LINEAR 24-TSSOP
MAX6974ATL+ IC LED DRIVER LINEAR 40-TQFN
MAX6977AAE+ IC LED DRIVER LINEAR 16-SSOP
相关代理商/技术参数
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
MAX694CPA 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
MAX694CPA+ 功能描述:监控电路 MPU Supervisor 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
MAX694EJA 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
MAX694EPA 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
MAX694EPA+ 功能描述:监控电路 MPU Supervisor 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
MAX694MJA 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
MAX694MJA/883B 功能描述:监控电路 MPU Supervisor 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