参数资料
型号: MAX9879ERV+
厂商: MAXIM INTEGRATED PRODUCTS INC
元件分类: 音频控制
英文描述: Stereo Class D Audio Subsystem with DirectDrive Headphone Amplifier; Package: UCSP (R);30 pin;6 mm² ; Temperature: -40°C to +85°C
中文描述: 2 CHANNEL(S), VOLUME CONTROL CIRCUIT, PBGA30
封装: 2.50 X 3 MM, 0.50 MM PITCH, ROHS COMPLAINT, UCSP-30
文件页数: 20/31页
文件大小: 539K
代理商: MAX9879ERV+
MAX9879
Stereo Class D Audio Subsystem
with DirectDrive Headphone Amplifier
______________________________________________________________________________________
27
Read Data Format
Send the slave address with the R/W bit set to 1 to initi-
ate a read operation. The MAX9879 acknowledges
receipt of its slave address by pulling SDA low during
the 9th SCL clock pulse. A START (S) command fol-
lowed by a read command resets the address pointer
to register 0x00. The first byte transmitted from the
MAX9879 is the contents of register 0x00. Transmitted
data is valid on the rising edge of SCL. The address
pointer autoincrements after each read data byte. This
autoincrement feature allows all registers to be read
sequentially within one continuous frame. A STOP (P)
condition can be issued after any number of read data
bytes. If a STOP (P) condition is issued followed by
another read operation, the first data byte to be read
will be from register 0x00.
The address pointer can be preset to a specific register
before a read command is issued. The master presets
the address pointer by first sending the MAX9879‘s
slave address with the R/W bit set to 0 followed by the
register address. A REPEATED START (Sr) condition is
then sent followed by the slave address with the R/W
bit set to 1. The MAX9879 then transmits the contents
of the specified register. The address pointer autoincre-
ments after transmitting the first byte. The master
acknowledges receipt of each read byte during the
acknowledge clock pulse. The master must acknowl-
edge all correctly received bytes except the last byte.
The final byte must be followed by a not acknowledge
from the master and then a STOP (P) condition. Figure
11 illustrates the frame format for reading one byte from
the MAX9879. Figure 12 illustrates the frame format for
reading multiple bytes from the MAX9879.
Applications Information
Filterless Class D Operation
Traditional Class D amplifiers require an output filter to
recover the audio signal from the amplifier’s output. The
filters add cost, increase the solution size of the amplifier,
and can decrease efficiency and THD+N performance.
The traditional PWM scheme uses large differential out-
put swings (2 x VDD(P-P)) and causes large ripple cur-
rents. Any parasitic resistance in the filter components
results in a loss of power, lowering the efficiency.
The MAX9879 does not require an output filter. The
device relies on the inherent inductance of the speaker
coil and the natural filtering of both the speaker and the
human ear to recover the audio component of the
square-wave output. Eliminating the output filter results
in a smaller, less costly, more efficient solution.
Because the frequency of the MAX9879 output is well
beyond the bandwidth of most speakers, voice coil
movement due to the square-wave frequency is very
small. Although this movement is small, a speaker not
designed to handle the additional power can be dam-
aged. For optimum results, use a speaker with a series
inductance > 10H. Typical 8
Ω speakers exhibit series
inductances in the 20H to 100H range.
Component Selection
Optional Ferrite Bead Filter
In applications where speaker leads exceed 20mm,
additional EMI suppression can be achieved by using a
filter constructed from a ferrite bead and a capacitor to
ground. A ferrite bead with low DC resistance, high-
frequency (> 1.176MHz) impedance of 100
Ω to 600Ω,
and rated for at least 1A should be used. The capacitor
value varies based on the ferrite bead chosen and the
ACKNOWLEDGE FROM MAX9879
1 BYTE
AUTOINCREMENT INTERNAL
REGISTER ADDRESS POINTER
ACKNOWLEDGE FROM MAX9879
A
AP
0
ACKNOWLEDGE FROM MAX9879
R/W
SA
R/W
REPEATED START
Sr
1
SLAVE ADDRESS
REGISTER ADDRESS
SLAVE ADDRESS
DATA BYTE
Figure 12. Reading n Bytes of Indexed Data from the MAX9879
MAX9879
OUT+
OUT-
Figure 13. Optional Ferrite Bead Filter
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MAX9879ERV+T 功能描述:音频放大器 Audio Subsystem w/DirectDrive RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel
MAX9879EVKIT+ 功能描述:音频放大器 Stereo Class D Audio Subsystem with DirectDrive Headphone Amplifier RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel
MAX987ESA 功能描述:校验器 IC Single uPower Comparator RoHS:否 制造商:STMicroelectronics 产品: 比较器类型: 通道数量: 输出类型:Push-Pull 电源电压-最大:5.5 V 电源电压-最小:1.1 V 补偿电压(最大值):6 mV 电源电流(最大值):1350 nA 响应时间: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SC-70-5 封装:Reel
MAX987ESA+ 功能描述:校验器 IC Single uPower Comparator RoHS:否 制造商:STMicroelectronics 产品: 比较器类型: 通道数量: 输出类型:Push-Pull 电源电压-最大:5.5 V 电源电压-最小:1.1 V 补偿电压(最大值):6 mV 电源电流(最大值):1350 nA 响应时间: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SC-70-5 封装:Reel
MAX987ESA+T 功能描述:校验器 IC Single uPower Comparator RoHS:否 制造商:STMicroelectronics 产品: 比较器类型: 通道数量: 输出类型:Push-Pull 电源电压-最大:5.5 V 电源电压-最小:1.1 V 补偿电压(最大值):6 mV 电源电流(最大值):1350 nA 响应时间: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SC-70-5 封装:Reel