參數(shù)資料
型號(hào): LM4935WL
廠(chǎng)商: National Semiconductor Corporation
元件分類(lèi): ADC
英文描述: Audio Sub-System with Dual-Mode Stereo Headphone and Mono High Efficiency Loudspeaker Amplifiers and Multi-Purpose ADC
中文描述: 音頻子系統(tǒng)的雙模單聲道立體聲耳機(jī)和揚(yáng)聲器放大器的高效率和多功能模數(shù)轉(zhuǎn)換器
文件頁(yè)數(shù): 60/112頁(yè)
文件大小: 5017K
代理商: LM4935WL
12.0 Status & Control Registers
(Continued)
12.37 SAR OVERVIEW
The SAR controller works via a scheduler that allocates time slots for each of the four channels. All four channels can operate up
to the same maximum frequency. When the sampling frequency of a channel is to be reduced the time slot allocated to that
channel is simply enabled less often. For example if one slot is to work at a quarter of the frequency of the others then only one
in four of its allocated slot triggers the SAR to activate:
Each time slot is used to sample a single fixed input, slot 0 is used for VSAR 1, slot 1 for VSAR 2, slot 2 for either D_V
DD
or
BB_V
DD
* and slot 3 for the A_V
DD
. When a particular time slot is activated the correct mux, clock and enable controls to the ADC
module are produced and the output sampled when ready. If the D_V
or the A_V
are being sampled then a voltage divider
is used to half the input to below the full scale reference of 2.5V. As this results in a current path to ground it is only inserted while
the ADC is settling to reduce power consumption.
Using this method, samples can be taken using as little power as possible while allowing sample rates as low as 1 Hz. The data
can either be read directly or used to trigger interrupts when set voltages are passed. This reduces the baseband controllers
software overhead and IO bandwidth, further reducing system power.
The full scale digital output from the SAR is equal to 2.5V. The A_V
and D_V
inputs are divided by two during sampling. The
SAR ADC can be activated at any time, even while the chip is in shutdown mode (chip mode ’00’). This allows the LM4935 to
perform housekeeping duties such as voltage monitoring with minimal power consumption.
*Depending on SLOT_2_VBB in SAR_SLOT23 (0x1Ch).
20134118
FIGURE 13. Internal SAR Control Signals to SAR Module
L
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM4935WLX 制造商:NSC 制造商全稱(chēng):National Semiconductor 功能描述:Audio Sub-System with Dual-Mode Stereo Headphone and Mono High Efficiency Loudspeaker Amplifiers and Multi-Purpose ADC
LM4936 制造商:NSC 制造商全稱(chēng):National Semiconductor 功能描述:Stereo 2W Audio Power Amplifiers with Volume Control and Selectable Control Interface (SPI or I2C)
LM49360 制造商:TI 制造商全稱(chēng):Texas Instruments 功能描述:Mono Class D Audio Codec PMU with Ground Referenced Headphone Amplifiers, Earpiece Driver, Audio DSP, 2 Step-Down DC-DC Converters, and 7 LDO Regulators
LM49360RL 制造商:TI 制造商全稱(chēng):Texas Instruments 功能描述:Mono Class D Audio Codec PMU with Ground Referenced Headphone Amplifiers, Earpiece Driver, Audio DSP, 2 Step-Down DC-DC Converters, and 7 LDO Regulators
LM49360RLX 制造商:TI 制造商全稱(chēng):Texas Instruments 功能描述:Mono Class D Audio Codec PMU with Ground Referenced Headphone Amplifiers, Earpiece Driver, Audio DSP, 2 Step-Down DC-DC Converters, and 7 LDO Regulators