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| 型號： | NCP2820EVB |
| 廠商： | ON Semiconductor |
| 文件頁數(shù)： | 6/21頁 |
| 文件大?。?/td> | 0K |
| 描述： | BOARD EVAL NCP2820 |
| 產(chǎn)品變化通告： | 1Q2012 Discontinuation 30/Mar/2012 |
| 設(shè)計資源： | NCP2820EVB Gerber Files |
| 標(biāo)準(zhǔn)包裝： | 1 |
| 放大器類型： | D 類 |
| 輸出類型： | 1-通道（單聲道） |
| 在某負(fù)載時最大輸出功率 x 通道數(shù)量： | 2.65W x 1 @ 4 歐姆 |
| 電源電壓： | 2.5 V ~ 5.5 V |
| 工作溫度： | -40°C ~ 85°C |
| 板類型： | 完全填充 |
| 已用 IC / 零件： | NCP2820 |
| 已供物品： | 板 |
NCP2820 Series
http://onsemi.com
14
APPLICATION INFORMATION
NCP2820 PWM Modulation Scheme
The NCP2820 uses a PWM modulation scheme with each
output switching from 0 to the supply voltage. If Vin = 0 V
outputs OUTM and OUTP are in phase and no current is
flowing through the differential load. When a positive signal
is applied, OUTP duty cycle is greater than 50% and OUTM
is less than 50%. With this configuration, the current through
the load is 0 A most of the switching period and thus power
losses in the load are lowered.
Figure 35. Output Voltage and Current Waveforms into an Inductive Loudspeaker
DC Output Positive Voltage Configuration
OUTP
OUTM
Load Current
+Vp
0 V
Vp
0 A
Voltage Gain
The first stage is an analog amplifier. The second stage is
a comparator: the output of the first stage is compared with
a periodic ramp signal. The output comparator gives a pulse
width modulation signal (PWM). The third and last stage is
the direct conversion of the PWM signal with MOS
transistors Hbridge into a powerful output signal with low
impedance capability.
With an 8
W load, the total gain of the device is typically
set to:
300 kW
Ri
Input Capacitor Selection (Cin)
The input coupling capacitor blocks the DC voltage at the
amplifier input terminal. This capacitor creates a highpass
filter with Rin, the cutoff frequency is given by
Fc +
1
2
p
Ri
Ci
.
When using an input resistor set to 150 k
W, the gain
configuration is 2 V/V. In such a case, the input capacitor
selection can be from 10 nF to 1
mF with cutoff frequency
values between 1 Hz and 100 Hz. The NCP2820 also
includes a built in low pass filtering function. It’s cut off
frequency is set to 20 kHz.
Optional Output Filter
This filter is optional due to the capability of the speaker
to filter by itself the high frequency signal. Nevertheless, the
high frequency is not audible and filtered by the human ear.
An optional filter can be used for filtering high frequency
signal before the speaker. In this case, the circuit consists of
two inductors (15
mH) and two capacitors (2.2 mF)
(Figure 36). The size of the inductors is linked to the output
power requested by the application. A simplified version of
this filter requires a 1
mF capacitor in parallel with the load,
instead of two 2.2
mF connected to ground (Figure 37).
Cellular phones and portable electronic devices are great
applications for Filterless ClassD as the track length
between the amplifier and the speaker is short, thus, there is
usually no need for an EMI filter. However, to lower radiated
emissions as much as possible when used in filterless mode,
a ferrite filter can often be used. Select a ferrite bead with the
high impedance around 100 MHz and a very low DCR value
in the audio frequency range is the best choice. The
MPZ1608S221A1 from TDK is a good choice. The package
size is 0603.
Optimum Equivalent Capacitance at Output Stage
If the optional filter described in the above section isn’t
selected. Cellular phones and wireless portable devices
design normally put several Radio Frequency filtering
capacitors and ESD protection devices between Filter less
Class D outputs and loudspeaker. Those devices are usually
connected between amplifier output and ground. In order to
achieve the best sound quality, the optimum value of total
equivalent capacitance between each output terminal to the
ground should be less than or equal to 150 pF. This total
equivalent capacitance consists of the radio frequency
filtering capacitors and ESD protection device equivalent
parasitic capacitance.
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參數(shù)描述 |
|---|---|
| NCP2820FCT1 | 功能描述:音頻放大器 2.65W Mono Class D RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
| NCP2820FCT1G | 功能描述:音頻放大器 2.65W Mono Class D Audio Ind. Temp RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
| NCP2820FCT1G-CUT TAPE | 制造商:ON 功能描述:NCP Series 1 Channel 5.5 V SMT Filterless Class-D Audio Power Amplifier - CSP-9 |
| NCP2820FCT2G | 功能描述:音頻放大器 ANA CLAS D AUDIO AMP RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
| NCP2820MUTBG | 功能描述:音頻放大器 CLASS D AUDIO AMP RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
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