- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄363333 > NLMD5820 (ON SEMICONDUCTOR) 2.65 W Filterless Class-D Audio Amplifier with Integrated Dual SPST Switch PDF資料下載
參數(shù)資料
| 型號： | NLMD5820 |
| 廠商： | ON SEMICONDUCTOR |
| 英文描述： | 2.65 W Filterless Class-D Audio Amplifier with Integrated Dual SPST Switch |
| 中文描述： | 2.65糯無濾波器D類音頻放大器集成雙路SPST開關(guān) |
| 文件頁數(shù)： | 18/21頁 |
| 文件大小： | 228K |
| 代理商： | NLMD5820 |
NLMD5820
http://onsemi.com
18
APPLICATION INFORMATION
NLMD5820 PWM Modulation Scheme
The NLMD5820 uses a PWM modulation scheme with
each output switching from 0 to the supply voltage. If V
in
=
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 47. 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 H-bridge into a powerful output signal with low
impedance capability.
With an 8 load, the total gain of the device is typically
set to:
300k
Ri
Input Capacitor Selection (C
in
)
The input coupling capacitor blocks the DC voltage at the
amplifier input terminal. This capacitor creates a high-pass
filter with R
in
, the cut-off frequency is given by
1
2
Ri
When using an input resistor set to 150 k , the gain
configuration is 2 V/V. In such a case, the input capacitor
selection can be from 10 nF to 1
F with cutoff frequency
values between 1 Hz and 100 Hz. The NLMD5820 also
includes a built in low pass filtering function. It's cut off
frequency is set to 20 kHz.
Fc
Ci
.
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 H) and two capacitors (2.2 F). The size
of the inductors is linked to the output power requested by
the application. A simplified version of this filter requires a
1 F capacitor in parallel with the load, instead of two 2.2 F
connected to ground).
Cellular phones and portable electronic devices are great
applications for Filterless Class-D 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.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| NLMD5820MUTAG | 2.65 W Filterless Class-D Audio Amplifier with Integrated Dual SPST Switch |
| NLSF2500 | Keypad Multiplexer |
| NLSF2500MN1R2G | Keypad Multiplexer |
| NLSF302 | Quad 2−Input NOR Gate |
| NLSF302_06 | Quad 2−Input NOR Gate |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| NLMD5820MUTAG | 功能描述:音頻放大器 ANLOG SWCH 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: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
| NLN | 制造商:LITTELFUSE 制造商全稱:Littelfuse 功能描述:NLN/NLS Class K5 Fuses |
| NLN 20 AMP | 制造商:Littelfuse 功能描述:Fuse;Cylinder;One-Time;20A;Class K5;Dims 0.56x2";Cartridge;250/600VAC;Clip |
| NLN 30 AMP | 制造商:Littelfuse 功能描述:Fuse;Cylinder;One-Time;30A;Class K5;Dims 0.56x2";Cartridge;250/600VAC;Clip |
| NLN002 | 制造商:Littelfuse 功能描述:Fuse Class K5 2A 250V Slow Blow 2-Pin Holder |
發(fā)布緊急采購，3分鐘左右您將得到回復。