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參數(shù)資料
| 型號： | MAX9879ERV+ |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 音頻控制 |
| 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 |
| 封裝： | 2.50 X 3 MM, 0.50 MM PITCH, ROHS COMPLAINT, UCSP-30 |
| 文件頁數(shù)： | 13/31頁 |
| 文件大小： | 539K |
| 代理商： | MAX9879ERV+ |
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MAX9879
Stereo Class D Audio Subsystem
with DirectDrive Headphone Amplifier
20
______________________________________________________________________________________
DirectDrive Headphone Amplifier
Traditional single-supply headphone amplifiers have
outputs biased at a nominal DC voltage (typically half
the supply). Large coupling capacitors are needed to
block this DC bias from the headphone. Without these
capacitors, a significant amount of DC current flows to
the headphone, resulting in unnecessary power dissi-
pation and possible damage to both the headphone
and headphone amplifier.
Maxim’s DirectDrive architecture uses a charge pump
to create an internal negative supply voltage. This
allows the headphone outputs of the MAX9879 to be
biased at GND while operating from a single supply
(Figure 5). Without a DC component, there is no need
for the large DC-blocking capacitors. Instead of two
large (220F, typ) capacitors, the MAX9879 charge
pump requires two small ceramic capacitors, conserv-
ing board space, reducing cost, and improving the fre-
quency response of the headphone amplifier. See the
Output Power vs. Load Resistance graph in the
Typical
Operating Characteristics for details of the possible
capacitor sizes. There is a low DC voltage on the ampli-
fier outputs due to amplifier offset. However, the offset of
the MAX9879 is typically ±1.5mV, which, when com-
bined with a 32Ω load, results in less than 47A of DC
current flow to the headphones.
In addition to the cost and size disadvantages of the
DC-blocking capacitors required by conventional head-
phone amplifiers, these capacitors limit the amplifier’s
low-frequency response and can distort the audio sig-
nal. Previous attempts at eliminating the output-cou-
pling capacitors involved biasing the headphone return
(sleeve) to the DC bias voltage of the headphone
amplifiers. This method raises some issues:
FREQUENCY (MHz)
AMPLITUDE
(dB
μ
V/m)
160
140
120
100
80
60
10
15
20
25
30
35
40
TEST LIMIT
MAX9879 OUTPUT
TEST LIMIT
5
30
180
200
240
260
280
300
220
FREQUENCY (MHz)
AMPLITUDE
(dB
μ
V/m)
600
550
500
450
400
350
15
20
25
35
40
10
300
650
700
800
850
900
1000
950
750
Figure 4. EMI with 152mm of Speaker Cable
DirectDrive is a registered trademark of Maxim Integrated
Products, Inc.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX9879ERV+T | 功能描述:音頻放大器 Audio Subsystem w/DirectDrive 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 |
| MAX9879EVKIT+ | 功能描述:音頻放大器 Stereo Class D Audio Subsystem with DirectDrive Headphone Amplifier 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 |
| MAX987ESA | 功能描述:校驗(yàn)器 IC Single uPower Comparator RoHS:否 制造商:STMicroelectronics 產(chǎn)品: 比較器類型: 通道數(shù)量: 輸出類型:Push-Pull 電源電壓-最大:5.5 V 電源電壓-最小:1.1 V 補(bǔ)償電壓（最大值）:6 mV 電源電流（最大值）:1350 nA 響應(yīng)時(shí)間: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SC-70-5 封裝:Reel |
| MAX987ESA+ | 功能描述:校驗(yàn)器 IC Single uPower Comparator RoHS:否 制造商:STMicroelectronics 產(chǎn)品: 比較器類型: 通道數(shù)量: 輸出類型:Push-Pull 電源電壓-最大:5.5 V 電源電壓-最小:1.1 V 補(bǔ)償電壓（最大值）:6 mV 電源電流（最大值）:1350 nA 響應(yīng)時(shí)間: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SC-70-5 封裝:Reel |
| MAX987ESA+T | 功能描述:校驗(yàn)器 IC Single uPower Comparator RoHS:否 制造商:STMicroelectronics 產(chǎn)品: 比較器類型: 通道數(shù)量: 輸出類型:Push-Pull 電源電壓-最大:5.5 V 電源電壓-最小:1.1 V 補(bǔ)償電壓（最大值）:6 mV 電源電流（最大值）:1350 nA 響應(yīng)時(shí)間: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SC-70-5 封裝:Reel |
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