参数资料
型号: TS4994EIJT
厂商: STMICROELECTRONICS
元件分类: 音频/视频放大
英文描述: 1.2 W, 1 CHANNEL, AUDIO AMPLIFIER, PBGA9
封装: ROHS COMPLIANT, FCP-9
文件页数: 18/35页
文件大小: 694K
代理商: TS4994EIJT
TS4994FC
Application information
25/35
must introduce a mismatch factor (Rin1 xCin ≠ Rin2 xCin2) that will decrease the PSRR
performance.
From 200Hz to 5kHz, the Cin impedance is low enough to be neglected when
compared with Rin, and the Cfeed impedance is high enough to be neglected as well. In
this range, we can reach the PSRR performance of the TS4994 itself.
From 5kHz to 20kHz, the Cin impedance is low to be neglected when compared to Rin,
and the Cfeed impedance decreases to a finite value. Due to tolerance of Cfeed1,2, we
introduce a mismatching factor (Rfeed1 xCfeed1 ≠ Rfeed2 xCfeed2) that will decrease the
PSRR performance.
4.5
Calculating the influence of mismatching on PSRR
performance
For calculating PSRR performance, we consider that Cin and Cfeed have no influence. We
use the same kind of resistor (same tolerance) and
ΔR is the tolerance value in %.
The following PSRR equation is valid for frequencies ranging from DC to about 1kHz.
The PSRR equation is (
ΔR in %):
This equation doesn't include the additional performance provided by bypass capacitor
filtering. If a bypass capacitor is added, it acts, together with the internal high output
impedance bias, as a low-pass filter, and the result is a quite important PSRR improvement
with a relatively small bypass capacitor.
The complete PSRR equation (
ΔR in %, Cb in microFarad and F in Hz) is:
Example: With
ΔR = 0.1% and Cb = 0, the minimum PSRR is -60dB. With a 100nF bypass
capacitor, at 100Hz the new PSRR would be -93dB.
This example is a worst case scenario, where each resistor has extreme tolerance. It
illustrates the fact that with only a small bypass capacitor, the TS4994 provides high PSRR
performance.
Note also that this is a theoretical formula. Because the TS4994 has self-generated noise,
you should consider that the highest practical PSRR reachable is about -110dB. It is
therefore unreasonable to target a -120dB PSRR.
)
dB
(
)
R
10000
(
100
R
Log
20
PSRR
2
Δ
×
Δ
×
PSRR
20
log
×
R
100
×
Δ
(1000
R
2
)
1F
2
C
b
2
22.2
×
+
×
Δ
---------------------------------------------------------------------------------------------------------
dB
()
相关PDF资料
PDF描述
TS4994EIKJT 1.2 W, 1 CHANNEL, AUDIO AMPLIFIER, PBGA9
TS4994IQT 1 W, 1 CHANNEL, AUDIO AMPLIFIER, DSO8
TS4994IST 1 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8
TS4995EIJT 1.2 W, 1 CHANNEL, AUDIO AMPLIFIER, PBGA9
TS4998IQT 1 W, 2 CHANNEL, AUDIO AMPLIFIER, QCC16
相关代理商/技术参数
参数描述
TS4994EIKJT 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:1.2 W differential input/output audio power amplifier with selectable standby
TS4994FC 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:1.2 W differential input/output audio power amplifier with selectable standby
TS4994IJT 功能描述:音频放大器 STANDARD LINEAR 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
TS4994IQT 功能描述:音频放大器 1W diff input/output audio Pwr 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
TS4994IST 功能描述:音频放大器 1W Audio Power Amp 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