AN108 [SMSC]
capacitor Selection for Internal Regulator Output Pins; 电容选择内部稳压器输出引脚
| 型号： | AN108 |
| 厂家： | 
SMSC CORPORATION |
| 描述： | capacitor Selection for Internal Regulator Output Pins |
| 文件： | 总4页 (文件大小：356K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Application Note 10.8
USB97C223 and USB97C243
Capacitor Selection for Internal Regulator Output Pins
SMSC AN 10.8
Rev. 12-16-03
APPLICATION NOTE
USB97C223 and USB97C243 Capacitor Selection for Internal Regulator Output Pins
80 Arkay Drive
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SMSC AN 10.8
Page 2
Rev. 12-16-03
APPLICATION NOTE
USB97C223 and USB97C243 Capacitor Selection for Internal Regulator Output Pins
Overview
The USB97C223 and USB97C243 have two internal 1.8V regulators used to provide the digital and analog 1.8V
supplies. The output pins of the regulator have very specific capacitor requirements that are described below.
It is important that the customer designs their product with the specifications set forth in this document.
Requirements
Table 1 lists the capacitor requirements on the regulator output pins.
Table 1 – Regulator Output Pins
USB97C223
PIN NUMBER
PIN NAME
PIN DESCRIPTION
CAPACITOR REQUIREMENT
10uF +/- 20 % with < 0.65 Ohm ESR
98
VDDP
Analog Regulator
Output
91
VDDCORE
Digital Regulator
Output
10uF +/- 20 % with < 0.65 Ohm ESR
USB97C243
50
43
VDDP
Analog Regulator
10uF +/- 20 % with < 0.65 Ohm ESR
10uF +/- 20 % with < 0.65 Ohm ESR
Output
VDDCORE (closest
to VREG)
Digital Regulator
Output
Figure 1 and Figure 2 show an example of the degradation in performance of the USB97C223 and USB97C243
as the ESR of the capacitor on the output of the regulators is increased to 0.65 Ohm.
Figure 1 - 10uF Capacitor with 0.1 Ohm ESR
Figure 2 - 10uF Capacitor with 0.65 Ohm ESR
SMSC AN 10.8
Page 3
Rev. 12-16-03
APPLICATION NOTE
USB97C223 and USB97C243 Capacitor Selection for Internal Regulator Output Pins
SMSC recommends the use of ceramic 10uF capacitors to meet the low ESR requirements of the regulator
output pins of the USB97C223. Ceramic capacitors typically have an ESR of < 0.1 Ohm.
Recommended Capacitors, or equivalent:
Kemet C0805C106K9PACTU (0805 Package)
Kemet C1206C106K9PACTU (1206 Package)
Panasonic ECJ-2FF0J106Z
Panasonic ECJ-2FF1A106Z
(0805 Package)
(0805 Package)
Tantalum capacitors that have low ESR specifications can also be used, but typically have an ESR closer to 0.5
Ohm.
SMSC AN 10.8
Page 4
Rev. 12-16-03
APPLICATION NOTE
相关型号：
AN1081S
Operational Amplifier, 1 Func, 10000uV Offset-Max, PDSO8, 0.225 INCH, PLASTIC, SOP-8
PANASONIC
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