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參數(shù)資料
| 型號： | TL431A |
| 廠商： | ON SEMICONDUCTOR |
| 英文描述： | Programmable Precision References(可編程精密基準) |
| 中文描述： | 可編程精密參考（可編程精密基準） |
| 文件頁數(shù)： | 12/19頁 |
| 文件大?。?/td> | 176K |
| 代理商： | TL431A |
TL431, A, B Series, NCV431A
http://onsemi.com
12
Figure 31. Simplified TL431 Device Model
+
R
L
V
CC
C
L
15 k
9.0 F
Input
8.25 k
3
Cathode
500 k
V
ref
1.78 V
R
ref
16
G
M
Anode
2
R
GM
1.0 M
Ref
1
Go
1.0 mho
C
P2
0.265 pF
R
P2
10 M
R
Z1
15.9 k
C
P1
20 pF
f, FREQUENCY (Hz)
10
2
10
1
20
30
20
60
0
A
Figure 32. Example 1 Circuit Open Loop Gain Plot
Example 2.
I
C
= 7.5 mA, R
L
= 2.2 k , C
L
= 0.01 F. Cathode tied to
reference input pin. An examination of the data sheet
stability boundary curve (Figure 15) shows that this value of
load capacitance and cathode current is on the boundary.
Define the transfer gain.
The DC gain is:
TL431 OPENLOOP VOLTAGE GAIN VERSUS FREQUENCY
40
10
4
10
3
10
7
10
5
10
6
10
10
50
G
GMRGMGoRL
(2.323)(1.0 M)(1.25 )(2200)
The resulting open loop Bode plot is shown in Figure 33.
The asymptotic plot may be expressed as the following
equation:
6389
76 dB
Av
615
1
jf
500 kHz
1
jf
8.0 kHz
1
jf
60 kHz
1
jf
7.2 kHz
Note that the transfer function now has an extra pole
formed by the load capacitance and load resistance.
Note that the crossover frequency in this case is about
250 kHz, having a phase margin of about 46 degrees.
Therefore, instability of this circuit is likely.
f, FREQUENCY (Hz)
10
2
10
1
20
40
20
80
0
A
Figure 33. Example 2 Circuit Open Loop Gain Plot
With three poles, this system is unstable. The only hope
for stabilizing this circuit is to add a zero. However, that can
only be done by adding a series resistance to the output
capacitance, which will reduce its effectiveness as a noise
filter. Therefore, practically, in reference voltage
applications, the best solution appears to be to use a smaller
value of capacitance in low noise applications or a very
large value to provide noise filtering and a dominant pole
rolloff of the system.
TL431 OPENLOOP BODE PLOT WITH LOAD CAP
60
10
4
10
3
10
6
10
5
相關PDF資料 |
PDF描述 |
|---|---|
| TL431B | Programmable Precision References(可編程精密基準) |
| TL431C | programmable precision references |
| TL431A | Programmable Shunt Regulator（Programmable Output Volage to 36V)(可調(diào)分流穩(wěn)壓器（輸出電壓可達36V）) |
| TL432AZ | Low Voltage(1.24V) Adjustable Precision Shunt Regulator |
| TL432-AZ | Low Voltage(1.24V) Adjustable Precision Shunt Regulator |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| TL431A(B)SA-7 | 功能描述:基準電壓& 基準電流 Adj Precision Shunt 0.2 Ohm Vref to 36V RoHS:否 制造商:STMicroelectronics 產(chǎn)品:Voltage References 拓撲結(jié)構:Shunt References 參考類型:Programmable 輸出電壓:1.24 V to 18 V 初始準確度:0.25 % 平均溫度系數(shù)（典型值）:100 PPM / C 串聯(lián) VREF - 輸入電壓（最大值）: 串聯(lián) VREF - 輸入電壓（最小值）: 分流電流（最大值）:60 mA 最大工作溫度:+ 125 C 封裝 / 箱體:SOT-23-3L 封裝:Reel |
| TL431A(B)W5-7 | 功能描述:基準電壓& 基準電流 Adj Precision Shunt 0.2 Ohm Vref to 36V RoHS:否 制造商:STMicroelectronics 產(chǎn)品:Voltage References 拓撲結(jié)構:Shunt References 參考類型:Programmable 輸出電壓:1.24 V to 18 V 初始準確度:0.25 % 平均溫度系數(shù)（典型值）:100 PPM / C 串聯(lián) VREF - 輸入電壓（最大值）: 串聯(lián) VREF - 輸入電壓（最小值）: 分流電流（最大值）:60 mA 最大工作溫度:+ 125 C 封裝 / 箱體:SOT-23-3L 封裝:Reel |
| TL431A_13 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:PRECISION PROGRAMMABLE REFERENCE |
| TL431A1 | 制造商:Panasonic Industrial Company 功能描述:SUB ONLY IC |
| TL431A3 | 制造商:CYSTEKEC 制造商全稱:Cystech Electonics Corp. 功能描述:Adjustable Precision Shunt Regulators |
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