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參數(shù)資料
| 型號： | LP2951ACDM |
| 廠商： | ON SEMICONDUCTOR |
| 元件分類： | 固定／可調(diào)正電壓單路輸出LDO穩(wěn)壓器 |
| 英文描述： | Micropower Voltage Regulators |
| 中文描述： | FIXED/ADJUSTABLE POSITIVE LDO REGULATOR, 0.45 V DROPOUT, PDSO8 |
| 封裝： | PLASTIC, MICROPAK-8 |
| 文件頁數(shù)： | 18/18頁 |
| 文件大?。?/td> | 164K |
| 代理商： | LP2951ACDM |
LP2950, LP2951, NCV2951
http://onsemi.com
9
Figure 17. Adjustable Regulator
Error
Output
Shutdown
Input
Vin
Vout
1.23 to 30 V
3.3
mF
0.01
mF
NC
R2
R1
100 k
5
3
Error
SD
GND
FB
47
6
VO T
SNS
2
Vout
Vin
8
1
The complete equation for the output voltage is:
Vout + Vref (1 ) R1 R2) ) IFB R1
where Vref is the nominal 1.235 V reference voltage and IFB
is the feedback pin bias current, nominally - 20 nA. The
minimum recommended load current of 1.0
mA forces an
upper limit of 1.2 M
W on the value of R2, if the regulator
must work with no load. IFB will produce a 2% typical error
in Vout which may be eliminated at room temperature by
adjusting R1. For better accuracy, choosing R2 = 100 k
reduces this error to 0.17% while increasing the resistor
program current to 12
mA. Since the LP2951 typically draws
75
mA at no load with Pin 2 open circuited, the extra 12 mA
of current drawn is often a worthwhile tradeoff for
eliminating the need to set output voltage in test.
Output Noise
In many applications it is desirable to reduce the noise
present at the output. Reducing the regulator bandwidth by
increasing the size of the output capacitor is the only method
for reducing noise on the 3 lead LP2950. However,
increasing the capacitor from 1.0
mF to 220 mF only
decreases the noise from 430
mV to 160 mVrms for a 100 kHz
bandwidth at the 5.0 V output.
Noise can be reduced fourfold by a bypass capacitor
across R1, since it reduces the high frequency gain from 4
to unity. Pick
C
Bypass [
1
2
pR1 x 200 Hz
or about 0.01
mF. When doing this, the output capacitor must
be increased to 3.3
mF to maintain stability. These changes
reduce the output noise from 430
mV to 126 mVrms for a
100 kHz bandwidth at 5.0 V output. With bypass
capacitor added, noise no longer scales with output voltage
so that improvements are more dramatic at higher output
voltages.
Figure 18. 1.0 A Regulator with 1.2 V Dropout
0.01
mF
10 k
MTB23P06E
1.0
mF
Unregulated
Input
Error
Output
Shutdown
Input
Vout
5.0 V
±1.0%
0 to 1.0 A
220
mF
2.0 k
5
3
Error
SD
GND FB
47
6
VO T
SNS
2
Vout
Vin
8
1
0.002
mF
1.0 M
LP2951CN
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LP2951ACDM-3.3 | Micropower Voltage Regulators |
| LP2951ACD | Micropower Voltage Regulators |
| LP2951ACN | Micropower Voltage Regulators |
| LP2951CM-3.3 | 150mA ADJUSTABLE VOLTAGE REGULATOR |
| LP2951CM-5 | 150mA ADJUSTABLE VOLTAGE REGULATOR |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LP2951ACDM3.0 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:100 mA, Low Power Low Dropout Voltage Regulator |
| LP2951ACDM-3.0 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:Micropower Voltage Regulators |
| LP2951ACDM-3.0R2 | 功能描述:低壓差穩(wěn)壓器 - LDO 3V 100mA Low Power RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| LP2951ACDM-3.0RG | 功能描述:低壓差穩(wěn)壓器 - LDO ANA 100MA 3V LDO VREG RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| LP2951ACDM3.3 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:100 mA, Low Power Low Dropout Voltage Regulator |
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