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參數(shù)資料
| 型號： | LP3906SQX-TKXII |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHING REGULATOR, 2000 kHz SWITCHING FREQ-MAX, QCC24 |
| 封裝： | 5 X 4 MM, 0.80 MM HEIGHT, LLP-24 |
| 文件頁數(shù)： | 29/40頁 |
| 文件大小： | 4200K |
| 代理商： | LP3906SQX-TKXII |
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MODE BOUNCE
PFM-PWM transition at low load current.
To improve efficiency at lower load currents LP3906 buck
converters employ an automatically invoked PFM mode for
the low load operation. The PFM mode operates with a much
lower value quiescent current (I
Q) than the PWM mode of op-
eration that is used in the higher load currents.
As shown in the datasheet section about SW operation, there
is a DC voltage difference between the two modes of opera-
tion, with Vout PFM being typically 1.2% higher than Vout
PWM. So there is a DC voltage level transition and some as-
sociated dynamic perturbation at the mode transition point.
The transition between the two modes of operation has an
associated hysterisis in the transition current value, That is,
the transition point for increasing current (PFM to PWM) is at
a higher value that the decreasing current (PWM to PFM).
This hysterisis is to ensure that in the event that the load cur-
rent values equals the PFM PWM transition value, the device
will not make multiple transitions between modes; this re-
duces the noise at this load by eliminating multiple transitions
between modes (also known as mode bounce).
Under some conditions of high Vin and Low Vout the hystersis
value is reduced and some amount of mode bounce can oc-
cur. Under these conditions, the regulator still maintains DC
regulation, however the output ripple is more pronounced.
Refer to the attached Vout vs Vin chart below that shows the
operational area that may exhibit this increased output ripple.
If the application is expected to be operated in the area of
concern AND have a static load current of the transition cur-
rent value, the user can avoid the possible noise increase by
invoking the components’ “Force PWM mode”.
LP3906 Buck Converter
V
OUT vs VIN Operating Range
during PFM-PWM-PPM Transition
20197865
35
www.national.com
LP3906
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LP3906SQX-TKXII/NOPB | 功能描述:低壓差穩(wěn)壓器 - LDO 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 |
| LP3906SQX-VPFP/NOPB | 功能描述:其他電源管理 RoHS:否 制造商:Texas Instruments 輸出電壓范圍: 輸出電流:4 mA 輸入電壓范圍:3 V to 3.6 V 輸入電流: 功率耗散: 工作溫度范圍:- 40 C to + 110 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-48 封裝:Reel |
| LP3907 | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Dual High-Current Step-Down DC/DC and Dual Linear Regulator with I2C Compatible Interface |
| LP3907QSQ-JJXP/NOPB | 功能描述:上下轉(zhuǎn)換器 Dual Hi-Current SD DC/DC RoHS:否 制造商:Texas Instruments 產(chǎn)品:Down Converters 射頻:52 MHz to 78 MHz 中頻:300 MHz LO頻率: 功率增益: P1dB: 工作電源電壓:1.8 V, 3.3 V 工作電源電流:120 mA 最大功率耗散:1 W 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFP-128 |
| LP3907QSQ-JXI7/NOPB | 功能描述:低壓差穩(wěn)壓器 - LDO 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 |
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