參數(shù)資料
型號(hào)： LP2994M
廠商： NATIONAL SEMICONDUCTOR CORP
元件分類： 通用總線功能
英文描述： DDR Termination Regulator
中文描述： BUS TERMINATOR SUPPORT CIRCUIT, PDSO8
封裝： SOP-8
文件頁(yè)數(shù)： 12/15頁(yè)
文件大小： 257K
代理商： LP2994M
Typical Application Circuits
(Continued)
how to use two resistors to level shift V
above the internal
reference voltage of V
/2. To calculate the exact voltage
at V
TT
the following equation can be used.
V
TT
= (V
DDQ
/2) x ( 1 + R1/R2)
Conversely, the R2 resistor can be placed between V
and V
to shift the V
TT
output lower than the internal
reference voltage of V
/2. The equations relating V
TT
and
the resistors can be seen below:
V
TT
= (V
DDQ
/2) x ( 1 - R1/R2)
Reference Voltage
DDR-SDRAM and the motherboard chipsets usually require
a reference voltage which tracks V
. To implement this
feature in most applications it is advisable to use two equal
resistors as a resistor divider. This prevents long V
traces
from running across the motherboard picking up noise which
can interfere with performance. However, in a few applica-
tions it may be desirable to use the V
TT
output on the
LP2994 to generate the V
signal. The can be accom-
plished by using an RC filter on the output of V
to create a
V
signal. Typically, the reference voltage required by
chipsets and memory is well under 1μAcombined, therefore,
a fairly large resistor such as 1k
or larger can be used. A
recommended capacitor would be a 1uF X7R ceramic
capacitor.
20045909
FIGURE 9. Increasing V
TT
by Level Shifting
20045910
FIGURE 10. Decreasing V
TT
by Level Shifting
L
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LP2994M/NOPB 功能描述:IC DDR TERMINATION REG 8SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,000 系列:- 應(yīng)用:電源，ICERA E400，E450 輸入電壓:4.1 V ~ 5.5 V 輸出數(shù):10 輸出電壓:可編程 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:42-WFBGA，WLCSP 供應(yīng)商設(shè)備封裝:42-WLP 包裝:帶卷 (TR)
LP2994M/NOPB 制造商:Texas Instruments 功能描述:Linear Voltage Regulator IC
LP2994MX/NOPB 功能描述:IC REGULATOR DDR TERM 8-SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,000 系列:- 應(yīng)用:電源，ICERA E400，E450 輸入電壓:4.1 V ~ 5.5 V 輸出數(shù):10 輸出電壓:可編程 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:42-WFBGA，WLCSP 供應(yīng)商設(shè)備封裝:42-WLP 包裝:帶卷 (TR)
LP2995LQ 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(dòng)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
LP2995LQ/7002047 制造商:Rochester Electronics LLC 功能描述: 制造商:Texas Instruments 功能描述:
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