- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄30765 > LT1054MJ8#PBF (LINEAR TECHNOLOGY CORP) SWITCHED CAPACITOR REGULATOR, 40 kHz SWITCHING FREQ-MAX, CDIP8 PDF資料下載
參數(shù)資料
| 型號： | LT1054MJ8#PBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHED CAPACITOR REGULATOR, 40 kHz SWITCHING FREQ-MAX, CDIP8 |
| 封裝： | 0.300 INCH, LEAD FREE, HERMETIC SEALED, CERAMIC, DIP-8 |
| 文件頁數(shù)： | 14/16頁 |
| 文件大小： | 264K |
| 代理商： | LT1054MJ8#PBF |
LT1054/LT1054L
7
1954lfg
PIN FUNCTIONS
is charging, the peak supply current will be approximately
equal to 2.2 times the output current. During the time that
CIN is delivering charge to COUT the supply current drops
to approximately 0.2 times the output current. An input
supply bypass capacitor will supply part of the peak input
current drawn by the LT1054 and average out the current
drawn from the supply. A minimum input supply bypass
capacitorof2F,preferablytantalumorsomeotherlowESR
type is recommended. A larger capacitor may be desirable
in some cases, for example, when the actual input supply
is connected to the LT1054 through long leads, or when
the pulse current drawn by the LT1054 might affect other
circuitry through supply coupling.
APPLICATIONS INFORMATION
Theory of Operation
To understand the theory of operation of the LT1054, a re-
viewofabasicswitched-capacitorbuildingblockishelpful.
In Figure 3 when the switch is in the left position, capaci-
tor C1 will charge to voltage V1. The total charge on C1
will be q1 = C1V1. The switch then moves to the right,
discharging C1 to voltage V2. After this discharge time
the charge on C1 is q2 = C1V2. Note that charge has been
transferred from the source V1 to the output V2. The
amount of charge transferred is:
q = q1 – q2 = C1(V1 – V2)
If the switch is cycled f times per second, the charge
transfer per unit time (i.e., current) is:
I = (f)(
q) = (f)[C1(V1 – V2)]
To obtain an equivalent resistance for the switched-
capacitor network we can rewrite this equation in terms
of voltage and impedance equivalence:
I
=
V1– V2
1/ fC1
=
V1– V2
REQUIV
A new variable REQUIV is defined such that REQUIV = 1/fC1.
Thus the equivalent circuit for the switched-capacitor
network is as shown in Figure 4. The LT1054 has the same
switching action as the basic switched-capacitor building
block.Eventhoughthissimplificationdoesn’tincludefinite
switch on-resistance and output voltage ripple, it provides
anintuitivefeelforhowthedeviceworks.
These simplified circuits explain voltage loss as a function
of frequency (see Typical Performance Characteristics).
As frequency is decreased, the output impedance will
eventually be dominated by the 1/fC1 term and voltage
losses will rise.
Note that losses also rise as frequency increases. This is
caused by internal switching losses which occur due to
some finite charge being lost on each switching cycle. This
chargelossper-unit-cycle,whenmultipliedbytheswitching
frequency, becomes a current loss. At high frequency this
loss becomes significant and voltage losses again rise.
The oscillator of the LT1054 is designed to run in the
frequency band where voltage losses are at a minimum.
Regulation
The error amplifier of the LT1054 servos the drive to the
PNPswitchtocontrolthevoltageacrosstheinputcapaci-
tor (CIN) which in turn will determine the output voltage.
Using the reference and error amplifier of the LT1054,
an external resistive divider is all that is needed to set
the regulated output voltage. Figure 5 shows the basic
regulator configuration and the formula for calculating
the appropriate resistor values. R1 should be chosen to
f
C1
C2
RL
V2
LT1054 F03
V1
Figure 3. Switched-Capacitor Building Block
Figure 3. Switched-Capacitor Equivalent Circuit
C2
RL
REQUIV
REQUIV =
V2
LT1054 F04
V1
1
fC1
相關PDF資料 |
PDF描述 |
|---|---|
| LT1054IN8#TRPBF | SWITCHED CAPACITOR REGULATOR, 40 kHz SWITCHING FREQ-MAX, PDIP8 |
| LT1054MJ8#TRPBF | SWITCHED CAPACITOR REGULATOR, 40 kHz SWITCHING FREQ-MAX, CDIP8 |
| LT1076HVCT#TRPBF | 3.2 A SWITCHING REGULATOR, 125 kHz SWITCHING FREQ-MAX, PZFM7 |
| LT1076IT-5#TR | 3.2 A SWITCHING REGULATOR, 120 kHz SWITCHING FREQ-MAX, PZFM5 |
| LT1076HVIT-5#TRPBF | 3.2 A SWITCHING REGULATOR, 120 kHz SWITCHING FREQ-MAX, PZFM5 |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LT1055AMH/883 | 制造商:Linear Technology 功能描述:OP Amp Single GP ±20V 8-Pin TO-5 |
| LT1055CH | 制造商:Linear Technology 功能描述:OP Amp Single GP ±20V 8-Pin TO-5 制造商:Linear Technology 功能描述:OP Amp Single GP 20V 8-Pin TO-5 |
| LT1055CN8 | 功能描述:IC PREC OP-AMP JFET HI-SPD 8-DIP RoHS:否 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 標準包裝:50 系列:- 放大器類型:通用 電路數(shù):2 輸出類型:滿擺幅 轉換速率:1.8 V/µs 增益帶寬積:6.5MHz -3db帶寬:4.5MHz 電流 - 輸入偏壓:5nA 電壓 - 輸入偏移:100µV 電流 - 電源:65µA 電流 - 輸出 / 通道:35mA 電壓 - 電源，單路/雙路(±):1.8 V ~ 5.25 V，±0.9 V ~ 2.625 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應商設備封裝:10-MSOP 包裝:管件 |
| LT1055CN8#PBF | 功能描述:IC PREC OP-AMP JFET HI-SPD 8-DIP RoHS:是 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 產(chǎn)品培訓模塊:Differential Circuit Design Techniques for Communication Applications 標準包裝:1 系列:- 放大器類型:RF/IF 差分 電路數(shù):1 輸出類型:差分 轉換速率:9800 V/µs 增益帶寬積:- -3db帶寬:2.9GHz 電流 - 輸入偏壓:3µA 電壓 - 輸入偏移:- 電流 - 電源:40mA 電流 - 輸出 / 通道:- 電壓 - 電源，單路/雙路(±):3 V ~ 3.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:16-VQFN 裸露焊盤，CSP 供應商設備封裝:16-LFCSP-VQ 包裝:剪切帶 (CT) 產(chǎn)品目錄頁面:551 (CN2011-ZH PDF) 其它名稱:ADL5561ACPZ-R7CT |
| LT1055CN8#PBF | 制造商:Linear Technology 功能描述:IC OP AMP HIGH SPEED 4.5MHZ |
發(fā)布緊急采購，3分鐘左右您將得到回復。