- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄377761 > LTC1700EMS (LINEAR TECHNOLOGY CORP) Synchronous 8-Bit Up/Down Binary Counters 24-SOIC 0 to 70 PDF資料下載
參數(shù)資料
| 型號(hào)： | LTC1700EMS |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Synchronous 8-Bit Up/Down Binary Counters 24-SOIC 0 to 70 |
| 中文描述： | 1 A SWITCHING CONTROLLER, 630 kHz SWITCHING FREQ-MAX, PDSO10 |
| 封裝： | PLASTIC, MSOP-10 |
| 文件頁(yè)數(shù)： | 10/16頁(yè) |
| 文件大?。?/td> | 194K |
| 代理商： | LTC1700EMS |
第1頁(yè)第2頁(yè)第3頁(yè)第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)當(dāng)前第10頁(yè)第11頁(yè)第12頁(yè)第13頁(yè)第14頁(yè)第15頁(yè)第16頁(yè)
LTC1700
10
To eliminate this subharmonic oscillations, a compensat-
ing ramp is added internally to the LTC1700 on the
inductor current waveform when the duty cycle exceeds
5%. This scheme, known as slope compensation, makes
the loop perceive that there is more inductor current than
it actually has. As a result, the maximum current capability
of the regulator is reduced. This reduction is proportional
to the duty cycle and is shown in Figure 5. Hence for
applications that operate at high duty cycles, the
N-channel MOSFET chosen should have a lower R
DS(ON)
to make up for this reduction (See Design Example).
L
V
DC
f I
MIN
IN MAX
(
L
≥
)
With Burst Mode operation enabled on the LTC1700, the
ripple current is normally set such that the inductor
current is continuous during burst periods. Remember
that during bursting, the peak current is clamped at
approximately:
I
BURST(PEAK)
36mV/R
DS(ON)
Hence the peak-to-peak ripple selected for optimal burst
mode operation should not exceed I
BURST(PEAK)
. This
implies a minimum inductance of:
L
V
DC
( )
f
I
1
DC
MINBURST
IN MAX
(
OMAX
–
=
)
( )0 66
)
In applications that invoke Burst Mode operation, the
inductor should be chosen so it has low ripple (0.4I
OMAX
)
current during heavy load and continuous operation dur-
ing bursting. The criteria for selecting which equation to
use is:
Use L
MIN
for Duty Cycle > 36%
Use L
MINBURST
for Duty Cycle
≤
36%
A smaller value than L
MIN
could be used in the circuit;
however, the inductor current will not be continuous
during burst periods. The advantage of using a smaller
inductance than L
MIN
is primarily size. The disadvantage is
higher output ripple.
Inductor Core Selection
Once the value for L is known, the type of inductor must be
selected. High efficiency converters generally cannot af-
ford the core loss found in low cost powdered iron cores,
forcing the use of more expensive ferrite, molypermalloy,
or Kool M
μ
cores. Actual core loss is independent of core
size for a fixed inductor value, but it is very dependent on
inductance selected. As inductance increases, core losses
go down. Unfortunately, increased inductance requires
more turns of wire and therefore copper losses will
Kool M
μ
is a registered trademark of Magnetics, Inc.
Inductor Value Selection
Given the input voltage, inductor value and operating
frequency, the ripple current can be calculated:
I
V
DC
fL
L
IN
=
Lower ripple current reduces core losses in the inductor,
ESR losses in the output capacitors and output voltage
ripple. Thus, highest efficiency operation is obtained at
low frequency with small ripple current. To achieve this,
however, requires a larger inductor.
A reasonable starting point is to choose a ripple current
that is about 40% of I
O(MAX)
. Note that the largest ripple
current occurs at the highest V
IN
. To guarantee that ripple
current does not exceed a specified maximum, the induc-
tor should be chosen according to:
Figure 5. Maximum Output Current vs Duty Cycle
APPLICATIO
S I
FOR
ATIO
U
W
U
U
DUTY CYCLE (%)
0
N
1.2
1.0
0.8
0.6
0.4
0.2
0
30
50
1700 F05
10
20
40
60
70
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC1702CGN | Dual 550kHz Synchronous 2-Phase Switching Regulator Controller |
| LTC1702 | Synchronous 8-Bit Up/Down Binary Counters 24-SOIC 0 to 70 |
| LTC1702C | Synchronous 8-Bit Up/Down Binary Counters 24-SOIC 0 to 70 |
| LTC1702I | Synchronous 8-Bit Up/Down Binary Counters 24-SOIC 0 to 70 |
| LTC1702IGN | Dual 550kHz Synchronous 2-Phase Switching Regulator Controller |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC1700EMS#PBF | 功能描述:IC REG CTRLR BST PWM CM 10-MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 特色產(chǎn)品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 標(biāo)準(zhǔn)包裝:1 系列:PowerWise® PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.5 V ~ 18 V 降壓:是 升壓:無(wú) 回掃:無(wú) 反相:無(wú) 倍增器:無(wú) 除法器:無(wú) Cuk:無(wú) 隔離:無(wú) 工作溫度:-5°C ~ 125°C 封裝/外殼:32-WFQFN 裸露焊盤 包裝:Digi-Reel® 產(chǎn)品目錄頁(yè)面:1303 (CN2011-ZH PDF) 其它名稱:LM3754SQDKR |
| LTC1700EMS#TR | 功能描述:IC REG CTRLR BST PWM CM 10-MSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無(wú) 升壓:是 回掃:無(wú) 反相:無(wú) 倍增器:無(wú) 除法器:無(wú) Cuk:無(wú) 隔離:無(wú) 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LTC1700EMS#TRPBF | 功能描述:IC REG CTRLR BST PWM CM 10-MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無(wú) 升壓:是 回掃:無(wú) 反相:無(wú) 倍增器:無(wú) 除法器:無(wú) Cuk:無(wú) 隔離:無(wú) 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LTC1701BES5 | 制造商:Linear Technology 功能描述:1.1 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO5 |
| LTC1701BES5#PBF | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 2.5V to 5.5V 5-Pin TSOT-23 制造商:Linear Technology 功能描述:DP-SWREG/Monolithic, CUT TAPE 1MHz Step-dn DC/DC Con in SOT-23 |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。