- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄377765 > LTC1871-7 (Linear Technology Corporation) Quadruple 2-Input Positive-AND Gate 14-SOIC -40 to 85 PDF資料下載
參數(shù)資料
| 型號： | LTC1871-7 |
| 廠商： | Linear Technology Corporation |
| 英文描述： | Quadruple 2-Input Positive-AND Gate 14-SOIC -40 to 85 |
| 中文描述： | 2相升壓型DC / DC控制器 |
| 文件頁數(shù)： | 10/36頁 |
| 文件大小： | 411K |
| 代理商： | LTC1871-7 |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁當(dāng)前第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁
10
LTC1871
APPLICATIOU
When the oscillator’s internal logic circuitry detects a
synchronizing signal on the MODE/SYNC pin, the internal
oscillator ramp is terminated early and the slope compen-
sation is increased by approximately 30%. As a result, in
applications requiring synchronization, it is recommended
that the nominal operating frequency of the IC be pro-
grammed to be about 75% of the external clock frequency.
Attempting to synchronize to too high an external fre-
quency (above 1.3f
O
) can result in inadequate slope com-
pensation and possible subharmonic oscillation (or jitter).
The external clock signal must exceed 2V for at least 25ns,
and should have a maximum duty cycle of 80%, as shown
in Figure 5. The MOSFET turn on will synchronize to the
rising edge of the external clock signal.
W
U
U
to charge and discharge an internal oscillator capacitor. A
graph for selecting the value of R
T
for a given operating
frequency is shown in Figure 6.
Figure 6. Timing Resistor (R
T
) Value
Figure 5. MODE/SYNC Clock Input and Switching
Waveforms for Synchronized Operation
1871 F05
2V TO 7V
MODE/
SYNC
GATE
I
L
t
MIN
= 25ns
0.8T
D = 40%
T
T = 1/f
O
FREQUENCY (kHz)
100
R
T
)
300
1000
1871 F06
10
100
200
1000
900
800
700
600
500
400
0
Programming the Operating Frequency
The choice of operating frequency and inductor value is a
tradeoff between efficiency and component size. Low
frequency operation improves efficiency by reducing
MOSFET and diode switching losses. However, lower
frequency operation requires more inductance for a given
amount of load current.
The LTC1871 uses a constant frequency architecture that
can be programmed over a 50kHz to 1000kHz range with
a single external resistor from the FREQ pin to ground, as
shown in Figure 1. The nominal voltage on the FREQ pin is
0.6V, and the current that flows into the FREQ pin is used
INTV
CC
Regulator Bypassing and Operation
An internal, P-channel low dropout voltage regulator pro-
duces the 5.2V supply which powers the gate driver and
logic circuitry within the LTC1871, as shown in Figure 7.
The INTV
CC
regulator can supply up to 50mA and must be
bypassed to ground immediately adjacent to the IC pins
with a minimum of 4.7
μ
F tantalum or ceramic capacitor.
Good bypassing is necessary to supply the high transient
currents required by the MOSFET gate driver.
For input voltages that don’t exceed 7V (the absolute
maximum rating for this pin), the internal low dropout
regulator in the LTC1871 is redundant and the INTV
CC
pin
can be shorted directly to the V
IN
pin. With the INTV
CC
pin
shorted to V
IN
, however, the divider that programs the
regulated INTV
CC
voltage will draw 10
μ
A of current from
the input supply, even in shutdown mode. For applications
that require the lowest shutdown mode input supply
current, do not connect the INTV
CC
pin to V
IN
. Regardless
of whether the INTV
CC
pin is shorted to V
IN
or not,
it is
always necessary to have the driver circuitry bypassed
with a 4.7
μ
F tantalum or low ESR ceramic capacitor to
ground immediately adjacent to the INTV
CC
and GND
pins.
In an actual application, most of the IC supply current is
used to drive the gate capacitance of the power MOSFET.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC1871EMS | Quadruple 2-Input Positive-AND Gate 14-SO -40 to 85 |
| LTC1873EG | Quadruple 2-Input Positive-AND Gate 14-TSSOP -40 to 85 |
| LTC1873 | Dual 550kHz Synchronous 2-Phase Switching Regulator Controller with 5-Bit VID(550kHz,雙 路,同步2相開關(guān)穩(wěn)壓器(帶5位VID)) |
| LTC1874 | Dual Constant Frequency Current Mode Step-Down DC/DC Controller(雙路(3.3V,1.8V輸出）恒定頻率，電流模式，步降DC/DC控制器) |
| LTC1874EGN | Quadruple 2-Input Positive-AND Gate 14-VQFN -40 to 85 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC1871EMS | 功能描述:IC REG CTRLR BST FLYBK CM 10MSOP 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 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LTC1871EMS#PBF | 功能描述:IC REG CTRLR BST FLYBK CM 10MSOP 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 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-5°C ~ 125°C 封裝/外殼:32-WFQFN 裸露焊盤 包裝:Digi-Reel® 產(chǎn)品目錄頁面:1303 (CN2011-ZH PDF) 其它名稱:LM3754SQDKR |
| LTC1871EMS#TR | 功能描述:IC REG CTRLR BST FLYBK CM 10MSOP 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 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LTC1871EMS#TRPBF | 功能描述:IC REG CTRLR BST FLYBK CM 10MSOP 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 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LTC1871EMS-1#PBF | 功能描述:IC REG CTRLR BST FLYBK CM 10MSOP 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 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。