欧美成人免费电影,国产欧美一区二区三区精品酒店,精品国产a毛片,色网在线免费观看

參數資料
型號: LTC3445EUF#TRPBF
廠商: Linear Technology
文件頁數: 19/24頁
文件大小: 475K
描述: IC REG TRPL BUCK/LINEAR 24-QFN
標準包裝: 2,500
拓撲: 降壓(降壓)(1),線性(LDO)(2)
功能: 任何功能
輸出數: 3
頻率 - 開關: 1.5MHz
電壓/電流 - 輸出 1: 0.85 V ~ 1.55 V,600mA
電壓/電流 - 輸出 2: 可調至0.6V,50mA
電壓/電流 - 輸出 3: 可調至0.6V,50mA
帶 LED 驅動器:
帶監控器:
帶序列發生器:
電源電壓: 2.5 V ~ 5.5 V
工作溫度: -40°C ~ 85°C
安裝類型: 表面貼裝
封裝/外殼: 24-WFQFN 裸露焊盤
供應商設備封裝: 24-QFN 裸露焊盤(4x4)
包裝: 帶卷 (TR)
19
LTC3445
3445fa
Checking Transient Response
The regulator loop response can be checked by looking at
the load transient response. Switching regulators take
several cycles to respond to a step in load current. When
a load step occurs, V
OUT
 immediately shifts by an amount
equal to (I
LOAD
 " ESR), where ESR is the effective series
resistance of C
OUT
. I
LOAD
 also begins to charge or
discharge C
OUT
, which generates a feedback error signal.
The regulator loop then acts to return V
OUT
 to its steady-
state value. During this recovery time V
OUT
 can be moni-
tored for overshoot or ringing that would indicate a stability
problem. For a detailed explanation of switching control
loop theory, see Application Note 76.
A second, more severe transient is caused by switching in
loads with large (>1礔) supply bypass capacitors. The
discharged bypass capacitors are effectively put in parallel
with C
OUT
, causing a rapid drop in V
OUT
. No regulator can
deliver enough current to prevent this problem if the load
switch resistance is low and it is driven quickly. The only
solution is to limit the rise time of the switch drive so that
the load rise time is limited to approximately (25 " C
LOAD
).
Thus, a 10礔 capacitor charging to 3.3V would require a
250祍 rise time, limiting the charging current to about
130mA.
LDO REGULATORS
The LDOs in the LTC3445 are 50mA low dropout regula-
tors with low quiescent and shutdown currents. Each
device is capable of supplying 50mA at a dropout voltage
of 300mV. The LDOs are current limited to greater than
50mA but less than 75mA. The output voltages of the
LDOs are set with external resistive dividers according to
the following formula:
V
LDOOUT1
 = 0.6(1 + R1/R2)
(4)
V
LDOOUT2
 = 0.6(1 + R3/R4)
(5)
Output Capacitance and Transient Response
The LTC3445 LDOs are designed to be stable with a wide
range of output capacitors. A minimum output capacitor
of 2.2礔 with an ESR of 3& or less is recommended to
internal power MOSFET switches. Each time the gate is
switched from high to low to high again, a packet of
charge, dQ, moves from V
CC1
 to ground. The resulting
dQ/dt is the current out of V
CC1
 that is typically larger
than the DC bias current. In continuous mode, I
GATECHG
= f(Q
T
 + Q
B
) where Q
T
 and Q
B
 are the gate charges of the
internal top and bottom switches. Both the DC bias and
gate charge losses are proportional to V
CC1
 and thus
their effects will be more pronounced at higher supply
voltages.
2. I
2
R losses are calculated from the resistances of the
internal switches, R
SW
, and external inductor R
L
. In
continuous mode, the average output current flowing
through inductor L is chopped between the main
switch and the synchronous switch. Thus, the series
resistance looking into the SW pin is a function of both
top and bottom MOSFET R
DS(ON)
 and the duty cycle
(DC) as follows:
R
SW
 = (R
DS(ON)TOP
)(DC) + (R
DS(ON)BOT
)(1  DC)
The R
DS(ON)
 for both the top and bottom MOSFETs can
be obtained from the Typical Performance Charateristics
curves. Thus, to obtain I
2
R losses, simply add R
SW
 to
R
L
 and multiply the result by the square of the average
output current.
Other losses including C
IN
 and C
OUT
 ESR dissipative
losses and inductor core losses generally account for
less than 2% total additional loss.
APPLICATIO S I FOR ATIO
U
U
U
Figure 8. Power Loss vs Load Current, V
CC1
 = 3.6V
LOAD CURRENT (mA)
1
10
100
1000
0.1
10
100    1000
3445 F08
0.1
1
DAC MIN
DAC MAX
相關PDF資料
PDF描述
LTC3446IDE#PBF IC REG TRPL BCK/LINEAR 14-DFN
LTC3537EUD#TRPBF IC REG DL BST/LINEAR SYNC 16-QFN
LTC3541EDD#TRPBF IC REG DL BCK/LINEAR SYNC 10-DFN
LTC3670EDDB#TRPBF IC REG TRPL BCK/LINEAR 12DFN
LTC3672BEDC-1#TRPBF IC REG TRPL BCK/LINEAR 8-DFN
相關代理商/技術參數
參數描述
LTC3446 制造商:LINER 制造商全稱:Linear Technology 功能描述:Monolithic Buck Regulator with Dual VLDO Regulators
LTC3446EDE 制造商:LINER 制造商全稱:Linear Technology 功能描述:Monolithic Buck Regulator with Dual VLDO Regulators
LTC3446EDE#PBF 功能描述:IC REG TRPL BCK/LINEAR 14-DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩壓器 - 線性 + 切換式 系列:- 標準包裝:2,500 系列:- 拓撲:降壓(降壓)同步(3),線性(LDO)(2) 功能:任何功能 輸出數:5 頻率 - 開關:300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅動器:無 帶監控器:無 帶序列發生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應商設備封裝:* 包裝:*
LTC3446EDE#TRPBF 功能描述:IC REG TRPL BCK/LINEAR 14-DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩壓器 - 線性 + 切換式 系列:- 標準包裝:2,500 系列:- 拓撲:降壓(降壓)同步(3),線性(LDO)(2) 功能:任何功能 輸出數:5 頻率 - 開關:300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅動器:無 帶監控器:無 帶序列發生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應商設備封裝:* 包裝:*
LTC3446EDE-PBF 制造商:LINER 制造商全稱:Linear Technology 功能描述:Monolithic Buck Regulator with Dual VLDO Regulators
主站蜘蛛池模板: 西畴县| 奎屯市| 库尔勒市| 吉林省| 达日县| 关岭| 岫岩| 蒲城县| 临泽县| 汉中市| 峡江县| 广平县| 中宁县| 石阡县| 南平市| 巴彦淖尔市| 余江县| 屏边| 吉安县| 电白县| 崇州市| 鹤岗市| 祁连县| 盖州市| 佛冈县| 绥阳县| 辉县市| 岑巩县| 枝江市| 甘泉县| 太康县| 天柱县| SHOW| 西藏| 夏河县| 东至县| 罗平县| 大洼县| 定日县| 商南县| 齐齐哈尔市|