參數(shù)資料
型號: LTC3456EUF
廠商: LINEAR TECHNOLOGY CORP
元件分類: 穩(wěn)壓器
英文描述: ECONOLINE: RSZ/P - 1kVDC
中文描述: 0.9 A BATTERY CHARGE CONTROLLER, 1200 kHz SWITCHING FREQ-MAX, PQCC24
封裝: 4 X 4 MM, PLASTIC, MO-220-WGGD, QFN-24
文件頁數(shù): 22/28頁
文件大小: 358K
代理商: LTC3456EUF
22
LTC3456
3456f
When the device is powered from the USB input (AC
adapter is not present), the V
EXT
pin is charged close to the
USB voltage. The reverse leakage current of the diode D1
flows through R1 and R2 as shown in Figure 15. If the
leakage current is large enough to pull the WALLFB pin
above 1.25V, then the USB power is switched off. The
LTC3456 will then enter into a hiccup mode with USB
power being turned on and off in a periodic fashion.
A 4.32k or smaller resistor should be chosen for R1 to
prevent this behavior. When the power is being delivered
from the wall adapter, efficiency is not a big concern and
choosing small value R1 and R2 resistors should be
acceptable.
Connect the WALLFB pin to ground if the wall adapter is
not used.
Rectifier Diode Selection
The diode, D1, shown in Figures 14 and 15 is used to
connect the V
EXT
pin to the AC adapter input. The IC is
powered through the diode D1 when running off the AC
adapter. A Schottky diode is recommended to minimize
the voltage drop from the AC adapter to the V
EXT
pin.
V
EXT(MIN)
= V
ADAPTER(MIN)
– V
DIODE(MAX)
APPLICATIU
W
U
U
Always ensure that V
EXT
> 4V during regular operation.
Choose a diode with a current rating high enough to handle
the input current.
Choose a Schottky diode with low reverse leakage current
(as explained in previous section). ON Semiconductor
MBRM120E (20V/1A) is a good choice for a low leakage
Schottky rectifier.
The Zetex ZLLS400 (40V/0.5A) Schottky diode is available
in a small surface mount package and is also a good fit for
this application.
BOARD LAYOUT CONSIDERATION
As with all switching regulators, careful attention must be
paid to the PCB board layout and component placement.
To prevent electromagnetic interference (EMI) problems,
proper layout of high frequency switching paths is essen-
tial. Minimize the length and area of all traces connected to
the switching node pins (SW1, SW2_BK, SW2_BST).
Keep the feedback pins FB1 and AIN away from the
switching nodes. The power traces shown as bold lines in
Figure 16 should be kept short, direct and wide.
Figure 15. Diode D1 Leakage Current Flow in USB Powered Mode
USB
POWER
AC ADAPTER
NOT PRESENT
R2
1
I
LKG
D1
R1
4.7
μ
F
10
μ
F
3456 F15
USB
WALLFB
EN
LTC3456
V
EXT
相關(guān)PDF資料
PDF描述
LTC3828EG Dual 2-Phase Step-Down Controller with Tracking
LTC3828EUH Model HB Series Horizontal Stacking Banana Plug Patch Cord, Banana Plug Each End Operating Voltage 30VAC/60VDC Max, Current-15A Cont, Operating Temp Max +55 degrees C, Color-Red, Length-24" RoHS Compliant: Yes
LTC3828 16-Bit Bus Transceiver With 3-State Outputs 48-SSOP -40 to 85
LTC486 Quad Low Power RS485 Driver
LTC486C ; LED Color:Red; Luminous Intensity:63mcd; Viewing Angle:80 ; Forward Current:20mA; Forward Voltage:2.1V; Operating Temperature Range:-40 C to +100 C RoHS Compliant: Yes
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC3456EUF#PBF 功能描述:IC CONV DC/DC USB BATT 24-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 電源管理 - 專用 系列:- 標準包裝:1 系列:- 應(yīng)用:手持/移動設(shè)備 電流 - 電源:- 電源電壓:3 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:14-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:14-LLP-EP(4x4) 包裝:Digi-Reel® 配用:LP3905SD-30EV-ND - BOARD EVALUATION LP3905SD-30 其它名稱:LP3905SD-30DKR
LTC3456EUF#TRPBF 功能描述:IC CONV DC/DC USB BATT 24-QFN RoHS:否 類別:集成電路 (IC) >> PMIC - 電源管理 - 專用 系列:- 標準包裝:1 系列:- 應(yīng)用:手持/移動設(shè)備 電流 - 電源:- 電源電壓:3 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:14-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:14-LLP-EP(4x4) 包裝:Digi-Reel® 配用:LP3905SD-30EV-ND - BOARD EVALUATION LP3905SD-30 其它名稱:LP3905SD-30DKR
LTC3458 制造商:LINER 制造商全稱:Linear Technology 功能描述:1.7A, 1.5MHz Synchronous Step-Up DC/DC Converter with Output Disconnect
LTC3458EDE 功能描述:IC REG BOOST SYNC ADJ 1.4A 12DFN RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標準包裝:2,500 系列:- 類型:降壓(降壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V,1.5V,1.8V,2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP,10-MSOP(0.118",3.00mm 寬)裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤
LTC3458EDE#PBF 功能描述:IC REG BOOST SYNC ADJ 1.4A 12DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標準包裝:250 系列:- 類型:降壓(降壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V 輸入電壓:2.05 V ~ 6 V PWM 型:電壓模式 頻率 - 開關(guān):2MHz 電流 - 輸出:500mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:6-UFDFN 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:6-SON(1.45x1) 產(chǎn)品目錄頁面:1032 (CN2011-ZH PDF) 其它名稱:296-25628-2