- 您現在的位置：買賣IC網 > PDF目錄30771 > LTC3823IGN#TRPBF (LINEAR TECHNOLOGY CORP) 4 A SWITCHING CONTROLLER, PDSO28 PDF資料下載
參數資料
| 型號： | LTC3823IGN#TRPBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 4 A SWITCHING CONTROLLER, PDSO28 |
| 封裝： | 0.150 INCH, LEAD FREE, PLASTIC, SSOP-28 |
| 文件頁數： | 6/26頁 |
| 文件大?。?/td> | 302K |
| 代理商： | LTC3823IGN#TRPBF |
LTC3823
14
3823fd
does not exceed a specied maximum, the inductance
should be chosen according to:
L
V
fI
V
OUT
LMAX
OUT
IN MAX
=
Δ ()
()
1
Once the value for L is known, the type of inductor must
be selected. High efciency converters generally cannot
afford the core loss found in low cost powdered iron cores,
forcing the use of more expensive ferrite, molypermalloy
or Kool Mμ
cores. A variety of inductors designed for
high current, low voltage applications are available from
manufacturers such as Sumida, Panasonic, Coiltronics,
Coilcraft and Toko.
Schottky Diode D1 Selection
The Schottky diode D1 shown in Figure 12 conducts dur-
ing the dead time between the conduction of the power
MOSFET switches. It is intended to prevent the body diode
of the bottom MOSFET from turning on and storing charge
during the dead time, which can cause a modest (about
1%) efciency loss. The diode can be rated for about one
half to one fth of the full load current since it is on for
only a fraction of the duty cycle. In order for the diode
to be effective, the inductance between it and the bottom
MOSFET must be as small as possible, mandating that
these components be placed adjacently. The diode can
be omitted if the efciency loss is tolerable.
CIN and COUT Selection
The input capacitance CIN is required to lter the square
wave current at the drain of the top MOSFET. Use a low ESR
capacitor sized to handle the maximum RMS current.
II
V
RMS
OUT MAX
OUT
IN
OUT
()
–1
This formula has a maximum at VIN = 2VOUT, where
IRMS = IOUT(MAX)/2. This simple worst-case condition is
commonly used for design because even signicant de-
viations do not offer much relief. Note that ripple current
ratings from capacitor manufacturers are often based on
only 2000 hours of life which makes it advisable to derate
the capacitor.
The selection of COUT is primarily determined by the
ESR required to minimize voltage ripple and load step
transients. The output ripple ΔVOUT is approximately
bounded by:
ΔΔ
V
I ESR
fC
OUT
L
OUT
≤+
1
8
Since ΔIL increases with input voltage, the output ripple
is highest at maximum input voltage. Typically, once the
ESR requirement is satised, the capacitance is adequate
for ltering and has the necessary RMS current rating.
Multiple capacitors placed in parallel may be needed to
meet the ESR and RMS current handling requirements.
Dry tantalum, special polymer, aluminum electrolytic and
ceramic capacitors are all available in surface mount pack-
ages. Special polymer capacitors offer very low ESR but
have lower capacitance density than other types. Tantalum
capacitors have the highest capacitance density but it is
important to only use types that have been surge tested
for use in switching power supplies. Aluminum electrolytic
capacitors have signicantly higher ESR, but can be used
in cost-sensitive applications providing that consideration
is given to ripple current ratings and long term reliability.
Ceramic capacitors have excellent low ESR characteris-
tics but can have a high voltage coefcient and audible
piezoelectric effects. The high Q of ceramic capacitors with
trace inductance can also lead to signicant ringing. When
used as input capacitors, care must be taken to ensure that
ringing from inrush currents and switching does not pose
an overvoltage hazard to the power switches and control-
ler. To dampen input voltage transients, add a small 5μF
to 50μF aluminum electrolytic capacitor with an ESR in
the range of 0.5Ω to 2Ω. High performance through-hole
capacitors may also be used, but an additional ceramic
capacitor in parallel is recommended to reduce the effect
of their lead inductance.
Top MOSFET Driver Supply (CB, DB)
An external bootstrap capacitor CBconnectedtotheBOOST
pin supplies the gate drive voltage for the topside MOSFET.
This capacitor is charged through diode DB from INTVCC
when the switch node is low. When the top MOSFET turns
APPLICATIONS INFORMATION
相關PDF資料 |
PDF描述 |
|---|---|
| LTC3851AEMSE-1#PBF | 0.05 A SWITCHING CONTROLLER, 810 kHz SWITCHING FREQ-MAX, PDSO16 |
| LTC3851AIUD-1#TRPBF | 0.05 A SWITCHING CONTROLLER, 810 kHz SWITCHING FREQ-MAX, PQCC16 |
| LTC3851AMPMSE-1#PBF | 0.05 A SWITCHING CONTROLLER, 810 kHz SWITCHING FREQ-MAX, PDSO16 |
| LTC3856IFE#PBF | SWITCHING CONTROLLER, PDSO38 |
| LTC3856EFE#PBF | SWITCHING CONTROLLER, PDSO38 |
相關代理商/技術參數 |
參數描述 |
|---|---|
| LTC3823IUH#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 特色產品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 標準包裝:1 系列:PowerWise® PWM 型:電壓模式 輸出數: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® 產品目錄頁面:1303 (CN2011-ZH PDF) 其它名稱:LM3754SQDKR |
| LTC3823IUH#PBF | 制造商:Linear Technology 功能描述:IC SYNC STEP-DOWN DC/DC CONTROLLER QFN32 |
| LTC3823IUH#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:2,500 系列:- PWM 型:電流模式 輸出數: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) |
| LTC3824EMSE | 制造商:Linear Technology 功能描述:DC DC Cntrlr Single-OUT Step Down 4V to 60V Input 10-Pin MSOP EP |
| LTC3824EMSE#PBF | 功能描述:IC REG CTRLR BUCK 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:- 特色產品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 標準包裝:1 系列:PowerWise® PWM 型:電壓模式 輸出數: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® 產品目錄頁面:1303 (CN2011-ZH PDF) 其它名稱:LM3754SQDKR |
發(fā)布緊急采購，3分鐘左右您將得到回復。