參數(shù)資料
型號(hào)： LTC3109EGN#PBF
廠商： LINEAR TECHNOLOGY CORP
元件分類： 穩(wěn)壓器
英文描述： 0.026 A SWITCHING REGULATOR, PDSO20
封裝： 0.150 INCH, LEAD FREE, PLASTIC, SSOP-20
文件頁(yè)數(shù)： 8/24頁(yè)
文件大?。?/td> 329K
代理商： LTC3109EGN#PBF
LTC3109
3109f
applicaTions inForMaTion
Note that there must be enough energy available from the
input voltage source for VOUT to recharge the capacitor
during the interval between load pulses (as discussed in
Design Example 1). Reducing the duty cycle of the load
pulse will allow operation with less input energy.
The VSTORE capacitor may be of very large value (thou-
sands of microfarads or even Farads), to provide energy
storage at times when the input voltage is lost. Note that
this capacitor can charge all the way to the VAUX clamp
voltage of 5.25V typical (regardless of the settings for
VOUT), so be sure that the holdup capacitor has a work-
ing voltage rating of at least 5.5V at the temperature that
it will be used.
The VSTORE input is not designed to provide high pulse
load currents to VOUT. The current path from VSTORE to
VOUT is limited to about 26mA max.
The VSTORE capacitor can be sized using the following
formula:
C
A I
I
t
f
t
STORE
Q
LDO
PULSE
STORE
≥
+ +
+
(
)
(
)
7
5
.225 – VOUT
where 7A is the quiescent current of the LTC3109, IQ is
the load on VOUT in between pulses, ILDO is the load on
the LDO between pulses, IPULSE is the total load during the
pulse, tPULSE is the duration of the pulse, f is the frequency
of the pulses, tSTORE is the total storage time required
and VOUT is the output voltage required. Note that for a
programmed output voltage of 5V, the VSTORE capacitor
cannot provide any beneficial storage time to VOUT.
To minimize losses and capacitor charge time, all capaci-
tors used for VOUT and VSTORE should be low leakage.
See Table 6 for recommended storage capacitors.
Table 6. Recommended Storage Capacitors
VENDOR
PART NUMBER/SERIES
AVX
www.avx.com
BestCap Series
TAJ and TPS Series Tantalum
Cap-XX
www.cap-xx.com
GZ Series
Cooper/Bussman
www.bussmann.com/3/PowerStor.html
KR Series
P Series
Vishay/Sprague
www.vishay.com/capacitors
Tantamount 592D
595D Tantalum
Note that storage capacitors requiring voltage balancing
resistors are not recommended due to the steady-state
current draw of the resistors.
PCB LAYOUT GUIDELINES
Due to the rather low switching frequency of the resonant
converter and the low power levels involved, PCB layout
is not as critical as with many other DC/DC converters.
There are however, a number of things to consider.
Duetotheverylowinputvoltagesthecircuitoperatesfrom,
the connections to VIN, the primary of the transformers
and the SW, VIN and GND pins of the LTC3109 should be
designed to minimize voltage drop from stray resistance,
and able to carry currents as high as 500mA. Any small
voltage drop in the primary winding conduction path will
lower efficiency and increase start-up voltage and capaci-
tor charge time.
Also, due to the low charge currents available at the out-
puts of the LTC3109, any sources of leakage current on
the output voltage pins must be minimized. An example
board layout is shown in Figure 4.
Figure 4. Example Component Placement for 2-Layer PC Board
(QFN Package). Note That VSTORE and VOUT Capacitor Sizes
are Application Dependent
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC3109EGN-TRPBF 制造商:LINER 制造商全稱:Linear Technology 功能描述:Auto-Polarity, Ultralow Voltage Step-Up Converter and Power Manager
LTC3109EUF#PBF 功能描述:IC BOOST CONVERTER PMU 20QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 電源管理 - 專用 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 應(yīng)用:手持/移動(dòng)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
LTC3109EUF#TRPBF 功能描述:IC BOOST CONVERTER PMU 20QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 電源管理 - 專用 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 應(yīng)用:手持/移動(dòng)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
LTC3109EUF-PBF 制造商:LINER 制造商全稱:Linear Technology 功能描述:Auto-Polarity, Ultralow Voltage Step-Up Converter and Power Manager
LTC3109EUF-TRPBF 制造商:LINER 制造商全稱:Linear Technology 功能描述:Auto-Polarity, Ultralow Voltage Step-Up Converter and Power Manager
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