參數(shù)資料
型號(hào): LT1933
廠商: Linear Technology Corporation
元件分類: 基準(zhǔn)電壓源/電流源
英文描述: RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS
中文描述: 抗輻射高效,5安培開關(guān)穩(wěn)壓器
文件頁(yè)數(shù): 8/16頁(yè)
文件大?。?/td> 629K
代理商: LT1933
8
LT1933
1933f
voltage rating. This situation is easily avoided; see the Hot
Plugging Safely section.
Output Capacitor
The output capacitor has two essential functions. Along
with the inductor, it filters the square wave generated by
the LT1933 to produce the DC output. In this role it
determines the output ripple, and low impedance at the
switching frequency is important. The second function is
to store energy in order to satisfy transient loads and
stabilize the LT1933’s control loop.
Ceramic capacitors have very low equivalent series resis-
tance (ESR) and provide the best ripple performance. A
good value is
C
OUT
= 60/V
OUT
where C
OUT
is in
μ
F. Use X5R or X7R types, and keep in
mind that a ceramic capacitor biased with V
OUT
will have
less than its nominal capacitance. This choice will provide
low output ripple and good transient response. Transient
performance can be improved with a high value capacitor,
but a phase lead capacitor across the feedback resistor R1
may be required to get the full benefit (see the Compensa-
tion section).
High performance electrolytic capacitors can be used for
the output capacitor. Low ESR is important, so choose one
that is intended for use in switching regulators. The ESR
should be specified by the supplier, and should be 0.1
or
less. Such a capacitor will be larger than a ceramic
capacitor and will have a larger capacitance, because the
capacitor must be large to achieve low ESR. Table 2 lists
several capacitor vendors.
Figure 1 shows the transient response of the LT1933 with
several output capacitor choices. The output is 3.3V. The
load current is stepped from 100mA to 400mA and back
to 100mA, and the oscilloscope traces show the output
voltage. The upper photo shows the recommended value.
The second photo shows the improved response (less
voltage drop) resulting from a larger output capacitor and
a phase lead capacitor. The last photo shows the response
to a high performance electrolytic capacitor. Transient
performance is improved due to the large output capaci-
tance, but output ripple (as shown by the broad trace) has
increased because of the higher ESR of this capacitor.
Table 2. Capacitor Vendors
Vendor
Panasonic
Phone
(714) 373-7366
URL
www.panasonic.com
Part Series
Ceramic,
Polymer,
Tantalum
Ceramic,
Tantalum
Ceramic,
Polymer,
Tantalum
Ceramic
Ceramic,
Tantalum
Ceramic
Comments
EEF Series
Kemet
(864) 963-6300
www.kemet.com
T494, T495
Sanyo
(408) 749-9714
www.sanyovideo.com
POSCAP
Murata
AVX
(404) 436-1300
www.murata.com
www.avxcorp.com
TPS Series
Taiyo Yuden
(864) 963-6300
www.taiyo-yuden.com
APPLICATIU
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相關(guān)PDF資料
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LT1934ES6-1 RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS
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參數(shù)描述
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LT1933ES6 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 3.6V to 36V 6-Pin TSOT-23
LT1933ES6#PBF 制造商:Linear Technology 功能描述:IC STEP-DOWN REGULATOR 6-TSOT-23
LT1933ES6#TR 功能描述:IC REG BUCK ADJ 0.6A TSOT23-6 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(biāo)準(zhǔn)包裝:2,500 系列:- 類型:升壓(升壓) 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式,混合 頻率 - 開關(guān):600kHz 電流 - 輸出:500mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC(0.154",3.90mm 寬) 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:8-SOIC
LT1933ES6#TRM 功能描述:IC REG BUCK ADJ 0.6A TSOT23-6 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(biāo)準(zhǔn)包裝:2,500 系列:- 類型:升壓(升壓) 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式,混合 頻率 - 開關(guān):600kHz 電流 - 輸出:500mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC(0.154",3.90mm 寬) 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:8-SOIC