參數(shù)資料
型號： PTN78000WAST
廠商： TEXAS INSTRUMENTS INC
元件分類： 穩(wěn)壓器
英文描述： 3.2 A SWITCHING REGULATOR, 660 kHz SWITCHING FREQ-MAX, DMA5
文件頁數(shù)： 6/26頁
文件大?。?/td> 634K
代理商： PTN78000WAST
CAPACITOR RECOMMENDATIONS FOR PTN78000 WIDE-OUTPUT
PTN78000W Input Capacitor
PTN78000H Input Capacitor
PTN78000W and PTN78000H Output Capacitors
Ceramic Capacitors
SLTS230C – NOVEMBER 2004 – REVISED SEPTEMBER 2008...................................................................................................................................... www.ti.com
ADJUST POWER MODULES
The minimum requirement for the input of PTN78000W is 2.2 F of ceramic capacitance. The dielectric may be
either an X5R or X7R temperature characteristic. Ceramic capacitors should be located within 0.5 inch (1,27 cm)
of the regulator input pins. Electrolytic capacitors can be used at the input, but only in addition to the required
ceramic capacitance. The minimum ripple current rating for any nonceramic capacitance must be at least
650 mArms. The ripple current rating of electrolytic capacitors is a major consideration when they are used at the
input. This ripple current requirement can be reduced by placing more ceramic capacitors at the input, in addition
to the minimum required capacitance.
Tantalum capacitors are not recommended for use at the input bus, as none were found to meet the minimum
voltage rating of 2 x (maximum dc voltage + ac ripple). The 2x rating is standard practice for regular tantalum
capacitors to ensure reliability. Polymer-tantalum capacitors are more reliable and are available with a maximum
rating of typically 20 V. These can be used with input voltages up to 16 V.
The minimum requirement for the input of PTN78000H is 2 × 4.7 F of ceramic capacitance. The dielectric may
be either an X5R or X7R temperature characteristic. Ceramic capacitors should be located within 0.5 inch
(1,27 cm) of the regulator input pins. Electrolytic capacitors can be used at the input, but only in addition to the
required ceramic capacitance. The minimum ripple current rating for any nonceramic capacitance must be at
least 350 mArms. The ripple current rating of electrolytic capacitors is a major consideration when they are used
at the input. This ripple current requirement can be reduced by placing more ceramic capacitors at the input, in
addition to the minimum required capacitance.
Tantalum capacitors are not recommended for use at the input bus, as none were found to meet the minimum
voltage rating of 2 x (maximum dc voltage + ac ripple). The 2× rating is standard practice for regular tantalum
capacitors to ensure reliability. Polymer-tantalum capacitors are more reliable and are available with a maximum
rating of typically 20 V. These can be used with input voltages up to 16 V.
The minimum capacitance required to insure stability is a 100 F. Either ceramic or electrolytic-type capacitors
can be used. The minimum ripple current rating for the nonceramic capacitance must be at least 150 mA rms.
The stability of the module and voltage tolerances will be compromised if the capacitor is not placed near the
output bus pins. A high-quality, computer-grade electrolytic capacitor should be adequate. A ceramic capacitor
can be also be located within 0.5 inch (1,27 cm) of the output pin.
For applications with load transients (sudden changes in load current), the regulator response improves with
additional capacitance. Additional electrolytic capacitors should be located close to the load circuit. These
capacitors provide decoupling over the frequency range, 2 kHz to 150 kHz. Aluminum electrolytic capacitors are
suitable for ambient temperatures above 0°C. For operation below 0°C, tantalum or OS-CON type capacitors are
recommended. When using one or more nonceramic capacitors, the calculated equivalent ESR should be no
lower than 10 m
(17 m using the manufacturer's maximum ESR for a single capacitor). A list of capacitors
and vendors are identified in Table 5 and Table 6, the recommended capacitor tables.
Above 150 kHz the performance of aluminum electrolytic capacitors becomes less effective. To further reduce
the reflected input ripple current, or the output transient response, multilayer ceramic capacitors must be added.
Ceramic capacitors have low ESR and their resonant frequency is higher than the bandwidth of the regulator.
When placed at the output, their combined ESR is not critical as long as the total value of ceramic capacitance
does not exceed 200 F.
14
Copyright 2004–2008, Texas Instruments Incorporated
Product Folder Link(s): PTN78000W PTN78000H
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
PTN78000WAZ 功能描述:DC/DC轉(zhuǎn)換器 ADJ SWITCHING REGULATOR RoHS:否 制造商:Murata 產(chǎn)品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標(biāo)稱）: 輸出端數(shù)量:1 輸出電壓（通道 1）:3.3 V 輸出電流（通道 1）:600 mA 輸出電壓（通道 2）: 輸出電流（通道 2）: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體尺寸:
PTN78000WAZT 功能描述:DC/DC轉(zhuǎn)換器 ADJ SWITCHING REGULATOR RoHS:否 制造商:Murata 產(chǎn)品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標(biāo)稱）: 輸出端數(shù)量:1 輸出電壓（通道 1）:3.3 V 輸出電流（通道 1）:600 mA 輸出電壓（通道 2）: 輸出電流（通道 2）: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體尺寸:
PTN78020A 制造商:TI 制造商全稱:Texas Instruments 功能描述:25-W, WIDE-INPUT ADJUSTABLE POSITIVE-TO-NEGATIVE VOLTAGE REGULATOR MODULE
PTN78020AAH 功能描述:DC/DC轉(zhuǎn)換器 4A Wide Inp/Neg Out Adj Module RoHS:否 制造商:Murata 產(chǎn)品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標(biāo)稱）: 輸出端數(shù)量:1 輸出電壓（通道 1）:3.3 V 輸出電流（通道 1）:600 mA 輸出電壓（通道 2）: 輸出電流（通道 2）: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體尺寸:
PTN78020AAS 功能描述:DC/DC轉(zhuǎn)換器 4A Wide Inp/Neg Out Adj Module RoHS:否 制造商:Murata 產(chǎn)品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標(biāo)稱）: 輸出端數(shù)量:1 輸出電壓（通道 1）:3.3 V 輸出電流（通道 1）:600 mA 輸出電壓（通道 2）: 輸出電流（通道 2）: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體尺寸:
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