数据搜索系统,热门电子元器件搜索 |
|
TL783 数据表(PDF) 9 Page - Texas Instruments |
|
|
TL783 数据表(HTML) 9 Page - Texas Instruments |
9 / 13 page TL783 HIGH-VOLTAGE ADJUSTABLE REGULATOR SLVS036E – SEPTEMBER 1981 – REVISED FEBRUARY 2000 9 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 DESIGN CONSIDERATIONS bypass capacitors The TL783 regulator is stable without bypass capacitors; however, any regulator becomes unstable with certain values of output capacitance if an input capacitor is not used. Therefore, the use of input bypassing is recommended whenever the regulator is located more than four inches from the power-supply filter capacitor. A 1- µF tantalum or aluminum electrolytic capacitor usually is sufficient. Adjustment-terminal capacitors are not recommended for use on the TL783 because they can seriously degrade load transient response as well as create a need for extra protection circuitry. Excellent ripple rejection presently is achieved without this added capacitor. Due to the relatively low gain of the MOS output stage, output voltage dropout may occur under large load transient conditions. The addition of an output bypass capacitor greatly enhances load transient response and prevents dropout. For most applications, it is recommended that an output bypass capacitor be used, with a minimum value of: Co (µF) = 15/VO Larger values provide proportionally better transient-response characteristics. protection circuitry The TL783 regulator includes built-in protection circuits capable of guarding the device against most overload conditions encountered in normal operation. These protective features are current limiting, safe-operating-area protection, and thermal shutdown. These circuits protect the device under occasional fault conditions only. Continuous operation in the current limit or thermal shutdown mode is not recommended. The internal protection circuits of the TL783 protect the device up to maximum-rated VI as long as certain precautions are taken. If Vl is instantaneously switched on, transients exceeding maximum input ratings may occur, which can destroy the regulator. These are usually caused by lead inductance and bypass capacitors causing a ringing voltage on the input. In addition, when rise times in excess of 10 V/ns are applied to the input, a parasitic npn transistor in parallel with the DMOS output can be turned on, causing the device to fail. If the device is operated over 50 V and the input is switched on rather than ramped on, a low-Q capacitor, such as tantalum or aluminum electrolytic should be used rather than ceramic, paper, or plastic bypass capacitors. A Q factor of 0.015 or greater usually provides adequate damping to suppress ringing. Normally, no problems occur if the input voltage is allowed to ramp upward through the action of an ac line rectifier and filter network. Similarly, when an instantaneous short circuit is applied to the output, both ringing and excessive fall times can result. A tantalum or aluminum electrolytic bypass capacitor is recommended to eliminate this problem. However, if a large output capacitor is used and the input is shorted, addition of a protection diode may be necessary to prevent capacitor discharge through the regulator. The amount of discharge current delivered is dependent on output voltage, size of capacitor, and fall time of Vl. A protective diode (see Figure 17) is required only for capacitance values greater than: Co (µF) = 3 x 104/(VO)2 Care always should be taken to prevent insertion of regulators into a socket with power on. Power should be turned off before removing or inserting regulators. |
类似零件编号 - TL783 |
|
类似说明 - TL783 |
|
|
链接网址 |
隐私政策 |
ALLDATASHEETCN.COM |
ALLDATASHEET是否为您带来帮助? [ DONATE ] |
关于 Alldatasheet | 广告服务 | 联系我们 | 隐私政策 | 链接交换 | 制造商名单 All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |