- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄382289 > MBR0520LTI (National Semiconductor Corporation) DB-LM3S102 Daughterboard PDF資料下載
參數(shù)資料
| 型號(hào)： | MBR0520LTI |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | DB-LM3S102 Daughterboard |
| 中文描述： | 同步降壓控制器，帶有預(yù)偏置啟動(dòng)和可選時(shí)鐘同步 |
| 文件頁數(shù)： | 8/23頁 |
| 文件大?。?/td> | 1002K |
| 代理商： | MBR0520LTI |
Block Diagram
20150903
Application Information
The LM2747 is a voltage-mode, high-speed synchronous
buck regulator with a PWM control scheme. It is designed for
use in set-top boxes, thin clients, DSL/Cable modems, and
other applications that require high efficiency buck convert-
ers. It has output shutdown (SD), input undervoltage lock-out
(UVLO) mode and power good (PWGD) flag (based on
overvoltage and undervoltage detection). The overvoltage
and undervoltage signals are OR-gated to drive the power
good signal and provide a logic signal to the system if the
output voltage goes out of regulation. Current limit is
achieved by sensing the voltage V
DS
across the low side
MOSFET. The LM2747 is also able to start-up with the
output pre-biased with a load and allows for the switching
frequency to be synchronized with an external clock source.
START UP/SOFT-START
When V
exceeds 2.79V and the shutdown pin (SD) sees
a logic high, the soft-start period begins. Then an internal,
fixed 10 μA source begins charging the soft-start capacitor.
During soft-start the voltage on the soft-start capacitor C
is
connected internally to the non-inverting input of the error
amplifier. The soft-start period lasts until the voltage on the
soft-start capacitor exceeds the LM2747 reference voltage
of 0.6V. At this point the reference voltage takes over at the
non-inverting error amplifier input. The capacitance of C
determines the length of the soft-start period, and can be
approximated by:
Where C
SS
is in μF and t
SS
is in ms.
During soft start the Power Good flag is forced low and it is
released when the FB pin voltage reaches 70% of 0.6V. At
this point the chip enters normal operation mode, and the
output overvoltage and undervoltage monitoring starts.
SETTING THE OUTPUT VOLTAGE
The LM2747 regulates the output voltage by controlling the
duty cycle of the high side and low side MOSFETs (see
Typical Application Circuit).The equation governing output
voltage is:
SETTING THE SWITCHING FREQUENCY
During fixed-frequency mode of operation the PWM fre-
quency is adjustable between 50 kHz and 1 MHz and is set
by an external resistor, R
FADJ
, between the FREQ/SYNC pin
and ground. The resistance needed for a desired frequency
L
www.national.com
8
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MBR1100 | SCHOTTKY BARRIER RECTIFIER 1.0 AMPERE 100 VOLTS |
| MBR1100RL | SCHOTTKY BARRIER RECTIFIER 1.0 AMPERE 100 VOLTS |
| MBR130LSFT1 | Surface Mount Schottky Power Rectifier Plastic SOD−123 Package |
| MBR130 | SCHOTTKY BARRIER RECTIFIER 1.0 AMPERES 30 VOLTS |
| MBR130T1 | SCHOTTKY BARRIER RECTIFIER 1.0 AMPERES 30 VOLTS |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MBR0520LTJ | 制造商:ARC-TRONICS 功能描述: |
| MBR0520L-TP | 功能描述:DIODE SCHOTTKY 0.5A 20V SOD-123 RoHS:是 類別:分離式半導(dǎo)體產(chǎn)品 >> 單二極管/整流器 系列:- 標(biāo)準(zhǔn)包裝:100 系列:- 二極管類型:標(biāo)準(zhǔn) 電壓 - (Vr)（最大）:50V 電流 - 平均整流 (Io):6A 電壓 - 在 If 時(shí)為正向 (Vf)（最大）:1.4V @ 6A 速度:快速恢復(fù) = 200mA（Io） 反向恢復(fù)時(shí)間(trr):300ns 電流 - 在 Vr 時(shí)反向漏電:15µA @ 50V 電容@ Vr, F:- 安裝類型:底座，接線柱安裝 封裝/外殼:DO-203AA，DO-4，接線柱 供應(yīng)商設(shè)備封裝:DO-203AA 包裝:散裝 其它名稱:*1N3879 |
| MBR0520LW | 制造商:KEXIN 制造商全稱:Guangdong Kexin Industrial Co.,Ltd 功能描述:Schottky Rectifier Diodes |
| MBR0520-M | 制造商:FORMOSA 制造商全稱:Formosa MS 功能描述:Chip Schottky Barrier Diodes - Silicon epitaxial planer type |
| MBR0520-N | 制造商:FORMOSA 制造商全稱:Formosa MS 功能描述:Chip Schottky Barrier Diodes - Silicon epitaxial planer type |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。