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參數資料
| 型號： | LMZ14201EXTTZX-ADJ |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHING REGULATOR, PSSO7 |
| 封裝： | 10.16 X 13.77 MM, 4.57 MM HEIGHT, ROHS COMPLIANT, TO-PMOD-7 |
| 文件頁數： | 5/18頁 |
| 文件大?。?/td> | 3944K |
| 代理商： | LMZ14201EXTTZX-ADJ |
should be routed away from the body of the LMZ14201EXT
to minimize noise.
4. Make input and output bus connections as wide as
possible.
This reduces any voltage drops on the input or output of the
converter and maximizes efficiency. To optimize voltage ac-
curacy at the load, ensure that a separate feedback voltage
sense trace is made to the load. Doing so will correct for volt-
age drops and provide optimum output accuracy.
5. Provide adequate device heat-sinking.
Use an array of heat-sinking vias to connect the exposed pad
to the ground plane on the bottom PCB layer. If the PCB has
a plurality of copper layers, these thermal vias can also be
employed to make connection to inner layer heat-spreading
ground planes. For best results use a 6 x 6 via array with
minimum via diameter of 10mils (254
μm) thermal vias spaced
59mils (1.5 mm). Ensure enough copper area is used for heat-
sinking to keep the junction temperature below 125°C.
Additional Features
OUTPUT OVER-VOLTAGE COMPARATOR
The voltage at FB is compared to a 0.92V internal reference.
If FB rises above 0.92V the on-time is immediately terminat-
ed. This condition is known as over-voltage protection (OVP).
It can occur if the input voltage is increased very suddenly or
if the output load is decreased very suddenly. Once OVP is
activated, the top MOSFET on-times will be inhibited until the
condition clears. Additionally, the synchronous MOSFET will
remain on until inductor current falls to zero.
CURRENT LIMIT
Current limit detection is carried out during the off-time by
monitoring the current in the synchronous MOSFET. Refer-
ring to the Functional Block Diagram, when the top MOSFET
is turned off, the inductor current flows through the load, the
PGND pin and the internal synchronous MOSFET. If this cur-
rent exceeds 2.0 (typical) the current limit comparator dis-
ables the start of the next on-time period. The next switching
cycle will occur only if the FB input is less than 0.8V and the
inductor current has decreased below 2.0A. Inductor current
is monitored during the period of time the synchronous MOS-
FET is conducting. So long as inductor current exceeds 2.0A,
further on-time intervals for the top MOSFET will not occur.
Switching frequency is lower during current limit due to the
longer off-time. It should also be noted that current limit is
dependent on both duty cycle and temperature as illustrated
in the graphs in the typical performance section.
THERMAL PROTECTION
The junction temperature of the LMZ14201EXT should not be
allowed to exceed its maximum ratings. Thermal protection is
implemented by an internal Thermal Shutdown circuit which
activates at 165 °C (typ) causing the device to enter a low
power standby state. In this state the main MOSFET remains
off causing V
O to fall, and additionally the CSS capacitor is
discharged to ground. Thermal protection helps prevent
catastrophic failures for accidental device overheating. When
the junction temperature falls back below 145 °C (typ Hyst =
20 °C) the SS pin is released, V
O rises smoothly, and normal
operation resumes.
Applications requiring maximum output current especially
those at high input voltage may require application derating
at elevated temperatures.
ZERO COIL CURRENT DETECTION
The current of the lower (synchronous) MOSFET is monitored
by a zero coil current detection circuit which inhibits the syn-
chronous MOSFET when its current reaches zero until the
next on-time. This circuit enables the DCM operating mode,
which improves efficiency at light loads.
13
www.national.com
LMZ14201EXT
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相關代理商/技術參數 |
參數描述 |
|---|---|
| LMZ14201H | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:1A SIMPLE SWITCHER? Power Module for High Output Voltage |
| LMZ14201H_1106 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:1A SIMPLE SWITCHER?? Power Module for High Output Voltage |
| LMZ14201H_13 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:LMZ14201H 1A SIMPLE SWITCHER?? Power Module for High Output Voltage |
| LMZ14201HEVAL/NOPB | 功能描述:電源管理IC開發(fā)工具 LMZ14201H EVAL BOARD RoHS:否 制造商:Maxim Integrated 產品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
| LMZ14201HEVAL/NOPB | 制造商:Texas Instruments 功能描述:EVAL BOARD, LMZ14201H 12V, 1A REGULATOR |
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