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參數(shù)資料
| 型號： | LM25574Q0MTX |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHING REGULATOR, PDSO16 |
| 封裝： | TSSOP-16 |
| 文件頁數(shù)： | 14/20頁 |
| 文件大?。?/td> | 394K |
| 代理商： | LM25574Q0MTX |
Pin Descriptions
Pin(s)
Name
Description
Application Information
1
VCC
Output of the bias regulator
Vcc tracks Vin up to 9V. Beyond 9V, Vcc is regulated to 7
Volts. A 0.1uF to 1uF ceramic decoupling capacitor is
required. An external voltage (7.5V – 14V) can be applied
to this pin to reduce internal power dissipation.
2
SD
Shutdown or UVLO input
If the SD pin voltage is below 0.7V the regulator will be in a
low power state. If the SD pin voltage is between 0.7V and
1.225V the regulator will be in standby mode. If the SD pin
voltage is above 1.225V the regulator will be operational. An
external voltage divider can be used to set a line
undervoltage shutdown threshold. If the SD pin is left open
circuit, a 5A pull-up current source configures the regulator
fully operational.
3
Vin
Input supply voltage
Nominal operating range: 6V to 42V
4
SYNC
Oscillator synchronization input or output The internal oscillator can be synchronized to an external
clock with an external pull-down device. Multiple
LM25574Q0 devices can be synchronized together by
connection of their SYNC pins.
5
COMP
Output of the internal error amplifier
The loop compensation network should be connected
between this pin and the FB pin.
6
FB
Feedback signal from the regulated
output
This pin is connected to the inverting input of the internal
error amplifier. The regulation threshold is 1.225V.
7
RT
Internal oscillator frequency set input
The internal oscillator is set with a single resistor, connected
between this pin and the AGND pin.
8
RAMP
Ramp control signal
An external capacitor connected between this pin and the
AGND pin sets the ramp slope used for current mode
control. Recommended capacitor range 50pF to 2000pF.
9
AGND
Analog ground
Internal reference for the regulator control functions
10
SS
Soft-start
An external capacitor and an internal 10A current source
set the time constant for the rise of the error amp reference.
The SS pin is held low during standby, Vcc UVLO and
thermal shutdown.
11
OUT
Output voltage connection
Connect directly to the regulated output voltage.
12
PGND
Power ground
Low side reference for the PRE switch and the IS sense
resistor.
13
IS
Current sense
Current measurement connection for the re-circulating
diode. An internal sense resistor and a sample/hold circuit
sense the diode current near the conclusion of the off-time.
This current measurement provides the DC level of the
emulated current ramp.
14
SW
Switching node
The source terminal of the internal buck switch. The SW pin
should be connected to the external Schottky diode and to
the buck inductor.
15
PRE
Pre-charge assist for the bootstrap
capacitor
This open drain output can be connected to SW pin to aid
charging the bootstrap capacitor during very light load
conditions or in applications where the output may be pre-
charged before the LM25574Q0 is enabled. An internal pre-
charge MOSFET is turned on for 250ns each cycle just prior
to the on-time interval of the buck switch.
16
BST
Boost input for bootstrap capacitor
An external capacitor is required between the BST and the
SW pins. A 0.022F ceramic capacitor is recommended.
The capacitor is charged from Vcc via an internal diode
during the off-time of the buck switch.
3
www.national.com
LM25574Q0
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM25574Q0MTX/NOPB | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM25574-Q1 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:LM25574/LM25574-Q1 SIMPLE SWITCHER 42V, 0.5A Step-Down Switching Regulator |
| LM25574QMT | 制造商:TI 制造商全稱:Texas Instruments 功能描述:LM25574/LM25574-Q1 SIMPLE SWITCHER 42V, 0.5A Step-Down Switching Regulator |
| LM25574QMT/NOPB | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM25574QMTX | 制造商:TI 制造商全稱:Texas Instruments 功能描述:LM25574/LM25574-Q1 SIMPLE SWITCHER 42V, 0.5A Step-Down Switching Regulator |
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