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參數(shù)資料
| 型號(hào)： | MIC4684BM |
| 廠商： | MICREL INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 150000 SYSTEM GATE 2.5 VOLT FPGA - NOT RECOMMENDED for NEW DESIGN |
| 中文描述： | SWITCHING REGULATOR, 225 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | SOP-8 |
| 文件頁數(shù)： | 2/16頁 |
| 文件大?。?/td> | 213K |
| 代理商： | MIC4684BM |
MIC4684
Pin Configuration
Micrel
MIC4684
2
July 2001
Pin Description
Pin Number
Pin Name
Pin Function
1
SW
Switch (Output): Emitter of NPN output switch. Connect to external storage
inductor and Shottky diode.
2, 6, 7
GND
Ground
3
IN
Supply (Input): Unregulated +4V to 30V supply voltage (34V transient)
4
BS
Booststrap Voltage Node (External Component): Connect to external boost
capacitor.
5
FB
Feedback (Input): Outback voltage feedback to regulator. Connect to output
of supply for fixed versions. Connect to 1.23V tap of resistive divider for
adjustable versions.
8
EN
Enable (Input): Logic high = enable; logic low = shutdown
1
SW
GND
VIN
BS
8
EN
GND
GND
FB
7
6
5
2
3
4
8-Pin SOP (M)
Detailed Pin Description
Switch (SW, pin 1)
The switch pin is tied to the emitter of the main internal NPN
transistor. This pin is biased up to the input voltage minus the
V
SAT
of the main NPN pass element. The emitter is also
driven negative when the output inductor
’
s magnetic field
collapses at turn-off. During the OFF time the SW pin is
clamped by the output schottky diode to a
–
0.5V typically.
Ground (GND, pins 2,6,7)
There are two main areas of concern when it comes to the
ground pin, EMI and ground current. In a buck regulator or
any other non-isolated switching regulator the output
capacitor(s) and diode(s) ground is referenced back to the
switching regulator
’
s or controller
’
s ground pin. Any resis-
tance between these reference points causes an offset
voltage/IR drop proportional to load current and poor load
regulation. This is why its important to keep the output
grounds placed as close as possible to the switching regulator
’
s
ground pin. To keep radiated EMI to a minimum its necessary
to place the input capacitor ground lead as close as possible
to the switching regulators ground pin.
Input Voltage (V
IN
, pin 3)
The V
IN
pin is the collector of the main NPN pass element.
This pin is also connected to the internal regulator. The output
diode or clamping diode should have its cathode as close as
possible to this point to avoid voltage spikes adding to the
voltage across the collector.
Bootstrap (BS, pin 4)
The bootstrap pin in conjunction with the external bootstrap
capacitor provides a bias voltage higher than the input
voltage to the MIC4684
’
s main NPN pass element. The
bootstrap capacitor sees the dv/dt of the switching action at
the SW pin as an AC voltage. The bootstrap capacitor then
couples the AC voltage back to the BS pin plus the dc offset
of V
IN
where it is rectified and used to provide additional drive
to the main switch, in this case a NPN transistor.
This additional drive reduces the NPN
’
s saturation voltage
and increases efficiency, from a V
SAT
of 1.8V, and 75%
efficiency to a V
SAT
of 0.5V and 88% efficiency respectively.
Feedback (FB, pin 5)
The feedback pin is tied to the inverting side of a GM error
amplifier. The noninverting side is tied to a 1.235V bandgap
reference. Fixed voltage versions have an internal voltage
divider from the feedback pin. Adjustable versions require an
external resistor voltage divider from the output to ground,
with the center tied to the feedback pin.
Enable (EN, pin 8)
The enable (EN) input is used to turn on the regulator and is
TTL compatible. Note: connect the enable pin to the input if
unused. A logic-high enables the regulator. A logic-low shuts
down the regulator and reduces the stand-by quiescent input
current to typically 150
μ
A. The enable pin has an upper
threshold of 2.0V minimum and lower threshold of 0.8V
maximum. The hysterisis provided by the upper and lower
thresholds acts as an UVLO and prevents unwanted turn on
of the regulator due to noise.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MIC4684BM TR | 功能描述:IC REG BUCK ADJ 2A 8SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:SuperSwitcher™ 標(biāo)準(zhǔn)包裝:20 系列:SIMPLE SWITCHER® 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:12V 輸入電壓:4 V ~ 60 V PWM 型:電壓模式 頻率 - 開關(guān):52kHz 電流 - 輸出:1A 同步整流器:無 工作溫度:-40°C ~ 125°C 安裝類型:通孔 封裝/外殼:16-DIP（0.300"，7.62mm） 包裝:管件 供應(yīng)商設(shè)備封裝:16-DIP 其它名稱:*LM2575HVN-12LM2575HVN-12 |
| MIC4684YM | 功能描述:直流/直流開關(guān)調(diào)節(jié)器 SO-8 Efficient Simple Buck Regulator (Lead Free) RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| MIC4684YM TR | 功能描述:直流/直流開關(guān)調(diào)節(jié)器 SO-8 Efficient Simple Buck Regulator (Lead Free) RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| MIC4684YM | 制造商:Micrel Inc 功能描述:IC VOLTAGE REGULATOR SOIC |
| MIC4684YM | 制造商:Micrel Inc 功能描述:Voltage Regulator IC |
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