- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄367562 > LM2682MX DC-to-DC Voltage Converter PDF資料下載
參數(shù)資料
| 型號(hào)： | LM2682MX |
| 英文描述： | DC-to-DC Voltage Converter |
| 中文描述： | 型DC - DC電壓轉(zhuǎn)換器 |
| 文件頁數(shù)： | 7/9頁 |
| 文件大?。?/td> | 244K |
| 代理商： | LM2682MX |
Detailed Device Description
(Continued)
is added is determined by the parasitic resistance (R
(on) of
the MOSFET switches and the ESR of the capacitors) and
the charge transfer loss between capacitors.
Shutdown and Load Disconnect
In addition to the nominal charge pump and regulator func-
tions, the LM2685 features shutdown and load disconnect
circuitry. CE (chip enable) and SDP (shutdown positive) per-
form the same task with opposite input polarities. When CE
is low or SDP is high, all circuit blocks are disabled and V
05
falls to ground potential. This is the same result as when the
die temperature exceeds 150C (typical), and the device’s
internal thermal shutdown is triggered.
Forcing SDN (shutdown negative) high disables only the in-
verting charge pump. The doubling charge pump and the
LDO regulator continue to operate, so the V
05
and the V
PSW
remain at 5V.
The LM2685 incorporates two low impedance switches tied
to the V
and V
outputs, because some special applica-
tions require load disconnect and this is achievable via the
switches. Switch PSW connects V
to V
, and switch
NSW connects V
to V
. In normal operation, these
switches are closed, allowing 5V loads to be tied to either
V
05
or V
and 5V loads to be tied to either V
or
V
. Driving SDN high opens switch NSW only, while forc-
ing CE low or SDP high, opens both the PSW and NSW.
Application Information
Capacitor Selection
The output resistance and ripple voltage are dependent on
the capacitance and ESR values of the external capacitors.
Voltage Doubler External Capacitors
The selection of capacitors are based on the specifications
of the dropout voltage (which equals I
OUT
R
OUT
), the output
voltage ripple, and the converter efficiency.
where R
SW
is the sum of the ON resistance of the internal
MOSFET switches as shown in Figure 2
The peak-to-peak output voltage ripple is determined by the
oscillator frequency, the capacitance and ESR of the capaci-
tor C3.
High capacitance (2.2μF to higher), low ESR capacitors can
reduce the output resistance and the voltage ripple.
where I
(V+) is the quiescent power loss of the IC device,
and I
2L
R is the conversion loss associated with the switch
on-resistance, the two external capacitors and their ESRs.
Low ESR capacitors (table to be referenced) are recom-
mended to maximize efficiency, reduce the output voltage
drop and voltage ripple.
+5 LDO Regulator External Capacitors
The voltage doubler output capacitor, C3, serves as the input
capacitor of the +5 LDO regulator. The output capacitor C4,
must meet the requirement for minimum amount of capaci-
tance and appropriate ESR (Equivalent Serving Resistance)
for proper operation. The ESR value must remain within the
regions of stability as shown in Figure 4 Figure 5and Figure
6 to ensure output’s stability. A minimum capacitance of 1μF
is required at the output. This can be increased without limit,
but a 4.7μF tantalum capacitor is recommended for loads
ranging upto the maximum specification. With lighter loads
of less or equal to 10mA, ceramic capacitor of at least 1μF
and ESR in the milliohms can be used. This has to be con-
nected to V
PSW
pin instead of the V
05
pin.
Any output capacitor used should have a good tolerance
over temperature for capacitance and ESR values. The
larger the capacitor, with ESR within the stable region, the
better the stability and noise performance.
DS101100-5
FIGURE 3. Voltage Inverter Principle
DS101100-25
FIGURE 4. ESR Curve for C
OUT
= 2.2μF
L
www.national.com
7
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM2685 | |
| LM2685MTC | DC-to-DC Voltage Converter |
| LM2698 | |
| LM2698MM-ADJ | SIMPLE SWITCHER 1.35A Boost Regulator |
| LM2902D | Advanced LinCMOS(TM) Low-Noise Chopper-Stabilized Operational Amplifier 8-SOIC |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM2682MX/NOPB | 功能描述:IC REG SWITCHD CAP DBL INV 8SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:3.3V 輸入電壓:4.5 V ~ 24 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:125mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 包裝:Digi-Reel® 供應(yīng)商設(shè)備封裝:SOT-6 其它名稱:MAX1836EUT33#TG16DKR |
| LM2685B E WAF | 制造商:Texas Instruments 功能描述: |
| LM2685MTC | 制造商:Texas Instruments 功能描述:VOLT CONVERTER SMD 2685 TSSOP14 |
| LM2685MTC | 制造商:Texas Instruments 功能描述:VOLT CONVERTER SMD 2685 TSSOP14 |
| LM2685MTC/NOPB | 功能描述:IC REG MULTI CONFIG DL 14-TSSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:3.3V 輸入電壓:4.5 V ~ 24 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:125mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 包裝:Digi-Reel® 供應(yīng)商設(shè)備封裝:SOT-6 其它名稱:MAX1836EUT33#TG16DKR |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。