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参数资料
| 型号： | LM2686MTC/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHED CAPACITOR REGULATOR, 180 kHz SWITCHING FREQ-MAX, PDSO14 |
| 封装： | TSSOP-14 |
| 文件页数： | 6/8页 |
| 文件大小： | 243K |
| 代理商： | LM2686MTC/NOPB |
Detailed Device Description
The LM2686 CMOS charge pump voltage converter oper-
ates as an input voltage doubler, +5V regulator for an input
voltage in the range of +2.85V to +6.5V. It delivers maximum
load currents of 50mA for the regulated +5V, with an operat-
ing current of only 450A. It also has a typical shutdown
current of 6A. All these performance qualities make the
LM2686 an ideal device for battery powered systems.
The LM2686 has two main functional blocks: a voltage dou-
bler and a low dropout (LDO) regulator. Figure 1 shows the
LM2686 functional block diagram.
VOLTAGE DOUBLER
The voltage doubler ties directly to V
IN and doubles the input
voltage in the range from +2.85V to +5.4V up to 5.7V to
10.8V at the V
DBL pin. For VIN above 5.4V, the doubler shuts
off and the input voltage is passed directly to VDBL via an
internal power switch.
The doubler contains four large CMOS switches which are
switched in a sequence to double the input supply voltage.
Figure 2 illustrates the voltage conversion scheme. When S2
and S4 are closed, C1 charges to the supply voltage V
IN.
During this time interval, switches S1 and S3 are open. In the
next time interval, S2 and S4 are opened at the same time,
S1 and S3 are closed, the sum of the input voltage V
IN and
the voltage across C1 gives the 2V
In and the voltage across
C2 gives the 2V
IN at VDBL output. VDBL supplies the LDO
regulator. It is recommended not to load V
DBL when V05 has
a load of 50mA. For proper operation, the sum of V
DBL and
V
05 loads must not be more than 50mA.
+5 LDO REGULATOR
V
DBL is the input to an LDO regulator that regulates it to a +5
output voltage at V
05.VPSW is tied to V05 through a series
switch PSW. The LDO output capacitor (4.7F Tantalum)
may be connected to either V
05 or VPSW.
SHUTDOWN AND LOAD DISCONNECT
In addition to the nominal charge pump and regulator func-
tions, the LM2686 features shutdown and load disconnect
circuitry. CE (chip enable) and SD (shutdown positive) per-
form the same task with opposite input polarities. When CE
is low or SD 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, and the device’s internal
thermal shutdown is triggered.
The LM2686 incorporates a low impedance switch tied to the
V
05 output, because some special applications require load
disconnect and this is achievable via the switch. Switch PSW
connects V
05 to VPSW. In normal operation, this switch is
closed, allowing 5V loads to be tied to either V
05 or VPSW.
Forcing CE low or SD high opens the PSW.
10114103
FIGURE 1. Functional Block Diagram
10114104
FIGURE 2. Voltage Doubler Principle
LM2686
www.national.com
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM2686MTCX/NOPB | 功能描述:IC REG SWITCHED CAP DBL 14-TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:1 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:3.3V 输入电压:4.5 V ~ 24 V PWM 型:- 频率 - 开关:- 电流 - 输出:125mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 包装:Digi-Reel® 供应商设备封装:SOT-6 其它名称:MAX1836EUT33#TG16DKR |
| LM2687LD | 制造商:Texas Instruments 功能描述: |
| LM2687LD/NOPB | 功能描述:IC REG SWITCHD CAP INV ADJ 8-LLP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:1 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:3.3V 输入电压:4.5 V ~ 24 V PWM 型:- 频率 - 开关:- 电流 - 输出:125mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 包装:Digi-Reel® 供应商设备封装:SOT-6 其它名称:MAX1836EUT33#TG16DKR |
| LM2687LDX | 功能描述:电荷泵 RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 输出电压:- 1.5 V to - 5.5 V, 3 V to 11 V 输出电流:100 mA 电源电流:1 mA 最大工作温度:+ 70 C 封装 / 箱体:SOIC-8 Narrow 封装:Tube |
| LM2687LDX/NOPB | 功能描述:电荷泵 RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 输出电压:- 1.5 V to - 5.5 V, 3 V to 11 V 输出电流:100 mA 电源电流:1 mA 最大工作温度:+ 70 C 封装 / 箱体:SOIC-8 Narrow 封装:Tube |
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