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参数资料
| 型号： | LT1054IP |
| 厂商： | TEXAS INSTRUMENTS INC |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHED CAPACITOR REGULATOR, 35 kHz SWITCHING FREQ-MAX, PDIP8 |
| 封装： | ROHS COMPLIANT, PLASTIC, DIP-8 |
| 文件页数： | 2/30页 |
| 文件大小： | 607K |
| 代理商： | LT1054IP |
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LT1054
SWITCHED-CAPACITOR VOLTAGE CONVERTERS
WITH REGULATORS
SLVS033F FEBRUARY 1990 REVISED NOVEMBER 2004
10
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
PRINCIPLES OF OPERATION
The voltage reference (Vref) output provides a 2.5-V reference point for use in LT1054-based regulator circuits. The
temperature coefficient (TC) of the reference voltage has been adjusted so that the TC of the regulated output voltage
is near zero. As seen in the typical performance curves, this requires the reference output to have a positive TC. This
nonzero drift is necessary to offset a drift term inherent in the internal reference divider and comparator network tied
to the feedback terminal. The overall result of these drift terms is a regulated output that has a slight positive TC at
output voltages below 5 V and a slight negative TC at output voltages above 5 V. For regulator feedback networks,
reference output current should be limited to approximately 60
μA. Vref draws approximately 100 μA when shorted
to ground and does not affect the internal reference/regulator. This terminal also can be used as a pullup for LT1054
circuits that require synchronization.
CAP+ is the positive side of input capacitor CIN and is driven alternately between VCC and ground. When driven to
VCC, CAP+ sources current from VCC. When driven to ground, CAP+ sinks current to ground. CAP is the negative
side of the input capacitor and is driven alternately between ground and VOUT. When driven to ground, CAP sinks
current to ground. When driven to VOUT, CAP sources current from COUT. In all cases, current flow in the switches
is unidirectional, as should be expected when using bipolar switches.
OSC can be used to raise or lower the oscillator frequency or to synchronize the device to an external clock. Internally,
OSC is connected to the oscillator timing capacitor (Ct ≈ 150 pF), which is charged and discharged alternately by
current sources of
±7 μA, so that the duty cycle is approximately 50%. The LT1054 oscillator is designed to run in
the frequency band where switching losses are minimized. However, the frequency can be raised, lowered, or
synchronized to an external system clock if necessary.
The frequency can be increased by adding an external capacitor (C2 in Figure 15) in the range of 520 pF from CAP+
to OSC. This capacitor couples a charge into Ct at the switch transitions. This shortens the charge and discharge
times and raises the oscillator frequency. Synchronization can be accomplished by adding an external pullup resistor
from OSC to Vref. A 20-kΩ pullup resistor is recommended. An open-collector gate or an npn transistor then can be
used to drive OSC at the external clock frequency as shown in Figure 15.
The frequency can be lowered by adding an external capacitor (C1 in Figure 15) from OSC to ground. This increases
the charge and discharge times, which lowers the oscillator frequency.
C1
LT1054
VOUT
VREF
OSC
VCC
CAP
GND
CAP+
FB/SD
C2
VIN
Pin numbers shown are for the P package.
+
1
2
3
4
8
7
6
5
Figure 15. External-Clock System
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1054IP | 制造商:Texas Instruments 功能描述:Voltage Regulator IC Package/Case:8-PDIP |
| LT1054IPE4 | 功能描述:电荷泵 Switched-Capacitor Voltage Converter 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 |
| LT1054IS8 | 功能描述:IC REG SWITCHD CAP DBL INV 8SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
| LT1054IS8#PBF | 功能描述:IC REG SWITCHD CAP DBL INV 8SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:250 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V 输入电压:2.05 V ~ 6 V PWM 型:电压模式 频率 - 开关:2MHz 电流 - 输出:500mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:6-UFDFN 包装:带卷 (TR) 供应商设备封装:6-SON（1.45x1） 产品目录页面:1032 (CN2011-ZH PDF) 其它名称:296-25628-2 |
| LT1054IS8#PBF | 制造商:Linear Technology 功能描述:DC/DC Converter IC |
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