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参数资料
| 型号： | LTC1503CS8-1.8#TR |
| 厂商： | Linear Technology |
| 文件页数： | 7/12页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SWITCHED CAP 8SOIC |
| 标准包装： | 2,500 |
| 类型： | 降压（降压），切换电容（充电泵） |
| 输出类型： | 固定 |
| 输出数： | 1 |
| 输出电压： | 1.8V |
| 输入电压： | 2.4 V ~ 6 V |
| 频率 - 开关： | 600kHz |
| 电流 - 输出： | 100mA |
| 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： | 8-SOIC（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 8-SOIC |
LTC1503-1.8/LTC1503-2
APPLICATIO S I FOR ATIO
V IN
S5
φ 2
C1 +
S1
φ 1
V OUT
maintain regulation. This will only occur as V IN /V OUT nears
a 3-to-2 or 1-to-1 transition point. For example, under light
C1 –
C1
(EXTERNAL)
S4
φ 2
load conditions, the LTC1503-X can operate in 2-to-1
mode when V IN equals 4.1V with greater than 90% effi-
ciency. However, when the load is increased, the part can
S7
φ 2
S2
φ 1
C2 +
C2
(EXTERNAL)
no longer supply enough output current in 2-to-1 mode to
maintain regulation. This causes V OUT to droop below the
regulation point until COMP2 trips and forces the part to
skip from 2-to-1 mode to 3-to-2 mode. The COMP2
threshold is about 17mV (V OUT referred) below the main
C2 –
S3
φ 1
GND
S6
φ 2
comparator regulation point. Hysteresis in COMP2 will
force the part to transition in and out of mode skipping.
This will result in a slight V OUT decrease of approximately
20mV under mode skipping conditions.
1503-1.8/2 F01b
Figure 1b. Step-Down Charge Pump in 3-to-2 Mode
In 1-to-1 mode, switch S1 and S2 are connected in series
between V IN and V OUT as needed to boost V OUT back into
regulation (see Figure 1c). The REG ENABLE signal from
the main comparator (COMP1) controls switches S1 and
S2 directly. Since all of the V OUT current is sourced from
V IN , the efficiency in 1-to-1 mode is approximately equal
to that of a linear regulator.
Shutdown/Soft-Start Operation
The SHDN/SS pin is used to implement both low current
shutdown and soft-start. The soft-start feature limits
inrush currents when the regulator is initially powered up
or taken out of shutdown. Forcing a voltage lower than
0.35V (typ) will put the part into shutdown mode. Shut-
down mode disables all control circuitry and forces the
charge pump V OUT into a high impedance state. A 2 μ A pull-
up current on the SHDN/SS pin will force the part into
active mode if the pin is left floating or is driven with an
open-drain output that is in a high impedance state. If the
V IN
S2
C1 +
S1
C1
(EXTERNAL)
V OUT
pin is not driven with an open-drain device, it must be
forced to a logic high voltage of 2.2V (min) to ensure
proper V OUT regulation. The SHDN/SS pin should not be
driven to a voltage higher than V IN .
C1 –
1503-1.8/2 F01c
To implement soft-start, the SHDN/SS pin must be driven
Figure 1c. Step-Down Charge Pump in 1-to-1 Mode
Mode Selection and Mode Skipping
The optimal step-down conversion mode is chosen based
on V IN to V OUT differential voltage and output load condi-
tions. Two internal comparators are used to select the
default step-down mode based on the V IN and V OUT
voltage. A separate comparator (COMP2) is used to sense
a droop on V OUT due to a heavy output load and force the
charge pump to skip to a higher output current mode to
with an open-drain device and a capacitor must be
connected from the SHDN/SS pin to GND. Once the open-
drain device is turned off, a 2 μ A pull-up current will begin
charging the external SS capacitor and force the voltage
on the pin to ramp towards V IN . As soon as the SHDN
threshold is reached (0.35V typ), the internal reference
voltage which controls the V OUT regulation point will
follow the ramp voltage on the SHDN/SS pin (minus a
0.35V offset to account for the SHDN threshold) until the
reference reaches its final band gap voltage. This occurs
when the voltage on the SHDN/SS pin reaches
7
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC1503CS8-2 | 功能描述:IC REG BUCK SWITCHD CAP 2V 8SOIC RoHS:否 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 |
| LTC1503CS8-2#PBF | 功能描述:IC REG BUCK SWITCHD CAP 2V 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 |
| LTC1503CS8-2#TR | 功能描述:IC REG BUCK SWITCHD CAP 2V 8SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:升压（升压） 输出类型:可调式 输出数:1 输出电压:1.24 V ~ 30 V 输入电压:1.5 V ~ 12 V PWM 型:电流模式，混合 频率 - 开关:600kHz 电流 - 输出:500mA 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:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) 供应商设备封装:8-SOIC |
| LTC1503CS8-2#TRPBF | 功能描述:IC REG BUCK SWITCHD CAP 2V 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:20 系列:SIMPLE SWITCHER® 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:12V 输入电压:4 V ~ 60 V PWM 型:电压模式 频率 - 开关:52kHz 电流 - 输出:1A 同步整流器:无 工作温度:-40°C ~ 125°C 安装类型:通孔 封装/外壳:16-DIP（0.300"，7.62mm） 包装:管件 供应商设备封装:16-DIP 其它名称:*LM2575HVN-12LM2575HVN-12 |
| LTC1503IS8-1.8 | 功能描述:IC REG BUCK SWITCHED CAP 8SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:升压（升压） 输出类型:可调式 输出数:1 输出电压:1.24 V ~ 30 V 输入电压:1.5 V ~ 12 V PWM 型:电流模式，混合 频率 - 开关:600kHz 电流 - 输出:500mA 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:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) 供应商设备封装:8-SOIC |
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