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参数资料
| 型号： | LT3980IDE#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 16/24页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 2A 14DFN |
| 标准包装： | 91 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.79 V ~ 52.2 V |
| 输入电压： | 3.6 V ~ 58 V |
| PWM 型： | 电流模式，Burst Mode? |
| 频率 - 开关： | 225kHz ~ 2.25MHz |
| 电流 - 输出： | 2A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 14-WFDFN 裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 14-DFN-EP（4x3） |
LT3980
APPLICATIONS INFORMATION
create a voltage ramp at this pin. Figure 7 shows the start-
up and shutdown waveforms with the soft-start circuit.
By choosing a large RC time constant, the peak start-up
current can be reduced to the current that is required to
regulate the output, with no overshoot. Choose the value
of the resistor so that it can supply 20μA when the RUN/
SS pin reaches 2.5V.
Synchronization
To select low ripple Burst Mode operation, tie the SYNC
pin below 0.5V (this can be ground or a logic output). Tie
to a voltage above 0.8V to select pulse-skipping mode.
Synchronizing the LT3980 oscillator to an external fre-
quency can be done by connecting a square wave (with
20% to 80% duty cycle) to the SYNC pin. The square
wave amplitude should have valleys that are below 0.3V
and peaks that are above 0.8V (up to 6V).
The LT3980 will not enter Burst Mode operation at low
output loads while synchronized to an external clock, but
instead will skip pulses to maintain regulation.
The LT3980 may be synchronized over a 150kHz to 2MHz
range. The R T resistor should be chosen to set the LT3980
switching frequency 25% below the lowest synchronization
input. For example, if the synchronization signal will be
250kHz and higher, the R T should be chosen for 200kHz.
To assure reliable and safe operation the LT3980 will only
synchronize when the output voltage is near regulation
RUN
15k
as indicated by the PG flag. It is therefore necessary to
choose a large enough inductor value to supply the required
output current at the frequency set by the R T resistor. See
the Inductor Selection section. It is also important to note
that slope compensation is set by the R T value: When the
sync frequency is much higher than the one set by R T , the
slope compensation will be significantly reduced which
may require a larger inductor value to prevent subharmonic
oscillation.
Shorted and Reversed Input Protection
If an inductor is chosen that will not saturate excessively,
an LT3980 buck regulator will tolerate a shorted output.
There is another situation to consider in systems where
the output will be held high when the input to the LT3980
is absent. This may occur in battery charging applications
or in battery backup systems where a battery or some
other supply is diode ORed with the LT3980’s output. If
the V IN pin is allowed to float and the RUN/SS pin is held
high (either by a logic signal or because it is tied to V IN ),
then the LT3980’s internal circuitry will pull its quiescent
current through its SW pin. This is fine if your system can
tolerate a few mA in this state. If you ground the RUN/
SS pin, the SW pin current will drop to essentially zero.
However, if the V IN pin is grounded while the output is
held high, then parasitic diodes inside the LT3980 can pull
large currents from the output through the SW pin and the
I L
1A/DIV
0.22μF
RUN/SS
GND
2ms/DIV
3680 F07
V RUN/SS
2V/DIV
V OUT
2V/DIV
Figure 7. To Soft-Start the LT3980, Add a
Resistor and Capacitor to the RUN/SS Pin
3980fa
16
For more information www.linear.com/LT3980
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| LT3980IMSE#PBF | 功能描述:IC REG BUCK ADJ 2A 16MSOP RoHS:是 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 |
| LT3980IMSE#TRPBF | 功能描述:IC REG BUCK ADJ 2A 16MSOP RoHS:是 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 |
| LT3980IMSEPBF | 制造商:Linear Technology 功能描述:58V 2A 2.4MHz Buck Regulator 85uA MSOP16 |
| LT3988 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual 60V Monolithic 1A Step-Down Switching |
| LT3988EMSE#PBF | 功能描述:IC REG BUCK ADJ 1A DL 16-MSOP 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 |
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