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| 型号： | LT3681EDE#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 10/24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： | 1.27 V ~ 20 V |
| 输入电压： | 3.6 V ~ 34 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 300kHz ~ 2.8MHz |
| 电流 - 输出： | 2A |
| 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： | 14-WFDFN 裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 14-DFN-EP（4x3） |
| 产品目录页面： | 1332 (CN2011-ZH PDF) |
LT3681
APPLICATIONS INFORMATION
L = ? OUT D ? ? 1– OUT D ?
frequency will be necessary to achieve safe operation at
high input voltages.
If the output is in regulation and no short-circuit or start-up
events are expected, then input voltage transients of up to
36V are acceptable regardless of the switching frequency.
In this mode, the LT3681 may enter pulse skipping opera-
tion where some switching pulses are skipped to maintain
output regulation. In this mode the output voltage ripple
and inductor current ripple will be higher than in normal
operation.
The minimum input voltage is determined by either the
LT3681’s minimum operating voltage of ~3.6V or by its
maximum duty cycle (see equation in previous section).
The minimum input voltage due to duty cycle is:
at least 3.5A at low duty cycles and decreases linearly to
2.5A at DC = 0.8. The maximum output current is a func-
tion of the inductor ripple current:
I OUT(MAX) = I LIM – Δ I L /2
Be sure to pick an inductor ripple current that provides
suf?cient maximum output current (I OUT(MAX) ).
The largest inductor ripple current occurs at the highest
V IN . To guarantee that the ripple current stays below the
speci?ed maximum, the inductor value should be chosen
according to the following equation:
? ?
? V + V ? ? V + V ?
? f ? I L ? ? V IN ( MAX ) ?
V IN ( MIN ) =
V OUT + V D
1– f SW t OFF ( MIN )
– V D + V SW
where V D is the voltage drop of the integrated Schottky
diode (~0.55V), V IN(MAX) is the maximum input voltage,
V OUT is the output voltage, f SW is the switching frequency
where V IN(MIN) is the minimum input voltage, and t OFF(MIN)
is the minimum switch off time (150ns). Note that higher
switching frequency will increase the minimum input
voltage. If a lower dropout voltage is desired, a lower
switching frequency should be used.
Inductor Selection
For a given input and output voltage, the inductor value
and switching frequency will determine the ripple current.
The ripple current Δ I L increases with higher V IN or V OUT
and decreases with higher inductance and faster switch-
(set by RT), and L is in the inductor value.
The inductor’s RMS current rating must be greater than the
maximum load current and its saturation current should be
about 30% higher. For robust operation in fault conditions
(start-up or short circuit) and high input voltage (>30V),
the saturation current should be above 3.5A. To keep the
ef?ciency high, the series resistance (DCR) should be less
than 0.1 Ω , and the core material should be intended for
high frequency applications. Table 1 lists several vendors
and suitable types.
Table 1. Inductor Vendors
ing frequency. A reasonable starting point for selecting
the ripple current is:
Δ I L = 0.4(I OUT(MAX) )
where I OUT(MAX) is the maximum output load current. To
guarantee suf?cient output current, peak inductor current
must be lower than the LT3681’s switch current limit (I LIM ).
The peak inductor current is:
I L(PEAK) = I OUT(MAX) + Δ I L /2
where I L(PEAK) is the peak inductor current, I OUT(MAX) is
the maximum output load current, and Δ I L is the inductor
VENDOR
Murata
TDK
Toko
Sumida
NEC
URL
www.murata.com
www.componenttdk.com
www.toko.com
www.sumida.com
www.nec.tokin.com
PART SERIES
LQH55D
SLF7045
SLF10145
D75C
D75F
FDV0620
CDRH74
CDRH6D38
CR75
CDRH8D43
PLC-0745
TYPE
Open
Shielded
Shielded
Shielded
Open
Shielded
Shielded
Shielded
Open
Shielded
Shielded
ripple current. The LT3681’s switch current limit (I LIM ) is
3681f
10
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3682 | 制造商:LINER 制造商全称:Linear Technology 功能描述:42V, 750mA Step-Down Regulator with 2.5μA |
| LT3682EDD#PBF | 功能描述:IC REG BUCK ADJ 1A 12DFN 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 |
| LT3682EDD#TRPBF | 功能描述:IC REG BUCK ADJ 1A 12DFN 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:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
| LT3682EDD-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:1A Micropower Step-Down |
| LT3682EDD-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:1A Micropower Step-Down |
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