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参数资料
| 型号： | LTC3542ES6#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 12/16页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ TSOT23-6 |
| 标准包装： | 2,500 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.6 V ~ 5.5 V |
| 输入电压： | 2.5 V ~ 5.5 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 2.25MHz |
| 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： | SOT-23-6 细型，TSOT-23-6 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | TSOT-23-6 |
LTC3542
APPLICATIONS INFORMATION
parallel with C OUT , causing a rapid drop in V OUT . No regula-
tor can deliver enough current to prevent this problem, if
the switch connecting the load has low resistance and is
driven quickly. The solution is to limit the turn-on speed of
the load switch driver. A Hot Swap TM controller is designed
speci?cally for this purpose and usually incorporates cur-
rent limit, short circuit protection and soft-start.
C IN will require an RMS current rating of at least
0.25A ? I LOAD(MAX) /2 at temperature and C OUT will require
ESR of less than 0.2 Ω . In most cases, ceramic capacitors
will satisfy these requirements. Select C OUT = 10μF and
C IN = 10μF.
For the feedback resistors, choose R1 = 75k, R2 can be
calculated from:
R 2 = ? OUT – 1 ? ? R 1 = ?
– 1 ? ? 75 k = 150k
Design Example
As a design example, assume the LTC3542 is used in a single
? V ? ? 1. 8 V
? 0 . 6 V ? ? 0 . 6 V
?
?
? V OUT ? ? 1 – OUT ?
L =
lithium-ionbattery-poweredcellularphoneapplication.The
V IN will be operating from a maximum of 4.2V down to
about 2.7V. The load current requirement is a maximum
of 0.5A, but most of the time it will be in standby mode,
requiring only 2mA. Ef?ciency at both low and high load
currents is important. Output voltage is 1.8V.
With this information we can calculate L using:
1 ? V ?
f ? Δ I L ? V IN ?
Substituting V OUT = 1.8V, V IN = 4.2V, Δ I L = 200mA and
f = 2.25MHz gives:
Figure 3 shows the complete circuit along with its ef?ciency
curve, load step response and recommended layout
PC Board Layout Checklist
When laying out the printed circuit board, the following
checklist should be used to ensure proper operation of
the LTC3542. These items are also illustrated graphically
in Figure 3b. Check the following in your layout:
1. The power traces, consisting of the GND trace, the SW
trace and the V IN trace should be kept short, direct and
wide.
? ? 1 –
L =
1 . 8 V ?
2 . 25 MHz ? 200 mA ?
1 .8 V ?
4 . 2 V ? ?
= 2 . 28 μH
2. Does the V FB pin connect directly to the feedback re-
sistors? The resistive divider R1/R2 must be connected
between the (+) plate of C OUT and ground.
Choosing a vendor’s closest inductor value of 2.2μH results
in a maximum ripple current of:
3. Does the (+) plate of C IN connect to V IN as closely as
possible? This capacitor provides the AC current to the
? ? 1 –
Δ I L =
1 . 8 V ?
2 . 25 MHz ? 2 . 2 μH ?
1 . 8 V ?
4 . 2 V ? ?
= 207 .88mA
internal power MOSFETs.
4. Keep the (–) plates of C IN and C OUT as close as pos-
sible.
5. Keep the switching node, SW, away from the sensitive
V FB node.
Hot Swap is a trademark of Linear Technology Corporation.
3542fa
12
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相关代理商/技术参数 |
参数描述 |
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| LTC3542IDC#TRMPBF | 功能描述:IC REG BUCK SYNC ADJ 0.5A 6DFN 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: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 |
| LTC3542IDC#TRPBF | 功能描述:IC REG BUCK SYNC ADJ 0.5A 6DFN 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: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 |
| LTC3542IDC-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA, 2.25MHz Synchronous Step-Down DC/DC Converter |
| LTC3542IDC-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA, 2.25MHz Synchronous Step-Down DC/DC Converter |
| LTC3542IS6#PBF | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 2.5V to 5.5V 6-Pin TSOT-23 制造商:Linear Technology 功能描述:DP-SWREG/Monolithic, Cut Tape 500mA, 2.25MHz Synchronous Step-Down DC/DC Convert |
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