参数资料
| 型号： | LT3479EDE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 9/20页 |
| 文件大小： | 0K |
| 描述： | IC REG BOOST INV ADJ 3A 14DFN |
| 标准包装： | 2,500 |
| 类型： | 升压（升压），反相 |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1.24 V ~ 42 V |
| 输入电压： | 2.5 V ~ 24 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 200kHz ~ 3.5MHz |
| 电流 - 输出： | 3A |
| 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： | 带卷 (TR) |
| 供应商设备封装： | 14-DFN-EP（4x3） |
LT3479
APPLICATIONS INFORMATION
V OUT = – 1 . 235 V ?
? R 4 ?
Diode Selection
Schottky diodes, with their low forward voltage drop and
fast switching speed, are ideal for LT3479 applications.
Table 3 lists several Schottky diodes that work well with the
LT3479. The diode’s average current rating must exceed
the average output current. The diode’s maximum reverse
voltage must exceed the output voltage. The diode conducts
Setting Negative Output Voltages
To set a negative output voltage, select the values of R3 and
R4 (see Figure 3) according to the following equation:
? R 3 ?
?
–V OUT
current only when the power switch is turned off (typically
less than 50% duty cycle), so a 3A diode is suf?cient for
most designs. The companies below also offer Schottky
diodes with high voltage and current ratings.
Table 3. Suggested Diodes
LT3479
FBP
V REF
FBN
R3
R4
MANUFACTURER
PART NUMBER
MAX
CURRENT (A)
MAX REVERSE
VOLTAGE (V) MANUFACTURER
3479 F03
UPS340
UPS315
B220
B230
B240
B320
B330
B340
SBM340
3
3
2
2
2
3
3
3
3
40
15
20
30
40
20
30
40
40
Microsemi
www.microsemi.com
Diodes, Inc
www.diodes.com
Figure 3. Negative Output Voltage Feedback Connections
Board Layout
As with all switching regulators, careful attention must
be paid to the PCB board layout and component place-
ment. To maximize ef?ciency, switch rise and fall times
are made as short as possible. To prevent radiation and
Setting Positive Output Voltages
To set a positive output voltage, select the values of R1 and
R2 (see Figure 2) according to the following equation:
high frequency resonance problems, proper layout of the
high frequency switching path is essential. Minimize the
length and area of all traces connected to the SW pin and
always use a ground plane under the switching regulator
V OUT = 1 . 235 V ? 1 +
R 2 ?
?
?
R 1 ?
?
to minimize interplane coupling. The signal path including
the switch, output diode D1 and output capacitor C OUT ,
contains nanosecond rise and fall times and should be
kept as short as possible. Recommended component
placement is shown in Figure 4.
FBP
LT3479
V REF
FBN
V OUT
R1
R2
Soft-Start
For many applications, it is necessary to minimize the
inrush current at start-up. The built-in soft-start circuit
signi?cantly reduces the start-up current spike and output
3479 F02
Figure 2. Positive Output Voltage Feedback Connections
voltage overshoot. A typical value is 10nF for 1.65ms.
Figure 5 shows the start-up output voltage and induc-
tor current waveforms in a typical application without a
soft-start capacitor. Notice the output voltage overshoot
and the large initial current. The addition of a 22nF capaci-
tor eliminates the output overshoot and reduces the peak
inductor current (Figure 6).
3479fc
9
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相关代理商/技术参数 |
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| LT3479EFE | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Up 2.5V to 24V 16-Pin TSSOP EP |
| LT3479EFE#PBF | 功能描述:IC REG BOOST INV ADJ 3A 16TSSOP 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 |
| LT3479EFE#TR | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Up 2.5V to 24V 16-Pin TSSOP EP T/R |
| LT3479EFE#TRPBF | 功能描述:IC REG BOOST INV ADJ 3A 16TSSOP 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 |
| LT3479EFEPBF | 制造商:Linear Technology 功能描述:3A, 42V 3MHz Step-Up Regulator LT3479EFE |
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