参数资料
| 型号： | LT3493IDCB#TRMPBF |
| 厂商： | Linear Technology |
| 文件页数： | 10/20页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 1.2A 6DFN |
| 标准包装： | 500 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.78 V ~ 34.2 V |
| 输入电压： | 3.6 V ~ 36 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 750kHz |
| 电流 - 输出： | 1.2A |
| 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： | 6-WFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 6-DFN-EP（2x3） |
LT3493
APPLICATIONS INFORMATION
Table 1. Inductor Values
VENDOR
URL
PART SERIES
INDUCTANCE RANGE (μH) SIZE (MM)
Sumida
Toko
Würth Elektronik
www.sumida.com
www.toko.com
www.we-online.com
CDRH4D28
CDRH5D28
CDRH8D28
A916CY
D585LC
WE-TPC(M)
WE-PD2(M)
WE-PD(S)
1.2 to 4.7
2.5 to 10
2.5 to 33
2 to 12
1.1 to 39
1 to 10
2.2 to 22
1 to 27
4.5 × 4.5
5.5 × 5.5
8.3 × 8.3
6.3 × 6.2
8.1 × 8.0
4.8 × 4.8
5.2 × 5.8
7.3 × 7.3
Input Capacitor
Bypass the input of the LT3493 circuit with a 1μF or
higher value ceramic capacitor of X7R or X5R type. Y5V
types have poor performance over temperature and ap-
plied voltage and should not be used. A 1μF ceramic is
adequate to bypass the LT3493 and will easily handle the
ripple current. However, if the input power source has
high impedance, or there is signi?cant inductance due to
long wires or cables, additional bulk capacitance may be
necessary. This can be provided with a low performance
electrolytic capacitor.
Step-down regulators draw current from the input sup-
ply in pulses with very fast rise and fall times. The input
capacitor is required to reduce the resulting voltage
ripple at the LT3493 and to force this very high frequency
switching current into a tight local loop, minimizing EMI.
A 1μF capacitor is capable of this task, but only if it is
placed close to the LT3493 and the catch diode; see the
PCB Layout section. A second precaution regarding the
ceramic input capacitor concerns the maximum input
voltage rating of the LT3493. A ceramic input capacitor
combined with trace or cable inductance forms a high
quality (underdamped) tank circuit. If the LT3493 circuit
is plugged into a live supply, the input voltage can ring to
twice its nominal value, possibly exceeding the LT3493’s
voltage rating. This situation is easily avoided; see the Hot
Plugging Safely section.
Output Capacitor
The output capacitor has two essential functions. Along
with the inductor, it ?lters the square wave generated
by the LT3493 to produce the DC output. In this role it
determines the output ripple so low impedance at the
switching frequency is important. The second function
is to store energy in order to satisfy transient loads and
stabilize the LT3493’s control loop.
Ceramic capacitors have very low equivalent series re-
sistance (ESR) and provide the best ripple performance.
A good value is:
C OUT = 65/V OUT
where C OUT is in μF. Use X5R or X7R types and keep in
mind that a ceramic capacitor biased with V OUT will have
less than its nominal capacitance. This choice will provide
low output ripple and good transient response. Transient
performance can be improved with a high value capacitor,
but a phase lead capacitor across the feedback resistor
R1 may be required to get the full bene?t (see the Com-
pensation section).
For small size, the output capacitor can be chosen ac-
cording to:
C OUT = 25/V OUT
where C OUT is in μF. However, using an output capacitor
this small results in an increased loop crossover frequency
and increased sensitivity to noise. A 22pF capacitor con-
nected between V OUT and the FB pin is required to ?lter
noise at the FB pin and ensure stability.
High performance electrolytic capacitors can be used for
the output capacitor. Low ESR is important, so choose one
that is intended for use in switching regulators. The ESR
should be speci?ed by the supplier and should be 0.1Ω
or less. Such a capacitor will be larger than a ceramic
capacitor and will have a larger capacitance, because the
3493fb
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相关代理商/技术参数 |
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|---|---|
| LT3493IDCB-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:1.2A, 750kHz Step-Down Switching Regulator in 2mm × 3mm DFN |
| LT3494 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Micropower Low Noise Boost Converters with Output Disconnect |
| LT3494A | 制造商:LINER 制造商全称:Linear Technology 功能描述:20mA LED Driver and OLED Driver with Integrated Schottky in 3mm x 2mm DFN |
| LT3494AEDDB | 制造商:LINER 制造商全称:Linear Technology 功能描述:Micropower Low Noise Boost Converters with Output Disconnect |
| LT3494AEDDB#PBF | 制造商:Linear Technology 功能描述:BOOST 2.3 - 16V 0.35A 40V 制造商:Linear Technology 功能描述:BOOST, 2.3 - 16V, 0.35A, 40V, 20QFN |
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