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参数资料
| 型号： | LT3434EFE |
| 厂商： | Linear Technology |
| 文件页数： | 21/24页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 3A 16TSSOP |
| 标准包装： | 95 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1.25 V ~ 54 V |
| 输入电压： | 3.3 V ~ 60 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 200kHz |
| 电流 - 输出： | 3A |
| 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： | 16-TSSOP（0.173"，4.40mm）裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 16-TSSOP-EP |
LT3434
APPLICATIO S I FOR ATIO
Example: with V IN = 40V, V OUT = 5V and I OUT = 2A:
ing increase in internal dissipation is of insufficient time
( 0 . 15 )( 2 ) ( 5 ) +
P SW
=
40
2
( 77 e – 9 ) ( 1 / 2 ) ( 2 )( 40 ) ( 200 e 3 )
duration to raise die temperature significantly.
A second consideration is controllability. A potential limi-
tation occurs with a high step-down ratio of V IN to V OUT ,
0 . 08 + 0 . 62 = 0 . 7
P BOOST = ( 5 ) 2 ( 2 /40 ) = 0 . 03
40
P Q = 40 ( 0 . 0026 ) + 5 ( 0 . 001 ) = 0 . 109
Total power dissipation is:
P TOT = 0.7 + 0.03 + 0.109 = 0.84
Thermal resistance for the LT3434 package is influenced
by the presence of internal or backside planes. With a full
plane under the FE16 package, thermal resistance will be
about 45 ° C/W. No plane will increase resistance to about
150 ° C/W. To calculate die temperature, use the proper
thermal resistance number for the desired package and
add in worst-case ambient temperature:
T J = T A + Q JA (P TOT )
With the FE16 package (Q JA = 45 ° C/W) at an ambient
temperature of 70 ° C:
T J = 70 + 45(0.84) = 108 ° C
Input Voltage vs Operating Frequency Considerations
The absolute maximum input supply voltage for the LT3434
is specified at 60V. This is based solely on internal semi-
conductor junction breakdown effects. Due to internal
power dissipation the actual maximum V IN achievable in a
particular application may be less than this.
A detailed theoretical basis for estimating internal power
loss is given in the section Thermal Considerations. Note
that AC switching loss is proportional to both operating
frequency and output current. The majority of AC switch-
ing loss is also proportional to the square of input voltage.
For example, while the combination of V IN = 40V, V OUT =
5V at 2A and f OSC = 200kHz may be easily achievable,
simultaneously raising V IN to 60V and f OSC to 700kHz is
not possible. Nevertheless, input voltage transients up to
60V can usually be accommodated, assuming the result-
as this requires a correspondingly narrow minimum switch
on time. An approximate expression for this (assuming
continuous mode operation) is given as follows:
t ON(MIN) = V OUT + V F /V IN (f OSC )
where:
V IN = input voltage
V OUT = output voltage
V F = Schottky diode forward drop
f OSC = switching frequency
A potential controllability problem arises if the LT3434 is
called upon to produce an on time shorter than its typical
value of 250ns. Feedback loop action will lower then
reduce the V C control voltage to the point where some sort
of cycle-skipping or Burst Mode behavior is exhibited.
In summary:
1. Be aware that the simultaneous requirements of high
V IN , high I OUT and high f OSC may not be achievable in
practice due to internal dissipation. The Thermal Con-
siderations section offers a basis to estimate internal
power. In questionable cases a prototype supply should
be built and exercised to verify acceptable operation.
2. The simultaneous requirements of high V IN , low V OUT
and high f OSC can result in an unacceptably short
minimum switch on time. Cycle skipping and/or Burst
Mode behavior will result although correct output volt-
age is usually maintained.
FREQUENCY COMPENSATION
Before starting on the theoretical analysis of frequency
response the following should be remembered—the worse
the board layout, the more difficult the circuit will be to
stabilize. This is true of almost all high frequency analog
circuits. Read the Layout Considerations section first.
Common layout errors that appear as stability problems
are distant placement of input decoupling capacitor and/or
3434fb
21
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| LT3434EFE#PBF | 功能描述:IC REG BUCK 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 |
| LT3434EFE#TR | 功能描述:IC REG BUCK ADJ 3A 16TSSOP RoHS:否 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 |
| LT3434EFE#TRPBF | 功能描述:IC REG BUCK 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:- 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 |
| LT3434EFEPBF | 制造商:Linear Technology 功能描述:LT3434 adj 3A Buck SD dc-dc converter |
| LT3434IFE | 功能描述:IC REG BUCK ADJ 3A 16TSSOP RoHS:否 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 |
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