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参数资料
| 型号： | LT1976HFE#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 24/28页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 1.5A 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： | 1.2 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： | 1.5A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 150°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 |
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LT1976/LT1976B
APPLICATIO S I FOR ATIO
P Q = 40 ( ) + 5 ( ) = 0 . 08 W
Board layout also has a significant effect on thermal
resistance. Pin 8 and the exposed die pad, Pin 17, are a
continuous copper plate that runs under the LT1976 die.
This is the best thermal path for heat out of the package.
Reducing the thermal resistance from Pin 8 and exposed
pad onto the board will reduce die temperature and in-
crease the power capability of the LT1976. This is achieved
by providing as much copper area as possible around the
exposed pad. Adding multiple solder filled feedthroughs
under and around this pad to an internal ground plane will
also help. Similar treatment to the catch diode and coil
terminations will reduce any additional heating effects.
THERMAL CALCULATIONS
Power dissipation in the LT1976 chip comes from four
sources: switch DC loss, switch AC loss, boost circuit
current, and input quiescent current. The following formu-
las show how to calculate each of these losses. These
formulas assume continuous mode operation, so they
should not be used for calculating efficiency at light load
currents.
Example: with V IN = 40V, V OUT = 5V and I OUT = 1A:
P SW = ( 0 . 3 )( 1 ) 2 ( 5 ) + ( 97 e – 9 ) ( 1 / 2 ) ( 1 )( 40 )( 200 e 3 )
40
0 . 04 + 0 . 388 = 0 . 43 W
P BOOST = ( 5 ) 2 ( 1 / 36 ) = 0 . 02 W
40
0 . 0015 0 . 003
Total power dissipation is:
P TOT = 0.43 + 0.02 + 0.08 = 0.53W
Thermal resistance for the LT1976 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 )
R SW ( I OUT ) ( V OUT )
Switch loss:
2
P SW =
V IN
Boost current loss:
+ t EFF ( 1 / 2 )( I OUT )( V IN )( f )
With the FE16 package (Q JA = 45 ° C/W) at an ambient
temperature of 70 ° C:
T J = 70 + 45(0.53) = 94 ° C
If a more accurate die temperature is required, a measure-
ment of the SYNC pin resistance to ground can be used.
P BOOST
=
( V OUT ) 2 ( I OUT / 36 )
V IN
The SYNC pin resistance can be measured by forcing a
voltage no greater than 0.25V at the pin and monitoring the
pin current versus temperature in a controlled temperature
Quiescent current loss: (LT1976)
P Q = V IN (0.0015) + V OUT (0.003)
R SW = switch resistance ( ≈ 0.3 when hot )
environment. The measurement should be done with
minimal device power dissipation (pull the V C pin to
ground for sleep mode) in order to calibrate the SYNC pin
resistance with the ambient temperature.
t EFF = effective switch current/voltage overlap time
(t r + t f + t IR + t IF )
t r = (V IN /1.7)ns
t f = (V IN /1.2)ns
t IR = t IF = (I OUT /0.05)ns
f = switch frequency
1976bfg
24
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1976IFE | 功能描述:IC REG BUCK ADJ 1.5A 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 |
| LT1976IFE#PBF | 功能描述:IC REG BUCK ADJ 1.5A 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 |
| LT1976IFE#PBF | 制造商:Linear Technology 功能描述:DC/DC Converter IC |
| LT1976IFE#TR | 功能描述:IC REG BUCK ADJ 1.5A 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 |
| LT1976IFE#TRPBF | 功能描述:IC REG BUCK ADJ 1.5A 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 |
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