参数资料
| 型号： | LT1936HMS8E#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 14/20页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 1.4A 8MSOP |
| 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： | 1.2 V ~ 31.3 V |
| 输入电压： | 3.6 V ~ 36 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 500kHz |
| 电流 - 输出： | 1.4A |
| 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： | 8-TSSOP，8-MSOP（0.118"，3.00mm 宽）裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 8-MSOP-EP |
LT1936
APPLICATIONS INFORMATION
the SHDN pin, the SW pin current will drop to essentially
zero. However, if the V IN pin is grounded while the output
is held high, then parasitic diodes inside the LT1936 can
MINIMIZE
LT1936
C2, D1 LOOP
IN
C2
GND
R4
pull large currents from the output through the SW pin
and the V IN pin. Figure 6 shows a circuit that will run only
when the input voltage is present and that protects against
a shorted or reversed input.
D2
C3
D4
MBRS140
D1
R2
R1
V IN
V IN
BOOST
L1
C1
LT1936
SHDN
V C
SW
V OUT
OUT
GND
COMP GND FB
VIAS
1936 F07
BACKUP
1936 F06
Figure 6. Diode D4 Prevents a Shorted Input from Discharging
a Backup Battery Tied to the Output; It Also Protects the Circuit
from a Reversed Input. The LT1936 Runs Only When the Input
is Present
PCB Layout
For proper operation and minimum EMI, care must be
taken during printed circuit board layout. Figure 7 shows
the recommended component placement with trace,
ground plane and via locations. Note that large, switched
currents ?ow in the LT1936’s V IN and SW pins, the catch
diode (D1) and the input capacitor (C2). The loop formed
by these components should be as small as possible. These
components, along with the inductor and output capacitor,
should be placed on the same side of the circuit board,
and their connections should be made on that layer. Place
a local, unbroken ground plane below these components.
The SW and BOOST nodes should be as small as possible.
Finally, keep the FB and V C nodes small so that the ground
traces will shield them from the SW and BOOST nodes.
The Exposed Pad on the bottom of the package must be
soldered to ground so that the pad acts as a heat sink. To
keep thermal resistance low, extend the ground plane as
much as possible, and add thermal vias under and near
Figure 7. A Good PCB Layout Ensures Low EMI Operation
High Temperature Considerations
The die temperature of the LT1936 must be lower than the
maximum rating of 125°C (150°C for the H grade). This is
generally not a concern unless the ambient temperature
is above 85°C. For higher temperatures, care should be
taken in the layout of the circuit to ensure good heat sink-
ing of the LT1936. The maximum load current should be
derated as the ambient temperature approaches 125°C
(150°C for the H grade).
The die temperature is calculated by multiplying the LT1936
power dissipation by the thermal resistance from junction
to ambient. Power dissipation within the LT1936 can be
estimated by calculating the total power loss from an
ef?ciency measurement and subtracting the catch diode
loss. The resulting temperature rise at full load is nearly
independent of input voltage. Thermal resistance depends
on the layout of the circuit board, but values from 40°C/W
to 60°C/W are typical.
Die temperature rise was measured on a 4-layer, 5cm ×
6.5cm circuit board in still air at a load current of 1.4A.
For 12V input to 3.3V output the die temperature elevation
above ambient was 26°C; for 24V in to 3.3V out the rise
was 31°C; for 12V in to 5V the rise was 31°C and for 24V
in to 5V the rise was 34°C.
the LT1936 to additional ground planes within the circuit
board and on the bottom side.
1936fd
14
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| LT1936IMS8E | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 3.6V to 36V 8-Pin MSOP EP |
| LT1936IMS8E#PBF | 功能描述:IC REG BUCK ADJ 1.4A 8MSOP 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 |
| LT1936IMS8E#TRPBF | 功能描述:IC REG BUCK ADJ 1.4A 8MSOP 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 |
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| LT1936IMS8E-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:1.4A, 500kHz Step-Down Switching Regulator |
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