参数资料
型号: LT3837IFE#TRPBF
厂商: LINEAR TECHNOLOGY CORP
元件分类: 稳压器
英文描述: SWITCHING CONTROLLER, 110 kHz SWITCHING FREQ-MAX, PDSO16
封装: 4.40 MM, LEAD FREE, PLASTIC, TSSOP-16
文件页数: 17/28页
文件大小: 247K
代理商: LT3837IFE#TRPBF
LT3837
24
3837fc
APPLICATIONS INFORMATION
IC Thermal Considerations
Take care to ensure that the LT3837 junction temperature
does not exceed 125°C. Power is computed from the aver-
age supply current, the sum of quiescent supply current
(ICC in the specications) plus gate drive currents.
The primary gate drive current is computed as:
fOSC QG
where QG is the total gate charge at max VGS (obtained from
the gate charge curve) and f is the switching frequency.
Since the synchronous driver is usually driving a capacitive
load, the power dissipation is:
fOSC CS VSGMAX
where CS is the SG capacitive load and VSGMAX is the SG
pin max voltage.
So total IC dissipation is computed as:
PD(TOTAL) = VCC (ICC + f (QGPRI + CS VSGMAX))
VCC is the worst-case LT3837 supply voltage.
Junction temperature is computed as:
TJ = TA + PD θJA
where:
TA is the ambient temperature
θJA is the FE16 package junction-to-ambient thermal
impedance (40°C/W).
PC Board Layout Considerations
In order to minimize switching noise and improve output
load regulation, connect the GND pin of the LT3837 directly
to the ground terminal of the VCC decoupling capacitor,
the bottom terminal of the current sense resistor, the
ground terminal of the input capacitor, and the ground
plane (multiple vias). Place the VCC capacitor immediately
adjacent to the VCC and GND pins on the IC package.
This capacitor carries high di/dt MOSFET gate drive cur-
rents. Use a low ESR ceramic capacitor.
Take care in PCB layout to keep the traces that conduct high
switching currents short, wide and with minimal overall
loop area. These are typically the traces associated with
the switches. This reduces the parasitic inductance and
also minimizes magnetic eld radiation. Figure 9 outlines
the critical paths.
Keep electric eld radiation low by minimizing the length
and area of traces (keep stray capacitances low). The drain
of the primary side MOSFET is the worst offender in this
category. Always use a ground plane under the switcher
circuitry to prevent coupling between PCB planes.
Check that the maximum BVDSS ratings of the MOSFETs
are not exceeded due to inductive ringing. This is done by
viewing the MOSFET node voltages with an oscilloscope. If
it is breaking down either choose a higher voltage device,
add a snubber or specify an avalanche-rated MOSFET.
Place the small-signal components away from high fre-
quency switching nodes. This allows the use of a pseudo-
Kelvin connection for the signal ground, where high di/dt
gate driver currents ow out of the IC ground pin in one
direction (to the bottom plate of the VCC decoupling
capacitor) and small-signal currents ow in the other
direction.
Keep the trace from the feedback divider tap to the FB
short to preclude inadvertent pickup.
For applications with multiple switching power converters
connected to the same input supply, make sure that the
input lter capacitor for the LTC3837 is not shared with
other converters. AC input current from another converter
could cause substantial input voltage ripple and this could
interfere with the LT3837 operation. A few inches of PC
trace or wire (L
100nH) between the CIN of the LT3837
and the actual source VIN is sufcient to prevent current
sharing problems.
相关PDF资料
PDF描述
LT3845AMPFE#TRPBF SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO16
LT3845AIFE#TRPBF SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO16
LT3845AMPFE#PBF SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO16
LT3845EFE#TR SWITCHING CONTROLLER, 600 kHz SWITCHING FREQ-MAX, PDSO16
LT3956IUHE#TRPBF SWITCHING REGULATOR, PQCC36
相关代理商/技术参数
参数描述
LT383L313 制造商:未知厂家 制造商全称:未知厂家 功能描述:Optoelectronic
LT3844 制造商:LINER 制造商全称:Linear Technology 功能描述:High Voltage, Current Mode Switching Regulator Controller with Programmable Operating Frequency
LT3844EFE 制造商:LINER 制造商全称:Linear Technology 功能描述:High Voltage, Current Mode Switching Regulator Controller with Programmable Operating Frequency
LT3844EFE#PBF 功能描述:IC REG CTRLR BST INV PWM 16TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR
LT3844EFE#TRPBF 功能描述:IC REG CTRLR BST INV PWM 16TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR)