- 您现在的位置：买卖IC网 > PDF目录1849 > MAX8744AETJ+T (Maxim Integrated Products)IC CNTRLR PWR SUP QUAD 32TQFN PDF资料下载
参数资料
| 型号： | MAX8744AETJ+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 33/36页 |
| 文件大小： | 0K |
| 描述： | IC CNTRLR PWR SUP QUAD 32TQFN |
| 标准包装： | 2,500 |
| 应用： | 控制器，笔记本电脑电源系统 |
| 输入电压： | 6 V ~ 26 V |
| 输出数： | 4 |
| 输出电压： | 3.3V，5V，1 V ~ 26 V |
| 工作温度： | 0°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-WFQFN 裸露焊盘 |
| 供应商设备封装： | 32-TQFN-EP（5x5） |
| 包装： | 带卷 (TR) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页当前第33页第34页第35页第36页
High-Efficiency, Quad-Output, Main Power-
Supply Controllers for Notebook Computers
V IN ( MIN ) = V OUT CHG + h ?
+ V
? 1 ? ( V OUT DIS )
+ V
? 1
? D MAX
?
?
PCB traces is a difficult task that must be
approached in terms of fractions of centimeters,
where a single milliohm of excess trace resistance
causes a measurable efficiency penalty.
where V CHG and V DIS are the parasitic voltage drops in
the charge and discharge paths, respectively. A rea-
sonable minimum value for h is 1.5, while the absolute
minimum input voltage is calculated with h = 1.
Maximum Input Voltage
The MAX8744A/MAX8745A controllers include a mini-
mum on-time specification, which determines the maxi-
mum input operating voltage that maintains the
selected switching frequency (see the Electrical
Characteristics table). Operation above this maximum
input voltage results in pulse-skipping operation,
regardless of the operating mode selected by SKIP . At
the beginning of each cycle, if the output voltage is still
above the feedback threshold voltage, the controller
does not trigger an on-time pulse, effectively skipping a
?
?
?
Minimize current-sensing errors by connecting
CSH_ and CSL_ directly across the current-sense
resistor (R SENSE_ ).
When trade-offs in trace lengths must be made, it is
preferable to allow the inductor charging path to be
made longer than the discharge path. For example,
it is better to allow some extra distance between the
input capacitors and the high-side MOSFET than to
allow distance between the inductor and the low-
side MOSFET or between the inductor and the out-
put filter capacitor.
Route high-speed switching nodes (BST_, LX_,
DH_, and DL_) away from sensitive analog areas
(REF, FB_, CSH_, CSL_).
V IN ( SKIP ) = V OUT ? ?
cycle. This allows the controller to maintain regulation
above the maximum input voltage, but forces the con-
troller to effectively operate with a lower switching fre-
quency. This results in an input threshold voltage at
which the controller begins to skip pulses (V IN(SKIP) ):
? 1 ?
? f OSC t ON ( MIN ) ?
where f OSC is the switching frequency selected by FSEL.
PCB Layout
Careful PCB layout is critical to achieving low switching
losses and clean, stable operation. The switching
power stage requires particular attention (Figure 9). If
possible, mount all the power components on the top
side of the board, with their ground terminals flush
against one another. Follow these guidelines for good
PCB layout:
Layout Procedure
Place the power components first, with ground termi-
nals adjacent (N L _ source, C IN , C OUT _, and D L _
anode). If possible, make all these connections on the
top layer with wide, copper-filled areas.
Mount the controller IC adjacent to the low-side MOSFET,
preferably on the back side opposite N L_ and N H_ to
keep LX_, GND, DH_, and the DL_ gate-drive lines short
and wide. The DL_ and DH_ gate traces must be short
and wide (50 mils to 100 mils wide if the MOSFET is 1in
from the controller IC) to keep the driver impedance low
and for proper adaptive dead-time sensing.
Group the gate-drive components (BST_ capacitor,
LDO5 bypass capacitor) together near the controller IC.
Make the DC-DC controller ground connections as
shown in Figures 1 and 9. This diagram can be viewed
as having two separate ground planes: power ground,
where all the high-power components go, and an ana-
?
?
Keep the high-current paths short, especially at the
ground terminals. This practice is essential for sta-
ble, jitter-free operation.
Keep the power traces and load connections short.
This practice is essential for high efficiency. Using
thick copper PCBs (2oz vs. 1oz) can enhance full-
load efficiency by 1% or more. Correctly routing
log ground plane for sensitive analog components. The
analog ground plane and power ground plane must
meet only at a single point directly at the IC.
Connect the output power planes directly to the output
filter capacitor positive and negative terminals with mul-
tiple vias. Place the entire DC-DC converter circuit as
close to the load as is practical.
______________________________________________________________________________________
33
相关PDF资料 |
PDF描述 |
|---|---|
| MAX8745ETJ+ | IC CNTRLR PWR SUP QUAD 32TQFN |
| MAX8751ETJ+T | IC CNTRLR CCFL INV 32-TQFN |
| MAX8752ETA+T | IC DC-DC CONV TFT LCD 8-TDFN |
| MAX8753ETI+T | IC DC-DC CONV TFT LCD 28TQFN |
| MAX8756ETI+T | IC CNTRL DUAL PS 28-TQFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8744AEVKIT+ | 制造商:Maxim Integrated Products 功能描述:MAX8744A EVAL KIT - Rail/Tube |
| MAX8744ETJ+ | 功能描述:电流型 PWM 控制器 Quad-Out Main Power Supply Controller RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX8744ETJ+T | 功能描述:电流和电力监控器、调节器 Quad-Out Main Power Supply Controller RoHS:否 制造商:STMicroelectronics 产品:Current Regulators 电源电压-最大:48 V 电源电压-最小:5.5 V 工作温度范围:- 40 C to + 150 C 安装风格:SMD/SMT 封装 / 箱体:HPSO-8 封装:Reel |
| MAX8744EVKIT | 制造商:Maxim Integrated Products 功能描述:HIGH-EFFICIENCY QUAD OUTPUT MAIN - Rail/Tube |
| MAX8744EVKIT+ | 制造商:Maxim Integrated Products 功能描述:HIGH-EFFICIENCY QUAD OUTPUT MAIN - Rail/Tube |
发布紧急采购，3分钟左右您将得到回复。