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| 型号： | MAX8723ETE+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 15/18页 |
| 文件大小： | 0K |
| 描述： | IC REG FOR LCD DISPLAY 16-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 应用： | 转换器，LCD |
| 输入电压： | 6 V ~ 13.2 V |
| 输出数： | 1 |
| 输出电压： | 3.3V，2 V ~ 3.6 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WQFN 裸露焊盘 |
| 供应商设备封装： | 16-TQFN-EP（4x4） |
| 包装： | 带卷 (TR) |
Low-Cost, Internal-Switch, Step-Down
Regulator for LCD Displays
External MOSFET
To improve efficiency, an external synchronous rectifier
MOSFET can be driven by EXT. When this MOSFET is
used, the Schottky diode ’s current rating can be
reduced or the diode can be omitted entirely. Choose a
MOSFET with low R DS(ON). Ensure that EXT is not
pulled up by the internal high-side switch turning on
due to parasitic drain-to-gate capacitance, causing
cross-conduction problems. Switching losses are not
an issue for the synchronous rectifier in the step-down
topology, since it is a zero-voltage switched device.
Applications Information
Thermal Considerations
The MAX8723 has a built-in power MOSFET switch and
gate-driver circuits. Although the step-down regulator
operates with high efficiency, inevitably the IC internal
power circuits consume some power and heat the IC
up, especially under heavy-load conditions. To ensure
the best performance of the silicon, thermal manage-
ment is critical in the application.
The built-in low-side MOSFET is not dedicated for syn-
chronous rectifier application and has high on-resis-
tance. An external freewheeling device such as
Schottky diode or MOSFET is essential for the circuit
operation. Without this freewheeling device, the heat
generated by the built-in low-side MOSFET imperils the
MOSFET and the IC operation, especially under heavy-
load conditions such as 2A load.
The TQFN package provides an exposed metal pad on
the MAX8723 backside. This back pad also serves as
heat sink to the internal silicon circuitry, as well as a
ground substrate. Soldering the exposed backside pad
to a large copper plane on PC board can significantly
help to dissipate heat generated inside the IC.
Typically, the large copper plane is not available on the
component side of PC board. Place a large solder pad
under the IC with multiple vias connecting to a large
ground plane on another board layer and solder the IC
exposed back pad to this solder pad.
PC Board Layout and Grounding
Good layout is necessary to achieve the MAX8723’s
intended output power level, high efficiency, and low
noise. Good layout includes the use of ground planes,
careful component placement, and correct routing of
traces using appropriate trace widths. The following
points are in order of decreasing importance:
1) Minimize switched-current and high-current ground
loops. Connect the input capacitor’s ground, the out-
put capacitor ’s ground, and PGND together with
short, wide traces or a small ground plane. Connect
the resulting island to GND at only one point.
2) Connect the input filter capacitor less than 5mm
away from IN. Place INL pin and REF pin bypass
capacitors as close to the device as possible, no
more than 5mm. The ground connection of the INL
bypass capacitor should be connected directly to
the GND pin with a wide trace.
3) Connect high-current loop components with short,
wide connections. Avoid using vias in the high-cur-
rent paths. If vias are unavoidable, use many vias in
parallel to reduce resistance and inductance. The
connecting copper trace carries large currents and
must be at least 1mm wide, preferably 2.5mm.
4) Place the LX node components as close together
and as near to the device as possible. Minimize the
length of the LX node while keeping it wide and
short. This reduces resistive and switching losses,
as well as noise. Keep the LX node away from FB
feedback node and analog ground. Use inner layers
etc., as shield if necessary.
5) Place feedback voltage-divider resistors as close to
the FB feedback pin as possible. The divider’s cen-
ter trace should be kept short. Placing the resistors
far away causes the FB traces to become antennas
that can pick up switching noise. Care should be
taken to avoid running any feedback trace near LX.
6) Minimize the length and maximize the width of the
traces between the output capacitors and the load
for best transient responses.
7) Ground planes are essential for optimum perfor-
mance. In most applications, the circuit is located on
a multilayer board and full use of the four or more
layers is recommended. For heat dissipation, con-
nect the exposed backside pad to a large analog
ground plane, preferably on a surface of the board
that receives good airflow. If the ground is not locat-
ed on the IC component side of PC board, use multi-
ple vias to the IC backside pad to lower thermal
resistance. Typical applications use multiple ground
planes to reduce thermal resistance. Avoid large AC
currents through the analog ground plane.
Refer to the MAX8723 evaluation kit for an example of
proper board layout.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8723EVKIT | 功能描述:电源管理IC开发工具 MAX8723 Eval Kit RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| MAX8724AETI+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX8724ETI | 功能描述:电池管理 RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX8724ETI+ | 功能描述:电池管理 Multichemistry Battery Charger RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX8724ETI+T | 功能描述:电池管理 Multichemistry Battery Charger RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
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