- 您现在的位置：买卖IC网 > PDF目录5145 > MAX8506ETE+T (Maxim Integrated Products)IC DC-DC CONV PWM 16-TQFN PDF资料下载
参数资料
| 型号： | MAX8506ETE+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 7/11页 |
| 文件大小： | 0K |
| 描述： | IC DC-DC CONV PWM 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，WCDMA |
| 输入电压： | 2.6 V ~ 5.5 V |
| 输出数： | 1 |
| 输出电压： | 0.4 V ~ 3.4 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) |
PWM Step-Down DC-DC Converters with 75m ?
Bypass FET for WCDMA and cdmaOne Handsets
PWM Control
The MAX8506/MAX8507/MAX8508 use a fixed-frequen-
cy, current-mode and PWM controller capable of achiev-
ing 100% duty cycle. Current-mode feedback provides
cycle-by-cycle current limiting and superior load and line
response, as well as overcurrent protection for the inter-
nal MOSFET and rectifier. A comparator at the P-channel
MOSFET switch detects overcurrent at 1.25A.
During PWM operation, the MAX8506/MAX8507/
MAX8508 regulate the output voltage by switching at a
constant frequency and then modulating the duty cycle
with PWM control. The error-amp output, the main
switch current-sense signal, and the slope-compensa-
tion ramp are all summed using a PWM comparator.
The comparator modulates the output power by adjust-
ing the peak inductor current during the first half of
each cycle based on the output-error voltage. The
MAX8506/MAX8507/MAX8508 have relatively low AC
loop gain coupled with a high-gain integrator to enable
the use of a small and low-valued output filter capaci-
tor. The resulting load regulation is 0.1% at 0 to 600mA.
Normal-Mode Operation
Connecting SKIP to GND enables normal operation. This
allows automatic PWM control at medium and heavy
loads and skip mode at light loads to improve efficiency
and reduce quiescent current to 180μA. Operating in
normal mode allows the MAX8506/MAX8507/MAX8508
to pulse skip when the peak inductor current drops
below 90mA. During skip operation, the MAX8506/
MAX8507/MAX8508 switch only as needed to service
the load, reducing the switching frequency and associat-
ed losses in the internal switch and synchronous rectifier.
There are three steady-state operating conditions for
the MAX8506/MAX8507/MAX8508 in normal mode:
1) The device performs in continuous conduction for
heavy loads in a manner identical to forced-PWM
mode. 2) The inductor current becomes discontinuous
at medium loads, requiring the synchronous rectifier to
be turned off before the end of a cycle as the inductor
current reaches zero. 3) The device enters into skip
mode when the converter output voltage exceeds its
regulation limit before the inductor current reaches its
skip threshold level.
During skip mode, a switching cycle initiates when the
output voltage has dropped out of regulation. The P-
channel MOSFET switch turns on and conducts current
to the output-filter capacitor and load until the inductor
current reaches the pulse-skipping current threshold.
Then the main switch turns off and the magnetic field in
the inductor collapses while current flows through the
synchronous rectifier to the output filter capacitor and
the load. The synchronous rectifier is turned off when
the inductor current reaches zero. The MAX8506/
MAX8507/MAX8508 wait until the skip comparator
senses a low output voltage again.
Forced-PWM Operation
Connect SKIP to BATT for forced-PWM operation.
Forced-PWM operation is desirable in sensitive RF and
data-acquisition applications to ensure that switching
harmonics do not interfere with sensitive IF and data-
sampling frequencies. A minimum load is not required
during forced-PWM operation since the synchronous
rectifier passes reverse-inductor current as needed to
allow constant-frequency operation with no load. Forced-
PWM operation uses higher supply current with no load
(1.75mA typ) compared to skip mode (180μA typ).
100% Duty-Cycle Operation and Dropout
The maximum on-time can exceed one internal oscilla-
tor cycle, which permits operation at 100% duty cycle.
Near dropout, cycles can be skipped, reducing switch-
ing frequency. However, voltage ripple remains small
because the current ripple is still low. As the input volt-
age drops even further, the duty cycle increases until
the internal P-channel MOSFET stays on continuously.
Dropout voltage at 100% duty cycle is the output cur-
rent multiplied by the sum of the internal PMOS on-
resistance (400m ? typ) and the inductor resistance.
For lower dropout, use the high-power bypass mode
(75m ? typ).
High-Power Bypass Mode
A high-power bypass mode is available for use when a
PA transmits at high power. This mode connects OUT
to BATT through the bypass PFET. Additionally, the
PWM buck converter is forced into 100% duty cycle to
further reduce dropout. The dropout in the bypass
PFET equals the load current multiplied by the on-resis-
tance (75 ? typ) in parallel with the buck converter and
inductor dropout resistance.
Undervoltage Lockout (UVLO)
The MAX8506/MAX8507/MAX8508 do not operate with
battery voltages below the UVLO threshold of 2.35V
(typ). The output remains off until the supply voltage
exceeds the UVLO threshold. This guarantees the
integrity of the output voltage regulation.
_______________________________________________________________________________________
7
相关PDF资料 |
PDF描述 |
|---|---|
| X40415S8I-B | IC VOLTAGE MON DUAL W/SUP 8-SOIC |
| MAX734CSA+T | IC SUPPLY PROG MEM 8-SOIC |
| X40415S8I-AT1 | IC VOLTAGE MON DUAL W/SUP 8-SOIC |
| MAX1543ETP+T | IC DC-DC CONV TFT-LCD 20-TQFN |
| X40415S8I-A | IC VOLTAGE MON DUAL W/SUP 8-SOIC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8506EVKIT | 功能描述:电源管理IC开发工具 MAX8506/7/8 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 |
| MAX8507ETE | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX8507ETE+ | 功能描述:直流/直流开关转换器 DC/DC Converter DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX8507ETE+T | 功能描述:直流/直流开关转换器 DC/DC Converter DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX8507ETE-T | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
发布紧急采购，3分钟左右您将得到回复。