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MAX1856：宽输入范围、可同步的、PWM SLIC电源

The MAX1856 offers a low-cost solution for generating a SLIC (ringer and off-hook) power supply. Using standard off-the-shelf transformers from multiple vendors, the MAX1856 generates various output voltages: -24V and -72V (dual output) for both ringer and off-hook supplies for voice-enabled broadband consumer premises equipment (CPE), -48V for IP phones and routers, -5V and -15V (single or dual output) for DSL CO line drivers, or negative voltages as high as -185V for MEMS bias supplies. The output voltages are adjusted with an external voltage divider. Due to its wide operating voltage range, the MAX1856 operates from a low-cost, unregulated DC power supply for cost-sensitive applications like xDSL, cable modems, set-top boxes, LMDS, MMDS, WLL, and FTTH CPE. The MAX1856 provides low audio-band noise for talk battery and a sturdy output capable of handling the ring trip conditions for ring battery. The operating frequency can be set between 100kHz and 500kHz with an external resistor in free-running mode. For noise-sensitive applications, the MAX1856's operating frequency can be synchronized to an external clock over its operating frequency range. The flyback topology allows operation close to 50% duty cycle, offering high transformer utilization, low ripple current, and less stress on input and output capacitors. Internal soft-start minimizes startup stress on the input capacitor, without any external components. The MAX1856's current-mode control scheme does not require external loop compensation. The low-side current-sense resistor provides accurate current-mode control and overcurrent protection.

关键特性 Low-Cost, Off-the-Shelf Transformer 3V to 28V Input Range Low Audio-Band Noise on Talk Battery Effectively Handles Ring Trip Transients Powers 2-, 4-, or 12-Line Equipment High Efficiency Extends Battery Life During Life-Line Support Conditions Adjustable 100kHz to 500kHz Switching Frequency Clock Synchronization Internal Soft-Start Current-Mode PWM and Idle Mode™ Control Scheme Logic-Level Shutdown 10-Pin µMAX Package

MAX1856：典型工作电路 应用 电缆与DSL调制解调器 CO DSL线驱动器电源 FTTH 工业电源 LMDS/MMDS MEMS偏置电源 路由器/交换机 机顶盒 VoIP振铃与摘机电压发生器 无线本地环路(WLL)

数据手册DataSheet

关键参数

开发工具

• MAX1856EVKIT

技术资料

• Flyback Transformer Design for MAX1856 SLIC Power Supplies
• Flyback Circuit Powers Broadband Phone Networks
• Selection of Ultra-Fast Recovery Diodes Used in Flyback Circuits
• Snubber Circuits Suppress Voltage Transient Spikes in Multiple Output DC-DC Flyback Converter Power Supplies
• Extending Soft-Start

质量和环境数据

• MAX1856.pdf

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