MAX1856 宽输入范围、可同步的、PWM SLIC电源

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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

应用/使用

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

	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)

Key Specifications: Switch-Mode DC-DC Power Supplies

Part Number

Topology

V_IN (min) (V)

V_IN (max) (V)

Number of DC-DC Outputs

Digital/VID Programmed Output

Min. Adjustable V_OUT (V)

Max. Adjustable V_OUT (V)

I_OUT (A)

Operating Current, I_CC (max) (mA)

Fixed Freq/PWM Operation

Operating Freq. (kHz)

Internal Power Switch(es)

Synchronous Rectifier

Package

Smallest Available Package (max w/pins) (mm²)

Price^**

MAX1856

Inverting

-185

0.3

0.4

Yes

500

uMAX/10

$1.57 @ 1k

See All Switch-Mode DC-DC Power Supplies (413)

Notes:
^**This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.