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Active: In Production.

Data Sheet

FULL DATA SHEET (PDF, 380kB) Download   E-Mail

Description

The MAX1864/MAX1865 power-supply controllers are designed to address cost-conscious applications such as cable modem Consumer Premise Equipment (CPE), xDSL CPE, and set-top boxes. Operating off a low-cost, unregulated DC supply (such as a wall adapter output), the MAX1864 generates three positive outputs, and the MAX1865 generates four positive outputs and one negative output to provide a cost-effective system power supply. The MAX1864 includes a current-mode synchronous step-down controller and two positive regulator gain blocks. The MAX1865 has one additional positive gain block and one negative regulator gain block. The main synchronous step-down controller generates a high-current output that is preset to 3.3V or adjustable from 1.236V to 0.8 x VIN with an external resistive-divider. The 100kHz/200kHz operating frequency allows the use of low-cost aluminum-electrolytic capacitors and low-cost power magnetics. Additionally, the MAX1864/MAX1865 step-down controllers sense the voltage across the low-side MOSFET's on-resistance to efficiently provide the current-limit signal, eliminating the need for costly current-sense resistors. The MAX1864/MAX1865 generate additional supply rails at low cost. The positive regulator gain blocks use an external PNP pass transistor to generate low-voltage rails directly from the main step-down converter (such as 2.5V or 1.8V from the main 3.3V output) or higher voltages using coupled windings from the step-down converter (such as 5V, 12V, or 15V). The MAX1865's negative gain block uses an external NPN pass transistor in conjunction with a coupled winding to generate -5V, -12V, or -15V. All output voltages are externally adjustable, providing maximum flexibility. Additionally, the MAX1864/MAX1865 feature soft-start for the step-down converter and all the positive linear regulators, and have a power-good output that monitors all of the output voltages.

An evaluation kit is available:  MAX1864EVKIT  

Key Features		Applications/Uses
4.5V to 28V Input Voltage Range Master DC-DC Step-Down Converter Preset 3.3V or Adjustable (1.236V to 0.8 x VIN) Output Voltage Fixed-Frequency (100kHz/200kHz) PWM Controller No Current-Sense Resistor Adjustable Current Limit 95% Efficient Two (MAX1864)/Four (MAX1865) Analog Gain Blocks Positive Analog Blocks Drive Low-Cost PNP Pass Transistors to Build Positive Linear Regulators Negative Analog Block (MAX1865) Drives a Low-Cost NPN Pass Transistor to Build a Negative Linear Regulator Power-Good Indicator Soft-Start Ramp for All Positive Regulators		Set-Top Boxes Wireless Local Loop (WLL) xDSL, Cable, and ISDN Modems

Diagram

Typical Operating Circuit

Application Notes

Application Note 735: Layout Considerations for Non-Isolated DC-DC Converters - MAX1864, MAX1865, MAX1865 Application Note 821: The MAX1864/MAX1865 Compensation Calculator - MAX1864, MAX1865 Application Note 905: Adding POR Function to the MAX1864 Generating Two Outputs - MAX1864 Application Note 906: The MAX1864 Generates 1.2V or Lower Output Voltage - MAX1864 Application Note 1843: Noise Reduction For ADSL Modem Power - MAX1864 Application Note 1857: DDR Memory-Termination Supply - MAX1864 Application Note 3626: Adding a Watchdog to a Dual-Output Power Supply - MAX1864 Application Note 3654: Current Limiting for the MAX1864 Auxiliary Regulator - MAX1864, MAX1865 Application Note 3672: Noise Reduction for the MAX1864 Auxiliary Regulator - MAX1864, MAX1865

Evaluation Kits

MAX1864EVKIT

Reliability Reports

Show FIT data for: MAX1864 MAX1865 Request Reliability Report for: MAX1864 MAX1865

Software/Models

none

Ordering Information

Notes: Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales. Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day. Part number suffixes: T or T&R = tape and reel;+ = RoHS/lead-free;# = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions. * Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.

Devices: 1-12 of 12

MAX1864	Free Sample	Buy	Status	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX1864TEEE			Active	QSOP;16 pin;30.9 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0167 (PDF) Use pkgcode/variation: E16-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX1864TEEE-T			Active	QSOP;16 pin;30.9 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0167 (PDF) Use pkgcode/variation: E16-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX1864UEEE			Active	QSOP;16 pin;30.9 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0167 (PDF) Use pkgcode/variation: E16-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX1864UEEE-T			Active	Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX1864TEEE+			Active	QSOP;16 pin;30.9 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0167 (PDF) Use pkgcode/variation: E16+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX1864TEEE+T			Active	QSOP;16 pin;30.9 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0167 (PDF) Use pkgcode/variation: E16+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX1865	Free Sample	Buy	Status	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX1865TEEP+			Active	QSOP;20 pin;54.2 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0168 (PDF) Use pkgcode/variation: E20+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX1865TEEP+T			Active	Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX1865TEEP			Active	QSOP;20 pin;54.2 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0168 (PDF) Use pkgcode/variation: E20-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX1865TEEP-T			Active	Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX1865UEEP			Active	QSOP;20 pin;54.2 mm² Outline Drawing: 21-0055 (PDF) Land Pattern: 90-0168 (PDF) Use pkgcode/variation: E20-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX1865UEEP-T			Active	Land Pattern: Not Available	-40°C to +85°C	See data sheet

More Information

New Product Press Release 2001-05-24  MAX1864, MAX1865Power Supply Cookbook

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