MAX8550

PRODUCTION

Integrated DDR Power-Supply Solutions for Desktops, Notebooks, and Graphic Cards

Data Sheet (Rev. 3) Product Selection Table

Part Models: 2
1ku List Price: Starting From $4.97

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Overview

Buck Controller
- Quick-PWM with 100ns Load-Step Response
- Up to 95% Efficiency
- 2V to 28V Input Voltage Range
- 1.8V/2.5V Fixed or 0.7V to 5.5V Adjustable Output
- Up to 600kHz Selectable Switching Frequency
- Programmable Current Limit with Foldback Capability
- 1.7ms Digital Soft-Start and Independent Shutdown
- Overvoltage/Undervoltage-Protection Option
- Power-Good Window Comparator
LDO Section
- Fully Integrated VTT and VTTR Capability
- VTT has ±3A Sourcing/Sinking Capability
- VTT and VTTR Outputs Track V_REFIN/2
- All-Ceramic Output-Capacitor Designs
- 1.0V to 2.8V Input Voltage Range
- Power-Good Window Comparator

The MAX8550/MAX8551 integrate a synchronous-buck PWM controller to generate V_DDQ, a sourcing and sinking LDO linear regulator to generate V_TT, and a 10mA reference output buffer to generate V_TTR. The buck controller drives two external N-channel MOSFETs to generate output voltages down to 0.7V from a 2V to 28V input with output currents up to 15A. The LDO can sink or source up to 1.5A continuous and 3A peak current. Both the LDO output and the 10mA reference buffer output can be made to track the REFIN voltage. These features make the MAX8550/MAX8551 ideally suited for DDR memory applications in desktops, notebooks, and graphic cards.

The PWM controller in the MAX8550/MAX8551 utilizes Maxim's proprietary Quick-PWM^™ architecture with programmable switching frequencies of up to 600kHz. This control scheme handles wide input/output voltage ratios with ease and provides 100ns response to load transients while maintaining high efficiency and a relatively constant switching frequency. The MAX8550 offers fully programmable UVP/OVP and skip-mode options ideal in portable applications. Skip mode allows for improved efficiency at lighter loads. The MAX8551, which is targeted towards desktop and graphic-card applications, does not offer the pulse-skip feature.

The VTT and VTTR outputs track to within 1% of V_REFIN/2. The high bandwidth of this LDO regulator allows excellent transient response without the need for bulk capacitors, thus reducing cost and size.

The buck controller and LDO regulators are provided with independent current limits. Adjustable lossless foldback current limit for the buck regulator is achieved by monitoring the drain-to-source voltage drop of the low-side MOSFET. Additionally, overvoltage and undervoltage protection mechanisms are built in. Once the overcurrent condition is removed, the regulator is allowed to enter soft-start again. This helps minimize power dissipation during a short-circuit condition. The MAX8550/MAX8551 allow flexible sequencing and standby power management using the active-low SHDNA, active-low SHDNB, and STBY inputs.

Both the MAX8550 and MAX8551 are available in a small 5mm x 5mm, 28-pin thin QFN package.

Applications

DDR I and DDR II Memory Power Supplies
Desktop Computers
Game Consoles
Graphic Cards
Networking
Notebooks and Desknotes
RAID

Part Models: 2
1ku List Price: Starting From $4.97

Documentation

Data Sheet 1

MAX8550-MAX8551: Integrated DDR Power-Supply Solutions for Desktops, Notebooks, and Graphic Cards Data Sheet (Rev.3) 06/07/2013

Reliability Data 1

MAX8550 Reliability Data 01/12/2023

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
MAX8550ETI+	28-LFCSP-5X5X0.75	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
MAX8550ETI+T	28-LFCSP-5X5X0.75	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Jun 20, 2016 - 1612 ASSEMBLY
		pcn_1612
MAX8550ETI+	PRODUCTION	pcn_1612

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Hardware Ecosystem

Parts	Product Life Cycle	Description
Switching Regulators & Controllers 7
MAX8553	PRODUCTION	4.5V to 28V Input, Synchronous PWM Buck Controllers for DDR Termination and Point-of-Load Applications
MAX8554	PRODUCTION	4.5V to 28V Input, Synchronous PWM Buck Controllers for DDR Termination and Point-of-Load Applications
MAX1917	PRODUCTION	Tracking, Sinking and Sourcing, Synchronous Buck Controller for DDR Memory and Termination Supplies
MAX1957	PRODUCTION	Low-Cost, High-Frequency, Current-Mode PWM Buck Controllers

MAX8537	PRODUCTION	Dual-Synchronous Buck Controllers for Point-of-Load, Tracking, and DDR Memory Power Supplies
MAX8539		Dual-Synchronous Buck Controllers for Point-of-Load, Tracking, and DDR Memory Power Supplies
MAX1809	PRODUCTION	3A, 1MHz, DDR Memory Termination Supply

Evaluation Kits

Evaluation Kit for the MAX8550, MAX8550A, MAX8551

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Features and Benefits

VDDQ Preset to 2.5V/12A

VTT 1.25V Source/Sink 1.5A Continuous/3A Peak

VTTR 1.25V Source/Sink 10mA

VIN Range: 9V to 20V

Optimized Switching Frequency: 600kHz

Overvoltage/Undervoltage Protection

Standby

Independent Shutdown

Power OK

Product Details

The MAX8550 evaluation kit (EV kit) is designed to evaluate the MAX8550 DDR power-supply solution for notebooks, desktops, and graphics cards. The EV kit board produces VDDQ at the output of the synchronous PWM buck, VTT at the output of the sourcing/sinking LDO linear regulator, and VTTR at the output of the reference buffer.

The VDDQ output is preset to 2.5V and sources up to 12A. The VTT output is always VDDQ/2 and can source/sink up to 3A of peak current and 1.5A of continuous current. The VTTR output is also always VDDQ/2 and can source/sink up to 10mA.

The MAX8550 EV kit was conveniently designed with jumpers to select the OVP/UVP, TON, SKIP-bar, STBY, and SHDN_-bar modes. The board's default settings enable OVP (overvoltage protection), 600kHz switching frequency, low-noise PWM mode, VDDQ, VTT, and VTTR.

The VIN input accepts voltages from 9V to 20V and VDD requires a 5V bias supply.

The EV kit comes with the MAX8550 installed. Contact the factory for free samples of the MAX8550A or MAX8551 to evaluate these parts.