QuickView - MAX8537, MAX8538, MAX8539 Dual-Synchronous Buck Controllers for Point-of-Load, Tracking, and DDR Memory Power Supplies

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Description

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The MAX8537/MAX8539 controllers provide a complete power-management solution for both double-data-rate (DDR) and combiner supplies. The MAX8537 and MAX8539 are configured for out-of-phase and in-phase DDR power-supply operations, respectively, and generate three outputs: the main memory voltage (V_DDQ), the tracking sinking/sourcing termination voltage (V_TT), and the termination reference voltage (V_TTR). The MAX8538 is configured as a dual out-of-phase controller for point-of-load supplies. Each buck controller can source or sink up to 25A of current, while the termination reference can supply up to 15mA output.

The MAX8537/MAX8538/MAX8539 use constant-frequency voltage-mode architecture with operating frequencies of 200kHz to 1.4MHz. An internal high- bandwidth (25MHz) operational amplifier is used as an error amplifier to regulate the output voltage. This allows fast transient response, reducing the number of output capacitors. An all-N-FET design optimizes efficiency and cost. The MAX8537/MAX8538/MAX8539 have a 1% accurate reference. The second synchronous buck controller in the MAX8537/MAX8539 and the V_TTR amplifier generate 1/2 V_DDQ voltage for V_TT and V_TTR, and track the V_DDQ within ±1%.

This family of controllers uses a high-side current-sense architecture for current limiting. ILIM pins allow the setting of an adjustable, lossless current limit for different combinations of load current and R_DSON. Alternately, more accurate overcurrent limit is achieved by using a sense resistor in series with the high-side FET. Overvoltage protection is achieved by latching off the high-side MOSFET and latching on the low-side MOSFET when the output voltage exceeds 17% of its set output. Independent enable, power-good, and soft-start features enhance flexibility.

Key Features

Applications/Uses

MAX8537/MAX8539: Complete DDR Supplies
MAX8538: Dual Nontracking Controller
Out-of-Phase (MAX8537/MAX8538) or In-Phase (MAX8539) Operation
4.5V to 23V Wide Input Range (Operate Down to 1.8V Input with External 5V Supply)
Tracking Supply Maintains V_TT = V_TTR = 1/2 V_DDQ
Adjustable Output from 0.8V to 3.6V with 1% Accuracy
VTTR Reference Sources and Sinks Up to 15mA
200kHz to 1.4MHz Adjustable Switching Frequency
All-Ceramic Design Achievable
>90% Efficiency
Independent POK_ and EN_
Adjustable Soft-Start and Soft-Stop for Each Output
Lossless Adjustable-Hiccup Current Limit
Output Overvoltage Protection
28-Pin QSOP Package

	Broadband Routers
	DDR Memory Power Supplies
	Networking Systems
	Notebooks and Desknotes
	Power Combiner in Advanced VGA Cards
	Power DSP Core Supplies
	RAMBUS Memory Power Supplies
	Servers and Storage Systems
	xDSL Modems and Routers

Key Specifications: Step-Down Switching Regulators

Part Number

V_IN (min) (V)

V_IN (max) (V)

Min. V_OUT (V)

Max. V_OUT (V)

I_OUT (A)

Output Adj. Method

Operating Current, I_CC (max) (mA)

Number of DC-DC Outputs

Operating Freq. (kHz)

Package

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

Price^**

MAX8537

4.5

0.8

3.6

Resistor

1400

QSOP/28

$1.80 @ 1k

MAX8538

$1.80 @ 1k

MAX8539

$1.80 @ 1k

See All Step-Down Switching Regulators (252)

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.