MAX1515ETG+T Datasheet MAX1515ETG+T, MAX1515ETG+ | P1-P3

General Description

The MAX1515 constant-off-time, pulse-width-modulated

(PWM) source/sink step-down DC-DC converter is opti-

mized for use in low-voltage active-termination power

rails or chipset power supplies in notebook and sub-

notebook computers. This device features dual internal

n-channel MOSFET power switches for high efficiency

and reduced component count. External Schottky

diodes are not required. An integrated boost switch

eliminates the need for an external boost diode. The

internal 40mΩ NMOS power switches easily source and

sink continuous load currents up to 3A. The MAX1515

produces an adjustable output from +0.5V to +2.7V

and achieves efficiencies as high as 95%.

The MAX1515 can be configured as a DDR regulator,

producing an output that is exactly half the memory

supply rail. The input of the power stage can be taken

from the memory supply rail itself, resulting in an effi-

cient power supply that returns the energy to the rail

from which it was sourced. The MAX1515 includes a

reference buffer that provides ±5mA of drive current.

The MAX1515 uses a unique current-mode, constant-

off-time, PWM control scheme. A selectable pulse-skip-

ping mode maintains high efficiency during light-load

operation, yet still sources and sinks current on

demand. The MAX1515 can also be operated in fixed-

PWM mode for low output ripple. The programmable

constant-off-time architecture sets switching frequen-

cies up to 1MHz, which allows the user to optimize per-

formance trade-offs between efficiency, output

switching noise, component size, and cost. The

MAX1515 features an adjustable soft-start to limit surge

currents during startup and a low-power shutdown

mode to disconnect the input from the output and

reduce supply current below 1µA. The MAX1515 is

available in a 24-pin thin QFN package with an

exposed backside pad.

Applications

Notebook DDR Memory Termination

Active-Termination Buses

Chipset/Graphics Processor Supplies

Features

♦ Dual 40mΩ Internal n-Channel MOSFETs

♦ Integrated Boost Switch

♦ +1.3V to +3.6V Input Voltage Range

♦ 1% V

OUT

Accuracy Over Line and Load

♦ 1MHz Maximum Switching Frequency

♦ DDR Termination Regulator (DDR Mode)

Tracking Output Voltage

Source/Sink Pulse Skipping

±5mA Reference Buffer

♦ Output Voltage (Non-DDR Mode)

+2.5V, +1.8V, or +1.5V Pin Selectable

+0.5V to +2.7V Adjustable

♦ 1.1V ±0.75% Reference Output

♦ Adjustable Soft-Start Inrush Current Limiting

♦ < 1µA (typ) Shutdown Supply Current

♦ < 800µA (max) Operating Supply Current

♦ Selectable Pulse-Skipping Operation at Light Loads

♦ Positive and Negative Current Limit

♦ Power-Good Window Comparator

♦ Output Short-Circuit Protection

MAX1515

Low-Voltage, Internal Switch,

Step-Down/DDR Regulator

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

MAX1515

GND

COMP

PGND

REFOUT

PGOOD

BIAS

(3.0V TO 3.6V)

(1.3V TO 3.6V)

OUT

= V

REFOUT

= V

TTR

DDQ

(2.5V OR 1.8V)

MODE

FBSEL1

BST

SHDN

SKIP

FBSEL0

REFIN

REF

TOFF

Minimal Operating Circuit

19-3507; Rev 1; 3/06

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

EVALUATION KIT

AVAILABLE

PART

TEMP RANGE

PIN-

PACKAGE

PKG CODE

MAX1515ETG

-40°C to +85°C

24 Thin QFN

4mm x 4mm

T2444-4

MAX1515ETG+

-40°C to +85°C

24 Thin QFN

4mm x 4mm

T2444-4

Pin Configuration appears at end of data sheet.

+Denotes lead-free package.

MAX1515

Low-Voltage, Internal Switch,

Step-Down/DDR Regulator

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(Circuit of Figure 1, V

= +3.3V, V

= V

= SHDN = MODE = +3.3V, V

REFIN

= V

REF

, SKIP = GND, T

= 0°C to +85°C, unless oth-

erwise noted. Typical values are at T

= +25°C.)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional

operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to

absolute maximum rating conditions for extended periods may affect device reliability.

, V

, LX, SHDN to GND ...................................-0.3V to +4V

MODE, IC to GND ....................................................-0.3V to +4V

COMP, FB, REF, REFIN, REFOUT, PGOOD

to GND.........................................................-0.3V to (V

+ 0.3V)

FBSEL0, FBSEL1, TOFF, SKIP, SS to GND....-0.3V to (V

+ 0.3V)

to V

...........................................................-0.3V to + 0.3V

IN to V

....................................................-0.3V to (V

+ 0.3V)

PGND to GND ...................................................... -0.3V to +0.3V

LX to BST................................................................. -4V to +0.3V

BST to GND .......................................................... -0.3V to +8.0V

LX Current (Note 1).............................................................±4.7A

REF Short Circuit to GND ...........................................Continuous

REFOUT Short Circuit to GND....................................Continuous

Continuous Power Dissipation (T

= +70°C)

24-Pin Thin QFN (derate 20.8mW/°C above +70°C;

part mounted on 1in

of 1oz copper)........................1667mW

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

PARAMETER

SYMBOL

CONDITIONS

MIN TYP MAX UNITS

PWM CONTROLLER

1.3 3.6

Input Voltage Range

, V

3.0 3.6

Output Adjust Range V

OUT

≤ V

0.5 2.7 V

= +25°C

to +85°C

-3 0 +3

REFIN

= +3.3V, I

LOAD

= 0,

MODE = V

= 0°C to

+85°C

-4 0 +4

= +25°C

to +85°C

2.463

2.5

2.537

FBSEL0 = V

FBSEL1 = V

REFIN = REF

= 0°C to

+85°C

2.450

2.5

2.550

= +25°C

to +85°C

1.782 1.800 1.827

FBSEL0 = V

FBSEL1 = GND,

REFIN = REF

= 0°C to

+85°C

1.773 1.800 1.836

= +25°C

to +85°C

1.477 1.500 1.523

FBSEL0=GND

FBSEL1=V

REFIN=REF

= 0°C to

+85°C

1.470 1.500 1.530

= +25°C

to +85°C

0.492 0.500 0.508

Feedback Voltage Accuracy

= +3.3V,

LOAD

= 0,

MODE = low

FBSEL0=GND

FBSEL1=GND

REFIN=0.5V

= 0°C to

+85°C

0.490 0.500 0.510

Feedback Load-Regulation Error

= +1.3V to +3.6V, I

LOAD

= 0 to 3A,

SKIP = V

0.1 %

Note 1: LX has clamp diodes to PGND and IN. If continuous current is applied through these diodes, thermal limits must be observed.

MAX1515

Low-Voltage, Internal Switch,

Step-Down/DDR Regulator

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(Circuit of Figure 1, V

= +3.3V, V

= V

= SHDN = MODE = +3.3V, V

REFIN

= V

REF

, SKIP = GND, T

= 0°C to +85°C, unless oth-

erwise noted. Typical values are at T

= +25°C.)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Sink-Mode Detect Threshold

REFIN

MODE = V

, V

REFIN

= +0.5V to +1.5V

+18 +32

Source-Mode Detect Threshold

REFIN

MODE = V

, V

REFIN

= +0.5V to +1.5V -32 -18 mV

MOSFET On-Resistance R

NMOS

= V

= +3.3V, I

LOAD

= 0.5A

0.04 0.10

Switching Frequency f

(Note 2) 1

MHz

Maximum Output Current

OUT

(

RMS

)

(Note 3) 3.3 A

LIMIT_P

= +3.3V, MODE = GND or V

positive or sourcing mode

3.60

4.2

4.85

Current-Limit Threshold

LIMIT_N

MODE = V

, negative or sinking mode

-3.0

Pulse-Skipping Current Threshold

SKIP_P

= +3.3V, MODE = GND or V

, positive

or sourcing mode

0.5 0.8 1.1 A

ZX_P

= +3.3V, MODE = GND or V

, positive

or sourcing mode

200

Zero Cross Current Threshold

ZX_N

MODE = V

, negative or sinking mode

-350

FB Input Bias Current FB = 1.01 x V

TARGET

(Note 4) -50

+50

TOFF

= 33.2kΩ 0.270 0.34 0.405

TOFF

= 110kΩ 0.85 1.00 1.15

Off-Time t

OFF

> 0.3 x V

TARGET

(Note 4)

TOFF

= 499kΩ

3.8 4.5 5.2

µs

Extended Off-Time

OFF

(

EXT

)

< 0.3 x V

TARGET

(Notes 2, 4)

4 x

OFF

µs

Minimum On-Time

(

MIN

)

(Note 2)

180

Maximum On-Time

(

MAX

)

511 µs

SS Source Current

(

SRC

)

3.50 5.25 6.75

µA

SS Sink Current

(

SNK

)

100

µA

MODE = GND,

FBSEL0 = GND,

FBSEL1 = GND,

= 1.01 x

TARGET

450

800

No-Load Supply Current

+ I

= 3.3V

(not switching) (Note 4)

MODE = V

= V

TARGET

700 1200

µA

+ I

SHDN = MODE = GND, LX = 0V or 3.3V 0.2 20

SHDN = MODE = GND, LX = 0V 0.2 20

Shutdown Supply Currents

SHDN = MODE = GND, LX = 3.3V 0.1 20

µA

P1-P3 P4-P6 P7-P9 P10-P12 P13-P15 P16-P18 P19-P21 P22-P24

MAX1515ETG+T

Mfr. #:

Buy MAX1515ETG+T

Manufacturer:

Maxim Integrated

Description:

Switching Voltage Regulators 3A 1MHz Step-Down DDR Regulator

Lifecycle:

New from this manufacturer.

Delivery:

DHL FedEx Ups TNT EMS

Payment:

T/T Paypal Visa MoneyGram Western Union

MAX1515ETG+T

MAX1515ETG+T

Products related to this Datasheet