MAX8550EVKIT Datasheet MAX8550EVKIT | P1-P3

General Description

The MAX8550 evaluation kit (EV kit) is designed to evalu-

ate the MAX8550 DDR power-supply solution for note-

books, 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 contin-

uous 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, STBY, and

SHDN_ modes. The board’s default settings enable

OVP (overvoltage protection), 600kHz switching fre-

quency, 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.

Features

♦ 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

Evaluates: MAX8550/MAX8550A/MAX8551

MAX8550 Evaluation Kit

________________________________________________________________ Maxim Integrated Products 1

19-3436; Rev 1; 11/04

Component List

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.

Ordering Information

PART

TEMP RANGE

IC PACKAGE

MAX8550EVKIT

0°C to +70°C

28 Thin QFN 5mm x 5mm

DESIGNATION QTY DESCRIPTION

C1 1

0.1µF ±10%, 50V X7R ceramic

capacitor (0603)

TDK C1608X7R1H104K

C2, C4A, C4B,

C4C, C4D,

C4E, C4F

10µF ±10%, 6.3V X5R ceramic

capacitors (1206)

TDK C3216X5R0J106K or

TDK C3216X5R0J106M

C3, C6, C13 3

1µF ±10%, 10V X5R ceramic

capacitors (0603)

TDK C1608X5R1A105K

C5 1

4.7µF ±20%, 6.3V X5R ceramic

capacitor (0805)

TDK C2012X5R0J475M

C7, C10 2

0.22µF ±20%, 16V X7R ceramic

capacitors (0603)

TDK C1608X7R1C224M

C8A, C8B, C8C 3

10µF ±20%, 25V X5R ceramic

capacitors (1210)

Taiyo Yuden TMK325BJ106MM

TDK C3225X5R1E106M

DESIGNATION QTY DESCRIPTION

C8D 0

Not installed

470µF ±20%, 25V aluminum

electrolytic capacitor (10mm x 16mm)

Sanyo 25MV470WX

C9 1

3900pF, 50V X7R ceramic capacitor

(0603)

Kemet C0603C392K5RAC

C11, C12 2

150µF, 4V, 25mΩ low-ESR POS

capacitors (D2E)

Sanyo 4TPE150M

C14 1

470pF ±5%, 50V COG ceramic

capacitor (0603)

TDK C1608COG1H471J

C15, C16 2 Not installed (0603)

D1 1

S chottky d i od e, 30V , 100m A ( S OD - 323)

Central CMDSH-3

JU1, JU2 2 4-pin headers

JU3–JU6 4 3-pin headers

Note: To evaluate the MAX8550A, request a free sample of the

MAX8550AETI when ordering the MAX8550 EV kit. To evaluate

the MAX8551, request a free sample of the MAX8551ETI when

ordering the MAX8550 EV kit.

Evaluates: MAX8550/MAX8550A/MAX8551

MAX8550 Evaluation Kit

2 _______________________________________________________________________________________

Recommended Equipment

• 5VDC power supply (500mA rated)

• 9VDC to 20VDC power supply (5A rated)

• Two digital voltmeters (DVM)

Quick Start

The MAX8550 EV kit is fully assembled and tested. Follow

these steps to verify board operation. Do not turn on the

power supplies until all connections are completed.

1) Ensure a shunt is placed across pins 1-4 of jumper

JU1 to enable OVP and UVP.

2) Ensure a shunt is placed across pins 1-2 of jumper

JU2 to set the switching frequency to approximately

600kHz.

3) Ensure a shunt is placed across pins 1-2 of jumper

JU3 to enable low-noise PWM mode.

4) Ensure a shunt is placed across pins 2-3 of jumper

JU4 to disable the VDDQ buck output.

5) Ensure a shunt is placed across pins 1-2 of jumper

JU5 to enable the VTT and VTTR outputs.

6) Ensure a shunt is placed across pins 2-3 of jumper

JU6 to set the board in normal operation mode.

7) Connect the 5VDC power supply across the VDD

pad and the PGND pad nearest VIN.

8) Connect the 12VDC power supply across the VIN

pad and the corresponding PGND pad.

9) Turn on both of the power supplies.

10)Set JU4 (1-2). This turns VDDQ on.

11)Using one of the DVMs, verify that the VDDQ voltage

between the VDDQ and PGND pads is 2.5V (±2%).

12)Using the other DVM, verify that the VTT voltage

between the VTT and PGND pads is 1.25V (±2%).

Detailed Description

Jumper Selection

Component List (continued)

DESIGNATION

QTY

DESCRIPTION

1.0µH, 20A, 1.6mΩ power inductor

(12.6mm x 12.6mm x 5.2mm)

TOKO FDA1254-1R0M

n-channel MOSFET 30V, 9mΩ (SO-8)

International Rectifier IRF7821

n-channel MOSFET 30V, 5mΩ (SO-8)

International Rectifier IRF7832

10Ω ±5% resistor (0603)

R2, R3

100kΩ ±5% resistors (0603)

75kΩ ±1% resistor (0603)

124kΩ ±1% resistor (0603)

R6, R7, R8

Not installed (0603)

R9, R10, R11

0Ω resistors (0603)

R12

Not installed (1812)

R13

20Ω ±5% resistor (0603)

MAX8550ETI (28-pin 5mm x 5mm Thin

QFN)

None

Shunts

None

MAX8550 EV kit PC board

JUMPER

SHUNT

POSITION

DESCRIPTION

JU1 1-2 Disable OVP and UVP.

JU1 1-3 Enable UVP. Disable OVP.

JU1 1-4* Enable OVP and UVP.

JU1 Open Enable OVP. Disable UVP.

*Default position.

Note: Refer to the MAX8550/MAX8551 or MAX8550A data

sheet for additional information on OVP/UVP. This mode does

not directly apply to the MAX8551.

Table 1. Overvoltage/Undervoltage

Control Input (OVP/UVP)

Component Suppliers

SUPPLIER PHONE WEBSITE

Central

Semiconductor

631-435-1110

www.centralsemi.com

International

Rectifier

310-322-3331

www.irf.com

Kemet

864-963-6300

www.kemet.com

Sanyo USA

619-661-6835

www.sanyo.com

TDK

847-803-6100

www.component.tdk.com

TOKO America

847-297-0070

www.tokoam.com

Note: Indicate that you are using the MAX8550 when contact-

ing these component suppliers.

Setting the Buck Regulator Output

Voltage (VDDQ)

The output voltage of the buck regulator is preset to

2.5V on the MAX8550 EV kit for DDR memory applica-

tions. To pin-strap the output voltage to 1.8V follow the

steps below:

1) Remove R9.

2) Solder the 0Ω resistor from step 1 in the R7 location.

Refer to the MAX8550/MAX8551 data sheet to change

the external components for optimum performance.

Low-Side MOSFET Snubber Circuit (Buck)

Fast switching transitions cause ringing because of the

resonating circuit formed by the parasitic inductance

and capacitance at the switching LX node. This high-

frequency ringing occurs at the LX node’s rising and

Evaluates: MAX8550/MAX8550A/MAX8551

MAX8550 Evaluation Kit

_______________________________________________________________________________________ 3

JUMPER

SHUNT

POSITION

DESCRIPTION

JU2 1-2* 600kHz switching frequency

JU2 1-3 450kHz switching frequency

JU2 1-4 200kHz switching frequency

JU2 Open 300kHz switching frequency

*Default position.

Note: Refer to the MAX8550/MAX8551 or MAX8550A data

sheet for additional information on TON.

Table 2. On-Time Selection Input (TON)

JUMPER

SHUNT

POSITION

DESCRIPTION

JU3 1-2* Low-noise PWM mode.

JU3 2-3

Pulse-skipping mode.

Use only this position when

evaluating the MAX8551.

*Default position.

Note: Refer to the MAX8550/MAX8551 or MAX8550A data

sheet for additional information on

SKIP

Caution: Do not connect an external controller to the

SKIP pad while a shunt is on jumper JU3.

Table 3. Pulse-Skipping Control Input

(SKIP)

JUMPER

SHUNT

POSITION

DESCRIPTION

JU4 1-2

The VDDQ buck output is enabled.

JU4 2-3*

The VDDQ buck output is shut

down.

*Default position.

Note: Refer to the MAX8550/MAX8551 or MAX8550A data

sheet for additional information on

SHDNA

SHDN

on the MAX8550A.

Caution: Do not connect an external controller to the

SHDNA pad while a shunt is on jumper JU4.

Table 4. Shutdown Control Input A

(SHDNA)

JUMPER

SHUNT

POSITION

DESCRIPTION

JU5 1-2*

The VTT and VTTR outputs are

enabled.

JU5 2-3

The VTT and VTTR outputs are

shut down.

*Default position.

Note: Refer to the MAX8550/MAX8551 or MAX8550A data

sheet for additional information on

SHDNB

is TP0 on

the MAX8550A.

Caution: Do not connect an external controller to the

SHDNB pad while a shunt is on jumper JU5.

Table 5. Shutdown Control Input B

(SHDNB)

JUMPER

SHUNT

POSITION

DESCRIPTION

JU6 1-2 The VTT output is shut down.

JU6 2-3* Normal operation.

*Default position.

Note: Refer to the MAX8550/MAX8551 or MAX8550A data

sheet for additional information on STBY. STBY is

STBY

on the

MAX8550A.

Caution: Do not connect an external controller to the

STBY pad while a shunt is on jumper JU6.

Table 6. Standby Control Input (STBY)

P1-P3 P4-P6 P7-P8

MAX8550EVKIT

Mfr. #:

Buy MAX8550EVKIT

Manufacturer:

Maxim Integrated

Description:

Power Management IC Development Tools Eval Kit MAX8550, MAX8550A, MAX8551 (Integrated DDR Power-SupplySolutions for Desktops, Notebooks, and

Lifecycle:

New from this manufacturer.

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MAX8550EVKIT