MAX1858AEEG+ Datasheet MAX1876AEEG+, MAX1858AEEG+, MAX1876AEEG+T | P1-P3

General Description

The MAX1858A/MAX1875A/MAX1876A dual, synchro-

nized, step-down controllers generate two outputs from

input supplies ranging from 4.5V to 23V. Each output is

adjustable from sub-1V to 18V and supports loads of 10A

or higher. Input voltage ripple and total RMS input ripple

current are reduced by synchronized 180° out-of-phase

operation.

The switching frequency is adjustable from 100kHz to

600kHz with an external resistor. Alternatively, the con-

troller can be synchronized to an external clock gener-

ated by another MAX1858A/MAX1875A/MAX1876A or a

system clock. One MAX1858A/MAX1875A/MAX1876A

can be set to generate an in-phase, or 90° out-of-

phase, clock signal for synchronization with additional

controllers. This allows two controllers to operate either

as an interleaved two- or four-phase system with each

output shifted by 90°. The MAX1858A/MAX1875A/

MAX1876A feature soft-start. The MAX1858A also fea-

tures first-on/last-off power sequencing and soft-stop.

The MAX1858A/MAX1875A/MAX1876A eliminate the

need for current-sense resistors by utilizing the low-side

MOSFET’s on-resistance as a current-sense element.

This protects the DC-DC components from damage dur-

ing output-overload conditions or output short-circuit

faults without requiring a current-sense resistor.

Adjustable foldback current limit reduces power dissipa-

tion during short-circuit conditions. The MAX1858A/

MAX1876A include a power-on reset (POR) output to sig-

nal the system when both outputs reach regulation.

The MAX1858A/MAX1875A/MAX1876A ensure that the

output voltage does not swing negative when the input

power is removed or when EN is driven low. The

MAX1875A/MAX1876A also allow prebias startup with-

out discharging the output.

The MAX1858A/MAX1875A/MAX1876A are available in a

24-pin QSOP package. Use the MAX1875 evaluation kit

or the MAX1858 evaluation kit to evaluate the

MAX1858A/MAX1875A/MAX1876A.

Applications

Network Power Supplies

Telecom Power Supplies

DSP, ASIC, and FPGA Power Supplies

Set-Top Boxes

Broadband Routers

Servers

Desknote Computers

Features

♦ 4.5V to 23V Input Supply Range

♦ 0 to 18V Output Voltage Range (Up to 10A)

♦ Adjustable Lossless Foldback Current Limit

♦ Adjustable 100kHz to 600kHz Switching

Frequency

♦ Optional Synchronization

♦ Clock Output for Master/Slave Synchronization

♦ 4 x 90° Out-of-Phase Step-Down Converters

(Using Two Controllers, Figure 7)

♦ Prebias Startup (MAX1875A/MAX1876A)

♦ Power Sequencing (MAX1858A)

♦ RST Output with 140ms Minimum Delay

(MAX1858A/MAX1876A)

♦ Fixed-Frequency Pulse-Width Modulation (PWM)

Operation

MAX1858A/MAX1875A/MAX1876A

Dual 180° Out-of-Phase Buck Controllers with

Sequencing/Prebias Startup and POR

________________________________________________________________ Maxim Integrated Products 1

LX2

DH2

BST2OSC

ILIM2

FB2

COMP2

TOP VIEW

DL2

PGND

DL1CKO

GND

REF

V+

BST1

DH1

LX1

COMP1

FB1

ILIM1

SYNC

QSOP

MAX1858A

MAX1875A

MAX1876A

RST (N.C.)

() ARE FOR THE MAX1875A ONLY

Pin Configuration

Ordering Information

19-2966; Rev 0; 10/03

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.

PART TEMP RANGE PIN-PACKAGE

MAX1858AEEG -40°C to +85°C 24 QSOP

MAX1875AEEG -40°C to +85°C 24 QSOP

MAX1876AEEG -40°C to +85°C 24 QSOP

MAX1858A/MAX1875A/MAX1876A

Dual 180° Out-of-Phase Buck Controllers with

Sequencing/Prebias Startup and POR

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

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+ to GND ..............................................................-0.3V to +25V

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

to GND ..................-0.3V to the lower of +6V and (V+ + 0.3V)

BST1, BST2 to GND ...............................................-0.3V to +30V

LX1 to BST1..............................................................-6V to +0.3V

LX2 to BST2..............................................................-6V to +0.3V

DH1 to LX1 ..............................................-0.3V to (V

BST1

+ 0.3V)

DH2 to LX2 ..............................................-0.3V to (V

BST2

+ 0.3V)

DL1, DL2 to PGND........................................-0.3V to (V

+ 0.3V)

CKO, REF, OSC, ILIM1, ILIM2,

COMP1, COMP2 to GND ..........................-0.3V to (V

+ 0.3V)

FB1, FB2, RST, SYNC, EN to GND...........................-0.3V to +6V

VL to GND Short Circuit .............................................Continuous

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

Continuous Power Dissipation (T

= +70°C)

24-Pin QSOP (derate 9.4mW/°C above +70°C)...........762mW

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

ELECTRICAL CHARACTERISTICS

(V+ = 12V, EN = ILIM_ = V

, SYNC = GND, I

= 0mA, PGND = GND, C

REF

= 0.22µF, C

= 4.7µF (ceramic), R

OSC

= 60kΩ,

compensation components for COMP_ are from Figure 1, T

= -40°C to +85°C (Note 1), unless otherwise noted.)

PARAMETER CONDITIONS MIN TYP MAX UNITS

GENERAL

(Note 2) 4.5 23.0

V+ Operating Range

= V+ (Note 2) 4.5 5.5

V+ Operating Supply Current V

unloaded, no MOSFETs connected 3.5 6 mA

V+ Standby Supply Current EN = LX_ = FB_ = 0V 0.3 0.6 mA

Thermal Shutdown Rising temperature, typical hysteresis = 10°C +160 °C

ILIM_ = V

75 100 125

ILIM_

= 100kΩ 32 50 62

Current-Limit Threshold PGND - LX_

ILIM_

= 600kΩ 225 300 375

REGULATOR

Output Voltage 5.5V < V+ < 23V, 1mA < I

LOAD

< 50mA 4.75 5 5.25 V

Undervoltage Lockout Rising

Trip Level

4.1 4.2 4.3 V

Undervoltage Lockout

Hysteresis

(Note 3) 100 mV

REFERENCE

Output Voltage I

REF

= 0µA 1.98 2.00 2.02 V

Reference Load Regulation 0µA < I

REF

< 50µA 0 4 10 mV

SOFT-START

Digital Ramp Period

Internal 6-bit DAC for one converter to ramp from 0V to

full scale (Note 4)

1024

DC-DC

clocks

Soft-Start Steps 64 Steps

FREQUENCY

0°C to +85°C 84 100 115

Low End of Range R

OSC

= 60kΩ

-40°C to +85°C 80 100 120

kHz

High End of Range R

OSC

= 10kΩ 540 600 660 kHz

DH_ Minimum Off-Time R

OSC

= 10kΩ 250 303 ns

MAX1858A/MAX1875A/MAX1876A

Dual 180° Out-of-Phase Buck Controllers with

Sequencing/Prebias Startup and POR

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(V+ = 12V, EN = ILIM_ = V

, SYNC = GND, I

= 0mA, PGND = GND, C

REF

= 0.22µF, C

= 4.7µF (ceramic), R

OSC

= 60kΩ,

compensation components for COMP_ are from Figure 1, T

= -40°C to +85°C (Note 1), unless otherwise noted.)

PARAMETER CONDITIONS MIN TYP MAX UNITS

SYNC Range

Switching frequency must be set to half of the SYNC

frequency

200 1200 kHz

High 100

SYNC Input Pulse Width (Note 4)

Low 100

SYNC Rise/Fall Time (Note 4) 100 ns

ERROR AMPLIFIER

FB_ Input Bias Current 250 nA

0°C to +85°C 0.985 1.00 1.015

FB_ Input Voltage Set Point

-40°C to +85°C 0.98 1.00 1.02

0°C to +85°C 1.25 1.8 2.70

FB_ to COMP_ Transconductance

-40°C to +85°C 1.2 1.8 2.9

DRIVERS

DL_, DH_ Break-Before-Make Time C

LOAD

= 5nF 30 ns

Low 1.5 2.5

DH_ On-Resistance

High 3 5

Ω

Low 0.6 1.5

DL_ On-Resistance

High 3 5

Ω

LOGIC INPUTS (EN, SYNC)

Input Low Level Typical 15% hysteresis, V

= 4.5V 0.8 V

Input High Level V

= 5.5V 2.4 V

Input High/Low Bias Current V

= 0 or 5.5V -1 +0.1 +1 µA

LOGIC OUTPUTS (CKO)

Output Low Level V

= 5V, sinking 5mA 0.4 V

Output High Level V

= 5V, sourcing 5mA 4.0 V

COMP_

Pulldown Resistance During

Shutdown and Current Limit

17 Ω

RST OUTPUT (MAX1858A/MAX1876A ONLY)

Output-Voltage Trip Level

Both FBs must be over this to allow the reset timer to

start; there is no hysteresis

0.87 0.9 0.93 V

= 5V, sinking 3.2mA 0.4

Output Low Level

= 1V, sinking 0.4mA 0.3

Output Leakage V+ = V

= 5V, V

RST

= 5.5V, V

= 1V 1 µA

Reset Timeout Period V

FB_

= 1V 140 315 560 ms

FB_ to Reset Delay FB_ overdrive from 1V to 0.85V 4 µs

Note 1: Specifications to -40°C are guaranteed by design and not production tested.

Note 2: Operating supply range is guaranteed by V

line regulation test. Connect V+ to V

for 5V operation.

Note 3: When V

falls and UVLO is tripped, the device is latched and V

must be discharged below 2.5V before normal operation

can resume.

Note 4: Guaranteed by design and not production tested.

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

MAX1858AEEG+

Mfr. #:

Buy MAX1858AEEG+

Manufacturer:

Maxim Integrated

Description:

Switching Controllers Dual 180 Out Buck Controllers

Lifecycle:

New from this manufacturer.

Delivery:

DHL FedEx Ups TNT EMS

Payment:

T/T Paypal Visa MoneyGram Western Union

MAX1858AEEG+

MAX1858AEEG+

Products related to this Datasheet