MAX6877 データシートの表示（PDF） - Maxim Integrated

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MAX6877

Dual-/Triple-Voltage, Power-Supply Trackers/Sequencers/Supervisors

Maxim Integrated 

19-3771; Rev 1; 10/05

EVAALVUAAILTAIOBNLEKIT

Dual-/Triple-Voltage, Power-Supply

Trackers/Sequencers/Supervisors

General Description

The MAX6877/MAX6878/MAX6879 multivoltage power

trackers/sequencers/supervisors monitor up to three

system voltages and provide proper power-up and

power-down control for systems requiring voltage track-

ing or sequencing. These devices ensure controlled

voltage tracking within a specified range or sequencing

in the proper order as system power supplies are

enabled. The MAX6877/MAX6878/MAX6879 generate

all required voltages and timing to control up to three

external n-channel pass FETs for the OUT1/OUT2/

OUT3 supply voltages (see the Selector Guide for dif-

ferent features of each device).

The MAX6877/MAX6878/MAX6879 feature adjustable

undervoltage thresholds for each input supply. When all

the voltages are above these adjustable thresholds, the

devices turn on the external n-channel MOSFETs to

either sequence or track the voltages to the system.

During voltage-tracking mode, the voltage at the GATE

of each MOSFET is increased to slowly bring up all

supplies at a controlled slew rate. The MAX6877/

MAX6878/MAX6879 feature an autoretry or latch-off

mode with capacitor-adjusted timing.

These devices also provide a controlled power-down

(tracking mode) when the system shuts off in an orderly

manner. When an unexpected fault occurs, the outputs

are all pulled down simultaneously with an internal

100Ω pulldown to help discharge capactive loads at

the MOSFET’s source. The MAX6877/MAX6878/

MAX6879 feature independent internal charge pumps

to fully enhance the external FETs for low-voltage drop

at highpass current. The MAX6877 and MAX6878 also

feature a power-good output with a selectable timeout

period that can be used for system reset.

The MAX6877/MAX6878/MAX6879 are available in

small 4mm x 4mm 24-pin and 16-pin thin QFN pack-

ages and are fully specified over the -40°C to +85°C

extended operating temperature range.

Multivoltage Systems

Networking Systems

Telecom

Storage Equipment

Servers/Workstations

Applications

Selector Guide appears at end of data sheet.

Features

♦ Pin-Selectable Tracking or Sequencing Control

for Up to Three Supply Voltages

♦ Capacitor-Adjustable Power-Up/Down Tracking

Slew Rate

♦ Capacitor-Adjustable Power-Up Sequencing Delay

♦ Internal Charge Pumps to Enhance External

n-Channel FETs

♦ Capacitor-Adjustable Timeout Period Power-Good

Output (MAX6877/MAX6878)

♦ Adjustable Undervoltage Lockout or

Logic-Enable Input

♦ Internal 100Ω Pulldown for Each Output to

Discharge Capacitive Load Quickly

♦ 0.5V to 5.5V Nominal IN_/OUT_ Range

♦ 2.7V to 5.5V Operating Voltage Range

♦ Immune to Short Voltage Transients

♦ Small 4mm x 4mm 24-Pin or 16-Pin Thin QFN

Packages

Ordering Information

PART

TEMP RANGE

PIN-

PACKAGE

PKG

CODE

MAX6877ETG+ -40°C to +85°C 24 Thin QFN T2444-4

Ordering Information continued at end of data sheet.

+Denotes lead-free package.

Pin Configurations

TOP VIEW

18 17 16 15 14 13

GATE2 19

12 TRK/SEQ

OUT1 20

11 LTCH/RTR

GATE1 21

IN3 22

MAX6877

IN2 23

EP*

+

IN1 24

12 3 4 5

10 TIMEOUT

9 SLEW

8 DELAY

7 GND

6

4mm x 4mm THIN QFN

*EXPOSED PADDLE CONNECTED TO GND.

Pin Configurations continued at end of data sheet.

________________________________________________________________ Maxim Integrated Products 1

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.

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