Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - system monitor Dual voltage detector TQFN 20 EP

General Description

The MAX6886 pin-selectable, multivoltage supply

supervisor monitors six voltage-detector inputs and one

watchdog input, asserting a RESET when inputs drop

below the selected voltage thresholds or the watchdog

timer expires. Manual reset and margin disable inputs

offer additional flexibility.

Five logic inputs select the MAX6886 thresholds. Logic

inputs select a supply tolerance (5% or 10%) and 1 of

32 factory-set threshold settings. Connect external

capacitors or use the factory default setting to set the

watchdog timeout periods and reset time delay.

The MAX6886 is available in a 20-pin TQFN (5mm x

5mm x 0.8mm) package and operates over the extend-

ed -40°C to +85°C temperature range.

Applications

Multivoltage Systems

Telecom

Networking

Servers/Workstations/Storage Systems

Features

o 32 Pin-Selectable Undervoltage Detector

Thresholds

o Capacitor-Adjustable Reset and Watchdog

Timeout Periods

o Factory Default Reset and Watchdog Timeout

Periods

o Margining Disable and Manual Reset Controls

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

o Small 5mm x 5mm 20-Pin Thin QFN Package

o Few External Components

o ±1% Threshold Accuracy

MAX6886

Pin-Selectable, Hex Power-Supply

Supervisory Circuit

________________________________________________________________

Maxim Integrated Products

PART TEMP RANGE PIN-PACKAGE

MAX6886ETP+ -40°C to +85°C 20 TQFN-EP*

Ordering Information

MARGIN

WDI

LOGIC OUTPUT

GND

µP

DC-DC

3.3V ALWAYS ON

TH4

DBP

TH3

TH2

TH1

TH0

DC-DC

IN1 IN2

SRT

IN3

SWT

IN4

1.5V

IN5 IN6

12V

RESET

12V

3.3V

2.5V

1.8V

MAX6886

1.2V

Typical Operating Circuit

19-3587; Rev 1; 1/12

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

Pin Configuration appears at end of data sheet.

Denotes a lead(Pb)-free/RoHS-compliant package.

Summary of content (13 pages)

PAGE 1
9-3587; Rev 1; 1/12 Pin-Selectable, Hex Power-Supply Supervisory Circuit Features The MAX6886 pin-selectable, multivoltage supply supervisor monitors six voltage-detector inputs and one watchdog input, asserting a RESET when inputs drop below the selected voltage thresholds or the watchdog timer expires. Manual reset and margin disable inputs offer additional flexibility. Five logic inputs select the MAX6886 thresholds.
PAGE 2
MAX6886 Pin-Selectable, Hex Power-Supply Supervisory Circuit ABSOLUTE MAXIMUM RATINGS (All voltages referenced to GND.) IN1–IN6, VCC, RESET, SRT, SWT .............................-0.3V to +6V TH0–TH4, WDI, MR, MARGIN ..................................-0.3V to +6V DBP ..........................................................................-0.3V to +3V Input/Output Current (all pins)..........................................
PAGE 3
Pin-Selectable, Hex Power-Supply Supervisory Circuit (VIN1–VIN4 or VCC = 2.7V to 5.8V, WDI = GND, TH0–TH4 = MARGIN = MR = DBP, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Notes 1, 2) PARAMETER SYMBOL CONDITIONS MIN MR, MARGIN, TH0–TH4, WDI Input Voltage VIH 1.
PAGE 4
Typical Operating Characteristics (VIN1–VIN4 or VCC = 5V, WDI = GND, TH0–TH4 = MARGIN = MR = DBP, TA = +25°C, unless otherwise noted.) 0.85 0.80 0.95 TA = +25°C TA = +85°C 0.90 0.85 0.80 215 TIMEOUT PERIOD (ms) 0.90 220 MAX6886 toc02 TA = +85°C SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) 0.95 1.00 MAX6886 toc01 1.00 RESET TIMEOUT PERIOD vs. TEMPERATURE (DEFAULT tRP = 200ms) VCC SUPPLY CURRENT vs. VCC SUPPLY VOLTAGE TA = +25°C MAX6886 toc03 IN1–IN4 SUPPLY CURRENT vs.
PAGE 5
Pin-Selectable, Hex Power-Supply Supervisory Circuit MR TO RESET OUTPUT PROPAGATION DELAY vs. TEMPERATURE 2.25 2.00 1.75 1.50 1.25 1.00 170 160 150 140 130 10 35 60 1.6 1.5 1.4 1.3 1.2 110 1.1 85 1.0 -40 TEMPERATURE (°C) -15 10 35 60 -40 85 -15 10 60 85 WATCHDOG TIMEOUT PERIOD vs. CSWT RESET TIMEOUT PERIOD vs. CSRT MAX6886 toc12 10,000 1000 TIMEOUT PERIOD (ms) 1000 35 TEMPERATURE (°C) TEMPERATURE (°C) 10,000 TIMEOUT PERIOD (ms) 1.7 100 10 MAX6886 toc13 -15 1.
PAGE 6
Pin-Selectable, Hex Power-Supply Supervisory Circuit MAX6886 Pin Description (continued) 6 PIN NAME 4 GND Ground 5 WDI Watchdog Timer Input. Logic input for the watchdog timer function. If WDI is not strobed with a valid low-to-high or high-to-low transition within the selected timeout period, RESET asserts. WDI is internally pulled down to GND through a 10µA current sink. 6 MR Active-Low Manual Reset Input. Pull MR low to assert RESET.
PAGE 7
Pin-Selectable, Hex Power-Supply Supervisory Circuit WDI MARGIN SWT *IN_ DETECTOR IN1 IN2 IN2 DETECTOR IN3 IN3 DETECTOR IN4 IN4 DETECTOR IN5 IN5 DETECTOR IN6 IN6 DETECTOR LOGIC ARRAY DBP SRT DBP RESET MR TH0 TH1 VIRTUAL DIODES VCC 1µF TH2 REFERENCE 2.55V LDO TH3 TH4 DBP 1µF MAX6886 *SEE THE VOLTAGE-DETECTOR INPUTS (IN_) SECTION FOR ADJUSTABLE INPUTS.
PAGE 8
MAX6886 Pin-Selectable, Hex Power-Supply Supervisory Circuit Detailed Description The MAX6886 pin-selectable, multivoltage supply supervisor monitors six voltage-detector inputs and one watchdog input. RESET asserts when any of the configured input thresholds have been reached, MR is asserted, or the watchdog timer expires. MARGIN allows a system to be tested without RESET being asserted. Logic inputs TH0–TH4 select 1 of 32 threshold sets for inputs IN1–IN6 (see Table 2, Threshold Options).
PAGE 9
Pin-Selectable, Hex Power-Supply Supervisory Circuit Manual Reset (MR) Many microprocessor-based (µP) products require manual reset capability to allow an operator or external logic circuitry to initiate a reset. The manual reset input (MR) can be connected directly to a switch without an external pullup resistor or debouncing network. MR is internally pulled up to DBP. Leave unconnected if not used. MR is internally pulled up to DBP through a 10µA current source.
PAGE 10
MAX6886 Pin-Selectable, Hex Power-Supply Supervisory Circuit Table 2. Threshold Options SELECTION TH4–TH0* 1 2 THRESHOLD VOLTAGES (V) IN1 IN2 IN3 IN4 IN5 IN6 11111 4.62 3.06 2.31 1.67 0.60 0.60 11110 4.62 2.78 2.31 1.67 0.60 0.60 3 11101 4.62 3.06 2.31 0.60 0.60 0.60 4 11100 4.62 2.78 2.31 0.60 0.60 0.60 5 11011 4.62 3.06 1.67 0.60 0.60 0.60 6 11010 4.62 2.78 1.67 0.60 0.60 0.60 7 11001 4.62 3.06 0.60 0.60 0.60 0.60 8 11000 4.62 2.78 0.
PAGE 11
Pin-Selectable, Hex Power-Supply Supervisory Circuit Watchdog Timer The MAX6886’s watchdog circuit monitors the µP’s activity. If the µP does not toggle the watchdog input (WDI) within the watchdog timeout period, RESET asserts. The internal watchdog timer is cleared by a reset, or by a transition at WDI (which can detect pulses as short as 50ns.) The watchdog timer remains cleared while RESET is asserted. The timer starts counting as soon as RESET goes high (see Figure 2).
PAGE 12
Set the RESET time delay by connecting a capacitor from SRT to GND using the following equation: t WD CSRT = 4.348 x 106 where tRP is in seconds and CSRT is in Farads. Connect SRT to VCC for a factory-default reset timeout of 200ms. RESET is open-drain and requires an external pullup resistor. RESET remains low for 1V ≤ VCC ≤ 2.5V. Applications Information Layout and Bypassing For better noise immunity, bypass each of the voltagedetector inputs to GND with 0.
PAGE 13
Pin-Selectable, Hex Power-Supply Supervisory Circuit REVISION NUMBER REVISION DATE 0 2/05 Initial release — 1 1/12 Updated Table 2. 10 DESCRIPTION PAGES CHANGED Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.