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MAX6339KUT+T中文资料

General Description

The MAX6339 is a precision quad voltage monitor with microprocessor (μP) supervisory reset timing. The device can monitor up to four system supply voltages without any external components and asserts a single reset if any supply voltage drops below its preset threshold. The device significantly reduces system size and component count while improving reliability compared to separate ICs or discrete components.

A variety of factory-trimmed threshold voltages are avail-able to accommodate different supply voltages and toler-ances with minimal external component requirements.The selection includes internally fixed options for monitor-ing +5.0V, +3.3V, +3.0V, +2.5V, +1.8V, and -5.0V sup-plies with -5% and/or -10% tolerances. The device is also available with one or two user-adjustable threshold options if non-standard thresholds are desired (use exter-nal resistor-divider network).

The quad monitor provides a single active-low reset out-put that is asserted when any monitored input is below its associated threshold. The output is open drain with a weak internal pullup (10μA) to IN2. Reset remains low for a reset timeout period (140ms min) after all voltages are above the selected thresholds. The output is valid as long as either the IN1 or IN2 input voltage remains > 1V.

The MAX6339 is available in a small 6-pin SOT23 pack-age and operates over the extended (-40°C to +85°C)temperature range.

________________________Applications

Telecommunications High-End Printers

Desktop and Network Computers Data Storage Equipment Networking Equipment Industrial Equipment Set-Top Boxes

Features

?Monitors Four Power-Supply Voltages

?Precision Factory-Set Reset Threshold Options for +5.0V, +3.3V, +3.0, +2.5V, +1.8V, and -5.0V Supplies ?User-Adjustable Voltage Monitoring Threshold Options ?Low 55μA Supply Current

?Open-Drain RESET Output with 10μA Internal Pullup ?140ms (min) Reset Timeout Period ?RESET Valid to IN1 = 1V or IN2 = 1V

?Immune to Short Monitored Supply Transients ?No External Components Required ?Guaranteed from -40°C to +85°C ?Small 6-Pin SOT23 Package

MAX6339

Quad Voltage μP Supervisory Circuit

in SOT Package

________________________________________________________________Maxim Integrated Products 1

19-1756; Rev 3; 12/05

Ordering Information

*Insert the desired letter from the Selector Guide into the blank to complete the part number. There is a 2500 piece minimum order increment requirement on the SOT package and these devices are available in tape-and-reel only.

Devices are available in both leaded and lead-free packaging.Specify lead-free by replacing “-T” with “+T” when ordering.

Pin Configuration appears at end of data sheet.

Typical Operating Circuit

For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at https://www.wendangku.net/doc/7e14398303.html,.

M A X 6339

Quad Voltage μP Supervisory Circuit in SOT Package 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.

Terminal Voltage (with respect to GND)

Input Voltages (IN_ ) (except -5V)............................-0.3V to +6V RESET .......................................................................-0.3V to +6V Input Voltage (-5V Input)..........................................-6V to +0.3V Continuous RESET Current.................................................20mA Continuous Power Dissipation (T A = +70°C)

6-pin SOT23 (derate 8.7mW/°C above +70°C).........695.7mW

Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range.............................-65°C to +150°C Junction Temperature......................................................+150°C Lead Temperature (soldering, 10s).................................+300°C

ELECTRICAL CHARACTERISTICS

(V = +1V to +5.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at V = +3.0V to +3.3V, T = +25°C, unless

MAX6339

Quad Voltage μP Supervisory Circuit

in SOT Package

_______________________________________________________________________________________3

ELECTRICAL CHARACTERISTICS (continued)

(V IN2= +1V to +5.5V, T A = -40°C to +85°C, unless otherwise noted. Typical values are at V IN2= +3.0V to +3.3V, T A = +25°C, unless otherwise noted.) (Note 1)

Note 1:100% production tested at T A = +25°C. Limits over temperature guaranteed by design.Note 2:The device is powered from input IN2.

Note 3:The RESET output is guaranteed to be in the correct state for IN1 or IN2 down to 1V.

Note 4:

Monitored voltage (+3.3V, +3.0V) is also the device power supply. Supply current splits as follows: 25μA for the resistor- divider (for the monitored voltage) and 30μA for other circuits.

3550454055606570758085-40

-20

I IN2 INPUT CURRENT vs. TEMPERATURE

TEMPERATURE (°C)I I N 2 I N P U T C U R R E N T (μA )

50605570658075853.0

4.0

3.5

4.5

5.0

5.5

I IN2 INPUT CURRENT vs. I IN2 VOLTAGE

M A X 6339t o c 02

INPUT VOLTAGE (V)I I N 2 I N P U T C U R R E N T (μ

A )

-0.30

-0.15-0.20-0.25-0.10-0.500.050.100.15

-40

-20

NORMALIZED THRESHOLD ERROR

vs. TEMPERATURE

TEMPERATURE (°C)

N O R M A L I Z E D T H R E S H O L D E R R O R (%)Typical Operating Characteristics

(V IN2= +3.0V, T A = +25°C)

Pin Description

M A X 6339

Quad Voltage μP Supervisory Circuit in SOT Package Typical Operating Characteristics (continued)

IN2= +3.0V, T A = +25°C)

180

190185195200205210215-40

-20

RESET TIMEOUT DELAY vs. TEMPERATURE

M A X 6339t o c 07

TEMPERATURE (°C)

R E S E T T I M E O U T D E L A Y (m s )

RESET 2V/div

IN_2V/div

200ms/div

RESET TIMEOUT DELAY

M A X 6339t o c 08

2V/div

201030607050408002003004005001006007008009001000

MAXIMUM IN_ TRANSIENT DURATION vs. RESET THRESHOLD OVERDRIVE

RESET THRESHOLD OVERDRIVE (mV)

M A X I M U M I N _ T R A N S I E N T D U R A T I O N (μs )

2010

306070504080

02003004005001006007008009001000

RESET DELAY vs. RESET THRESHOLD

OVERDRIVE (IN_ decreasing)

M A X 6339t o c 05

RESET THRESHOLD OVERDRIVE (mV)

R E S E T D E L A Y (μs )

RESET 2V/div

IN_100mV/div

10μs/div

RESET PULLUP AND PULLDOWN

RESPONSE (C L = 47pF)

M A X 6339t o c 06

MAX6339

Quad Voltage μP Supervisory Circuit

in SOT Package

_______________________________________________________________________________________5

Detailed Description

The MAX6339 is a very small, low-power, quad voltage μP supervisory circuit designed to maintain system integrity in multi-supply systems (Figure 1). The device offers several internally trimmed undervoltage threshold options that minimize or eliminate the need for external components. Preset voltage monitoring options for +5.0V, +3.3V, +3.0V, +2.5V, +1.8V, and -5.0V make it ideal for telecommunications, desktop and notebook computers, high-end printers, data storage equipment,and networking equipment applications.

The quad monitor/reset includes an accurate bandgap reference, four precision comparators, and a series of internal trimmed resistor-divider networks to set the fac-tory-fixed reset threshold options. The resistor networks scale the specified IN_ reset voltages to match the internal bandgap reference/comparator voltage. User-adjustable threshold options bypass the internal resis-tor networks and connect directly to one of the comparator inputs (an external resistor-divider network is required for threshold matching). All threshold volt-age options, fixed and adjustable, are indicated through a single-letter code in the product number (see the Selector Guide ).

Each of the internal comparators has a typical hystere-sis of 0.3% with respect to its reset threshold. This built-in hysteresis improves the monitor’s immunity to ambient noise without significantly reducing threshold accuracy when an input sits at its specified reset volt-age. The MAX6339 is also designed to ignore short IN_transients. See the Typical Operating Characteristics for a glitch immunity graph.

Applications Information

Reset Output

The MAX6339 RESET output is asserted low when any of the monitored IN_ voltages drop below its specified reset threshold (or above for -5V option) and remain low for the reset timeout period (140ms minimum) after all inputs exceed their thresholds (Figure 2). The output is open drain with a weak internal pullup to the moni-tored IN2 supply (10μA typ). For many applications no external pullup resistor is required to interface with other logic devices. An external pullup resistor to any voltage from 0 to +5.5V can overdrive the internal pullup if interfacing to different logic supply voltages (Figure 3). Internal circuitry prevents reverse current flow from the external pullup voltage to IN2.

The MAX6339 is normally powered from the monitored IN2 supply when all input voltages are above their specified thresholds. When any supply drops below its

threshold, the reset output is asserted and guaranteed to remain low while either IN1 or IN2 is above +1.0V.

User-Adjustable Thresholds

The MAX6339 offers several monitor options with user-adjustable reset thresholds. The threshold voltage at each adjustable IN_ input is typically 1.23V. To monitor a voltage > 1.23V, connect a resistor-divider network to the circuit as shown in Figure 4.

V INTH = 1.23V x (R1 + R2) / R2

or, solved in terms of R1:

R1 = R2 ((VI NTH / 1.23V) - 1)

Because the MAX6339 has a guaranteed input current of ±0.1μA on its adjustable inputs, resistor values up to 100k ?can be used for R2 with < 1% error.

Unused Inputs

If some monitor inputs are to be unused, they must be tied to a supply voltage greater in magnitude than their specified threshold voltages. For unused IN3 or IN4options with positive thresholds (fixed or adjustable),the inputs can be connected directly to the IN2 supply.For unused IN4 options with negative thresholds, the input must be tied to a more negative supply. The IN2input must always be used for normal operation (device power-supply pin). Unused pins cannot be connected to ground or allowed to float.

Negative Voltage Monitoring Beyond -5V

The MAX6339 is offered with options to monitor -5V sup-plies with internally fixed thresholds. To monitor supplies more negative than -5V, a low-impedance resistor-divider network can be used external to the MAX6339 as shown in Figure 5. The current through the external resis-tor-divider should be greater than the input current for the -5V monitor options. For an input monitor current error of < 1%, the resistor-divider current should ≥ 2mA (for I IN4= 20μA max). Set R2 = 2.5k ?. Calculate R1based on the desired V IN_reset threshold voltage, using the following formula:

R1 = R2 ?[(V INTH / V TH ) -1]

where R2 ≤2.49k ?, V INTH = desired threshold voltage and V TH is the internal threshold voltage.

M A X 6339

Quad Voltage μP Supervisory Circuit in SOT Package 6_______________________________________________________________________________________

Figure 1. Functional Diagram

MAX6339

Quad Voltage μP Supervisory Circuit

in SOT Package

_______________________________________________________________________________________7

For -V IN = -12V nominal, VI NTH = -11.1V, V TH = -4.63V,and R2 = 2.49k ?,

R1 = 2.49k ??[(-11.1 / -4.63) -1]

R1 = 3.48k ?

Power-Supply Bypassing and Grounding

The MAX6339 is normally powered from the monitored IN2 supply input. All monitor inputs are immune to short supply transients. If higher immunity is desired in noisy applications, connect 0.1μF bypass capacitors from the IN2 input to ground. Additionally, capacitance can be added to IN1, IN3, and IN4 to increase their noise immunity.

Chip Information

TRANSISTOR COUNT: 896PROCESS: BiCMOS

Figure 4. Setting the Auxiliary Monitor

M A X 6339

Quad Voltage μP Supervisory Circuit in SOT Package 8_______________________________________________________________________________________

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.

Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600_____________________9?2005 Maxim Integrated Products

is a registered trademark of Maxim Integrated Products, Inc.

6L S O T .E P S

MAX6339

Quad Voltage μP Supervisory Circuit

in SOT Package

Package Information

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,go to https://www.wendangku.net/doc/7e14398303.html,/packages .)