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MAX6312UK27D3-T中文资料

General Description

The MAX6305–MAX6313 CMOS microprocessor (μP)supervisory circuits are designed to monitor more than one power supply. Ideal for monitoring both 5V and 3.3V in personal computer systems, these devices assert a system reset if any of the monitored supplies falls outside the programmed threshold. Low supply current (15μA) and a small package suit them for portable applications. The MAX6305–MAX6313 are specifically designed to ignore fast transients on any monitored supply.

These devices are available in a SOT23-5 package,have factory-programmed reset thresholds from 2.5V to 5.0V (in 100mV increments), and feature four power-on reset timeout periods. Ten standard versions are avail-able. Contact the factory for availability of non standard versions.

Applications

Portable Computers Computers Controllers

Intelligent Instruments

Portable/Battery-Powered Equipment Multivoltage Systems: 3V/5V, 5V/12V, 5V/24V Embedded Control Systems

Features

o Small 5-Pin SOT23 Package

o Precision Factory-Set V CC Reset Thresholds;Available in 0.1V Increments from 2.5V to 5V o Immune to Short V CC Transients

o Guaranteed RESET Valid to V CC = 1V o Guaranteed Over Temperature o 8μA Supply Current

o Factory-Set Reset Timeout Delay from 1ms (min) to 1120ms (min)o No External Components o Manual Reset Input

o Under/Overvoltage Supply Monitoring

MAX6305–MAX6313

5-Pin, Multiple-Input,Programmable Reset ICs

________________________________________________________________Maxim Integrated Products

1

19-1145; Rev 5; 4/08

?The MAX6306/MAX6307/MAX6309/MAX6310/MAX6312/MAX6313 are available with factory-set V CC reset thresholds from 2.5V to 5V, in 0.1V increments. Insert the desired nominal reset threshold (from Table 1) into the blanks following the letters UK.All parts also offer factory-programmed reset timeout periods.Insert the number corresponding to the desired nominal timeout period index following the “D” in the part number (D1 = 1ms min,D2 = 20ms min, D3 = 140ms min, and D4 = 1120ms min). There are 10 standard versions with a required order increment of 2,500pieces. Sample stock is generally held on the standard versions only (see Standard Versions table). Required order increment is 10,000 pieces for non-standard versions. Contact factory for availability of non-standard versions. All devices 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 Configurations and Typical Operating Circuit appear at

end of data sheet.

Ordering Information continued at end of data sheet.Standard Versions Table appears at end of data sheet.

_______________________________________________________________Selector Table

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,or visit Maxim’s website at https://www.wendangku.net/doc/e54531120.html,.

M A X 6305–M A X 6313

5-Pin, Multiple-Input, Programmable Reset ICs

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

V CC = +2.5V to +5.5V for the MAX6305/MAX6308/MAX6311, V CC = (V TH + 2.5%) to +5.5V for the MAX6306/MAX6307/MAX6309/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 CC ...........................................................................-0.3V to +6V All Other Pins..............................................-0.3V to (V CC + 0.3V)Input/Output Current, All Pins.............................................20mA Rate of Rise, V CC ............................................................100V/μs Continuous Power Dissipation (T A = +70°C)

SOT23-5 (derate 7.1mW/°C above +70°C).................571mW

Operating Temperature Range

MAX63_ _UK _ _D_-T.........................................0°C to +70°C MAX63_ _EUK _ _D_-T...................................-40°C to +85°C Storage Temperature Range.............................-65°C to +160°C Lead Temperature (soldering, 10sec).............................+300°C

MAX6305–MAX6313

5-Pin, Multiple-Input, Programmable Reset ICs

_______________________________________________________________________________________3

ELECTRICAL CHARACTERISTICS (continued)

V CC = +2.5V to +5.5V for the MAX6305/MAX6308/MAX6311, V CC = (V TH + 2.5%) to +5.5V for the MAX6306/MAX6307/MAX6309/

Note 2: The MAX6305/MAX6308/MAX6311 switch from undervoltage reset to normal operation between 1.5V < V CC < 2.5V.

Note 3: The MAX6306/MAX6307/MAX6309/MAX6310/MAX6312/MAX6313 monitor V CC through an internal factory-trimmed voltage

divider, which programs the nominal reset threshold. Factory-trimmed reset thresholds are available in approximately 100mV increments from 2.5V to 5V (Table 1).

Note 4:Guaranteed by design.

M A X 6305–M A X 6313

5-Pin, Multiple-Input, Programmable Reset ICs 4_______________________________________________________________________________________

__________________________________________Typical Operating Characteristics

(V CC = +5V, T A = +25°C, unless otherwise noted.)

5.0

5.5

6.06.5

7.07.5

8.08.5

9.09.5

-60

-40

-20

20

40

60

80

100

SUPPLY CURRENT vs. TEMPERATURE

TEMPERATURE (°C)S U P P L Y C U R R E N T (μA )

01020304050607080-60

-40

-20

20

40

60

80

100

V CC FALLING PROPAGATION DELAY

vs. TEMPERATURE

TEMPERATURE (°C)P R O P A G A T I O N D E L A Y (n s )

010203040506070

-60

-40-20020406080100

OVRST IN RISING PROPAGATION DELAY vs. TEMPERATURE (OVERVOLTAGE RESET INPUT)

TEMPERATURE (°C)

P R O P A G A T I O N D E L A Y (n s )

020406080100120-60

-40

-20

20

40

60

80

100RST IN_ FALLING PROPAGATION DELAY vs. TEMPERATURE

TEMPERATURE (°C)R S T I N _ P R O P A G A T I O N D E L A Y (n s )

10

400

1200

800

MAXIMUM TRANSIENT DURATION vs.V

CC RESET THRESHOLD OVERDRIVE

10

OVERDRIVE, V TH - V CC (mV)

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

1001000

10,000

0.90

0.920.940.960.981.001.021.041.061.081.10-60-40-20020406080100

RESET TIMEOUT vs. TEMPERATURE

6305 T O C 05

TEMPERATURE (°C)N O R M A L I Z E D R E S E T T I M E O U T

0.990

0.9920.9940.9960.9981.0001.0021.0041.0061.0081.010

-60

-40

-20

20

40

60

80

100

RESET THRESHOLD vs. TEMPERATURE

6305 T O C 06

TEMPERATURE (°C)

N O R M A L I Z E D R E S E T T H R E S H O L D (V /V )

10

400

1200

800

MAXIMUM TRANSIENT DURATION vs.

OVRST IN THRESHOLD OVERDRIVE

10

OVERDRIVE, V OVRST IN - V REF (mV)

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

100

1000

10,000

10

400

1200

800

MAXIMUM TRANSIENT DURATION vs.RST IN_ THRESHOLD OVERDRIVE

10

OVERDRIVE, V REF - V RST IN (mV)

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

100

1000

10,000

_______________Detailed Description

The MAX6305–MAX6313 CMOS microprocessor (μP)supervisory circuits are designed to monitor more than one power supply and issue a system reset when any monitored supply falls out of regulation. The MAX6305/MAX6308/MAX6311 have two adjustable undervoltage reset inputs (RST IN1 and RST IN2). The MAX6306/MAX6307/MAX6309/MAX6310/MAX6312/MAX6313 mon-itor V CC through an internal, factory-trimmed voltage divider. The MAX6306/MAX6309/MAX6312 have, in addition, an adjustable undervoltage reset input and a manual-reset input. The internal voltage divider sets the reset threshold as specified in the device part number (Table 1). The MAX6307/MAX6310/ MAX6313 feature an adjustable undervoltage reset input (RST IN) and an adjustable overvoltage reset input (OVRST IN) in addition to the factory-trimmed reset threshold on the V CC moni-tor. Program the adjustable reset inputs with an external resistor divider (see Adjustable Reset Inputs section).

Reset Outputs

A μP’s reset input starts the μP in a known state. These μP supervisory circuits assert reset to prevent code-execution errors during power-up, power-down, or brownout conditions.

RESET (MAX6305–MAX6310) and RESET (MAX6311/MAX6312/MAX6313) are guaranteed to be asserted at a valid logic level for V CC > 1V (see Electrical Characteristics ). Once all monitored voltages exceed their programmed reset thresholds, an internal timer keeps reset asserted for the reset timeout period (t RP );after this interval, reset deasserts.

If a brownout condition occurs (any or all monitored volt-ages dip outside their programmed reset threshold),reset asserts (RESET goes high; RESET goes low). Any time any of the monitored voltages dip below their reset threshold, the internal timer resets to zero and reset asserts. The internal timer starts when all of the moni-tored voltages return above their reset thresholds, and reset remains asserted for a reset timeout period. The MAX6305/MAX6306/MAX6307 feature an active-low,

MAX6305–MAX6313

5-Pin, Multiple-Input, Programmable Reset ICs

_______________________________________________________________________________________

5

______________________________________________________________Pin Description

M A X 6305–M A X 6313

open-drain, N-channel output. The MAX6308/MAX6309/MAX6310 feature an active-low, complementary output structure that both sinks and sources current, and the MAX6311/MAX6312/MAX6313 have an active-high com-plementary reset output.

The MAX6305/MAX6308/MAX6311 switch from under-voltage lockout operation to normal operation between 1.5V < V CC < 2.5V. Below 1.5V, V CC undervoltage-lockout mode asserts RESET . Above 2.5V, V CC normal-operation mode asserts reset if RST IN_ falls below the RST IN_ threshold.

Manual-Reset Input

(MAX6306/MAX6309/MAX6312)

Many μP-based products require manual-reset capability,allowing an operator or external logic circuitry to initiate a reset. A logic low on MR asserts reset. Reset remains asserted while MR is low, and for a reset active timeout period (t RP ) after MR returns high. This input has an inter-nal 63.5k Ωpull-up resistor, so it can be left open if it is not used. MR can be driven with TTL-logic levels in 5V sys-tems, with CMOS-logic levels in 3V systems, or with open-drain/collector output devices. Connect a normally open momentary switch from MR to GND to create a manual-reset function; external debounce circuitry is not required.If MR is driven from long cables or if the device is used in a noisy environment, connecting a 0.1μF capacitor from MR to ground provides additional noise immunity.

The MR pin has internal ESD-protection circuitry that may be forward biased under certain conditions, drawing excessive current. For example, assume the circuitry driv-ing MR uses a +5V supply other than V CC . If V CC drops or browns out lower than +4.7V, MR ’s absolute maximum rat-ing is violated (-0.3V to (V CC + 0.3V)), and undesirable current flows through the ESD structure from MR to V CC .To avoid this, it is recommended that the supply for the MR pin be the same as the supply monitored by V CC . In this way, the voltage at MR will not exceed V CC .

Adjustable Reset Inputs

The MAX6305–MAX6313 each have one or more reset inputs (RST IN_ /OVRST IN). These inputs are com-pared to the internal reference voltage (F igure 1).Connect a resistor voltage divider to RST IN_ such that V RST IN_falls below V RSTH (1.23V) when the monitored voltage (V IN ) falls below the desired reset threshold (V TH ) (F igure 2). Calculate the desired reset voltage with the following formula:

R1 + R2V TH = ________x V

RSTH

R2

5-Pin, Multiple-Input, Programmable Reset ICs 6_______________________________________________________________________________________

Figure 1. Functional Diagram

MAX6305–MAX6313

5-Pin, Multiple-Input, Programmable Reset ICs

_______________________________________________________________________________________7

The ±25nA max input leakage current allows resistors on the order of megohms. Choose the pull-up resistor in the divider to minimize the error due to the input leakage cur-rent. The error term in the calculated threshold is simply:

±25nA x R1

If you choose R1 to be 1M Ω, the resulting error is ±25 x 10-9x 1 x 106= ±25mV.

Like the V CC voltage monitors on the MAX6306/MAX6307/MAX6309/MAX6310/MAX6312/MAX6313, the RST IN_inputs (when used with a voltage divider) are designed to ignore fast voltage transients. Increase the noise immunity by connecting a capacitor on the order of 0.1μF between RST IN and GND (Figure 2). This creates a single-pole lowpass filter with a corner frequency given by:

f = (1/2π) / (R1 + R2)(R1 x R2 x C)

For example, if R1 = 1M Ωand R2 = 1.6M Ω, adding a 0.1μF capacitor from RST IN_ to ground results in a lowpass corner frequency of f = 2.59Hz. Note that adding capacitance to RST IN slows the circuit’s overall response time.

__________Applications Information

Interfacing to μPs with Bidirectional Reset Pins

Since the RESET output on the MAX6305/MAX6306/MAX6307 is open drain, these devices interface easily with μPs that have bidirectional reset pins, such as the Motorola 68HC11. Connecting the μP supervisor’s RESET output directly to the microcontroller’s RESET pin with a single pull-up resistor allows either device to assert reset (Figure 3).

Negative-Going V CC Transients

In addition to issuing a reset to the μP during power-up,power-down, and brownout conditions, these devices are relatively immune to short-duration, negative-going V CC transients (glitches).

The Typical Operating Characteristics show the Maximum Transient Duration vs. V CC Reset Threshold Overdrive, for which reset pulses are not generated.The graph was produced using negative-going pulses,starting at V TH max, and ending below the pro-grammed reset threshold by the magnitude indicated (reset threshold overdrive). The graph shows the maxi-mum pulse width that a negative-going V CC transient may typically have without causing a reset pulse to be issued. As the amplitude of the transient increases (i.e.,goes farther below the reset threshold), the maximum allowable pulse width decreases.

RST IN_/OVRST IN are also immune to negative/positive-going transients (see Typical Operating Characteristics ).A 0.1μF bypass capacitor mounted close to the RST IN_,OVRST IN, and/or the V CC pin provides additional tran-sient immunity.

Ensuring a Valid RESET /RESET

Output Down to V CC = 0V

When V CC falls below 1V, push/pull structured RESET /RESET current sinking (or sourcing) capabilities decrease drastically. High-impedance CMOS-logic inputs connected to RESET can drift to undetermined voltages. This presents no problem in most applica-tions, since most μPs and other circuitry do not operate with V CC below 1V. In those applications where RESET must be valid down to 0V, adding a pull-down resistor between RESET and ground sinks any stray leakage

Figure 2. Increasing Noise Immunity

Figure 3. Interfacing to μPs with Bidirectional Reset I/O

currents, holding RESET low (Figure 4). The pull-down resistor’s value is not critical; 100k Ωis large enough not to load RESET and small enough to pull RESET to ground. For applications where RESET must be valid to V CC , a 100k Ωpull-up resistor between RESET and V CC will hold RESET high when V CC falls below 1V (Figure 5).Since the MAX6305/MAX6306/MAX6307 have open-drain, active-low outputs, they typically use a pull-up resistor. With these devices and under these conditions (V CC < 1V), RESET will most likely not maintain an active condition, but will drift toward a nonactive level due to the pull-up resistor and the RESET output’s reduction in sinking capability. These devices are not recommended for applications that require a valid RESET output below 1V.

* Factory-trimmed reset thresholds are available in approximately 100mV increments with a ±1.5% room-temperature variance.

M A X 630

5–M A X 6313

5-Pin, Multiple-Input, Programmable Reset ICs 8___________________________

____________________________________________________________

Figure 4. Ensuring RESET Valid to V CC = 0V

Figure 5. Ensuring RESET Valid to V CC = 0V

Table 1. Factory-Trimmed Reset Thresholds*

MAX6305–MAX6313

5-Pin, Multiple-Input, Programmable Reset ICs

_______________________________________________________________________________________9

Chip Information

TRANSISTOR COUNT: 800

Typical Operating Circuit

?The MAX6306/MAX6307/MAX6309/MAX6310/MAX6312/

MAX6313 are available with factory-set V CC reset thresholds from 2.5V to 5V, in 0.1V increments. Insert the desired nominal reset threshold (from Table 1) into the blanks following the letters UK.All parts also offer factory-programmed reset timeout periods.Insert the number corresponding to the desired nominal timeout period index following the “D” in the part number (D1 = 1ms min,D2 = 20ms min, D3 = 140ms min, and D4 = 1120ms min). There are 10 standard versions with a required order increment of 2,500pieces. Sample stock is generally held on the standard versions only (see Standard Versions table). Required order increment is 10,000 pieces for non-standard versions. Contact factory for avail-ability of non-standard versions. All devices 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.

M A X 6305–M A X 6313

5-Pin, Multiple-Input, Programmable Reset ICs 10______________________________________________________________________________________

Pin Configurations

Package Information

For the latest package outline information, go to https://www.wendangku.net/doc/e54531120.html,/packages .

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 ____________________11

?2008 Maxim Integrated Products

is a registered trademark of Maxim Integrated Products, Inc.

MAX6305–MAX6313 5-Pin, Multiple-Input, Programmable Reset ICs

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