General Description
The MAX6412–MAX6420 low-power microprocessor supervisor circuits monitor system voltages from 1.6V to 5V. The devices are designed to asrt a ret signal whenever the V CC supply voltage or RESET IN falls below its ret threshold or the manual ret input is asrted.The ret output remains asrted for the ret timeout period after V CC and RESET IN ri above the ret threshold and the manual ret input is deasrted. The ret timeout is externally t by a capacitor to provide more flexibility.
The MAX6412/MAX6413/MAX6414 feature fixed thresholds from 1.575V to 5V in approximately 100mV increments and a manual ret input. The MAX6415/MAX6416/MAX6417are offered with an adjustable ret input that can monitor voltages down to 1.26V and the MAX6418/MAX6419/MAX6420 are offered with one fixed input and one adjustable input to monitor dual-voltage systems.
The MAX6412/MAX6415/MAX6418 have an active-low,push-pull ret output. The MAX6413/MAX6416/MAX6419 have an active-high, push-pull ret output and the MAX6414/MAX6
417/MAX6420 have an active-low, open-drain ret output. All of the devices are offered in a SOT23-5 package and are fully specified from -40°C to +125°C.
Applications
Automotive Medical Equipment Intelligent Instruments Portable Equipment
Battery-Powered Computers/Controllers Embedded Controllers Critical µP Monitoring Set-Top Boxes Computers
Features
♦Monitor System Voltages from 1.6V to 5V ♦Capacitor-Adjustable Ret Timeout Period ♦Manual Ret Input (MAX6412/MAX6413/MAX6414)♦Adjustable Ret Input Option (MAX6415–MAX6420)♦Dual-Voltage Monitoring
(MAX6418/MAX6419/MAX6420)♦Low Quiescent Current (1.7µA, typ)♦3 RESET Output Options
Push-Pull RESET Push-Pull RESET Open-Drain RESET
♦Guaranteed Ret Valid to V CC = 1V ♦Power-Supply Transient Immunity ♦Small SOT23-5 Packages
MAX6412–MAX6420
Low-Power, Single/Dual-Voltage µP Ret Circuits with Capacitor-Adjustable Ret Timeout Delay
________________________________________________________________Maxim Integrated Products
1
Ordering Information
颈动脉斑块形成
Pin Configuration
19-2336; Rev 2; 12/05
For pricing, delivery, and ordering information,plea contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at
Typical Operating Circuit appears at end of data sheet.Selector Guide appears at end of data sheet.
Note: The MAX6412/MAX6413/MAX6414 and MAX6418/MAX6419/MAX6420 are available with factory-t V CC ret thresholds from 1.575V to 5.0V in approximately 0.1V incre-ments. Inrt the desired nominal ret threshold suffix (from Table 1) into the blanks following the letters UK. There ar
e 33standard versions with a required order increment of 2500pieces. Sample stock is generally held on standard versions only (e Standard Versions Table). Required order increment is 10,000 pieces for nonstandard versions. Contact factory for availability. All 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.
M A X 6412–M A X 6420
with Capacitor-Adjustable Ret Timeout Delay
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ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V CC = 1V to 5.5V, T A = T MIN to T MAX , unless otherwi specified. Typical values are at V CC = 5V and T A = +25°C.) (Note 1)
Stress beyond tho listed under “Absolute Maximum Ratings” may cau permanent damage to t
he device. The are stress ratings only, and functional operation of the device at the or any other conditions beyond tho indicated in the operational ctions of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
All Voltages Referenced to GND
V CC ........................................................................-0.3V to +6.0V SRT, MR , -0.3V to (V CC + 0.3V)RESET, RESET (Push-Pull).........................-0.3V to (V CC + 0.3V)RESET (Open-Drain).............................................-0.3V to +6.0V Input Current (All Pins).....................................................±20mA Output Current (RESET , RESET)......................................±20mA
Continuous Power Dissipation (T A = +70°C)
5-Pin SOT23-5 (derate 7.1mW/°C above +70°C)........571mW Operating Temperature Range .........................-40°C to +125°C +150°C Storage -65°C to +150°C Lead Temperature (soldering, 10s).................................+300°C
MAX6412–MAX6420
with Capacitor-Adjustable Ret Timeout Delay
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ELECTRICAL CHARACTERISTICS (continued)
(V CC = 1V to 5.5V, T A = T MIN to T MAX , unless otherwi specified. Typical values are at V CC = 5V and T A = +25°C.) (Note 1)
Typical Operating Characteristics
(V CC = 5V, C SRT = 1500pF, T A = +25°C, unless otherwi noted.)
4
3
2
1
象棋的口诀
00
3
1
2
4
5
6
SUPPLY CURRENT vs.SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
S U P P L Y C U R R E N T (µA )
01.00.5
2.01.5
3.02.5
3.5-50
25
-25
50
75
100
羽毛球牌子
125
SUPPLY CURRENT vs.TEMPERATURE
TEMPERATURE (°C)
S U P P L Y C U R R E N T (µA )
0.11
100
10
1000
10,000
0.001
0.10.011101001000
RESET TIMEOUT PERIOD vs. C SRT
M A X 6412-20 t o c 03
C SRT (nF)
R E S E T T I M E O U T P E R I O D (m s )
M A X 6412–M A X 6420
一般纳税人with Capacitor-Adjustable Ret Timeout Delay
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4.05
4.10
4.20
学英语口语4.15
4.25
4.30-50
-25
25
50
75
国庆放假100
125
RESET TIMEOUT PERIOD vs. TEMPERATURE
TEMPERATURE (°C)
R E S E T T I M E O U T P E R I O D (m s )
RESET TIMEOUT PERIOD vs. TEMPERATURE
200
250
350300500550450400600
R E S E T T I M E O U T P E R I O D (µs )-50
25
-25
50
75100
125
TEMPERATURE (°C)
1.250
1.2601.2551.2701.2651.2751.280-50
25
50
-25
75
积水潭桥
100
125
RESET IN THRESHOLD VOLTAGE
vs. TEMPERATURE
M A X 6412-20 t o c 06
TEMPERATURE (°C)R E S E T I N T H R E S H O L D V O L T A G E (V
)
0
502510075150125175
400
200
600
800
1000
MAXIMUM TRANSIENT DURATION vs. RESET THRESHOLD OVERDRIVE
RESET THRESHOLD OVERDRIVE (mV)
T R A N S I E N T D U R A T I O N (µs )
Typical Operating Characteristics (continued)
(V CC = 5V, C SRT = 1500pF, T A = +25°C, unless otherwi noted.)
Detailed Description
The MAX6412–MAX6420 low-power microprocessor (µP) supervisory circuits provide maximum adjustability for supply-voltage monitoring and ret functionality. In addition, the MAX6412–MAX6420 ret timeout period is adjustable using an external capacitor.
The MAX6412/MAX6413/MAX6414 have factory-trimmed ret threshold voltages in approximately 100mV increments from 1.575V to 5.0V with a manual ret input. The MAX6415/MAX6416/MAX6417 contain a ret threshold that can be adjusted to any voltage above 1.26V using external resistors. The MAX6418/MAX6419/MAX6420 offer both a factory-trimmed ret threshold and an adjustable ret threshold input for dual-voltage monitoring.
A ret signal is asrted when V CC and/or RESET IN falls below the pret values or when MR is asrted.The ret remains asrted for an externally pro-grammed interval after V CC and/or RESET IN has rin above the ret threshold or MR is deasrted.
Ret Output
The ret output is typically connected to the ret input of a µP. A µP’s ret input starts or restarts the µP
in a known state. The MAX6412–MAX6420 µP supervi-sory circuits provide the ret logic to prevent code-execution errors during power-up, power-down, and brownout conditions (e Typical Operating Circuit ). F or the MAX6413, MAX6416, and MAX6419, RESET changes from low to high whenever V CC or RESET IN drops below the ret threshold voltages. Once RESET IN and V CC exceed their respective ret threshold volt-age(s), RESET remains high for the ret timeout period,then goes low.
On power-up, once V CC reaches 1V, RESET is guaran-teed to be a logic high. For applications requiring valid ret logic when V CC is less than 1V, e the ction Ensuring a Valid RESET/RESET Output Down to V CC = 0.The active-low RESET output of the remaining supervi-sors is the inver of the MAX6413, MAX6416, and MAX6419 active-high RESET output and is guaranteed valid for V CC ≥1V.
Ret Threshold
The MAX6415–MAX6420 monitor the voltage on RESET IN with an external resistor voltage-divider
(F igure 1).
MAX6412–MAX6420
with Capacitor-Adjustable Ret Timeout Delay
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Pin Description
M A X 6412–M A X 6420
U the following formula to calculate the externally monitored voltage (V MON_TH ):
V MON_TH = V RST ✕(R1 + R2)/R2
where V MON_TH is the desired ret threshold voltage and V RST is the ret input threshold (1.26V). Resistors R1 and R2 can have very high values to minimize cur-rent consumption due to low leakage currents. Set R2to some conveniently high value (1M Ω, for example)and calculate R1 bad on the desired monitored volt-age, using the following formula:
R1 = R2 x (V MON_TH /V RST - 1) (Ω)
Manual Ret Input
(MAX6412/MAX6413/MAX6414)
Many µP bad products require manual ret capabil-ity, allowing the operator, a technician, or external logic circuitry to initiate a ret. A logic low on MR asrts ret. Ret remains asrted while MR is low and for the ret timeout period after MR returns high.
The MR has an internal 20k Ωpullup resistor so it can be left open if not ud. Connect a normally open momentary switch from MR to ground to create a man-ual ret function (external debounce circuitry is not required for long ret timeout periods).
A manual ret option can easily be implemented with the MAX6415–MAX6420 by connecting a normally open momentary switch in parallel with R2 (Figure 2). When the switch is clod, the voltage on RESET IN goes to zero,initiating a ret. Similar to the MAX6412/MAX6413/MAX6414 manual ret, ret remains asrted while the switch is clod and for the ret timeout period after the switch is opened.
Monitoring Voltages Other than V CC
(MAX6415/MAX6416/MAX6417)
The MAX6415/MAX6416/MAX6417 contain an adjustable ret threshold input. The devices can be ud to monitor voltages other than V CC . Calculate V MON_TH as shown in the Ret Threshold ction. (See Figure 3.)
with Capacitor-Adjustable Ret Timeout Delay
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电脑耗电_______________________________________________________________________________________
Figure 1. Calculating the Monitored Threshold Voltage (V MON_TH )
MAX6415–MAX6420
Figure 3. Monitoring External Voltages
