View MAX803EXRT_4525782.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

19-0344; Rev 7; 2/10
3-Pin Microprocessor Reset Circuits
General Description
The MAX803/MAX809/MAX810 are microprocessor (P) supervisory circuits used to monitor the power supplies in P and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with +5V, +3.3V, +3.0V, or +2.5V powered circuits. These circuits perform a single function: they assert a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for at least 140ms after VCC has risen above the reset threshold. Reset thresholds suitable for operation with a variety of supply voltages are available. The MAX803 has an open-drain output stage, while the MAX809/MAX810 have push-pull outputs. The MAX803's open-drain RESET output requires a pullup resistor that can be connected to a voltage higher than VCC. The MAX803/MAX809 have an active-low RESET output, while the MAX810 has an active-high RESET output. The reset comparator is designed to ignore fast transients on VCC, and the outputs are guaranteed to be in the correct logic state for VCC down to 1V. Low supply current makes the MAX803/MAX809/ MAX810 ideal for use in portable equipment. The MAX803 is available in a 3-pin SC70 package, and the MAX809/MAX810 are available in 3-pin SC70 or SOT23 packages.
____________________________Features
Precision Monitoring of +2.5V, +3V, +3.3V, and +5V Power-Supply Voltages Fully Specified Over Temperature Available in Three Output Configurations Open-Drain RESET Output (MAX803) Push-Pull RESET Output (MAX809) Push-Pull RESET Output (MAX810) 140ms min Power-On Reset Pulse Width 12A Supply Current Guaranteed Reset Valid to VCC = +1V Power Supply Transient Immunity No External Components 3-Pin SC70 and SOT23 Packages
MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z
Ordering Information
PART MAX803_EXR-T MAX803_EXR+T MAX809_EXR-T MAX809_EXR+T MAX809_EUR-T MAX809_EUR+T MAX810_EXR-T MAX810_EXR+T MAX810_EUR-T MAX810_EUR+T TEMP RANGE -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +105C -40C to +105C -40C to +125C -40C to +125C -40C to +105C -40C to +105C PIN-PACKAGE 3 SC70 3 SC70 3 SC70 3 SC70 3 SOT23 3 SOT23 3 SC70 3 SC70 3 SOT23 3 SOT23
Applications
Computers Controllers Intelligent Instruments Critical P and C Power Monitoring Portable/Battery-Powered Equipment Automotive
Note: These parts are offered in 2.5k reels, and must be ordered in 2.5k increments. Insert the desired suffix letter from the Selector Guide into the blank to complete the part number. All versions of these products may not be available at the time of announcement. Contact factory for availability. Devices are available in both leaded and lead-free packaging. +Denotes a lead(Pb)-free/RoHS-compliant package.
Typical Operating Circuit
VCC VCC RPULLUP* VCC
Pin Configuration
TOP VIEW
GND 1
MAX803 MAX809
RESET RESET INPUT
P
MAX803 MAX809 MAX810
3
VCC
GND
GND
RESET (RESET) 2
*MAX803 ONLY
( ) ARE FOR MAX810. MAX803 AVAILABLE IN SC70-3 ONLY.
SC70-3/SOT23-3
________________________________________________________________ Maxim Integrated Products
1
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.
3-Pin Microprocessor Reset Circuits MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z
ABSOLUTE MAXIMUM RATINGS
Terminal Voltage (with respect to GND) VCC ....................................................................-0.3V to +6.0V RESET, RESET (push-pull) .....................-0.3V to (VCC + 0.3V) RESET (open drain)...........................................-0.3V to +6.0V Input Current, VCC ..............................................................20mA Output Current, RESET, RESET ..........................................20mA Rate of Rise, VCC ............................................................100V/s Continuous Power Dissipation (TA = +70C) 3-Pin SC70 (derate 2.17mW/C above +70C) ............174mW 3-Pin SOT23 (derate 4mW/C above +70C)...............320mW Operating Temperature Range 3-Pin SC70 .....................................................-40C to +125C 3-Pin SOT23...................................................-40C to +105C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C Soldering Temperature (reflow) .......................................+260C
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.
ELECTRICAL CHARACTERISTICS
(VCC = full range, TA = -40C to +105C (SOT23) or TA = -40C to +125C (SC70), unless otherwise noted. Typical values are at TA = +25C, VCC = 5V for L/M/J versions, VCC = 3.3V for T/S versions, VCC = 3V for R version, and VCC = 2.5V for Z version.) (Note 1)
PARAMETER VCC Range SYMBOL CONDITIONS TA = 0C to +70C TA = -40C to +105C (MAX8_ _ _EUR) TA = -40C to +125C (MAX8_ _ _EXR) TA = -40C to +85C Supply Current (SOT23) ICC TA = +85C to +105C TA = -40C to +85C Supply Current (SC70) ICC TA = +85C to +125C MAX8_ _L VCC < 5.5V, MAX8_ _L/M VCC < 3.6V, MAX8_ _R/S/T/Z VCC < 5.5V, MAX8_ _L/M VCC < 3.6V, MAX8_ _R/S/T/Z VCC < 5.5V, MAX8_ _L/M VCC < 3.6V, MAX8_ _R/S/T/Z VCC < 5.5V, MAX8_ _L/M VCC < 3.6V, MAX8_ _R/S/T/Z TA = +25C TA = -40C to +85C TA = -40C to +125C TA = +25C MAX8_ _M TA = -40C to +85C TA = -40C to +125C MAX809J (SOT only) Reset Threshold (SOT only) VTH MAX8_ _T TA = +25C TA = -40C to +85C TA = -40C to +125C TA = +25C TA = -40C to +85C TA = -40C to +125C TA = +25C MAX8_ _S TA = -40C to +85C TA = -40C to +125C TA = +25C MAX8_ _R TA = -40C to +85C TA = -40C to +125C 4.56 4.50 4.40 4.31 4.25 4.16 3.93 3.89 3.80 3.04 3.00 2.92 2.89 2.85 2.78 2.59 2.55 2.50 2.63 2.93 3.08 4.00 4.38 4.63 24 17 MIN 1.0 1.2 1.2 24 17 TYP MAX 5.5 5.5 5.5 60 50 100 100 35 30 60 60 4.70 4.75 4.86 4.45 4.50 4.56 4.06 4.10 4.20 3.11 3.15 3.23 2.96 3.00 3.08 2.66 2.70 2.76 V A V UNITS
2
_______________________________________________________________________________________
3-Pin Microprocessor Reset Circuits
ELECTRICAL CHARACTERISTICS (continued)
(VCC = full range, TA = -40C to +105C (SOT23) or TA = -40C to +125C (SC70), unless otherwise noted. Typical values are at TA = +25C, VCC = 5V for L/M/J versions, VCC = 3.3V for T/S versions, VCC = 3V for R version, and VCC = 2.5V for Z version.) (Note 1)
PARAMETER SYMBOL MAX8_ _L CONDITIONS TA = +25C TA = -40C to +85C TA = -40C to +125C TA = +25C MAX8_ _M TA = -40C to +85C TA = -40C to +125C TA = +25C MAX8_ _T Reset Threshold (SC70 only) VTH MAX8_ _S TA = -40C to +85C TA = -40C to +125C TA = +25C TA = -40C to +85C TA = -40C to +125C TA = +25C MAX8_ _R TA = -40C to +85C TA = -40C to +125C MAX8_ _Z (SC70 only) Reset Threshold Tempco VCC to Reset Delay (Note 2) Reset Active Timeout Period (SOT23) Reset Active Timeout Period (SC70) RESET Output Voltage Low (push-pull active low and opendrain active low, MAX803 and MAX809) VCC = VTH to (VTH - 100mV) TA = -40C to +85C TA = +85C to +105C TA = -40C to +85C TA = +85C to +125C VCC = VTH min, I SINK = 1.2mA, MAX803R/S/T/Z, MAX809R/S/T/Z VOL VCC = VTH min, I SINK = 3.2mA, MAX803L/M, MAX809J/L/M VCC > 1.0V, I SINK = 50A RESET Output Voltage High (push-pull active low MAX809) VCC > VTH max, ISOURCE = 500A, MAX803R/S/T/Z, MAX809R/S/T/Z VCC > VTH max, ISOURCE = 800A, MAX803L/M, MAX809J/L/M VCC = VTH max, ISINK = 1.2mA, MAX810R/S/T/Z VCC = VTH max, ISINK = 3.2mA, MAX810L/M 0.8VCC V VCC - 1.5 0.3 V 0.4 140 100 140 100 240 TA = +25C TA = -40C to +85C TA = -40C to +125C MIN 4.56 4.50 4.44 4.31 4.25 4.20 3.04 3.00 2.95 2.89 2.85 2.81 2.59 2.55 2.52 2.28 2.25 2.22 30 20 240 560 840 460 840 0.3 0.4 0.3 V 2.32 2.63 2.93 3.08 4.38 TYP 4.63 MAX 4.70 4.75 4.82 4.45 4.50 4.56 3.11 3.15 3.21 2.96 3.00 3.05 2.66 2.70 2.74 2.35 2.38 2.42 ppm/C s ms ms V UNITS
MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z
VOH
RESET Output Voltage Low (push-pull active high, MAX810)
VOL
_______________________________________________________________________________________
3
3-Pin Microprocessor Reset Circuits MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z
ELECTRICAL CHARACTERISTICS (continued)
(VCC = full range, TA = -40C to +105C (SOT23) or TA = -40C to +125C (SC70), unless otherwise noted. Typical values are at TA = +25C, VCC = 5V for L/M/J versions, VCC = 3.3V for T/S versions, VCC = 3V for R version, and VCC = 2.5V for Z version.) (Note 1)
PARAMETER RESET Output Voltage High (push-pull active high, MAX810) RESET Open-Drain Output Leakage Current (MAX803) (Note 3) SYMBOL VOH CONDITIONS 1.8V < VCC < VTH min, I SOURCE = 150A MIN 0.8VCC TYP MAX UNITS V
VCC > VTH, RESET deasserted
1
A
Note 1: Production testing done at TA = +25C; limits over temperature guaranteed by design only. Note 2: RESET output for MAX803/MAX809; RESET output for MAX810. Note 3: Guaranteed by design, not production tested.
Typical Operating Characteristics
(VCC = full range, TA = -40C to +105C, unless otherwise noted. Typical values are at TA = +25C, VCC = +5V for L/M/J versions, VCC = +3.3V for T/S versions, VCC = +3V for R version, and VCC = +2.5V for Z version.)
SUPPLY CURRENT vs. TEMPERATURE (SC70 PACKAGE, NO LOAD)
MAX803 toc01
POWER-DOWN RESET DELAY vs. TEMPERATURE (MAX8_ _R/S/T/Z)
MAX803-TOC3
POWER-DOWN RESET DELAY vs. TEMPERATURE (MAX8_ _J/L/M)
VOD = VTH - VCC VOD = 10mV
MAX803-TOC4
15
100 POWER-DOWN RESET DELAY (s)
140 POWER-DOWN RESET DELAY (s) 120 100 80 60 40 20 0
VOD = VTH - VCC VOD = 10mV
MAX8_ _L/M, VCC = 5V SUPPLY CURRENT (A) 10 MAX8_ _R/S/T, VCC = 3.3V MAX8_ _Z, VCC = 2.5V 5
80
60 VOD = 20mV 40
VOD = 20mV
20 0
VOD = 100mV VOD = 200mV -40 -20 20 0 40 TEMPERATURE (C) 60 85
VOD = 100mV VOD = 200mV -40 -20 20 0 40 TEMPERATURE (C) 60 85
MAX8_ _L/M/R/S/T/Z, VCC = 1V 0 -40 -20 0 20 40 60 85 TEMPERATURE (C)
POWER-UP RESET TIMEOUT vs. TEMPERATURE
MAX803-TOC5
NORMALIZED RESET THRESHOLD vs. TEMPERATURE
MAX803-TOC6
250 POWER-UP RESET TIMEOUT (ms)
1.003 1.002 NORMALIZED THRESHOLD 1.001 1.000 0.999 0.998 0.997
245 MAX8_ _J/L/M 240 MAX8_ _R/S/T/Z 235
230 225 -40 -20 0 20 40 60 85 TEMPERATURE (C)
-40
-20
0
20
40
60
85
TEMPERATURE (C)
4
_______________________________________________________________________________________
3-Pin Microprocessor Reset Circuits
Selector Guide
PART/SUFFIX MAX803L MAX803M MAX803T MAX803S MAX803R MAX803Z MAX809L MAX809M MAX809J MAX809T MAX809S MAX809R MAX809Z MAX810L MAX810M MAX810T MAX810S MAX810R MAX810Z RESET THRESHOLD (V) 4.63 4.38 3.08 2.93 2.63 2.32 4.63 4.38 4.00 3.08 2.93 2.63 2.32 4.63 4.38 3.08 2.93 2.63 2.32 OUTPUT TYPE OPEN-DRAIN RESET OPEN-DRAIN RESET OPEN-DRAIN RESET OPEN-DRAIN RESET OPEN-DRAIN RESET OPEN-DRAIN RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET PUSH-PULL RESET TOP MARK SOT AAAA ABAA CWAA ACAA ADAA AFAA AGAA AHAA AJAA AKAA ALAA SC70 AAZ ABA ABB ABC ABD ABE AAN AAO AAP AAQ AAR AAS AAT AAU AAV AAX AAW AAY
MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z
Detailed Description
A microprocessor's (P's) reset input starts the P in a known state. The MAX803/MAX809/MAX810 assert reset to prevent code-execution errors during powerup, power-down, or brownout conditions. They assert a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for at least 140ms after VCC has risen above the reset threshold. The MAX803 uses an open-drain output, and the MAX809/MAX810 have a push-pull output stage. Connect a pullup resistor on the MAX803's RESET output to any supply between 0 and 6V.
Applications Information
Negative-Going VCC Transients
In addition to issuing a reset to the P during power-up, power-down, and brownout conditions, the MAX803/ MAX809/MAX810 are relatively immune to short-duration negative-going VCC transients (glitches). Figure 1 shows typical transient duration vs. reset comparator overdrive, for which the MAX803/MAX809/ MAX810 do not generate a reset pulse. The graph was generated using a negative-going pulse applied to VCC, starting 0.5V above the actual reset threshold and ending below it by the magnitude indicated (reset comparator overdrive). The graph indicates the maximum pulse width a negative-going VCC transient can have without causing a reset pulse. As the magnitude of the transient increases (goes farther below the reset threshold), the maximum allowable pulse width decreases. Typically, for the MAX8__L and MAX8__M, a VCC transient that goes 100mV below the reset threshold and lasts 20s or less will not cause a reset pulse. A 0.1F bypass capacitor mounted as close as possible to the VCC pin provides additional transient immunity.
Pin Description
PIN 1 NAME GND RESET (MAX803/ MAX809) 2 RESET (MAX810) Ground RESET Output remains low while VCC is below the reset threshold, and for at least 140ms after VCC rises above the reset threshold. RESET Output remains high while VCC is below the reset threshold, and for at least 140ms after VCC rises above the reset threshold. Supply Voltage (+5V, +3.3V, +3.0V, or +2.5V) FUNCTION
3
VCC
When VCC falls below 1V, the MAX809 RESET output no longer sinks current--it becomes an open circuit.
5
Ensuring a Valid Reset Output Down to VCC = 0V
_______________________________________________________________________________________
3-Pin Microprocessor Reset Circuits MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z
Therefore, high-impedance CMOS logic inputs connected to RESET can drift to undetermined voltages. This presents no problem in most applications since most P and other circuitry is inoperative with V CC below 1V. However, in applications where RESET must be valid down to 0V, adding a pull-down resistor to RESET causes any stray leakage currents to flow to ground, holding RESET low (Figure 2). R1's value is not critical; 100k is large enough not to load RESET and small enough to pull RESET to ground. A 100k pullup resistor to VCC is also recommended for the MAX810 if RESET is required to remain valid for VCC < 1V.
Interfacing to Ps with Bidirectional Reset Pins
Since the RESET output on the MAX803 is open drain, this device interfaces easily with Ps that have bidirectional reset pins, such as the Motorola 68HC11. Connecting the P supervisor's RESET output directly to the microcontroller's (C's) RESET pin with a single pullup resistor allows either device to assert reset (Figure 3).
MAX803 Open-Drain RESET Output Allows Use with Multiple Supplies
Generally, the pullup connected to the MAX803 will connect to the supply voltage that is being monitored at the IC's VCC pin. However, some systems may use the open-drain output to level-shift from the monitored supply to reset circuitry powered by some other supply (Figure 4). Note that as the MAX803's VCC decreases
400 MAXIMUM TRANSIENT DURATION (s) TA = +25C 320
VCC
240
MAX809
RESET
160 MAX8_ _J/L/M 80 MAX8_ _R/S/T/Z 0 1 10 100 1000 RESET COMPARATOR OVERDRIVE, VTH - VCC (mV)
GND
R1 100k
Figure 2. RESET Valid to VCC = Ground Circuit
Figure 1. Maximum Transient Duration Without Causing a Reset Pulse vs. Reset Comparator Overdrive
+3.3V VCC VCC VCC VCC RPULLUP VCC +5.0V
MAX803
RESET RESET INPUT
P
MOTOROLA 68HCXX
5V SYSTEM
RESET INPUT
MAX803
RESET
GND GND GND
GND
Figure 3. Interfacing to Ps with Bidirectional Reset I/O
6
Figure 4. MAX803 Open-Drain RESET Output Allows Use with Multiple Supplies
_______________________________________________________________________________________
3-Pin Microprocessor Reset Circuits
below 1V, so does the IC's ability to sink current at RESET. Also, with any pullup, RESET will be pulled high as VCC decays toward 0. The voltage where this occurs depends on the pullup resistor value and the voltage to which it is connected.
Chip Information
TRANSISTOR COUNT: 275 (SOT23) 380 (SC70)
MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a "+", "#", or "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE 3 SC70 3 SOT23 PACKAGE CODE X3-2 U3-1 DOCUMENT NO. 21-0075 21-0051
Benefits of Highly Accurate Reset Threshold
Most P supervisor ICs have reset threshold voltages between 5% and 10% below the value of nominal supply voltages. This ensures a reset will not occur within 5% of the nominal supply, but will occur when the supply is 10% below nominal. When using ICs rated at only the nominal supply 5%, this leaves a zone of uncertainty where the supply is between 5% and 10% low, and where the reset may or may not be asserted. The MAX8_ _L/T/Z use highly accurate circuitry to ensure that reset is asserted close to the 5% limit, and long before the supply has declined to 10% below nominal.
_______________________________________________________________________________________
7
3-Pin Microprocessor Reset Circuits MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z
Revision History
REVISION NUMBER 0 7 REVISION DATE 12/94 2/10 Initial release. Updated Ordering information, added lead-free note, and added soldering temperature in the Absolute Maximum Ratings. DESCRIPTION PAGES CHANGED -- 1, 2
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.
8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.

▲Up To Search▲

Price & Availability of MAX803EXRT

	To Download MAX803EXRT Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .