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MAX794CSE+T

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MAX794CSE+T

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Part Number MAX794CSE+T
Manufacturer Maxim Integrated
Description IC SUPERVISOR MPU 16-SOIC
Datasheet MAX794CSE+T Datasheet
Package 16-SOIC (0.154", 3.90mm Width)
In Stock 273 piece(s)
Unit Price $ 4.1126 *
Lead Time Can Ship Immediately
Estimated Delivery Time Oct 3 - Oct 8 (Choose Expedited Shipping)
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Part Number # MAX794CSE+T (PMIC - Supervisors) is manufactured by Maxim Integrated and distributed by Heisener. Being one of the leading electronics distributors, we carry many kinds of electronic components from some of the world’s top class manufacturers. Their quality is guaranteed by its stringent quality control to meet all required standards.

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MAX794CSE+T Specifications

ManufacturerMaxim Integrated
CategoryIntegrated Circuits (ICs) - PMIC - Supervisors
Datasheet MAX794CSE+TDatasheet
Package16-SOIC (0.154", 3.90mm Width)
Series-
TypeBattery Backup Circuit
Number of Voltages Monitored1
OutputOpen Drain, Push-Pull
ResetActive High/Active Low
Reset Timeout140 ms Minimum
Voltage - ThresholdAdjustable/Selectable
Operating Temperature0°C ~ 70°C (TA)
Mounting TypeSurface Mount
Package / Case16-SOIC (0.154", 3.90mm Width)
Supplier Device Package16-SOIC

MAX794CSE+T Datasheet

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General Description The MAX793/MAX794/MAX795 microprocessor (µP) supervisory circuits monitor and control the activities of +3.0V/+3.3V µPs by providing backup-battery switchover, among other features such as low-line indication, µP reset, write protection for CMOS RAM, and a watchdog (see the Selector Guide below). The backup-battery volt- age can exceed VCC, permitting the use of 3.6V lithium batteries in systems using 3.0V to 3.3V for VCC. The MAX793/MAX795 offer a choice of reset threshold voltage range (denoted by suffix letter): 3.00V to 3.15V (T), 2.85V to 3.00V (S), and 2.55V to 2.70V (R). The MAX794’s reset threshold is set externally with a resistor divider. The MAX793/MAX794 are available in 16-pin DIP and narrow SO packages, and the MAX795 comes in 8-pin DIP and SO packages. ________________________Applications Battery-Powered Computers and Controllers Embedded Controllers Intelligent Controllers Critical µP Power Monitoring Portable Equipment ____________________________Features MAX793/MAX794/MAX795  Precision Supply-Voltage Monitor: Fixed Reset Trip Voltage (MAX793/MAX795) Adjustable Reset Trip Voltage (MAX794)  Guaranteed Reset Assertion to VCC = 1V  Backup-Battery Power Switching—Battery Voltage Can Exceed VCC  On-Board Gating of Chip-Enable Signals—7ns Max Propagation Delay MAX793/MAX794 Only  Battery Freshness Seal  Battery OK Output (MAX793)  Uncommitted Voltage Monitor for Power-Fail or Low-Battery Warning  Independent Watchdog Timer (1.6s timeout)  Manual Reset Input M A X 7 9 3 /M A X 7 9 4 /M A X 7 9 5 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits ________________________________________________________________ Maxim Integrated Products 1 MAX793 RESET LOWLINE WDI CE IN CE OUT 3.0V OR 3.3V +5V BATT A0-A15 MR+5V SUPPLY FAILURE BATT ON PFI WDO OUT CMOS RAM ADDRESS DECODER 0.1µF PMOS 0.1µF VCC PFO GND I/O µP NMI RESET VCC VCC 0.1µF3.6V BATT OK (OPTIONAL) Si9433DY SILICONIX 19-0366; Rev 6; 3/10 FEATURE Active-Low Reset Active-High Reset Programmable Reset Threshold Low-Line Early Warning Output MAX793    MAX794     MAX795  Backup-Battery Switchover External Switch Driver Power-Fail Comparator       Battery OK Output    _____________________Selector Guide __________Typical Operating Circuit Watchdog Input Battery Freshness Seal     Manual Reset Input   Chip-Enable Gating   Pin-Package 16-DIP/SO 16-DIP/SO 8-DIP/SO Pin Configurations appear at end of data sheet. 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. Ordering Information PART* TEMP RANGE PIN- PACKAGE MAX793_CPE 0°C to +70°C 16 Plastic DIP MAX793_CSE 0°C to +70°C 16 Narrow SO Ordering Information continued at end of data sheet. *The MAX793/MAX795 offer a choice of reset threshold voltage. Select the letter corresponding to the desired reset threshold voltage range (T = 3.00V to 3.15V, S = 2.85V to 3.00V, R = 2.55V to 2.70V) and insert it into the blank to complete the part number. The MAX794’s reset threshold is adjustable. Devices are available in both leaded and lead-free packaging. Specify lead free by adding the + symbol at the end of the part number when ordering.

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µA M A X 7 9 3 /M A X 7 9 4 /M A X 7 9 5 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits 2 _______________________________________________________________________________________ ABSOLUTE MAXIMUM RATINGS ELECTRICAL CHARACTERISTICS (VCC = 3.17V to 5.5V for the MAX793T/MAX795T, VCC = 3.02V to 5.5V for the MAX793S/MAX795S, VCC = 2.72V to 5.5V for the MAX793R/MAX794/MAX795R, VBATT = 3.6V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) 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) VCC......................................................................-0.3V to +6.0V VBATT...................................................................-0.3V to +6.0V All Other Inputs ..................-0.3V to the higher of VCC or VBATT Continuous Input Current VCC .................................................................................200mA VBATT ................................................................................50mA GND ..................................................................................20mA Output Current VOUT................................................................................200mA All Other Outputs ..............................................................20mA Continuous Power Dissipation (TA = +70°C) 8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) .....727mW 8-Pin SO (derate 5.88mW/°C above +70°C)..................471mW 16-Pin Plastic DIP (derate 10.53mW/°C above +70°C) .842mW 16-Pin Narrow SO (derate 9.52mW/°C above +70°C) ...696mW Operating Temperature Ranges MAX793_C_ _/MAX794C_ _/MAX795_C_ _ ......... 0°C to +70°C MAX793_E_ _/MAX794E_ _/MAX795_E_ _ ........-40°C to +85°C Storage Temperature Range .............................-65°C to +160°C Lead Temperature (soldering, 10s) .................................+300°C Soldering Temperature (reflow) .......................................+260°C MAX79_E MAX79_C VBATT > VCC (Note 6) IOUT = 250µA (Note 4) IOUT = 30mA (Note 4) VSW > VCC > 1.75V (Note 5) IOUT = 75mA VBATT = 2.3V CONDITIONS Battery Switch Threshold (VCC falling) V 2.30 2.41 2.52 VSW 2.55 2.68 2.80 2.69 2.82 2.95 mV20 65 VCC - VBATT V VBATT - 0.14 VOUT OUT Output Voltage in Battery-Backup Mode VBATT - 0.1 VBATT - 0.034 V 1.1 5.5 1.0 5.5Operating Voltage Range, VCC, VBATT (Note 1) V VCC - 0.001 VCC - 0.5mV VOUT OUT Output Voltage in Normal Mode VCC - 0.12 VCC - 0.050 VCC - 0.3 VCC - 0.125 µA0.5 Battery Leakage Current (Note 3) µA1 BATT Supply Current (excluding IOUT) (Note 2) UNITSMIN TYP MAXSYMBOLPARAMETER VCC = 0V, VOUT = 0V µA1 BATT Leakage Current, Freshness Seal Enabled IOUT = 250µA IOUT = 1mA MAX793T/MAX795T MAX793S/MAX795S This value is identical to the reset threshold, VCC rising for VBATT > VRSTVCC - VBATT MAX793R/MAX795R/ MAX794 VBATT < VRST mV25 65 Battery Switch Threshold (VCC rising) (Note 7) MAX793/MAX794, MR = VCC µA 62 80 ISUPPLY 46 60 VCC Supply Current (excluding IOUT, ICE OUT) VCC = 2.1V, VBATT = 2.3V µA 32 45 ISUPPLY VCC Supply Current in Battery-Backup Mode (excluding IOUT) VCC < 3.6V VCC < 5.5V MAX793/MAX794 MAX795 24 35 MAX795 49 70 35 50VCC < 3.6V VCC < 5.5V

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M A X 7 9 3 /M A X 7 9 4 /M A X 7 9 5 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits _______________________________________________________________________________________ 3 ELECTRICAL CHARACTERISTICS (continued) (VCC = 3.17V to 5.5V for the MAX793T/MAX795T, VCC = 3.02V to 5.5V for the MAX793S/MAX795S, VCC = 2.72V to 5.5V for the MAX793R/MAX794/MAX795R, VBATT = 3.6V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) CONDITIONS 2.85 2.925 3.00 3.00 3.075 3.15 UNITSMIN TYP MAXSYMBOLPARAMETER VCC falling 3.00 3.085 3.17 2.55 2.625 2.70 VRST V VRST IN V VCC falling VCC rising RESET IN Threshold (MAX794 only) 1.212 1.240 1.262 Reset Threshold (Note 8) 2.55 2.635 2.72 2.85 2.935 3.02 VLR mV MAX793LOWLINE-to-Reset Threshold, (VLOWLINE - VRST), VCC Falling VCC < 3.6V 5 15 25 30 45 60 mV MAX793S/MAX795S MAX793T/MAX795T MAX794 MAX793 3.08 Low-Line Comparator Hysteresis 3.23 mV 10 10 mstRP 140 200 280Reset Timeout Period V MAX793R/MAX795R 2.78 nA VPFI rising VPFI falling PFI Input Current MAX794 V -25 2 25 VTH 1.212 1.250 1.287 PFI Input Threshold 1.212 1.240 1.262 VLL 1.317 LOWLINE Threshold, VCC Rising VVBOK 2.00 2.25 2.50 BATT OK Threshold (MAX793) VOH VISOURCE = 300µA, VCC = VRST max BATT OK, BATT ON, WDO, LOWLINE Output-Voltage High ISOURCE = 300µA, VCC = VRST min 0.8VCC 0.86VCC VVOH 0.8VCC 0.86VCCRESET Output-Voltage High mV10 20PFI Hysteresis, PFI Rising MAX793T/MAX795T MAX793S/MAX795S MAX793R/MAX795R MAX793T/MAX795T MAX793S/MAX795S MAX793R/MAX795R nA RESET IN Leakage Current (MAX794 only) -25 2 25 MAX794 VOH VISOURCE = 65µA, VCC = VRST maxPFO Output-Voltage High 0.8VCC VOH VISOURCE = 100µA, VCC = 2.3V, VBATT = 3V BATT ON Output- Voltage High 0.8VBATT ILEAK µAVCC = VRST max RESET Output Leakage Current (Note 9) -1 -1 ISC µAVCC = 3.3V, V PFO = 0V PFO Output Short to GND Current 180 500 VOL V ISINK = 1.2mA; RESET, LOWLINE tested with VCC = VRST min; RESET, BATTOK, WDO tested with VCC = VRST max PFO, RESET, RESET, WDO, LOWLINE Output-Voltage Low 0.08 0.2VCC INPUT AND OUTPUT LEVELS VCC rising 1.212 1.250 1.282

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M A X 7 9 3 /M A X 7 9 4 /M A X 7 9 5 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits 4 _______________________________________________________________________________________ CONDITIONS VOL V VOL VISINK = 3.2mA, VCC = VRST max MAX79_E, VBATT = VCC = 1.2V, ISINK = 200µA BATT ON Output- Voltage Low MAX79_C, VBATT = VCC = 1.0V, ISINK = 40µA 0.2VCC RESET Output-Voltage Low UNITSMIN TYP MAXSYMBOLPARAMETER VIL V tMR nsMAX793/MAX794 only VRST max < VCC < 5.5V MR Pulse Width 100 All Inputs Including PFO (Note 10) 0.3VCC VIH 0.7VCC 0.17 0.3 0.13 0.3 ELECTRICAL CHARACTERISTICS (continued) (VCC = 3.17V to 5.5V for the MAX793T/MAX795T, VCC = 3.02V to 5.5V for the MAX793S/MAX795S, VCC = 2.72V to 5.5V for the MAX793R/MAX794/MAX795R, VBATT = 3.6V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) tMD ns MAX793/MAX794 only, MR = 0V MAX793/MAX794 only µA MR-to-Reset Delay 25 70 250MR Pullup Current 75 250 Ω nsVCC = VRST max, Figure 9 Enable mode, VCC = VRST max CE IN-to-CE OUT Propagation Delay Disable mode 2 7 CE IN-to-CE OUT Resistance VOH VOL V VCC = VRST max, IOUT = 1.6mA, V CE IN = 0V VCC = VRST max, IOUT = -1mA, V CE IN = VCC CE OUT Drive from CE IN 0.2VCC 0.8VCC nA 46 ILEAK ±10CE IN Leakage Current Note 1: VCC supply current, logic-input leakage, watchdog functionality (MAX793/MAX794), MR functionality (MAX793/MAX794), PFI functionality (MAX793/MAX794), and state of RESET and RESET (MAX793/MAX794) tested at VBATT = 3.6V and VCC = 5.5V. The state of RESET is tested at VCC = VCC min. Note 2: Tested at VBATT = 3.6V, VCC = 3.5V and 0V. The battery current rises to 10µA over a narrow transition window around VCC = 1.9V. Note 3: Leakage current into the battery is tested under the worst-case conditions at VCC = 5.5V, VBATT = 1.8V and VCC = 1.5V, VBATT = 1.0V. Note 4: Guaranteed by design. Note 5: When VSW > VCC > VBATT, OUT remains connected to VCC until VCC drops below VBATT. The VCC-to-VBATT comparator has a small 15mV typical hysteresis to prevent oscillation. For VCC < 1.75V (typical), OUT switches to BATT regardless of VBATT. Note 6: When VBATT > VCC > VSW, OUT remains connected to VCC until VCC drops below the battery switch threshold (VSW). Note 7: OUT switches from BATT to VCC when VCC rises above the reset threshold, if VBATT > VRST. In this case, switchover back to VCC occurs at the exact voltage that causes reset to be asserted, however, switchover occurs 200ms prior to reset. If VBATT < VRST, OUT switches from BATT to VCC when VCC exceeds VBATT. Note 8: The reset threshold tolerance is wider for VCC rising than for VCC falling to accommodate the 10mV typical hysteresis, which prevents internal oscillation. Note 9: The leakage current into or out of the RESET pin is tested with RESET not asserted (RESET output high impedance). Note 10: PFO is normally an output, but is used as an input when activating the battery freshness seal. µs10Reset to CE OUT High Delay tWD s 0V < VCC < 5.5V Watchdog Timeout Period IOH = 500µA, VCC < 2.3V µA 1.00 1.60 2.25 -1 0.01 1WDI Input Current VVOH 0.8VBATT CE OUT Output-Voltage High (reset active) nsWDI Pulse Width 100 MANUAL RESET INPUT CHIP-ENABLE GATING WATCHDOG (MAX793/MAX794 only)

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M A X 7 9 3 /M A X 7 9 4 /M A X 7 9 5 3.0V/3.3V/Adjustable Microprocessor Supervisory Circuits _______________________________________________________________________________________ 5 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 -40 100 VCC-TO-OUT ON-RESISTANCE vs. TEMPERATURE M A X 79 3 TO C 1 TEMPERATURE (°C) V C C -T O -O U T O N -R ES IS TA N C E (Ω ) 20-20 0 8040 60 IOUT = 30mA VCC = 3.0V VCC = 3.3V VCC = 5V 160 140 120 100 80 60 40 -40 100 BATT-TO-OUT ON-RESISTANCE vs. TEMPERATURE M A X 79 3 TO C 2 TEMPERATURE (°C) B A TT -T O -O U T O N -R ES IS TA N C E (Ω ) 20-20 0 8040 60 VBATT = 3.6V VBATT = 3.0V VBATT = 5V IOUT = 250µA VCC = 0V 70 60 50 40 30 20 10 0 -40 100 VCC SUPPLY CURRENT vs. TEMPERATURE (NORMAL OPERATING MODE) M A X 79 3 TO C 3 TEMPERATURE (°C) V C C S U P P LY C U R R EN T (µ A ) 20-20 0 8040 60 MAX793/4, VCC = 3.3V MAX795, VCC = 3.3V MAX793/4, VCC = 5V VBATT = VCC = VOUT MAX795, VCC = 5V 0.10 0.08 0.06 0.04 0.02 0 -40 100 BATTERY SUPPLY CURRENT vs. TEMPERATURE (BATTERY-BACKUP MODE) M A X 79 3 TO C 4 TEMPERATURE (°C) S U P P LY C U R R EN T (µ A ) 20-20 0 8040 60 VCC = 0V VBATT = 3.6V 100 90 80 70 60 50 40 30 20 10 0 -40 100 MAX793 LOWLINE-TO-RESET THRESHOLD vs. TEMPERATURE M A X 79 3 TO C 7 TEMPERATURE (°C) LO W LI N E- TO -R ES ET T H R ES H O LD ( m V ) 20-20 0 8040 60 VCC FALLING 250 200 150 100 50 0 -40 100 RESET TIMEOUT PERIOD vs. TEMPERATURE M A X 79 3 TO C 5 TEMPERATURE (°C) R ES ET T IM EO U T P ER IO D ( m s) 20-20 0 8040 60 VCC RISING FROM OV TO VRST MAX 30 25 20 15 10 5 0 -40 100 RESET COMPARATOR PROPAGATION DELAY vs. TEMPERATURE (VCC FALLING) M A X 79 3 TO C 6 TEMPERATURE (°C) P R O P A G A TI O N D EL A Y ( µs ) 20-20 0 8040 60 10 8 6 4 2 0 -40 100 MAX793/MAX794 LOWLINE COMPARATOR PROPAGATION DELAY vs. TEMPERATURE M A X 79 3 TO C 8 TEMPERATURE (°C) P R O P A G A TI O N D EL A Y ( µs ) 20-20 0 8040 60 40mV OVERDRIVE VCC RISING VCC FALLING 1.250 1.245 1.240 1.235 1.230 -40 100 MAX793/MAX794 PFI THRESHOLD vs. TEMPERATURE M A X 79 3 TO C 9 TEMPERATURE (°C) P FI T H R ES H O LD ( V ) 20-20 0 8040 60 __________________________________________Typical Operating Characteristics (TA = +25°C, unless otherwise noted.)

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M A X 7 9 3 /M A X 7 9 4 /M A X 7 9 5 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits 6 _______________________________________________________________________________________ ____________________________Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) 1.242 1.241 1.240 1.239 1.238 1.237 1.236 30 25 20 15 10 5 0 -40 100 MAX794 RESET IN THRESHOLD AND LOWLINE-TO-RESET IN THRESHOLD vs. TEMPERATURE TEMPERATURE (°C) R ES ET IN T H R ES H O LD ( V ) LO W LI N E- TO -R ES ET IN T H R ES H O LD ( m V ) 20-20 0 8040 60 VLOWLINE - VRST VRESET IN VCC FALLING M A X 79 3 TO C 10 2.5 2.0 1.5 1.0 0.5 0 -40 100 MAX793 BATT OK THRESHOLD vs. TEMPERATURE M A X 79 3 TO C 11 TEMPERATURE (°C) B A TT O K T H R ES H O LD ( V ) 20-20 0 8040 60 VBATT FALLING 60 50 40 30 20 10 0 -40 100 CE IN-TO-CE OUT ON-RESISTANCE vs. TEMPERATURE TEMPERATURE (°C) C E IN -T O -C E O U T O N -R ES IS TA N C E (Ω ) 20-20 0 8040 60 VCC = VRST MAX M A X 79 3 TO C 12 1.70 1.65 1.60 1.55 1.50 -40 100 MAX793/MAX794 WATCHDOG TIMEOUT PERIOD vs. TEMPERATURE M A X 79 3 TO C 13 TEMPERATURE (°C) W A TC H D O G T IM EO U T P ER IO D ( se c) 20-20 0 8040 60 20 15 10 5 0 -40 100 MAX793/MAX794 BATTERY FRESHNESS SEAL LEAKAGE CURRENT vs. TEMPERATURE M A X 79 3 TO C 14 TEMPERATURE (°C) LE A K A G E C U R R EN T (n A ) 20-20 0 8040 60 VBATT = 5.5V VCC = 0V VOUT = 0V 1.002 1.001 1.000 0.999 0.998 0.997 0.996 -40 100 RESET THRESHOLD vs. TEMPERATURE (NORMALIZED) M A X 79 3 TO C 15 TEMPERATURE (°C) V R S T (N O R M A LI ZE D ) 20-20 0 8040 60 VCC FALLING 10 8 6 4 2 0 -40 100 MAX793/MAX794 PFI TO PFO PROPAGATION DELAY vs. TEMPERATURE M A X 79 3 TO C 16 TEMPERATURE (°C) P R O P A G A TI O N D EL A Y ( µs ) 20-20 0 8040 60 VPFI FALLING 20mV OVERDRIVE

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M A X 7 9 3 /M A X 7 9 4 /M A X 7 9 5 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits _______________________________________________________________________________________ 7 ______________________________________________________________Pin Description PIN Supply Output for CMOS RAM. When VCC rises above the reset threshold or above VBATT, OUT is connected to VCC through an internal p-channel MOSFET switch. When VCC falls below VSW and VBATT, BATT connects to OUT. OUT1 1 Reset Input. Connect to an external resistor-divider to select the reset threshold. The reset threshold can be programmed anywhere in the VSW to 5.5V range. RESET IN (MAX794) 3 — Battery Status Output. High in normal operating mode when VBATT exceeds VBOK, other- wise low. VBATT is checked continuously. Disabled and logic low while VCC is below VSW. BATT OK (MAX793) Main Supply InputVCC2 2 Power-Fail Comparator Output. When PFI is less than VPFT or when VCC falls below VSW, PFO goes low; otherwise, PFO remains high. PFO is also used to enable the bat- tery freshness seal (see Battery Freshness Seal and Power-Fail Comparator sections). PFO7 — Active-High Reset Output. Sources and sinks current. RESET is the inverse of RESET.RESET13 Chip-Enable Output. CE OUT goes low only when CE IN is low and reset is not asserted. If CE IN is low when reset is asserted, CE OUT remains low for 10µs or until CE IN goes high, whichever occurs first. CE OUT is pulled up to OUT. CE OUT12 — 6 GroundGND6 Power-Fail Comparator Input. When PFI is less than VPFT or when VCC falls below VSW, PFO goes low; otherwise, PFO remains high (see Power-Fail Comparator section). Connect to VCC if unused. PFI4 Chip-Enable Input. The input to the chip-enable gating circuit. Connect to GND if unused.CE IN11 5 4 — Watchdog Output. WDO goes low if WDI remains either high or low for longer than the watchdog timeout period. WDO returns high on the next transition of WDI. WDO is a logic high for VSW < VCC < VRST, and low when VCC is below VSW. WDO9 — Manual Reset Input. A logic low on MR asserts reset. Reset remains asserted as long as MR is low and for 200ms after MR returns high. The active-low input has an internal 70µA pullup current. It can be driven from a TTL- or CMOS-logic line or shorted to ground with a switch. Leave open if unused. MR8 — Watchdog Input. If WDI remains either high or low for longer than the watchdog timeout period, the internal watchdog timer runs out and WDO goes low. WDO returns high on the next transition of WDI. Connect WDO to MR to generate a reset due to a watchdog fault. WDI10 — Early Power-Fail Warning Output. Low when VCC falls to VLR. This output can be used to generate an NMI to provide early warning of imminent power failure. LOWLINE14 — Open-Drain, Active-Low Reset Output. Pulses low for 200ms when triggered, and stays low whenever VCC is below the reset threshold or when MR is a logic low. It remains low for 200ms after either VCC rises above the reset threshold, the watchdog triggers a reset (WDO connected to MR), or MR goes low to high. RESET15 7 Backup-Battery Input. When VCC falls below VSW and VBATT, OUT switches from VCC to BATT. When VCC rises above the reset threshold or above VBATT, OUT reconnects to VCC. VBATT can exceed VCC. Connect VCC, OUT, and BATT together if no battery is used. BATT16 8 Logic Output/External Bypass Switch-Driver Output. High when OUT switches to BATT. Low when OUT switches to VCC. Connect the base/gate of PNP/PMOS transistor to BATT ON for IOUT requirements exceeding 75mA. BATT ON5 3 MAX793/ MAX794 FUNCTIONNAME MAX795

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M A X 7 9 3 /M A X 7 9 4 /M A X 7 9 5 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits 8 _______________________________________________________________________________________ _______________Detailed Description General Timing Characteristics The MAX793/MAX794/MAX795 are designed for 3.3V and 3V systems, and provide a number of supervisory functions (see the Selector Guide on the front page). Figures 1 and 2 show the typical timing relationships of the various outputs during power-up and power-down with typical VCC rise and fall times. Manual Reset Input (MAX793/MAX794) Many microprocessor-based products require manual- reset capability, allowing the operator, a test technician, or external logic circuitry to initiate a reset. On the MAX793/MAX794, a logic low on MR asserts reset. Reset remains asserted while MR is low, and for tRP (200ms) after it returns high. During the first half of the reset time- out period (tRP), the state of MR is ignored if PFO is exter- nally forced low to facilitate enabling the battery fresh- ness seal. MR has an internal 70µA pullup current, so it can be left open if it is not used. This input can be driven with TTL- or CMOS-logic levels, or with open-drain/collec- tor outputs. Connect a normally open momentary switch from MR to GND to create a manual-reset function; exter- nal debounce circuitry is not required. If MR is driven from long cables or the device is used in a noisy environ- ment, connect a 0.1µF capacitor from MR to ground to provide additional noise immunity. Reset Outputs A microprocessor’s (µP’s) reset input starts the µP in a known state. These MAX793/MAX794/MAX795 µP supervisory circuits assert a reset to prevent code exe- cution errors during power-up, power-down, and VLOWLINE (MAX793/MAX794) VRESET (PULLED UP TO VCC) VRESET (MAX793/MAX794) (PFO FOLLOWS PFI) VCE OUT VBATT VWDO (MAX793/MAX794) VBOK (MAX793) MAX794: VRESET IN = VCC (VRST IN / VRST) PFO (MAX793/MAX794) BATT ON SHOWN FOR VCC = 0V to 3.3V, VBATT = 3.6V, CE IN = GND. TYPICAL PROPAGATION DELAYS REFLECT A 40mV OVERDRIVE. 5µs VSW VCC VRST VLL tRP 25µs 25µs 25µs 25µs tRP tRP/2 tRP/2 Figure 1. Timing Diagram, VCC Rising

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brownout conditions. RESET is guaranteed to be a logic low for 0V < VCC < VRST, provided VBATT is greater than 1V. Without a backup battery (VBATT = VCC = VOUT), RESET is guaranteed valid for VCC ≥ 1V. Once VCC exceeds the reset threshold, an internal timer keeps RESET low for the reset timeout period (tRP); after this interval, RESET becomes high imped- ance (Figure 2). RESET is an open-drain output, and requires a pullup resistor to VCC (Figure 3). Use a 4.7kΩ to 1MΩ pullup resistor that provides sufficient current to assure the proper logic levels to the µP. If a brownout condition occurs (VCC dips below the reset threshold), RESET goes low. Each time RESET is asserted, it stays low for the reset timeout period. Any time VCC goes below the reset threshold, the internal timer restarts. The watchdog output (WDO) can also be used to initi- ate a reset. See the Watchdog Output section. The RESET output is the inverse of the RESET output, and it can both source and sink current. M A X 7 9 3 /M A X 7 9 4 /M A X 7 9 5 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits _______________________________________________________________________________________ 9 VCC VLOWLINE (MAX793/MAX794) VRESET (RESET PULLED UP TO VCC) VRESET (MAX793/MAX794) VCE OUT VWDO (MAX793/MAX794) VBOK (MAX793) VPFO (MAX793/MAX794) SHOWN FOR VCC = 3.3V to 0V, VBATT = 3.6V, CE IN = GND, PFI = VCC. TYPICAL DELAY TIMES REFLECT A 40mV OVERDRIVE VBATT ON MAX794: VRESET IN = VCC (VRST IN / VRST) VBATT VBATT 4µs VLL VRST VSW 20µs 20µs 25µs 10µs 25µs 25µs 25µs 25µs Figure 2. Timing Diagram, VCC Falling

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August 21, 2020

Item sent as described. Showed up quickly. Worked as it said and would recommend again.

Madd***** Bandi

August 20, 2020

I was glad to find this product being sold at a great price. They were the perfect replacement.

Kia*****eil

August 16, 2020

Superb pricing and super fast delivery.

Pau*****yons

August 13, 2020

It gives you a good quality product, with a great variety.. I will for sure order this set again when i start to run low

Urie*****ndall

August 10, 2020

Very supportive of my small orders, but very glad easy to work with. Hard to see how it could be any more efficient!

Ani*****Logan

July 31, 2020

good item, quick delivery, prefer to recommended.

Flor***** Mitra

July 23, 2020

Item came in time and looks as described.

Hel*****Saini

July 14, 2020

Awesome components selection and availability. Ordering process is easy. They don't spam me after the purchase.

Vale*****Soto

July 6, 2020

Reasonable prices, fast shipping, and the best customer service I've ever experienced! Absolutely will share it to my friends.

MAX794CSE+T Guarantees

Service Guarantee

Service Guarantees

We guarantee 100% customer satisfaction.

Our experienced sales team and tech support team back our services to satisfy all our customers.

Quality Guarantee

Quality Guarantees

We provide 90 days warranty.

If the items you received were not in perfect quality, we would be responsible for your refund or replacement, but the items must be returned in their original condition.

MAX794CSE+T Packaging

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MAX794CSE+T

Certified Quality

Heisener's commitment to quality has shaped our processes for sourcing, testing, shipping, and every step in between. This foundation underlies each component we sell.

ISO9001:2015, ICAS, IAF, UKAS

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0755-83210559 ext. 805 SalesDept@heisener.com heisener007 3008774228 Send Message

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