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Part: MAX6391KA23
Category:
Power Management
-> Supervisory Circuits
-> Microprocessor Supervisors
Description: MAX6391, MAX6392 Dual-voltage µP Supervisory Circuits With Sequenced Reset Outputs
Company: Maxim Integrated Products
Datasheet: Download MAX6391KA23 datasheet File size : 299 kB
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Datasheet text preview:
19-2210; Rev 1; 10/02
Dual-Voltage µP Supervisory Circuits with Sequenced Reset Outputs
General Description
The MAX6391/MAX6392 microprocessor (µP) supervisory circuits provide sequenced logic reset outputs for multicomponent or dual-voltage systems. Each device can monitor two supply voltages and time-sequence two reset outputs to control the order in which system components are turned on and off. The MAX6391/MAX6392 increase system reliability and reduce circuit complexity and cost compared to separate ICs or discrete components. The MAX6391/MAX6392 monitor V CC as the master reset supply. Both RESET1 and RESET2 are asserted whenever VCC drops below the selected factory-fixed reset threshold voltage. RESET1 remains asserted as l o n g as V C C i s below the threshold and deasserts 140ms (min) after VCC exceeds the thresholds. RESET IN2 is monitored as the secondary reset supply and is adjustable with an external resistive-divider netw o r k . RESET2 i s asserted whenever either V C C o r RESET IN2 is below the selected thresholds. RESET2 r e m a i n s asserted 140ms (min) or a capacitora d j u s t a b l e time period after V C C a n d RESET IN2 exceed their thresholds. RESET2 is always deasserted after RESET1 during system power-up and is always asserted before RESET1 during power-down. The MAX6391 includes two internal pullup resistors for RESET1 and RESET2 (the open-drain outputs can be externally connected to the desired pullup voltages). T h e MAX6392 includes an active-low manual reset input (MR) that asserts both RESET1 (push-pull) and RESET2 (open drain). The MAX6391/MAX6392 are available in small 8-pin SOT23 packages and are specified over the -40°C to +85°C extended temperature range.
Features
o Preset VCC Reset Threshold Voltages from 1.58V to 4.63V (master supply) o Customer-Adjustable RESET IN2 to Monitor Voltages Down to 625mV (secondary supply) o Fixed (140ms min) RESET1 Timeout o Fixed (140ms min) or Customer-Adjustable RESET2 Timeout Period o Guaranteed Reset Valid to VCC = 1V o Active-Low Open-Drain Outputs or PushPull/Open-Drain Combination o Internal Open-Drain Pullup Resistors (for external VOH voltage connections) o Manual Reset Input (MAX6392 only) o Immune to Short Negative VCC Transients o 15µA Typical Supply Current o Few External Components o Small 8-Pin SOT23 Package
MAX6391/MAX6392
Ordering Information
PART* MAX6391KA_ _-T MAX6392KA_ _-T TEMP RANGE -40°C to +85°C -40°C to +85°C PIN-PACKAGE SOT23-8 SOT23-8
Applications
Computers Controllers Critical µP Power Monitoring Set-Top Boxes Printers Servers/Workstations Industrial Equipment Multivoltage Monitoring
*Insert the desired suffix (see Selector Guide) into the blanks to complete the part number. The MAX6391/MAX6392 require a 2.5k minimum order increment and are available in tape-andreel only. Samples are typically available for standard versions (see Selector Guide for standard versions). Contact factory for availability.
Pin Configurations
TOP VIEW
RESET IN2 1 VCC 2 CSRT 3 8 7 R1 RESET1 R2 RESET2
MAX6391
6 5
GND 4
SOT23-8 Typical Operating Circuit appears at end of data sheet. Pin Configurations continued at end of data sheet. 1
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Dual-Voltage µP Supervisory Circuits with Sequenced Reset Outputs MAX6391/MAX6392
ABSOLUTE MAXIMUM RATINGS
VCC to GND ..-0.3V to +6.0V RESET1 (MAX6392), RESET IN2, CSRT, MR to GND ....-0.3V to (VCC + 0.3V) RESET1 (MAX6391), RESET2, R1, R2 to GND......-0.3V to +6.0V Input Current (VCC, GND, CSRT, R1, R2, MR) ........±20mA Output Current (RESET1, RESET2) ..........±20mA Continuous Power Dissipation (TA = +70°C) 8-Pin SOT23 (derate 5.26mW/°C above +70°C)..421mW Operating Temperature Range ...-40°C to +85°C Junction Temperature ......+150°C Storage Temperature Range .....-65°C to +150°C Lead Temperature (soldering, 10s) .........+300°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.
ELECTRICAL CHARACTERISTICS
(VCC = 1.2V to 5.5V, TA = TMIN to TMAX, unless otherwise specified. Typical values are at VCC = +5V and TA = +25°C.) (Note 1)
PARAMETER VCC Range Supply Current ICC SYMBOL CONDITIONS TA = 0°C to +85°C TA = -40°C to +85°C No load MAX639_UA46 MAX639_UA44 MAX639_UA31 MAX639_UA29 VCC Reset Threshold V TH1 MAX639_UA26 MAX639_UA23 MAX639_UA22 MAX639_UA17 MAX639_UA16 RESET IN2 Threshold RESET IN2 Input Current VCC to RESET1 Delay VCC or RESET IN2 to RESET2 Delay tRD1 tRD2 VCC falling at 1mV/µs (Note 2) 20 10 µs V TH2 VCC = 5V 4.50 4.25 3.00 2.85 2.55 2.25 2.12 1.62 1.54 610 MIN 1.0 1.2 15 4.63 4.38 3.08 2.93 2.63 2.32 2.19 1.67 1.58 625 TYP MAX 5.5 5.5 25 4.75 4.50 3.15 3.00 2.70 2.38 2.25 1.71 1.61 640 50 mV nA V UNITS V µA
2
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Dual-Voltage µP Supervisory Circuits with Sequenced Reset Outputs
ELECTRICAL CHARACTERISTICS (continued)
(VCC = 1.2V to 5.5V, TA = TMIN to TMAX, unless otherwise specified. Typical values are at VCC = +5V and TA = +25°C.) (Note 1)
PARAMETER RESET1 Timeout Period RESET2 Timeout Period (Note 3) SYMBOL tRP1 tRP2 CCSRT = 1500pF CCSRT = VCC ISINK = 50µA, reset asserted VOL VCC 1.0V, TA = 0°C to +85°C VCC 1.2V, TA = -40°C to +85°C CONDITIONS MIN 140 2.2 140 TYP 200 3.1 200 MAX 280 4.0 280 0.3 0.3 0.3 0.4 1.0 µA V UNITS ms ms
MAX6391/MAX6392
RESET_ Output Voltage Low
ISINK = 1.2mA, reset asserted, VCC 2.5V ISINK = 3.2mA, reset asserted, VCC 4.25V Open-Drain RESET Output Leakage Current Push-Pull RESET1 Output Voltage High (MAX6392 only) ILKG VCC VTH1, VRESET IN2 VTH2, reset not asserted VCC 2.25V, ISOURCE = 500µA, reset not asserted VOH VCC 4.5V, ISOURCE = 800µA, reset not asserted VCC > 4.0V 2.4
0.8 VCC 0.8 0.3 VCC 0.7 VCC 50 100
V
VIL VIH MR Input VIL
V
VCC < 4.0V VIH MR Minimum Pulse Width MR Glitch Rejection MR to RESET1 Delay MR to RESET2 Delay tMR Skew MR Pullup Resistance Reset Pullup Resistance tMR1 tMR2 tMR1 - tMR2 Pullup to VCC RESET1 to R1 or RESET2 to R2
µs ns µs ns µs 60 60 k k 10 100 10
35 35
47 47
Note 1: Overtemperature limits are guaranteed by design and not production tested. Devices tested at +25°C only. Note 2: RESET2 asserts before RESET1 when VCC goes below the threshold for all supply voltage and temperature ranges. Note 3: CSRT must be connected to either VCC (for fixed RESET2 timeout period) or an external capacitor (for useradjustable RESET2 timeout period).
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