Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - system monitor Reset/power-on reset SC 70 3

19-2242; Rev 2; 12/05

MAX6832–MAX6840

Ultra-Low-Voltage SC70 Voltage Detectors

and µP Reset Circuits

For pricing, delivery, and ordering information, please contact Maxim Direct

at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.

General Description

The MAX6832–MAX6840 are microprocessor (µP)

supervisory circuits used to monitor low-voltage power

supplies in µP and digital systems. They provide excel-

lent circuit reliability and low cost by eliminating exter-

nal components and adjustments when used with

+1.2V to +1.8V powered circuits.

These devices assert a reset signal whenever the V

supply voltage declines below a preset threshold or

whenever manual reset (MR) is asserted. Reset remains

asserted for a fixed timeout delay after V

has risen

above the reset threshold or when manual reset is

deasserted. Five different timeout periods are available:

70µs (voltage detector), 1.5ms, 30ms, 210ms, and 1.68s.

Reset thresholds suitable for operation with a variety of

supply voltages are available.

The MAX6832/MAX6835/MAX6838 have a push-pull

active-low reset output (RESET). The MAX6833/

MAX6836/MAX6839 have a push-pull active-high reset

output (RESET) and the MAX6834/MAX6837/MAX6840

have an open-drain active-low reset output (RESET). The

open-drain active-low reset output requires a pullup resis-

tor that can be connected to a voltage higher than V

The MAX6835/MAX6836/MAX6837 feature a debounced

manual reset input (MR), while the MAX6838/MAX6839/

MAX6840 provide a RESET-IN input allowing the user to

externally adjust the reset threshold. The reset compara-

tor is designed to ignore fast transients on V

Low supply current of 7.5µA makes the MAX6832–

MAX6840 ideal for use in portable equipment. These

devices are available in 3- and 4-pin SC70 packages.

Applications

Computers

Controllers

Intelligent Instruments

Critical µP and µC Power Monitoring

Portable/Battery-Powered Equipment

Features

o Factory-Set Reset Threshold Voltages for

Nominal Supplies from 1.2V to 1.8V

o Low Power Consumption: 7.5µA (typ)

o Space-Saving 3- and 4-Pin SC70 Packages

o ±2.5% Reset Threshold Accuracy Over

Temperature

o Five Different Timeout Periods Available: 70µs

(voltage detector), 1.5ms, 30ms, 210ms, and 1.68s

o Three Reset Output Configurations

Push-Pull RESET

Open-Drain RESET

o Guaranteed Reset Valid to V

0.55V—Active-Low

0.75V—Active-High

o Adjustable Threshold Reset-In Option

o Manual Reset Input Option

o Immune to Short Negative V

Transients

o Pin Compatible with MAX803/MAX809/MAX810,

MAX6711/MAX6712/MAX6713, and

MAX6381–MAX6390 Series

Ordering Information

Pin Configurations, Typical Operating Circuit, and Selector

Guide appear at end of data sheet.

PART TEMP RANGE PIN-PACKAGE

MAX6832_XRD_-T -40°C to +85°C 3 SC70-3

MAX6833_XRD_-T -40°C to +85°C 3 SC70-3

MAX6834_XRD_-T -40°C to +85°C 3 SC70-3

MAX6835_XSD_-T -40°C to +85°C 4 SC70-4

MAX6836_XSD_-T -40°C to +85°C 4 SC70-4

MAX6837_XSD_-T -40°C to +85°C 4 SC70-4

MAX6838XSD_-T -40°C to +85°C 4 SC70-4

MAX6839XSD_-T -40°C to +85°C 4 SC70-4

MAX6840XSD_-T -40°C to +85°C 4 SC70-4

Insert the desired suffix letter from the Threshold Suffix Guide

(MAX6832–MAX6837) and the Active Timeout Period Guide

tables into the blanks to complete the part number. Sample

stock is generally available on standard versions only (see

Standard Versions table). Standard versions require a minimum

order increment of 2.5k units. Nonstandard versions must be

ordered in 10k unit increments. Contact factory for availability.

All parts are offered 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.

Visit www.maximintegrated.com/products/patents

for

product patent marking information.

Summary of content (11 pages)

PAGE 1
MAX6832–MAX6840 Ultra-Low-Voltage SC70 Voltage Detectors and µP Reset Circuits General Description The MAX6832–MAX6840 are microprocessor (µP) supervisory circuits used to monitor low-voltage power supplies in µP and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with +1.2V to +1.8V powered circuits.
PAGE 2
MAX6832–MAX6840 Ultra-Low-Voltage SC70 Voltage Detectors and µP Reset Circuits ABSOLUTE MAXIMUM RATINGS Terminal Voltage (with respect to GND) VCC ........................................................................-0.3V to +6.0V Open-Drain RESET, MR .......................................-0.3V to +6.0V RESET-IN, Push-Pull RESET and RESET ..............................................-0.3V to (VCC + 0.3V) Input/Output Current (all pins) ............................................
PAGE 3
MAX6832–MAX6840 Ultra-Low-Voltage SC70 Voltage Detectors and µP Reset Circuits ELECTRICAL CHARACTERISTICS (continued) (VCC = +0.55V to +3.6V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER Propagation Delay (D0 only) SYMBOL tP Startup Time (D0 only) MR Input Voltage CONDITIONS VCC rising from 0 to 1.
PAGE 4
MAX6832–MAX6840 Ultra-Low-Voltage SC70 Voltage Detectors and µP Reset Circuits Typical Operating Characteristics (VCC = full range and TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C). VCC = 3.6V 14 VCC = 2.5V 10 VCC = 1.8V 8 VCC = 1.5V 6 4 2 VOD = OVERDRIVE (mV) 250 200 VOD = 10mV 150 VOD = 20mV 100 VOD = 100mV 50 VCC = 0.55V 0 VOD = 200mV 0 -40 -20 0 20 40 TEMPERATURE (°C) 60 80 -40 1.04 D1 OPTION 1.00 D2 OPTION 0.98 0.96 1.
PAGE 5
MAX6832–MAX6840 Ultra-Low-Voltage SC70 Voltage Detectors and µP Reset Circuits Pin Description—MAX6832–MAX6837 PIN MAX6833 SC70-3 MAX6832/ MAX6834 SC70-3 MAX6836 SC70-4 MAX6835/ MAX6837 SC70-4 NAME 1 1 1 1 GND — 2 2 — — 2 2 — FUNCTION Ground RESET Reset Output, Open-Drain or Push-Pull, Active-Low. RESET changes from HIGH to LOW when VCC drops below the selected reset threshold or MR is pulled low.
PAGE 6
MAX6832–MAX6840 Ultra-Low-Voltage SC70 Voltage Detectors and µP Reset Circuits Functional Diagrams MR (MAX6835/MAX6836/MAX6837 ONLY) VCC VCC MR PULLUP MANUAL RESET DETECT RESET TIMEOUT PERIOD RESET-IN RESET TIMEOUT PERIOD RESET OUTPUT RESET/ RESET VREF = 444mV VREF = 444mV RESET/ RESET RESET OUTPUT MAX6838/ MAX6839/ MAX6840 MAX6832– MAX6837 GND GND Detailed Description Reset Output A microprocessor’s (µP’s) reset input starts the µP in a known state.
PAGE 7
MAX6832–MAX6840 Ultra-Low-Voltage SC70 Voltage Detectors and µP Reset Circuits at RESET-IN allows for relatively large-value resistors to be used, which reduce power consumption. For example, for a 0.6V monitored trip level, if R2 = 200kΩ, then R1 = 70.3kΩ. Note that the minimum VCC of 1.1V is required to guarantee the RESET-IN threshold accuracy (see Electrical Characteristics table).
PAGE 8
MAX6832–MAX6840 Ultra-Low-Voltage SC70 Voltage Detectors and µP Reset Circuits Using The MAX6834/MAX6837/MAX6840 Open-Drain RESET Output with Multiple Supplies Generally, the pullup connected to the MAX6834/ MAX6837/MAX6840 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 levelshift from the monitored supply to reset circuitry powered by some other supply (Figure 5).
PAGE 9
MAX6832–MAX6840 Ultra-Low-Voltage SC70 Voltage Detectors and µP Reset Circuits Pin Configurations TOP VIEW GND GND 1 MAX6832 MAX6833 MAX6834 RESET (RESET) 3 2 4 1 MAX6835 MAX6836 MAX6837 VCC 2 RESET (RESET) 3 SC70-3 VCC RESET-IN MR VCC RESET (RESET) 2 3 GND SC70-4 ( ) ARE FOR MAX6836 Typical Operating Circuit 4 MAX6838 MAX6839 MAX6840 SC70-4 ( ) ARE FOR MAX6833 1 ( ) ARE FOR MAX6839 Selector Guide (continued) Table 3. Standard Versions (continued) VIN 3.3V DEVICE 1.
PAGE 10
MAX6832–MAX6840 Ultra-Low-Voltage SC70 Voltage Detectors and µP Reset Circuits Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.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.
PAGE 11
MAX6832–MAX6840 Ultra-Low-Voltage SC70 Voltage Detectors and µP Reset Circuits Package Information (continued) For the latest package outline information and land patterns (footprints), go to www.maximintegrated.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.