The MAX821/MAX822 microprocessor (µP) supervisory circuits monitor power supplies in µP and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with 5V-powered or 3V-powered circuits. The MAX821/MAX822 also provide a power-on reset timeout delay that is pin selectable to 1ms (max), 20ms (min), or 100ms (min).These devices perform a single function: they assert a reset signal whenever the VCC supply voltage falls below a preset threshold, and they keep reset asserted for the pin-selected reset timeout delay after VCC has risen above the reset threshold. The only difference between the two devices is that the MAX821 has an active-low RESET output (which is guaranteed to be in the correct state for VCC down to 1V), while the MAX822 has an active-high RESET output. The reset comparator is designed to ignore fast transients on VCC. Reset thresholds suitable for operation with a variety of supply voltages are available.Low supply current makes the MAX821/MAX822 ideal for use in portable equipment. These devices come in a 4-pin SOT143 package.ApplicationsBar-Code ScannersComputers: Desktop, Workstation, ServerControllersCritical µP and µC Power MonitoringIntelligent InstrumentsPortable Battery-Powered Equipment

The MAX836/MAX837 micropower voltage monitors contain a 1.204V precision bandgap reference and a comparator in a SOT143 package. The MAX836 has an open-drain, N-channel output driver, while the MAX837 has a push-pull output driver. Two external resistors set the trip threshold voltage.ApplicationsBattery-Powered SystemsLoad SwitchingPrecision Battery MonitoringThreshold Detectors

The MAX860/MAX861 charge-pump voltage converters invert input voltages ranging from +1.5V to +5.5V, or double input voltages ranging from +2.5V to +5.5V. Because of their high switching frequencies, these devices use only two small, low-cost capacitors. Their 50mA output makes switching regulators unnecessary, eliminating inductors and their associated cost, size, and EMI. Greater than 90% efficiency over most of the load-current range, combined with a typical operating current of only 200µA (MAX860), provides ideal performance for both battery-powered and board-level voltage-conversion applications.A frequency-control (FC) pin provides three switching-frequencies to optimize capacitor size and quiescent current and to prevent interference with sensitive circuitry. Each device has a unique set of three available frequencies. A shutdown (active-low SHDN) pin reduces current consumption to less than 1µA. The MAX860/MAX861 are suitable for use in applications where the ICL7660 and MAX660's switching frequencies are too low. The MAX860/MAX861 are available in 8-pin µMAX® and SO packages.ApplicationsHandheld Instruments (PDAs, Palmtops)Interface Power SuppliesMedical InstrumentsOperational Amplifier Power SuppliesPortable Computing

The MAX8867/MAX8868 low-noise, low-dropout linear regulators operate from a 2.5V to 6.5V input and deliver up to 150mA. Typical output noise for these devices is just 30µVRMS, and typical dropout is only 165mV at 150mA. The output voltage is preset to voltages in the range of 2.5V to 5.0V, in 100mV increments. The MAX8867 and MAX8868 are pin-compatible with the MAX8863 and MAX8864, except for the BP pin.Designed with an internal P-channel MOSFET pass transistor, the MAX8867/MAX8868 maintain a low 100µA supply current, independent of the load current and dropout voltage. Other features include a 10nA logic-controlled shutdown mode, short-circuit and thermal-shutdown protection, and reverse battery protection. The MAX8868 also includes an auto-discharge function, which actively discharges the output voltage to ground when the device is placed in shutdown. Both devices come in regular and thin 5-pin SOT23 packages.ApplicationsCell PhonesCordless PhonesElectronic PlannersHandheld Instruments (PDAs, Palmtops)ModemsPalmtop ComputersPCMCIA CardsPCS Telephones

The MAX8877/MAX8878 low-noise, low-dropout linear regulators operate from a 2.5V to 6.5V input and deliver up to 150mA. These devices are pin-compatible with the industry-standard '2982 and offer an improved dropout voltage. Typical output noise is 30µVRMS, and typical dropout is only 165mV at 150mA. The output voltage is preset to voltages in the range of 1.5V to 5.0V, in 100mV increments.Designed with an internal P-channel MOSFET pass transistor, the MAX8877/MAX8878 maintain a low 100µA supply current, independent of the load current and dropout voltage. Other features include a 10nA logic-controlled shutdown mode, short-circuit and thermal-shutdown protection, and reverse battery protection. The MAX8878 also includes an auto-discharge function, which actively discharges the output voltage to ground when the device is placed in shutdown. Both devices come in regular and thin 5-pin SOT23 package.ApplicationsAudio SystemsCordless PhonesElectronic PlannersHandheld Instruments (PDAs, Palmtops)ModemsPalmtop ComputersPCMCIA CardsPCS Telephones

The MAX891L/MAX892L smart, low-voltage, P-channel, MOSFET power switches are intended for high-side load-switching applications. These switches operate with inputs from 2.7V to 5.5V, making them ideal for both 3V and 5V systems. Internal current-limiting circuitry protects the input supply against overload. Thermal-overload protection limits power dissipation and junction temperatures.The MAX891L/MAX892L's maximum current limits are 500mA and 250mA, respectively. The current limit through the switch is programmed with a resistor from SET to ground. When the switch is on, the quiescent supply current is a low 13µA. When the switch is off, the quiescent current decreases to 0.1µA.The MAX891L/MAX892L are available in 8-pin µMAX® packages.ApplicationsAccess Bus SlotsPCMCIA SlotsPortable Equipment

The MAX931–MAX934 single, dual, and quad micropower, low-voltage comparators plus an on-board 2% accurate reference feature the lowest power consumption available. These comparators draw less than 4µA supply current over temperature (MAX931), and include an internal 1.182V ±2% voltage reference, programmable hysteresis, and TTL/CMOS outputs that sink and source current.Ideal for 3V or 5V single-supply applications, the MAX931–MAX934 operate from a single +2.5V to +11V supply (or a ±1.25V to ±5V dual supply), and each comparator's input voltage range extends from the negative supply rail to within 1.3V of the positive supply.The MAX931–MAX934's unique output stage continuously sources as much as 40mA. And by eliminating power-supply glitches that commonly occur when comparators change logic states, the MAX931–MAX934 minimize parasitic feedback, making them easier to use.The single MAX931 and dual MAX932/MAX933 provide a unique and simple method for adding hysteresis without feedback and complicated equations, using the HYST pin and two resistors.For applications that require increased precision with similar power requirements, see the MAX921–MAX924 data sheet. These devices include a 1% precision reference.ApplicationsAlarm CircuitsBattery-Powered ApplicationsOscillator CircuitsThreshold DetectorsWindow Comparators

The MAX941/MAX942/MAX944 are single/dual/quad high-speed comparators optimized for systems powered from a 3V or 5V supply. These devices combine high speed, low power, and rail-to-rail inputs. Propagation delay is 80ns, while supply current is only 350µA per comparator.The input common-mode range of the MAX941/MAX942/MAX944 extends beyond both power-supply rails. The outputs pull to within 0.4V of either supply rail without external pullup circuitry, making these devices ideal for interface with both CMOS and TTL logic. All input and output pins can tolerate a continuous short-circuit fault condition to either rail.Internal hysteresis ensures clean output switching, even with slow-moving input signals. The MAX941 features latch enable and device shutdown.The single MAX941 and dual MAX942 are offered in a tiny µMAX® package. Both the single and dual MAX942 are available in 8-pin DIP and SO packages. The quad MAX944 comes in 14-pin DIP and narrow SO packages.Applications3V/5V SystemsBattery-Powered SystemsLine ReceiversSampling CircuitsThreshold Detectors/DiscriminatorsZero-Crossing Detectors

The MAX941/MAX942/MAX944 are single/dual/quad high-speed comparators optimized for systems powered from a 3V or 5V supply. These devices combine high speed, low power, and rail-to-rail inputs. Propagation delay is 80ns, while supply current is only 350µA per comparator.The input common-mode range of the MAX941/MAX942/MAX944 extends beyond both power-supply rails. The outputs pull to within 0.4V of either supply rail without external pullup circuitry, making these devices ideal for interface with both CMOS and TTL logic. All input and output pins can tolerate a continuous short-circuit fault condition to either rail.Internal hysteresis ensures clean output switching, even with slow-moving input signals. The MAX941 features latch enable and device shutdown.The single MAX941 and dual MAX942 are offered in a tiny µMAX® package. Both the single and dual MAX942 are available in 8-pin DIP and SO packages. The quad MAX944 comes in 14-pin DIP and narrow SO packages.Applications3V/5V SystemsBattery-Powered SystemsLine ReceiversSampling CircuitsThreshold Detectors/DiscriminatorsZero-Crossing Detectors

The MAX941/MAX942/MAX944 are single/dual/quad high-speed comparators optimized for systems powered from a 3V or 5V supply. These devices combine high speed, low power, and rail-to-rail inputs. Propagation delay is 80ns, while supply current is only 350µA per comparator.The input common-mode range of the MAX941/MAX942/MAX944 extends beyond both power-supply rails. The outputs pull to within 0.4V of either supply rail without external pullup circuitry, making these devices ideal for interface with both CMOS and TTL logic. All input and output pins can tolerate a continuous short-circuit fault condition to either rail.Internal hysteresis ensures clean output switching, even with slow-moving input signals. The MAX941 features latch enable and device shutdown.The single MAX941 and dual MAX942 are offered in a tiny µMAX® package. Both the single and dual MAX942 are available in 8-pin DIP and SO packages. The quad MAX944 comes in 14-pin DIP and narrow SO packages.Applications3V/5V SystemsBattery-Powered SystemsLine ReceiversSampling CircuitsThreshold Detectors/DiscriminatorsZero-Crossing Detectors

The MAX971–MAX974 and MAX981–MAX984 single/dual/quad low-voltage comparators feature the lowest power consumption available. These micropower devices draw less than 4µA supply current over temperature (MAX971/MAX972/MAX981/MAX982), and include an internal 1.182V ±1% (MAX971/MAX973/MAX974) or ±2% (MAX981–MAX984) voltage reference and programmable hysteresis.Ideal for 3V or 5V single-supply applications, these devices operate from a single 2.5V to 11V supply (or ±1.25V to ±5.5V dual supplies), and each comparator's input voltage ranges from the negative supply rail to within 1.3V of the positive supply.The single MAX971/MAX981 and the dual MAX973/ MAX982/MAX983 provide a unique, simple method for adding hysteresis without feedback or complicated equations, simply by using the HYST pin plus two resistors.The MAX971–MAX974 and MAX981–MAX984's open-drain outputs permit wire-ORed configurations. Thanks to an 11V output range and separate GND pin for the output transistor (MAX971/MAX974, MAX981/MAX984), these devices are ideal for level translators and bipolar to single-ended converters. For similar devices with complementary output stages, see the MAX921-MAX924 (1% reference) and the MAX931–MAX934 (2% reference).ApplicationsBattery-Powered SystemsLevel TranslatorsOscillator CircuitsThreshold DetectorsWindow Comparators

The MAX976/MAX978/MAX998 dual/quad/single, high-speed, low-power comparators are optimized for +3V/+5V single-supply applications. They achieve a 20ns propagation delay while consuming only 225µA supply current per comparator. The MAX998 features a low-power shutdown mode that places the output in a high-impedance state and reduces supply current to 1nA.The MAX976/MAX978/MAX998 inputs have a common-mode voltage range that extends 200mV below ground. Their outputs are capable of rail-to-rail operation withoutexternal pullup circuitry, making these devices ideal for interface with CMOS/TTL logic. All inputs and outputs can tolerate a continuous short-circuit fault condition to either rail. The comparators' internal hysteresis ensures clean output switching, even with slow-moving input signals.For space-critical applications, the single MAX998 is available in a 6-pin SOT23 package, the dual MAX976 is available in an 8-pin µMAX® package, and the quad MAX978 is available in a 16-pin QSOP package.Applications3V SystemsBattery-Powered ApplicationsDigital-Line ReceiversIR ReceiversThreshold Detectors/Discriminators

The MAX971–MAX974 and MAX981–MAX984 single/dual/quad low-voltage comparators feature the lowest power consumption available. These micropower devices draw less than 4µA supply current over temperature (MAX971/MAX972/MAX981/MAX982), and include an internal 1.182V ±1% (MAX971/MAX973/MAX974) or ±2% (MAX981–MAX984) voltage reference and programmable hysteresis.Ideal for 3V or 5V single-supply applications, these devices operate from a single 2.5V to 11V supply (or ±1.25V to ±5.5V dual supplies), and each comparator's input voltage ranges from the negative supply rail to within 1.3V of the positive supply.The single MAX971/MAX981 and the dual MAX973/ MAX982/MAX983 provide a unique, simple method for adding hysteresis without feedback or complicated equations, simply by using the HYST pin plus two resistors.The MAX971–MAX974 and MAX981–MAX984's open-drain outputs permit wire-ORed configurations. Thanks to an 11V output range and separate GND pin for the output transistor (MAX971/MAX974, MAX981/MAX984), these devices are ideal for level translators and bipolar to single-ended converters. For similar devices with complementary output stages, see the MAX921-MAX924 (1% reference) and the MAX931–MAX934 (2% reference).ApplicationsBattery-Powered SystemsLevel TranslatorsOscillator CircuitsThreshold DetectorsWindow Comparators

The MAX987/MAX988/MAX991/MAX992/MAX995/MAX996 single/dual/quad micropower comparatorsfeature low-voltage operation and rail-to-rail inputs andoutputs. Their operating voltage ranges from +2.5V to+5.5V, making them ideal for both 3V and 5V systems.These comparators also operate with ±1.25V to ±2.75Vdual supplies. They consume only 48µA per comparatorwhile achieving a 120ns propagation delay.Input bias current is typically 1.0pA, and input offset voltageis typically 0.5mV. Internal hysteresis ensures cleanoutput switching, even with slow-moving input signals.The output stage's unique design limits supply-currentsurges while switching, virtually eliminating the supplyglitches typical of many other comparators. TheMAX987/MAX991/MAX995 have a push-pull outputstage that sinks as well as sources current. Large internaloutput drivers allow rail-to-rail output swing withloads up to 8mA. The MAX988/MAX992/MAX996 havean open-drain output stage that can be pulled beyondVCC to 6V (max) above VEE. These open-drain versionsare ideal for level translators and bipolar to single-endedconverters.The single MAX987/MAX988 are available in tiny 5-pinSC70 packages, while the dual MAX991/MAX992 areavailable in ultra-small µMAX® package.ApplicationsDigital-Line ReceiversGround/Supply SensingIR ReceiversLevel TranslatorsMobile CommunicationsPortable Battery-Powered SystemsThreshold DetectorsWindow ComparatorsZero-Crossing Detectors

The MAX987/MAX988/MAX991/MAX992/MAX995/MAX996 single/dual/quad micropower comparatorsfeature low-voltage operation and rail-to-rail inputs andoutputs. Their operating voltage ranges from +2.5V to+5.5V, making them ideal for both 3V and 5V systems.These comparators also operate with ±1.25V to ±2.75Vdual supplies. They consume only 48µA per comparatorwhile achieving a 120ns propagation delay.Input bias current is typically 1.0pA, and input offset voltageis typically 0.5mV. Internal hysteresis ensures cleanoutput switching, even with slow-moving input signals.The output stage's unique design limits supply-currentsurges while switching, virtually eliminating the supplyglitches typical of many other comparators. TheMAX987/MAX991/MAX995 have a push-pull outputstage that sinks as well as sources current. Large internaloutput drivers allow rail-to-rail output swing withloads up to 8mA. The MAX988/MAX992/MAX996 havean open-drain output stage that can be pulled beyondVCC to 6V (max) above VEE. These open-drain versionsare ideal for level translators and bipolar to single-endedconverters.The single MAX987/MAX988 are available in tiny 5-pinSC70 packages, while the dual MAX991/MAX992 areavailable in ultra-small µMAX® package.ApplicationsDigital-Line ReceiversGround/Supply SensingIR ReceiversLevel TranslatorsMobile CommunicationsPortable Battery-Powered SystemsThreshold DetectorsWindow ComparatorsZero-Crossing Detectors

The MAX705–MAX708/MAX813L microprocessor (µP) supervisory circuits reduce the complexity and number of components required to monitor power-supply and battery functions in µP systems. These devices significantly improve system reliability and accuracy compared to separate ICs or discrete components.The MAX705/MAX706/MAX813L provide four functions:A reset output during power-up, power-down, and brownout conditions.An independent watchdog output that goes low if the watchdog input has not been toggled within 1.6 seconds.A 1.25V threshold detector for power-fail warning, low-battery detection, or for monitoring a power supply other than +5V.An active-low manual-reset input.The MAX707/MAX708 are the same as the MAX705/MAX706, except an active-high reset is substituted for the watchdog timer. The MAX813L is the same as the MAX705, except RESET is provided instead of active-low RESET.Two supply-voltage monitor levels are available: The MAX705/MAX707/MAX813L generate a reset pulse when the supply voltage drops below 4.65V, while the MAX706/MAX708 generate a reset pulse below 4.40V. All four parts are available in 8-pin DIP, SO and µMAX® packages.ApplicationsComputersControllersCritical µP Power MonitoringIntelligent Instruments

The MAX705–MAX708/MAX813L microprocessor (µP) supervisory circuits reduce the complexity and number of components required to monitor power-supply and battery functions in µP systems. These devices significantly improve system reliability and accuracy compared to separate ICs or discrete components.The MAX705/MAX706/MAX813L provide four functions:A reset output during power-up, power-down, and brownout conditions.An independent watchdog output that goes low if the watchdog input has not been toggled within 1.6 seconds.A 1.25V threshold detector for power-fail warning, low-battery detection, or for monitoring a power supply other than +5V.An active-low manual-reset input.The MAX707/MAX708 are the same as the MAX705/MAX706, except an active-high reset is substituted for the watchdog timer. The MAX813L is the same as the MAX705, except RESET is provided instead of active-low RESET.Two supply-voltage monitor levels are available: The MAX705/MAX707/MAX813L generate a reset pulse when the supply voltage drops below 4.65V, while the MAX706/MAX708 generate a reset pulse below 4.40V. All four parts are available in 8-pin DIP, SO and µMAX® packages.ApplicationsComputersControllersCritical µP Power MonitoringIntelligent Instruments

The MAX709 provides a system reset during power-up, power-down, and brownout conditions. When VCC falls below the reset threshold, RESET goes low and holds the µP in reset for 140ms min after VCC rises above the threshold.The RESET output is guaranteed to be in the correct state with VCC down to 1V. The MAX709 provides excellent circuit reliability and low cost by eliminating external components and adjustments when used with +5V, +3.3V, or +3V powered systems. The MAX709 is available 8-pin DIP, µMAX®, and SO packages.ApplicationsMinimum Component Count, Low-Cost Processor Systems

The MAX730A/MAX738A/MAX744A are 5V-output CMOS, step-down switching regulators. The MAX738A/MAX744A accept inputs from 6V to 16V and deliver 750mA. The MAX744A guarantees 500mA load capability for inputs above 6V and has tighter oscillator frequency limits for low-noise (radio) applications. The MAX730A accepts inputs between 5.2V and 11V and delivers 450mA for inputs above 6V. Typical efficiencies are 85% to 96%. Quiescent supply current is 1.7mA and only 6µA in shutdown.Pulse-width modulation (PWM) current-mode control provides precise output regulation and excellent transient responses. Output voltage accuracy is guaranteed to be ±5% over line, load, and temperature variations. Fixed-frequency switching allows easy filtering of output ripple and noise, as well as the use of small external components. These regulators require only a single inductor value to work in most applications, so no inductor design is necessary.The MAX730A/MAX738A/MAX744A also feature cycle-by-cycle current limiting, overcurrent limiting, undervoltage lockout, and programmable soft-start protection.ApplicationsCell PhonesComputer PeripheralsDistributed Power SystemsPersonal CommunicatorsPortable Instrumentation

The MAX7401/MAX7405 8th-order, lowpass, Bessel, switched-capacitor filters (SCFs) operate from a single +5V (MAX7401) or +3V (MAX7405) supply. These devices draw only 2mA of supply current and allow corner frequencies from 1Hz to 5kHz, making them ideal for low-power post-DAC filtering and anti-aliasing applications. They feature a shutdown mode that reduces supply current to 0.2µA.Two clocking options are available on these devices: self-clocking (through the use of an external capacitor) or external clocking for tighter corner-frequency control. An offset adjust pin allows for adjustment of the DC output level.The MAX7401/MAX7405 Bessel filters provide low overshoot and fast settling. Their fixed response simplifies the design task to selecting a clock frequency.ApplicationsADC Anti-AliasingAir-Bag ElectronicsCT2 Base StationsPost-DAC FilteringSpeech Processing