The DS1233A EconoReset monitors two vital conditions for a microprocessor: power supply and external override. A precision temperature-compensated reference and comparator circuit are used to monitor the status of the power supply (VCC). When an out-of-tolerance condition is detected, an internal power fail signal is generated which forces reset to the active state. When VCC returns to an in-tolerance condition, the reset signal is kept in the active state for approximately 350ms to allow the power supply and processor to stabilize. The second function of the DS1233A is pushbutton reset control. The DS1233A debounces a pushbutton closure and will generate a 350ms reset pulse upon release.

The DS1233 EconoReset monitors two vital conditions for a microprocessor: power supply and external override. A precision temperature-compensated reference and comparator circuit are used to monitor the status of the power supply (VCC). When an out-of-tolerance condition is detected, an internal power-fail signal is generated which forces reset to the active state. When VCC returns to an in-tolerance condition, the reset signal is kept in the active state for approximately 350ms to allow the power supply and processor to stabilize. The second function of the DS1233 is pushbutton reset control. The DS1233 debounces a pushbutton closure and will generate a 350ms reset pulse upon release.

The DS1554 is a full-function, year 2000-compliant (Y2KC), real-time clock/calendar (RTC) with an RTC alarm, watchdog timer, power-on reset, battery monitor, and 32k x 8 nonvolatile static RAM. User access to all registers within the DS1554 is accomplished with a byte-wide interface as shown in Figure 1.The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour binary-coded decimal (BCD) format. Corrections for day of month and leap year are made automatically.The RTC registers are double-buffered into an internal and external set. The user has direct access to the external set. Clock/calendar updates to the external set of registers can be disabled and enabled to allow the user to access static data. Assuming the internal oscillator is turned on, the internal set of registers is continuously updated; this occurs regardless of external registers settings to guarantee that accurate RTCinformation is always maintained.The DS1554 has interrupt (active-low IRQ/FT) and reset (active-low RST) outputs which can be used to control CPU activity. The active-low IRQ/FT interrupt output can be used to generate an external interrupt when the RTC Register values match user programmed alarm values. The interrupt is always available while the device is powered from the system supply and can be programmed to occur when in the battery-backed state to serve as a systemwakeup. Either the active-low IRQ/FT or active-low RST outputs can also be used as a CPU watchdog timer, CPU activity is monitored and an interrupt or reset output will be activated if the correct activity is not detected within programmed limits. The DS1554 power-on reset can be used to detect a system power down or failure and hold the CPU in a safe reset state until normal power returns and stabilizes; the active-low RST output is used for this function.The DS1554 also contains its own power-fail circuitry, which automatically deselects the device when the VCC supply enters an out of tolerance condition. This feature provides a high degree of data security during unpredictable system operation brought on by low VCC levels.

The DS1557 is a full-function, year-2000-compliant (Y2KC), real-time clock/calendar (RTC) with an RTC alarm, watchdog timer, power-on reset, battery monitor, and 512k x 8 nonvolatile static RAM. User access to all registers within the DS1557 is accomplished with a byte-wide interface as shown in Figure1. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour BCD format. Corrections for day of month and leap year are made automatically.The RTC registers are double-buffered into an internal and external set. The user has direct access to the external set. Clock/calendar updates to the external set of registers can be disabled and enabled to allow the user to access static data. Assuming the internal oscillator is turned on, the internal set of registers is continuously updated; this occurs regardless of external registers settings to guarantee that accurate RTCinformation is always maintained.The DS1557 has interrupt (active-low IRQ/FT) and reset (active-low RST) outputs which can be used to control CPU activity.The (active-low IRQ/FT) interrupt output can be used to generate an external interrupt when the RTC register values match user programmed alarm values. The interrupt is always available while the device is powered from the system supply and can be programmed to occur when in the battery-backed state to serve as a system wakeup. Either the active-low IRQ/FT or active-low RST outputs can also be used as a CPU watchdog timer, CPU activity ismonitored and an interrupt or reset output will be activated if the correct activity is not detected within programmed limits. The DS1557 power-on reset can be used to detect a system power down or failure and hold the CPU in a safe reset state until normal power returns and stabilizes; the active-low RST output is used for this function.The DS1557 also contains its own power-fail circuitry, which automatically deselects the device when the VCC supply enters an out-of-tolerance condition. This feature provides a high degree of data securityduring unpredictable system operation brought on by low VCC levels.

The DS1558 is a full function, year 2000-compliant (Y2KC), real-time clock/calendar with an RTC alarm, watchdog timer, power-on reset, battery monitor, and NV SRAM controller. User access to all registers within the DS1558 is accomplished with a byte-wide interface as shown in Figure 1. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour BCD format. Corrections for day of month and leap year are made automatically.The DS1558 maps the RTC registers into the SRAM address space and constantly monitors A0-A18. When any of the upper 16 address locations are accessed, the DS1558 inhibits active-low CER and active-low OER to the SRAM, and redirects reads and writes to the RTC registers within the DS1558. The DS1558 can be used with SRAMs up to 524,272 addresses. Smaller SRAMs can be used, provided that the unused upper address lines on the DS1558 are connected to VCC.The RTC registers are double-buffered into an internal and external set. The user has direct access to the external set. Clock/calendar updates to the external set of registers can be disabled and enabled to allow the user to access static data. Assuming the internal oscillator is turned on, the internal set of registers is continuously updated; this occurs regardless of external register settings to guarantee that accurate RTC information is always maintained.The DS1558 has interrupt (active-low IRQ/FT) and reset (active-low RST) outputs that can be used to control CPU activity. The active-low IRQ/FT interrupt output can generate an external interrupt when the RTC register values match user-programmed alarm values. The interrupt is always available while the device is powered from the system supply, and it can be programmed to occur when in the battery-backed state to serve as a system wake-up. The active-low IRQ/FT output can also be used as a CPU watchdog timer. CPU activity is monitored and an interrupt or reset output is activated if the correct activity is not detected within programmed limits. The DS1558 power-on reset can be used to detect a system power-down or failure and hold the CPU in a safe reset state until normal power returns and stabilizes; the active-low RST output is used for this function.The DS1558 also contains its own power-fail circuitry, which automatically protects the data in the clock and SRAM against out-of-tolerance VCCI conditions by inhibiting the active-low CE input when the VCC supply enters an out-of-tolerance condition. When VCCI goes below the level of VBAT, the external battery is switched on to supply energy to the clock and the external SRAM. This feature provides a high degree of data security during unpredictable system operation brought on by low VCC levels.

The DS17285, DS17485, DS17885, DS17287, DS17487, and DS17887 real-time clocks (RTCs) are designed to be successors to the industry-standard DS12885 and DS12887. The DS17285, DS17485, and DS17885 (hereafter referred to as the DS17x85) provide a real-time clock/calendar, one time-of-day alarm, three maskable interrupts with a common interrupt output, a programmable square wave, and 114 bytes of battery-backed NV SRAM. The DS17x85 also incorporates a number of enhanced functions including a silicon serial number, power-on/off control circuitry, and 2K, 4K, or 8Kbytes of battery-backed NV SRAM. The DS17287, DS17487, and DS17887 (hereafter referred to as the DS17x87) integrate a quartz crystal and lithium energy source into a 24-pin encapsulated DIP package. The DS17x85 and DS17x87 power-control circuitry allows the system to be poweredon by an external stimulus such as a keyboard or by a time-and-date (wake-up) alarm. The active-low PWR output pin is triggered by one or either of these events, and is used to turn on an external power supply. The active-low PWR pin is under software control, so that when a task is complete, the system power can then be shut down.For all devices, the date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. It also operates in either 24-hour or 12-hour format with an AM/PM indicator. A precision temperature-compensated circuit monitors the status of VCC. If a primary power failure is detected, the device automatically switches to a backup supply. A lithium coin cell battery can be connected to the VBAT input pin on the DS17x85 to maintain time and date operation when primary power is absent. The DS17x85 and DS17x87 include a VBAUX input used to power auxiliary functions such as active-low PWR control. The device is accessed through a multiplexed byte-wide interface.ApplicationsEmbedded SystemsNetwork Hubs, Bridges, and RoutersSecurity SystemsUtility Meters

The DS1631, DS1631A, and DS1731 digital thermometers provide 9, 10, 11, or 12-bit temperature readings over a -55°C to +125°C range. The DS1631 and DS1631A thermometer accuracy is ±0.5°C from 0°C to +70°C with 3.0V ≤ VDD ≤ 5.5V, and the DS1731 accuracy is ±1°C from -10°C to +85°C with 3.0V ≤ VDD ≤ 5.5V. The thermostat on all three devices provides custom hysteresis with user-defined trip points (TH and TL). The TH and TL registers and thermometer configuration settings are stored in NV EEPROM so they can be programmed prior to installation. In addition, the DS1631A automatically begins taking temperature measurements at power-up, which allows it to function as a stand-alone thermostat.ApplicationsMedicalNetworkingPersonal ComputingRouters/SwitchesTest Measurement SystemsWireless Base Stations

The DS1744 is a full-function, year-2000-compliant (Y2KC), real-time clock/calendar (RTC) and 32k x 8 NV SRAM. User access to all registers within the DS1744 is accomplished with a byte-wide interface as shown in Figure 1. The RTC information and control bits reside in the eight uppermost RAM locations. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour BCD format. Corrections for the date of each month and leap year are made automatically. The RTC clock registers are double-buffered to avoid access of incorrect data that can occur during clock update cycles. The double-buffered system also prevents time loss as the timekeeping countdown continues unabated by access to time register data. The DS1744 also contains its own power-fail circuitry that deselects the device when the VCC supply is in an out-of-tolerance condition. This feature prevents loss of data from unpredictable system operation brought on by low VCC as errant access and update cycles are avoided.

The DS1775 digital thermometer and thermostatprovides temperature readings that indicate the device’stemperature. Thermostat settings and temperaturereadings are all communicated to/from the DS1775 overa simple 2-wire serial interface. No additional componentsare required; the device is truly a “temperature-to-digital”converter.For applications that require greater temperature resolution,the user can adjust the readout resolution from 9 to 12bits. This is particularly useful in applications wherethermal runaway conditions must be detected quickly.The open-drain thermal alarm output, O.S., becomesactive when the temperature of the device exceeds auser-defined temperature TOS. The number of consecutivefaults required to set O.S. active is configurable by theuser. The device can also be configured in the interrupt orcomparator mode, to customize the method which clearsthe fault condition.As a digital thermometer, the DS1775 is software compatiblewith the DS75 2-wire thermal watchdog. The DS1775 isassembled in a compact 5-pin SOT23 package, allowingfor low-cost thermal monitoring/control in spaceconstrainedapplications. The low thermal mass allows fortime constants previously only possible with thermistors.ApplicationsAny Thermally-Sensitive SystemCell PhonesOffice EquipmentPersonal Computers/Servers/Workstations

The DS17285, DS17485, DS17885, DS17287, DS17487, and DS17887 real-time clocks (RTCs) are designed to be successors to the industry-standard DS12885 and DS12887. The DS17285, DS17485, and DS17885 (hereafter referred to as the DS17x85) provide a real-time clock/calendar, one time-of-day alarm, three maskable interrupts with a common interrupt output, a programmable square wave, and 114 bytes of battery-backed NV SRAM. The DS17x85 also incorporates a number of enhanced functions including a silicon serial number, power-on/off control circuitry, and 2K, 4K, or 8Kbytes of battery-backed NV SRAM. The DS17287, DS17487, and DS17887 (hereafter referred to as the DS17x87) integrate a quartz crystal and lithium energy source into a 24-pin encapsulated DIP package. The DS17x85 and DS17x87 power-control circuitry allows the system to be poweredon by an external stimulus such as a keyboard or by a time-and-date (wake-up) alarm. The active-low PWR output pin is triggered by one or either of these events, and is used to turn on an external power supply. The active-low PWR pin is under software control, so that when a task is complete, the system power can then be shut down.For all devices, the date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. It also operates in either 24-hour or 12-hour format with an AM/PM indicator. A precision temperature-compensated circuit monitors the status of VCC. If a primary power failure is detected, the device automatically switches to a backup supply. A lithium coin cell battery can be connected to the VBAT input pin on the DS17x85 to maintain time and date operation when primary power is absent. The DS17x85 and DS17x87 include a VBAUX input used to power auxiliary functions such as active-low PWR control. The device is accessed through a multiplexed byte-wide interface.ApplicationsEmbedded SystemsNetwork Hubs, Bridges, and RoutersSecurity SystemsUtility Meters

The DS17285, DS17485, DS17885, DS17287, DS17487, and DS17887 real-time clocks (RTCs) are designed to be successors to the industry-standard DS12885 and DS12887. The DS17285, DS17485, and DS17885 (hereafter referred to as the DS17x85) provide a real-time clock/calendar, one time-of-day alarm, three maskable interrupts with a common interrupt output, a programmable square wave, and 114 bytes of battery-backed NV SRAM. The DS17x85 also incorporates a number of enhanced functions including a silicon serial number, power-on/off control circuitry, and 2K, 4K, or 8Kbytes of battery-backed NV SRAM. The DS17287, DS17487, and DS17887 (hereafter referred to as the DS17x87) integrate a quartz crystal and lithium energy source into a 24-pin encapsulated DIP package. The DS17x85 and DS17x87 power-control circuitry allows the system to be poweredon by an external stimulus such as a keyboard or by a time-and-date (wake-up) alarm. The active-low PWR output pin is triggered by one or either of these events, and is used to turn on an external power supply. The active-low PWR pin is under software control, so that when a task is complete, the system power can then be shut down.For all devices, the date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. It also operates in either 24-hour or 12-hour format with an AM/PM indicator. A precision temperature-compensated circuit monitors the status of VCC. If a primary power failure is detected, the device automatically switches to a backup supply. A lithium coin cell battery can be connected to the VBAT input pin on the DS17x85 to maintain time and date operation when primary power is absent. The DS17x85 and DS17x87 include a VBAUX input used to power auxiliary functions such as active-low PWR control. The device is accessed through a multiplexed byte-wide interface.ApplicationsEmbedded SystemsNetwork Hubs, Bridges, and RoutersSecurity SystemsUtility Meters

The DS1804 NV trimmer potentiometer is a nonvolatile digital potentiometer that has 100 positions. The device provides an ideal method for low-cost trimming applications using a CPU or manual control input with minimal external circuitry. Wiper position of the DS1804 can be stored in EEPROM memory on demand. The device's wiper position is manipulated by a three-terminal port that provides an increment/ decrement counter controlled interface. This port consists of the control inputs active-low CS, active-low INC, and U/active-low D. The DS1804 is available in three resistor grades, which include a 10kΩ, 50kΩ, and 100kΩ. The device is provided in an industrial temperature grade. Additionally, the DS1804 will operate from 3V or 5V supplies and is ideal for portable application requirements. Three packaging options are available and include the 8-pin (300 mils) DIP, 8-pin (150 mils) SO, and 8-pin (118 mils) µSOP.

The DS18B20-PAR digital thermometer provides 9 to 12-bit centigrade temperature measurements and has an alarm function with nonvolatile user-programmable upper and lower trigger points. The DS18B20-PAR does not need an external power supply because it derives power directly from the data line ('parasite power'). The DS18B20-PAR communicates over a 1-Wire® bus, which by definition requires only one data line (and ground) for communication with a central microprocessor. It has an operating temperature range of -55°C to +100°C and is accurate to ±0.5°C over a range of -10°C to +85°C.Each DS18B20-PAR has a unique 64-bit identification code, which allows multiple DS18B20-PARs to function on the same 1-wire bus; thus, it is simple to use one microprocessor to control many DS18B20-PARs distributed over a large area. Applications that can benefit from this feature include HVAC environmental controls, temperature monitoring systems inside buildings, equipment or machinery, and process monitoring and control systems.ApplicationsRemote Sensing Applications

The DS18B20 digital thermometer provides 9-bit to 12-bit Celsius temperature measurements and has an alarm function with nonvolatile user-programmable upper and lower trigger points. The DS18B20 communicates over a 1-Wire bus that by definition requires only one data line (and ground) for communication with a central microprocessor. In addition, the DS18B20 can derive power directly from the data line ('parasite power'), eliminating the need for an external power supply.Each DS18B20 has a unique 64-bit serial code, which allows multiple DS18B20s to function on the same 1-Wire bus. Thus, it is simple to use one microprocessor to control many DS18B20s distributed over a large area. Applications that can benefit from this feature include HVAC environmental controls, temperature monitoring systems inside buildings, equipment, or machinery, and process monitoring and control systems.How to Spatially Index 1-Wire® Sensors Using the MAXREFDES131 and DS18B20 FAQs: DS18B20ApplicationsConsumer ProductsIndustrial SystemsThermally Sensitive SystemsThermometersThermostatic Controls

The DS2401 enhanced Silicon Serial Number is a low-cost, electronic registration number that provides an absolutely unique identity which can be determined with a minimal electronic interface (typically, a single port pin of a microcontroller). The DS2401 consists of a 64-bit ROM that includes a unique 48-bitserial number, an 8-bit CRC, and an 8-bit Family Code (01h). Data is transferred serially via the 1-Wire® protocol that requires only a single data lead and a ground return. Power for reading and writing the device is derived from the data line itself with no need for an external power source. The DS2401 is an upgrade to the DS2400. The DS2401 is fully reverse-compatible with the DS2400 but provides the additional multi-drop capability that enables many devices to reside on a single data line. The familiar TO-92, SOT-223 or TSOC package provides a compact enclosure that allows standard assembly equipment to handle the device easily.ApplicationsEquipment RegistrationNetwork-Node IdentificationPCB IdentificationReference Design License Management

The DS2401 enhanced Silicon Serial Number is a low-cost, electronic registration number that provides an absolutely unique identity which can be determined with a minimal electronic interface (typically, a single port pin of a microcontroller). The DS2401 consists of a 64-bit ROM that includes a unique 48-bitserial number, an 8-bit CRC, and an 8-bit Family Code (01h). Data is transferred serially via the 1-Wire® protocol that requires only a single data lead and a ground return. Power for reading and writing the device is derived from the data line itself with no need for an external power source. The DS2401 is an upgrade to the DS2400. The DS2401 is fully reverse-compatible with the DS2400 but provides the additional multi-drop capability that enables many devices to reside on a single data line. The familiar TO-92, SOT-223 or TSOC package provides a compact enclosure that allows standard assembly equipment to handle the device easily.ApplicationsEquipment RegistrationNetwork-Node IdentificationPCB IdentificationReference Design License Management

The DS5001FP 128k Soft Microprocessor Chip is an 8051-compatible Secure Microcontroller family, which is based on nonvolatile RAM rather than ROM.Dallas' 'soft' microprocessors can be programmed after installation in a system, which facilitates frequent software upgrades, adaptive programs, customized systems, etc. The user-set program and data partitions can also be modified to optimize reprogramming.Dallas' nonvolatile CMOS technology sets the standard for low-power consumption. With a user-supplied lithium battery, the on-chip power management circuitry can maintain all nonvolatile resources for greater than 10 years in the absence of external power.DS5001FP also provides crashproof operation in portable systems by saving the operating state and providing a power-fail reset, power-fail interrupt, and watchdog timer.The DS5001FP is intended for applications requiring large memory addressing. It includes bank switching that, with a little extra logic, enable it to address 252kbytes of data memory. The DS5001FP is available in a module that includes the RAM, a lithium cell and real-time clock (see the DS2251).The DS5001FP is ideal for data logging applications that require large, nonvolatile memory storage. It easily connects to a Dallas real-time clock to add nonvolatile, time-stamped data entry. Note: Designers must have the following documents to fully use all the features of this device. This data sheet contains pin descriptions, feature overviews, and electrical specifications. Errata sheets contain deviations from published specifications. The user's guides offer detailed information about device features and operation. DS5001FP IC data sheet DS5001FP revision-specific errata sheet (Click here for availability) Secure Microcontroller User's Guide

The DS60 analog temperature sensor measures its own temperature and provides these measurements to the user in the form of an output voltage (VO) that is proportional to degrees centigrade. The output voltage characteristic is factory-calibrated for a typical sensitivity of +6.25mV/°C and a DC offset of +424mV at 0°C. Its operating temperature range is -40°C to +125°C, corresponding to an output voltage range of +174mV to +1205mV. The DS60 has ±2.0°C accuracy over a 0°C to +85°C temperature range and over the full +2.7V to +5.5V power supply range. Its accuracy is within ±3.0°C over the operating temperature range and full supply range. Because the output voltage is positive for the entire temperature range, there is no need for a negative power supply.The DS60's tiny size, low-current operation, and wide supply range make it ideal for use in battery-powered applications. To further reduce power dissipation, the DS60 can be powered by any logic gate output that is capable of sourcing 125µA, which allows the DS60 to be switched to a zero power standby state when the gate is forced to a logic 0.ApplicationsAutomotiveMedical EquipmentVending Machine

The Maxim ICL7129A/MAX7129 is a high precision monolithic 4-1/2 digit A/D converter that directly drives a multiplexed liquid crystal display. Using a novel 'successive integration' technique, the ICL7129A/MAX7129 has a ±20,000 count resolution on both 2.00000V and 200.00mV ranges. It features high impedance differential inputs, excellent differential linearity, true ratiometric operation and auto polarity. The only external active component required to make precision DVM/DPMs is a reference. The overrange and underrange outputs and the 10:1 range changing input facilitate the design of autoranging systems. The ICL7129A/MAX7129 detects and flags a LOW BATTERY condition and also checks for continuity, giving a visual indication and a logic level output which can be used to generate an audible signal.The MAX7129 has a fullscale accuracy of 0.0005%, resolution of 10µV, zero reading drift of 0.5µV/°C, an input bias of 10pA max, and a rollover error of less than 1 count. Maxim has reduced the noise of the ICL7129A to 3µV—significantly lower than the MAX7129.

The LM4050/LM4051 are precision two-terminal, shuntmode, bandgap voltage references available in fixed reverse breakdown voltages of 1.225V, 2.048V, 2.500V, 3.000V, 3.3V, 4.096V, and 5.000V. Ideal for space-critical applications, the LM4050/LM4051 are offered in the subminiature 3-pin SC70 surface-mount packages (1.8mm x 1.8mm), 50% smaller than comparable devices in SOT23 surface-mount package (SOT23 versions are also available).Laser-trimmed resistors ensure excellent initial accuracy. With a 50ppm/°C temperature coefficient, these devices are offered in three grades of initial accuracy ranging from 0.1% to 0.5%. The LM4050/LM4051 have a 60µA to 15mA shunt-current capability with low dynamic impedance, ensuring stable reverse breakdown voltage accuracy over a wide range of operating temperatures and currents. The LM4050/LM4051 do not require an external stabilizing capacitor while ensuring stability with any capacitive loads.The LM4050/LM4051 specifications are guaranteed over the temperature range of -40°C to +125°C.ApplicationsAutomotiveCell PhonesIndustrial Process ControlsNotebook ComputersPortable Battery-Powered Equipment