The DS1124 is an 8-bit programmable timing element similar in function to the DS1021-25. The 256-delay intervals are programmed by using a 3-wire serial interface. With a 0.25ns step size, the DS1124 can provide a delay time from 20ns up to 84ns with an integral nonlinearity of ±3ns.ApplicationsDigital Test EquipmentDigital Video ProjectionLCD TelevisionsSignal Generators and AnalyzersTelecommunications

The DS1100 series delay lines have five equally spaced taps providing delays from 4ns to 500ns. These devices are offered in surface-mount packages to save PCB area. Low cost and superior reliability over hybrid technology is achieved by the combination of a 100% silicon delay line and industry-standard µMAX® and SO packaging. The DS1100 5-tap silicon delay line reproduces the input-logic state at the output after a fixed delay as specified by the extension of the part number after the dash. The DS1100 is designed to reproduce both leading and trailing edges with equal precision. Each tap can drive up to 10 74LS loads.Maxim can customize standard products to meet special needs.

The DS1100 series delay lines have five equally spaced taps providing delays from 4ns to 500ns. These devices are offered in surface-mount packages to save PCB area. Low cost and superior reliability over hybrid technology is achieved by the combination of a 100% silicon delay line and industry-standard µMAX® and SO packaging. The DS1100 5-tap silicon delay line reproduces the input-logic state at the output after a fixed delay as specified by the extension of the part number after the dash. The DS1100 is designed to reproduce both leading and trailing edges with equal precision. Each tap can drive up to 10 74LS loads.Maxim can customize standard products to meet special needs.

The DS1110 delay line is an improved replacement for the DS1010. It has ten equally spaced taps providing delays from 5ns to 500ns. The devices are offered in a standard 16-pin SO, or 14-pin TSSOP. The DS1110 series delay lines provide a nominal accuracy of ±5% or ±2ns, whichever is greater, at 5V and +25°C. The DS1110 reproduces the input logic state at the tap 10 output after a fixed delay as specified by the dash number extension of the part number. The DS1110 is designed to produce both leading- and trailing-edge delays with equal precision. Each tap is capable of driving up to ten 74LS type loads. Dallas Semiconductor can customize standard products to meet special needs.ApplicationsAutomated Test Equipment (ATE)Communication SystemsMedical DevicesPC Peripheral Devices

The DS1244 256k NV SRAM with a Phantom clock is a fully static nonvolatile RAM (NV SRAM) (organized as 32k words by 8 bits) with a built-in real-time clock. The DS1244 has a self-contained lithium energy source and control circuitry, which constantly monitors VCC for an out-of-tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent garbled data in both the memory and real-time clock.The phantom clock provides timekeeping information for hundredths of seconds, seconds, minutes, hours, days, date, months, and years. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. The phantom clock operates in either 24-hour or 12-hour format with an AM/PM indicator.

The DS1248 1024K NV SRAM with Phantom Clock is a fully static nonvolatile RAM (organized as 128K words by 8 bits) with a built-in real-time clock. The DS1248 has a self-contained lithium energy source and control circuitry, which constantly monitors VCC for an out-of-tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on and writes protection is unconditionally enabled to prevent garbled data in both the memory and real-time clock.

The DS1305 serial alarm real-time clock provides a full binary coded decimal (BCD) clock calendar that is accessed by a simple serial interface. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The end of the month date is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with AM/PM indicator. In addition, 96 bytes of NV RAM are provided for data storage. The DS1305 will maintain the time and date, provided the oscillator is enabled, as long as at least one supply is at a valid level. An interface logic power-supply input pin (VCCIF) allows the DS1305 to drive SDO and active-low PF pins to a level that is compatible with the interface logic. This allows an easy interface to 3V logic in mixed supply systems.The DS1305 offers dual-power supplies as well as a battery input pin. The dual power supplies support a programmable trickle charge circuit that allows a rechargeable energy source (such as a super cap or rechargeable battery) to be used for a backup supply. The VBAT pin allows the device to be backed up by a non-rechargeable battery. The DS1305 is fully operational from 2.0V to 5.5V.Two programmable time-of-day alarms are provided by the DS1305. Each alarm can generate an interrupt on a programmable combination of seconds, minutes, hours, and day. 'Don't care' states can be inserted into one or more fields if it is desired for them to be ignored for the alarm condition. The time-of-day alarms can be programmed to assert two different interrupt outputs or to assert one common interrupt output. Both interrupt outputs operate when the device is powered by VCC1, VCC2, or VBAT.The DS1305 supports direct serial peripheral interface SPI™ to serial data ports or standard 3-wire interface. A straightforward address and data format is implemented in which data transfers can occur 1 byte at a time or in multiple-byte-Burst Mode®.

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.