The M41ST85W is a combination Serial Real-Time Clock, Microprocessor Supervisor, and NVRAM Supervisor. It is built in a low power CMOS SRAM process and has a 64-byte memory space with 44 bytes of NVRAM and 20 memory-mapped RTC registers (see Table 2 on page 20). The RTC registers are configured in binary coded decimal (BCD) format.
■ Automatic Battery Switchover and WRITE protect for:
– Internal serial RTC and
– External low power SRAM (LPSRAM)
■ 400kHz I2C serial interface
■ 3.0/3.3V operating voltage
–VCC= 2.7 to 3.6V
■ Ultra-low Battery supply current of 500nA (max)
■ RoHS compliant
– Lead-free second level interconnect
Serial RTC features
■ 400kHz I2C
■ 44 bytes of general purpose NVRAM
■ Counters for:
– Seconds, minutes, hours, day, date, month, and year
– 10ths/100ths of seconds
– Clock calibration register allows compensation for crystal variations over temperature
■ Programmable alarm with repeat modes
– Functions in Battery back-up mode
■ Power-down timestamp (HT Bit)
■ 2.5 to 5.5V oscillator operating voltage Microprocessor Supervisor features
■ Programmable watchdog
– 62.5ms to 128s time-out period
■ Early power-fail warning circuit (PFI/PFO) with 1.25V precision reference
■ Power-on reset/low voltage detect
– Open drain reset output
– Reset voltage, VPFD= 2.60V (nom)
– Two reset input pins
– Watchdog can be steered to reset output
Description The STM690A/692A/703/704/802/805/817/818/819 Supervisors are self-contained devices which provide microprocessor Supervisory functions with the ability to non-volatize and write-protect external LPSRAM. A precision voltage reference and comparator monitors the VCC input for an out-of-tolerance condition. When an invalid VCC condition occurs, the reset output (RST) is forced low (or high in the case of RST). These devices also offer a watchdog timer (except for STM703/704/819) as well as a power-fail comparator (except for STM818) to provide the system with an early warning of impending power failure.
Features ■ 5 V operating voltage ■ NVRAM Supervisor for external LPSRAM ■ Chip-enable gating (STM818 only) for external LPSRAM (7 ns max prop delay) ■ RST and RSToutputs ■ 200 ms (typ) trec ■ Watchdog timer - 1.6 sec (typ) ■ Automatic Battery Switchover ■ Low Battery supply current - 0.4 µA (typ) ■ Power-fail comparator (PFI/PFO) ■ Low supply current - 40 µA (typ) ■ Guaranteed RST(RST) assertion down to VCC = 1.0 V ■ Operating temperature: –40 °C to +85 °C (industrial grade) ■ RoHS compliance – Lead-free components are compliant with the RoHS directive
The MAX4959/MAX4960 overvoltage protection controllers protect low-voltage systems against high-voltage faults of up to +28V. When the input voltage exceeds the overvoltage lockout (OVLO) threshold, these devices turn off an external pFET to prevent damage to the protected components. The undervoltage lockout (UVLO) threshold holds the external pFET off until the input voltage rises to the correct level. An additional safety feature latches off the pFET when an incorrect low-power adapter is plugged in.
♦ Overvoltage Protection Up to +28V
♦ ± 2.5% Accurate Externally Adjustable OVLO/UVLO Thresholds
♦ Battery Switchover pFET Control
♦ Protection Against Incorrect Power Adapter
♦ Low (100µA Typ) Supply Current
♦ 25ms Input Debounce Timer
♦ 25ms Blanking Time
♦ 10-Pin (2mm x 2mm) µDFN and 10-Pin µMAX Packages
General Description The MAX1774 is a complete power-supply solution for PDAs and other hand-held devices. It integrates two high-efficiency step-down converters, a boost converter for backup Battery regulation, and four voltage detectors in a small 32-pin QFN or 28-pin QSOP package.
Features ♦ Dual, High-Efficiency, Synchronous-Rectified Step-Down Converters ♦ Thin, Small (1mm High) QFN Package ♦ Step-Up Converter for Backup Battery ♦ Main Power Adjustable from +1.25V to +5.5V Over 2A Load Current Up to 95% Efficiency ♦ Core Power Adjustable from 1V to 5V Internal Switches Up to 1.5A Load Current Up to 91% Efficiency ♦ Automatic Main Battery Switchover ♦ 100% (max) Duty Cycle ♦ Up to 1.25MHz Switching Frequency ♦ Input Voltage Range from +2.7V to +28V ♦ Four Low-Voltage Detectors ♦ 170µA Quiescent Current ♦ 8µA Shutdown Current ♦ Digital Soft-Start ♦ Independent Shutdown Inputs
Applications Hand-Held Computers PDAs Internet Access Tablets POS Terminals Subnotebooks
SUMMARY DESCRIPTION The M40Z111/W NVRAM Supervisor is a self-contained device which converts a standard lowpower SRAM into a non-volatile memory. A precision voltage reference and comparator monitors the VCC input for an out-of-tolerance condition. When an invalid VCC condition occurs, the conditioned chip enable (ECON) output is forced inactive to write-protect the stored data in the SRAM. During a power failure, the SRAM is switched from the VCC pin to the lithium cell within the SNAPHAT® to provide the energy required for data retention. On a subsequent power-up, the SRAM remains write protected until a valid power condition returns. The 28-pin, 330mil SOIC provides sockets with gold plated contacts at both ends for direct connection to a separate SNAPHAT housing containing the Battery. The unique design allows the SNAPHAT Battery package to be mounted on top of the SOIC package after the completion of the surface mount process.
FEATURES SUMMARY ■ CONVERT LOW POWER SRAMs INTO NVRAMs ■ PRECISION POWER MONITORING and POWER SWITCHING CIRCUITRY ■ AUTOMATIC WRITE-PROTECTION WHEN VCC IS OUT-OF-TOLERANCE ■ CHOICE OF SUPPLY VOLTAGES and POWER-FAIL DESELECT VOLTAGES: – M40Z111: VCC = 4.5 to 5.5V THS = VSS; 4.5 ≤ VPFD ≤ 4.75V THS = VOUT; 4.2 ≤ VPFD ≤ 4.5V – M40Z111W: VCC = 3.0 to 3.6V THS = VSS; 2.8 ≤ VPFD ≤ 3.0V VCC = 2.7 to 3.3V THS = VOUT; 2.5 ≤ VPFD ≤ 2.7V ■ LESS THAN 15ns CHIP ENABLE ACCESS PROPAGATION DELAY (for 5.0V device) ■ PACKAGING INCLUDES A 28-LEAD SOIC and SNAPHAT® TOP (to be ordered separately) ■ SOIC PACKAGE PROVIDES DIRECT CONNECTION FOR A SNAPHAT TOP WHICH CONTAINS THE Battery
SUMMARY DESCRIPTION The STM1403 family of security Supervisors are a low power family of intrusion (tamper) detection chips targeted at manufacturers of POS terminals and other systems, to enable them to meet physical and/or environmental intrusion monitoring requirements as mandated by various standards, such as Federal Information Processing Standards (FIPS) Pub 140 entitled “Security Requirements for Cryptographic Modules,” published by the National Institute of Standards and Technology, U.S. Department of Commerce), EMVCo, ISO, ZKA, and VISA PED. STM1403 supports target levels 3 and lower
FEATURES* ■ STM1403 SUPPORTS FIPS-140 SECURITY LEVEL 3+ – 4 High-Impedance Physical Tamper Inputs – Over/Under Operating Voltage Detector – Security Alarm (SAL) on Tamper Detection ■ SupervisorY FUNCTIONS – Automatic Battery Switchover – RST Output (Open Drain) – Manual (Push-button) Reset Input (MR) – Power-fail Comparator (PFI/PFO) ■ Vccsw (VCC SWITCH OUTPUT) – Low When Switched to VCC – High When Switched to VBAT (BATT ON Indicator) ■ Battery LOW VOLTAGE DETECTOR (POWER-UP) ■ OPTIONAL VREF (1.237V) (Available for STM1403A only) ■ LOW Battery SUPPLY CURRENT (2.8µA, typ) ■ SECURE LOW PROFILE 16-PIN, 3x3mm, QFN PACKAGE
The M41T93 is a low power Serial SPI Bus Real Time Clock with a built-in 32.768kHz oscillator (external crystal-controlled for the QFN16 package, and embedded crystal for the SOX18 package). Eight bytes of the Register Map (see Table 3 on page 18) are used for the clock/calendar function and are configured in binary coded decimal (BCD) format. An additional 17 bytes of the Register Map provide status/control of the two Alarms, Watchdog, 8-Bit Counter, and Square Wave functions. An additional seven bytes are made available as user SRAM.
■ Ultra-low Battery supply current of 365nA
■ Factory calibrated accuracy ±5PPM guaranteed after 2 reflows (SOX18)
– Much better accuracies achievable using built-in programmable analog and digital calibration circuits
■ 2.0V to 5.5V clock operating voltage
■ Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century
■ Automatic switch-over and reset output circuitry (fixed reference)
–M41T93S: VCC= 3.0V to 5.5V (2.85V≤VRST ≤ 3.00V)
–M41T93R: VCC= 2.7V to 5.5V (2.55V≤VRST ≤ 2.70V)
–M41T93Z: VCC= 2.38V to 5.50V (2.25V≤VRST≤2.38V)
■ Compatible with SPI busserial interface (positive clock SPI modes)
■ Programmable alarm with interrupt function (valid even during Battery back-up mode)
■ Optional 2nd programmable alarm available
■ Square wave output (defaults to 32kHz on power-up)
■ RESET (RST) output
■ Watchdog timer
■ Programmable 8-bit counter/timer
■ 7 bytes of Battery-backed user SRAM
■ Battery low flag
■ Power-down timestamp (HT bit)
■ Low operating current of 80µA
■ Oscillator stop detection
■ Battery or Super-cap™ back-up
■ Operating temperature of –40°C to +85°C
■ Package options include:
– a 16-lead QFN or an 18-lead embedded crystal SOIC
■ RoHS compliance: lead-free components are compliant with the RoHS directive
SUMMARY DESCRIPTION The M40SZ100Y/W NVRAM Controller is a selfcontained device which converts a standard lowpower SRAM into a non-volatile memory. A precision voltage reference and comparator monitors the VCC input for an out-of-tolerance condition.
FEATURES SUMMARY ■ CONVERT LOW POWER SRAMs INTO NVRAMs ■ 5V OR 3V OPERATING VOLTAGE ■ PRECISION POWER MONITORING and POWER SWITCHING CIRCUITRY ■ AUTOMATIC WRITE-PROTECTION WHEN VCC IS OUT-OF-TOLERANCE ■ CHOICE OF SUPPLY VOLTAGES and POWER-FAIL DESELECT VOLTAGES: – M40SZ100Y: VCC = 4.5 to 5.5V; 4.20V ≤ VPFD ≤ 4.50V – M40SZ100W: VCC = 2.7 to 3.6V; 2.55V ≤ VPFD ≤ 2.70V ■ RESET OUTPUT (RST) FOR POWER ON RESET ■ 1.25V REFERENCE (for PFI/PFO) ■ LESS THAN 10ns CHIP ENABLE ACCESS PROPAGATION DELAY (at 5V) ■ OPTIONAL PACKAGING INCLUDES A 28-LEAD SOIC and SNAPHAT® TOP (to be ordered separately) ■ 28-LEAD SOIC PACKAGE PROVIDES DIRECT CONNECTION FOR A SNAPHAT TOP WHICH CONTAINS THE Battery ■ Battery LOW PIN (BL)
SUMMARY DESCRIPTION The STM690A/692A/703/704/802/805/817/818/819 Supervisors are self-contained devices which provide microprocessor Supervisory functions with the ability to non-volatize and write-protect external LPSRAM. A precision voltage reference and comparator monitors the VCC input for an out-oftolerance condition. When an invalid VCC condition occurs, the reset output (RST) is forced low (or high in the case of RST). These devices also offer a watchdog timer (except for STM703/704/819) as well as a power-fail comparator (except for STM818) to provide the system with an early warning of impending power failure. These devices are available in a standard 8-pin SOIC package or a space-saving 8-pin TSSOP package.
FEATURES SUMMARY ■ 5V OPERATING VOLTAGE ■ NVRAM Supervisor FOR EXTERNAL LPSRAM ■ CHIP-ENABLE GATING (STM818 only) FOR EXTERNAL LPSRAM (7ns max PROP DELAY) ■ RST AND RST OUTPUTS ■ 200ms (TYP) trec ■ WATCHDOG TIMER - 1.6sec (TYP) ■ AUTOMATIC Battery Switchover ■ LOW Battery SUPPLY CURRENT - 0.4µA (TYP) ■ POWER-FAIL COMPARATOR (PFI/PFO) ■ LOW SUPPLY CURRENT - 40µA (TYP) ■ GUARANTEED RST (RST) ASSERTION DOWN TO VCC = 1.0V ■ OPERATING TEMPERATURE: –40°C to 85°C (Industrial Grade) ■ RoHS COMPLIANCE Lead-free components are compliant with the RoHS Directive.
General Description The MIC2755 is composed of multiple comparators, a reset pulse generator, and logic. It is designed for monitoring the Battery supply of portable digital systems, including PDAs and pagers.
Features • Optimized for PDAs, pagers and other hand-held devices. • Detects multiple Battery states: - Battery OK - low Battery - dead Battery • Adjustable voltage thresholds • High accuracy ±2% voltage thresholds • Reset generation at power-on (700ms min.) • Debounced manual reset function • Internal logic prevents chatter if Battery voltage fluctuates • Extremely low 2µA typical supply current • I/Os can be pulled above VDD (7V absolute maximum) • Immune to brief power supply transients • Low cost • 8-lead MSOP