DS1388Z-33+ ,I2C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROMFeatures22The DS1388 I C real-time clock (RTC), supervisor, and ♦ Fast (400kHz) I C InterfaceEEPROM ..
DS1388Z-33+ ,I2C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROMApplicationsDS1388Z-33 -40°C to +85°C 8 SO (150 mils) DS138833Portable InstrumentsDS1388Z-5 -40°C t ..
DS1390U-33 ,Low-Voltage SPI/3-Wire RTCs with Trickle ChargerApplications Ordering InformationHand-Held DevicesPIN-PART TEMP RANGE TOP MARKGPS/Telematics Device ..
DS1390U-33 ,Low-Voltage SPI/3-Wire RTCs with Trickle ChargerFeaturesThe low-voltage serial-peripheral interface (SPI™) ♦ Real-Time Clock Counts Hundredths of S ..
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DS1391 ,Low-Voltage SPI/3-Wire RTCs with Trickle ChargerApplications Ordering InformationHand-Held DevicesPIN-PART TEMP RANGE TOP MARKGPS/Telematics Device ..
DTC143TM , 100mA / 50V Digital transistors (with built-in resistors)
DTC143TM , 100mA / 50V Digital transistors (with built-in resistors)
DTC143TS , DTA/DTC SERIES
DTC143TS , DTA/DTC SERIES
DTC143XE , 100mA / 50V Digital transistors (with built-in resistors)
DTC143XK , DTA/DTC SERIES
DS1388Z-33-DS1388Z-33+
I2C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROM
General DescriptionThe DS1388 I2C real-time clock (RTC), supervisor, and
EEPROM is a multifunction device that provides a
clock/calendar, programmable watchdog timer, power-
supply monitor with reset, and 512 bytes of EEPROM.
The clock provides hundredths of seconds, seconds,
minutes, and hours, and operates in 24-hour or 12-hour
format with an AM/PM indicator. The calendar provides
day, date, month, and year information. The date at the
end of the month is automatically adjusted for months
with fewer than 31 days, including corrections for leap
year. A watchdog timer provides a reset for an unre-
sponsive microprocessor. It is programmable in 10ms
intervals from 0.01 to 99.99 seconds. A temperature-
compensated voltage reference and comparator circuit
monitors the status of VCC. If a primary power failure is
detected, the device automatically switches to the
backup supply and drives the reset output to the active
state. The backup supply maintains time and date
operation in the absence of VCC. When VCCreturns to
nominal levels, the reset is held low for a period to allow
the power supply and processor to stabilize. The
device also has a pushbutton reset controller, which
debounces a reset input signal. The device is
accessed through an I2C serial interface.
ApplicationsPortable Instruments
Point-of-Sale Equipment
Network Interface Cards
Wireless Equipment
FeaturesFast (400kHz) I2C InterfaceRTC Counts Hundredths of Seconds, Seconds,
Minutes, Hours, Day, Date, Month, and Year with
Leap Year Compensation Valid Up to 2100Programmable Watchdog TimerAutomatic Power-Fail Detect and Switch CircuitryReset Output with Pushbutton Reset Input
Capability512 x 8 Bits of EEPROMIntegrated Trickle-Charge Capability for Backup
SupplyThree Operating Voltages: 5.0V, 3.3V, and 3.0VLow Timekeeping Voltage Down to 1.3V-40°C to +85°C Temperature RangeUL Recognized
DS13882C RTC/Supervisor with Trickle Charger
and 512 Bytes EEPROM
Pin Configuration
Typical Operating CircuitRev 0; 4/05
A ’+’ symbol near the pin one indicator indicates lead-free.
+ = Lead free.
Ordering InformationPurchase of I2C components from Maxim Integrated Products,
Inc., or one of its sublicensed Associated Companies, conveys
a license under the Philips I2C Patent Rights to use these com-
ponents in an I2C system, provided that the system conforms
to the I2C Standard Specification as defined by Philips.
DS13882C RTC/Supervisor with Trickle Charger
and 512 Bytes EEPROM
ABSOLUTE MAXIMUM RATINGS
RECOMMENDED DC OPERATING CONDITIONSStresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Voltage Range on VCCPin Relative to Ground.....-0.3V to +6.0V
Voltage Range on Inputs Relative
to Ground...............................................-0.3V to (VCC+ 0.3V)
Operating Temperature Range
(noncondensing).............................................-40°C to +85°C
Storage Temperature Range.............................-55°C to +125°C
Soldering Temperature.....................See IPC/JEDEC J-STD-020
Specification
DC ELECTRICAL CHARACTERISTICS
DS13882C RTC/Supervisor with Trickle Charger
and 512 Bytes EEPROM
DC ELECTRICAL CHARACTERISTICS (continued)
DC ELECTRICAL CHARACTERISTICS
DS13882C RTC/Supervisor with Trickle Charger
and 512 Bytes EEPROM
AC ELECTRICAL CHARACTERISTICS(VCC= VCC(MIN)to VCC(MAX), TA= -40°C to +85°C, unless otherwise noted.) (Note 1)
DS13882C RTC/Supervisor with Trickle Charger
and 512 Bytes EEPROM
POWER-UP/POWER-DOWN CHARACTERISTICSFigure 1. Power-Up/Down Timing
Figure 2. Pushbutton Reset Timing
DS13882C RTC/Supervisor with Trickle Charger
and 512 Bytes EEPROM
WARNING: Under no circumstances are negative undershoots, of any
amplitude, allowed when device is in write protection.
Note 1:Limits at -40°C are guaranteed by design and are not production tested.
Note 2:All voltages are referenced to ground.
Note 3:Measured at VCC= typ, VBACKUP= 0V, register 0Ah, block 0h = A5h.
Note 4:The use of the 250Ωtrickle-charge resistor is not allowed at VCC> 3.63V and should not be enabled.
Note 5:Measured at VCC= typ, VBACKUP= 0V, register 0Ah, block 0h = A6h.
Note 6:Measured at VCC= typ, VBACKUP= 0V, register 0Ah, block 0h = A7h.
Note 7:The RSTpin has an internal 50kΩpullup resistor to VCC.
Note 8:ICCA—SCL clocking at max frequency = 400kHz.
Note 9:Specified with I2C bus inactive.
Note 10:Measured with a 32.768kHz crystal attached to X1 and X2.
Note 11:After this period, the first clock pulse is generated.
Note 12:A device must internally provide a hold time of at least 300ns for the SDA signal (referred to the VIHMINof the SCL signal)
to bridge the undefined region of the falling edge of SCL.
Note 13:The maximum tHD:DATneed only be met if the device does not stretch the LOW period (tLOW) of the SCL signal.
Note 14:A fast-mode device can be used in a standard-mode system, but the requirement tSU:DAT≥250ns must then be met. This
is automatically the case if the device does not stretch the LOW period of the SCL signal. If such a device does stretch the
LOW period of the SCL signal, it must output the next data bit to the SDA line tR(MAX)+ tSU:DAT= 1000 + 250 = 1250ns
before the SCL line is released.
Note 15:CB—total capacitance of one bus line in pF.
Note 16:The parameter tOSFis the period of time that the oscillator must be stopped for the OSF flag to be set over the voltage
range of 0V ≤VCC≤VCC(MAX)and 1.3V ≤VBACKUP≤3.7V.
Note 17:If the oscillator is disabled or stopped, RSTgoes inactive after tRSTplus the startup time of the oscillator.
DS13882C RTC/Supervisor with Trickle Charger
and 512 Bytes EEPROM
Typical Operating Characteristics(VCC= +3.3V, TA = +25°C, unless otherwise noted.)
DS13882C RTC/Supervisor with Trickle Charger
and 512 Bytes EEPROM
Block Diagram
DS13882C RTC/Supervisor with Trickle Charger
and 512 Bytes EEPROM
Detailed DescriptionThe DS1388 I2C RTC, supervisor, and EEPROM is a
multifunction device that provides a clock/calendar,
programmable watchdog timer, power-supply monitor
with reset, and 512 bytes of EEPROM. The clock pro-
vides hundredths of seconds, seconds, minutes, and
hours, and operates in 24-hour or 12-hour format with
an AM/PM indicator. The calendar provides day, date,
month, and year information. The date at the end of the
month is automatically adjusted for months with fewer
than 31 days, including corrections for leap year. A
watchdog timer provides a reset for an unresponsive
microprocessor. It is programmable in 10ms intervals
from 0.01 to 99.99 seconds. A temperature-compensat-
ed voltage reference and comparator circuit monitors
the status of VCC. If a primary power failure is detected,
the device automatically switches to the backup supply
and drives the reset output to the active state. When
VCCreturns to nominal levels, the reset is held low for a
period to allow the power supply and processor to sta-
bilize. The device also has a pushbutton reset con-
troller, which debounces a reset input signal. The
device is accessed through an I2C serial interface.
OperationThe DS1388 operates as a slave device on the I2C bus.
Access is obtained by implementing a START condition
and providing a device identification code followed by
data. Subsequent registers can be accessed sequen-
tially until a STOP condition is executed. See the Block
Diagram, which shows the main elements of the serial
real-time clock.
Power ControlThe power-control function is provided by a precise,
temperature-compensated voltage reference and a
comparator circuit that monitors the VCClevel. The
device is fully accessible and data can be written and
read when VCCis greater than VPF. However, when
VCCfalls below VPF, the internal clock registers are
blocked from any access. If VPFis less than VBACKUP,
the device power is switched from VCCto VBACKUP
when VCCdrops below VPF. If VPFis greater than
VBACKUP, the device power is switched from VCCto
VBACKUPwhen VCCdrops below VBACKUP. The regis-
ters are maintained from the VBACKUPsource until VCC
is returned to nominal levels (Table1). After VCC
returns above VPF, read and write access is allowed
after RSTgoes high (Figure1).
Oscillator CircuitThe DS1388 uses an external 32.768kHz crystal. The
oscillator circuit does not require any external resistors
or capacitors to operate. Table2 specifies several
crystal parameters for the external crystal, and Figure3
shows a functional schematic of the oscillator circuit.
Using a crystal with the specified characteristics, the
startup time is usually less than one second.
