DS1339U-33 ,Serial Real-Time ClockFEATURES The DS1339 serial real-time clock (RTC) is a low- Real-Time Clock (RTC) Counts Seconds, ..
DS1339U-33+ ,I2C Serial Real-Time ClockAPPLICATIONS 2 2*I C is a trademark of Philips Corp. Purchase of I C components Handhelds (GPS, POS ..
DS1339U-33+ ,I2C Serial Real-Time ClockELECTRICAL CHARACTERISTICS (V = MIN to MAX, T = -40°C to +85°C.) (Note 1) CC APARAMETER SYMBOLCONDI ..
DS1339U-33+T&R ,I²C Serial Real-Time ClockELECTRICAL CHARACTERISTICS (V = MIN to MAX, T = -40°C to +85°C.) (Note 2) CC APARAMETER SYMBOL COND ..
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DS1339C-2-DS1339C-3-DS1339U-3-DS1339U-33-DS1339U-33+
I2C Serial Real-Time Clock
GENERAL DESCRIPTION The DS1339 serial real-time clock (RTC) is a low-power clock/date device with two programmable time-of-day alarms and a programmable square-wave
output. Address and data are transferred serially
through an I2C* bus. The clock/date provides seconds, minutes, hours, 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. The clock
operates in either the 24-hour or 12-hour format with
AM/PM indicator. The DS1339 has a built-in power-sense circuit that detects power failures and automatically switches to the backup supply,
maintaining time and date operation.
APPLICATIONS Handhelds (GPS, POS Terminals)
Consumer Electronics (Set-Top Box, Digital
Recording, Network Appliance)
Office Equipment (Fax/Printers, Copier)
Medical (Glucometer, Medicine Dispenser)
Telecommunications (Routers, Switches, Servers)
Other (Utility Meter, Vending Machine, Thermostat,
Modem)
FEATURES Real-Time Clock (RTC) Counts Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap-Year Compensation Valid Up to 2100 Available in a Surface-Mount Package with an
Integrated Crystal (DS1339C) I2C Serial Interface Two Time-of-Day Alarms Programmable Square-Wave Output Oscillator Stop Flag Automatic Power-Fail Detect and Switch Circuitry Trickle-Charge Capability Underwriters Laboratory (UL) Recognized
Pin Configurations appear at end of data sheet. 2C is a trademark of Philips Corp. Purchase 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 components in an I2C system, provided
that the system conforms to the I2C Standard Specification as
defined by Philips.
ORDERING INFORMATION + Denotes a lead-free/RoHS-compliant device.
## = second line, revision code
2 = 2.0V (VCC ±10%)
3 = 3.0V (VCC ±10%)
33 = 3.3V (VCC ±10%)
DS13392C Serial Real-Time Clock
DS1339 I2C Serial Real-Time Clock
ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Pin Relative to Ground………………………………………………………………-0.3V to +6.0V
Operating Temperature Range…(Noncondensing)….…………………………………………………….-40°C to +85°C Storage Temperature Range………………………………………………………………………………..-55°C to +125°C
Soldering Temperature Range………….See precautions in the Handling, PC Board Layout, and Assembly section.
Stresses 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 the absolute maximum rating conditions for extended periods may affect device reliability.
RECOMMENDED DC OPERATING CONDITIONS (TA = -40°C to +85°C) (Note 1)
DC ELECTRICAL CHARACTERISTICS (VCC = MIN to MAX, TA = -40°C to +85°C.) (Note 1)
DS1339 I2C Serial Real-Time Clock
DC ELECTRICAL CHARACTERISTICS (continued) (VCC = MIN to MAX, TA = -40°C to +85°C.) (Note 1)
DC ELECTRICAL CHARACTERISTICS (VCC = 0V, TA = -40°C to +85°C.) (Note 1)
DS1339 I2C Serial Real-Time Clock
AC ELECTRICAL CHARACTERISTICS (VCC = MIN to MAX, TA = -40°C to +85°C.) (Note 12)
DS1339 I2C Serial Real-Time Clock
POWER-UP/DOWN CHARACTERISTICS (TA = -40 C to +85°C) (Note 1, Figure 1)
WARNING: Under no circumstances are negative undershoots, of any amplitude, allowed when device is in
battery-backup mode.
Note 1: Limits at -40°C are guaranteed by design and are not production tested.
Note 2: SCL only.
Note 3: SDA and SQW/INT.
Note 4: ICCA—SCL at fSC max, VIL = 0.0V, VIH = VCC, trickle charger disabled.
Note 5: Specified with the I2C bus inactive, VIL = 0.0V, VIH = VCC, trickle charger disabled.
Note 6: Using recommended crystal on X1 and X2.
Note 7: After this period, the first clock pulse is generated.
Note 8: A device must internally provide a hold time of at least 300ns for the SDA signal (referred to the VIHMIN of the SCL signal) to bridge
the undefined region of the falling edge of SCL.
Note 9: The maximum tHD:DAT need only be met if the device does not stretch the LOW period (tLOW) of the SCL signal.
Note 10: A fast-mode device can be used in a standard-mode system, but the requirement tSU:DAT � to 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 11: CB—total capacitance of one bus line in pF.
Note 12: Guaranteed by design. Not production tested.
Note 13: The parameter tOSF is the period of time the oscillator must be stopped for the OSF flag to be set over the voltage range of 0.0V �
VCC � VCCMAX and 1.3V � VBACKUP � 3.7V.
Note 14: This delay applies only if the oscillator is running. If the oscillator is disabled or stopped, no power-up delay occurs.
Figure 1. Power-Up/Down Timing
DS1339 I2C Serial Real-Time Clock
Figure 2. Timing Diagram
Figure 3. Block Diagram DS1339 I2C Serial Real-Time Clock
PIN DESCRIPTION
TYPICAL OPERATING CIRCUIT DS1339 I2C Serial Real-Time Clock
DETAILED DESCRIPTION The DS1339 serial real-time clock (RTC) is a low-power clock/date device with two programmable time-of-day
alarms and a programmable square-wave output. Address and data are transferred serially through an I2C bus. The clock/date provides seconds, minutes, hours, 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. The clock operates in either the 24-hour or 12-hour format with AM/PM indicator. The DS1339 has a built-in power-
sense circuit that detects power failures and automatically switches to the backup supply, maintaining time and date operation.
OPERATION The DS1339 operates as a slave device on the serial bus. Access is obtained by implementing a START condition
and providing a device identification code followed by data. Subsequent registers can be accessed sequentially until a STOP condition is executed. The device is fully accessible and data can be written and read when VCC is
greater than VPF. However, when VCC falls below VPF, the internal clock registers are blocked from any access. If
VPF is less than VBACKUP, the device power is switched from VCC to VBACKUP when VCC drops below VPF. If VPF is
greater than VBACKUP, the device power is switched from VCC to VBACKUP when VCC drops below VBACKUP. The registers are maintained from the VBACKUP source until VCC is returned to nominal levels. The block diagram in
Figure 3 shows the main elements of the serial real-time clock.
OSCILLATOR CIRCUIT The DS1339 uses an external 32.768kHz crystal. The oscillator circuit does not require any external resistors or capacitors to operate. Table 1 specifies several crystal parameters for the external crystal. Figure 4 shows a
functional schematic of the oscillator circuit. The startup time is usually less than 1 second when using a crystal with the specified characteristics.
DS1339 I2C Serial Real-Time Clock
Table 1. Crystal Specifications* *The crystal, traces, and crystal input pins should be isolated from RF generating signals. Refer to
Application Note 58: Crystal Considerations for Dallas Real-Time Clocks for additional specifications.
Figure 4. Oscillator Circuit Showing Internal Bias Network
CLOCK ACCURACY The accuracy of the clock is dependent upon the accuracy of the crystal and the accuracy of the match between the capacitive load of the oscillator circuit and the capacitive load for which the crystal was trimmed. Additional
error is added by crystal frequency drift caused by temperature shifts. External circuit noise coupled into the oscillator circuit may result in the clock running fast. Figure 5 shows a typical PC board layout for isolating the
crystal and oscillator from noise. Refer to Application Note 58: Crystal Considerations with Dallas Real-Time Clocks for detailed information
DS1339C ONLY The DS1339C integrates a standard 32,768Hz crystal in the package. Typical accuracy at nominal VCC and +25°C
is approximately 10ppm. Refer to Application Note 58 for information about crystal accuracy vs. temperature.
Figure 5. Typical PC Board Layout for Crystal
