DS1342 Maxim, DS1342 Datasheet
DS1342
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DS1342 Summary of contents
Page 1
... The DS1341/DS1342 support high-ESR crystals, which broaden the pool of usable crystals for the devices. The DS1341 uses a 6pF crystal, while the DS1342 uses a 12.5pF crystal. These devices are accessed through serial interface ...
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... CC A PARAMETER SYMBOL Operating Voltage Range Minimum Timekeeping Voltage V Timekeeping Current: DS1341 CLKIN = GND or CLKIN = V CC (Note 4) Timekeeping Current: DS1342 CLKIN = GND or CLKIN = V CC (Note 4) Logic 1 Input Logic 0 Input Input Leakage (SCL, CLKIN/INTA) Output Leakage (CLKIN/INTA, SQW/INTB) Output Logic ...
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... HD:DAT (Note 10) SU:DAT t SU:STA t (Note 11 (Note 11) F SU:STO C (Note 11 (Note 12) I/O t (Note 12 (Note 13) OSF (Note 14) CONDITIONS f O ESR DS1341 C L DS1342 MIN TYP MAX UNITS 400 kHz 1.3 Fs 0.6 Fs 1 0.9 Fs 100 ns 0 300 ns 0. 300 ns 0.1C B 0.6 Fs ...
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... CC CCMAX Note 14: The DS1341/DS1342 can detect any single SCL clock held low longer than t in reset state and can receive a new START condition when SCL is held low for at least t detects this condition, the SDA output is released. The oscillator must be running for this function to work. ...
Page 5
... OUTPUT CURRENT (mA RTCs for High-ESR Crystals Typical Operating Characteristics DS1341 I 550 500 450 400 +25°C 350 300 250 -40°C 200 4 5 DS1342 I 550 500 450 +85°C 400 350 300 250 200 4 5 SQW/INTB OUTPUT-VOLTAGE LOW vs. OUTPUT CURRENT 0 +1.8V +25° ...
Page 6
... X1 designed for operation with a crystal having a specified load capacitance ( 12.5pF (DS1342). Clock Input/Active-Low Interrupt Output. This I/O pin is used to output an alarm interrupt or 3 accept an external clock input to drive the RTC counter. In the output mode, this is an open CLKIN/INTA drain and requires an external pullup resistor. If not used, connect this pin to ground. ...
Page 7
... The oscillator circuit does not require any external resistors or capacitors to operate. The devices support a high-ESR crystal, which broadens the pool of usable crystals for the device. The DS1342 uses a 12.5pF crys- tal. The DS1341 uses a 6pF crystal, which decreases oscillator current draw, but is less commonly available than the 12 ...
Page 8
Low-Current I External Synchronization When an external clock reference is used, the input from CLKIN/INTA is divided down to 1Hz by the divi- sor selected by the CLKSEL[2:1] bits. The 1Hz from the divider (Ext-1Hz, see the Functional Diagram) ...
Page 9
... ECLK bit is set. The external clock reference must be within the defined frequency tolerance prior to initializing the LOS flag. Table 1 shows the map for the DS1341/DS1342 regis- ters. During a multibyte access, if the address pointer reaches the end of the register space (0Fh), it wraps around to location 00h ...
Page 10
... Years register rolls over from 99 to 00. Illogical time and date entries result in an unde- fined operation. The DS1341/DS1342 can be run in either 12hr or 24hr mode. Bit 6 of the Hours register is defined as the 12hr or 24hr mode select bit. When high, the 12hr mode is selected ...
Page 11
Low-Current I When the RTC register values match alarm register set- tings, the corresponding alarm flag bit (A1F or A2F) is set the Control/Status register. If the correspond- ing alarm interrupt enable bit (A1IE or A2IE) is ...
Page 12
Low-Current I BIT 7 BIT 6 OSF DOSF 1 0 Control/Status Register (0Fh) Bit 7: Oscillator Stop Flag (OSF). If the OSF bit that indicates the oscillator has stopped or was stopped for some period of ...
Page 13
... Low-Current Serial Port Operation I The DS1341/DS1342s’ slave address byte is D0h. The first byte sent to the device includes the device identifier and the R/W bit (Figure 5). The device address sent by 2 the I C master must match the address assigned to the device ...
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... D0h), the master is indicating it writes data to the slave (D1h in this case), the master is indi- cating it wants to read from the slave incorrect slave address is written, the DS1341/DS1342 assume the master is communicating with another I and ignore the communication until the next START condition is sent ...
Page 15
... SDA is an open-drain output and requires an external pullup resistor to realize a logic-high level. Because the DS1341/DS1342 do not use clock cycle stretching, a master using either an open-drain output with a pullup resistor or CMOS output driver (push-pull) could be used for SCL. ...
Page 16
... NUMBER DATE 0 10/09 Initial release Removed future status from the DS1342 in the Ordering Information table; added the Package Thermal Characteristics section; added the DS1342 I the DC Electrical Characteristics table; changed the ESR specification in the Crystal 1 12/10 Parameters table from 80kW (max) to 100kW (max) and removed 35kW typ; added the TDFN package to the Ordering Information, Pin Configurations, Pin Description, and Package Information ...