Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsIntegrated Circuits (ICs)Timer IC t- real time clock Clock/calendar PDIP 8

AVAILABLE

Functional Diagrams

Pin Configurations appear at end of data sheet.

Functional Diagrams continued at end of data sheet.

UCSP is a trademark of Maxim Integrated Products, Inc.

For pricing, delivery, and

ordering information, please contact Maxim Direct

at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.

19-4652; 7/09

DS1337

GENERAL DESCRIPTION

The DS1337 serial real-time clock is a low-power

clock/calendar with two programmable time-of-day

alarms and a programmable square-wave output.

Address and data are transferred serially through an

C bus. The clock/calendar 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 device is fully accessible through the serial

interface while V

is between 1.8V and 5.5V. I

operation is not guaranteed below 1.8V.

Timekeeping operation is maintained with V

as low

as 1.3V.

APPLICATIONS

Handhelds (GPS, POS Terminal, MP3 Player)

Consumer Electronics (Set-Top Box, VCR/Digital

Recording)

Office Equipment (Fax/Printer, Copier)

Medical (Glucometer, Medicine Dispenser)

Telecommunications (Router, Switch, Server)

Other (Utility Meter, Vending Machine, Thermostat,

Modem)

TYPICAL OPERATING CIRCUIT

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 (DS1337C)

 I

C Serial Interface

 Two Time-of-Day Alarms

 Oscillator Stop Flag

 Programmable Square-Wave Output

Defaults to 32kHz on Power-Up

 Available in 8-Pin DIP, SO, or SOP

 -40C to +85C Operating Temperature Range

ORDERING INFORMATION

PART TEMP RANGE PIN-PACKAGE

TOP

MARK†

DS1337+ -40°C to +85°C 8 DIP (300 mils) DS1337

DS1337S+ -40°C to +85°C 8 SO (150 mils) DS1337

DS1337U+ -40°C to +85°C

8 SOP

1337

DS1337C# -40°C to +85°C 16 SO (300 mils) DS1337C

+ Denotes a lead(Pb)-free/RoHS-compliant device.

# Denotes a RoHS-compliant device that may include lead that is

exempt under the RoHS requirements. The lead finish is JESD97

category e3, and is compatible with both lead-based and lead-free

soldering processes.

† A “+” anywhere on the top mark denotes a lead-free device. A

“#” denotes a RoHS-compliant device.

Pin Configurations appear at end of data sheet.

C Serial Real-Time Clock

www.maxim-ic.com

Summary of content (16 pages)

PAGE 1
LE AVAILAB DS1337 I C Serial Real-Time Clock 2 www.maxim-ic.com GENERAL DESCRIPTION FEATURES The DS1337 serial real-time clock is a low-power clock/calendar 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/calendar provides seconds, minutes, hours, day, date, month, and year information.
PAGE 2
DS1337 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…………………………………………………………See IPC/JEDEC J-STD-020 Specification Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device.
PAGE 3
DS1337 I2C Serial Real-Time Clock AC ELECTRICAL CHARACTERISTICS (VCC = 1.8V to 5.5V, TA = -40°C to +85°C.
PAGE 4
DS1337 I2C Serial Real-Time Clock Note 16: The parameter tOSF is the period of time that the oscillator must be stopped for the OSF bit to be set over the voltage range of VCC(MIN) ≤ VCC ≤ VCC(MAX).. TYPICAL OPERATING CHARACTERISTICS (VCC = 3.3V, TA = +25°C, unless otherwise noted.) ICC vs. VCC ICCTOSC 1000 ICCA vs. VCC ICCS 125 900 100 INTCN = 0 (Squarew ave on) 700 ICC (uA) ICC (nA) 800 600 50 INTCN = 1 (Squarew ave off) 500 75 25 400 0 300 1.3 1.8 2.3 2.8 3.3 3.
PAGE 5
DS1337 I2C Serial Real-Time Clock PIN DESCRIPTION 8 PIN NAME 16 1 — X1 2 — X2 3 INTA 14 FUNCTION Connections for a Standard 32.768kHz Quartz Crystal. The internal oscillator circuitry is designed for operation with a crystal having a specified load capacitance (CL) of 6pF. For more information about crystal selection and crystal layout considerations, refer to Application Note 58: Crystal Considerations with Dallas Real-Time Clocks. An external 32.768kHz oscillator can also drive the DS1337.
PAGE 6
DS1337 I2C Serial Real-Time Clock BLOCK DIAGRAM SQW/INTB X1 MUX/ BUFFER 1Hz/4.096kHz/8.192kHz/32.768kHz CL N 1Hz X2 ALARM, TRICKLE CHARGE, AND CONTROL REGISTERS CL "C" version only CONTROL LOGIC SDA N CLOCK AND CALENDAR REGISTERS DS1337 SCL INTA SERIAL BUS INTERFACE AND ADDRESS REGISTER USER BUFFER (7 BYTES) DETAILED DESCRIPTION The Block Diagram shows the main elements of the DS1337. As shown, communications to and from the DS1337 occur serially over an I2C bus.
PAGE 7
DS1337 I2C Serial Real-Time Clock 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. Crystal frequency drift caused by temperature shifts creates additional error. External circuit noise coupled into the oscillator circuit can result in the clock running fast.
PAGE 8
DS1337 I2C Serial Real-Time Clock ADDRESS MAP Table 2 shows the address map for the DS1337 registers. During a multibyte access, when the address pointer reaches the end of the register space (0Fh) it wraps around to location 00h. On an I2C START, STOP, or address pointer incrementing to location 00h, the current time is transferred to a second set of registers. The time information is read from these secondary registers, while the clock may continue to run.
PAGE 9
DS1337 I2C Serial Real-Time Clock CLOCK AND CALENDAR The time and calendar information is obtained by reading the appropriate register bytes. The RTC registers are illustrated in Table 2. The time and calendar are set or initialized by writing the appropriate register bytes. The contents of the time and calendar registers are in the binary-coded decimal (BCD) format. The day-of-week register increments at midnight. Values that correspond to the day of week are user-defined but must be sequential (i.e.
PAGE 10
DS1337 I2C Serial Real-Time Clock Table 3.
PAGE 11
DS1337 I2C Serial Real-Time Clock Bit 1: Alarm 2 Interrupt Enable (A2IE). When set to logic 1, this bit permits the alarm 2 flag (A2F) bit in the status register to assert INTA (when INTCN = 0) or to assert SQW/INTB (when INTCN = 1). When the A2IE bit is set to logic 0, the A2F bit does not initiate an interrupt signal. The A2IE bit is disabled (logic 0) when power is first applied. Bit 0: Alarm 1 Interrupt Enable (A1IE).
PAGE 12
DS1337 I2C Serial Real-Time Clock I2C SERIAL DATA BUS The DS1337 supports the I2C bus protocol. A device that sends data onto the bus is defined as a transmitter and a device receiving data as a receiver. The device that controls the message is called a master. The devices that are controlled by the master are referred to as slaves. A master device that generates the serial clock (SCL), controls the bus access, and generates the START and STOP conditions must control the bus.
PAGE 13
DS1337 I2C Serial Real-Time Clock Figure 2. Data Transfer on I2C Serial Bus Depending upon the state of the R/W bit, two types of data transfer are possible: 1) Data transfer from a master tr ansmitter to a slave receiver. The first byte transmitted by the master is the slave address. Next follows a number of data bytes. The slave returns an acknowledge bit after each received byte. Data is transferred with the most significant bit (MSB) first.
PAGE 14
DS1337 I2C Serial Real-Time Clock S 1101000 Figure 3. Data Write—Slave Receiver Mode 0 A XXXXXXXX A XXXXXXXX A S - Start A - Acknowledge (ACK) P - Stop XXXXXXXX A ... XXXXXXXX A P Master to slave DATA TRANSFERRED (X+1 BYTES + ACKNOWLEDGE) Slave to master S 1101000 Figure 4.
PAGE 15
DS1337 I2C Serial Real-Time Clock HANDLING, PC BOARD LAYOUT, AND ASSEMBLY The DS1337C package contains a quartz tuning-fork crystal. Pick-and-place equipment may be used, but precautions should be taken to ensure that excessive shocks are avoided. Ultrasonic cleaning should be avoided to prevent damage to the crystal. Avoid running signal traces under the package, unless a ground plane is placed between the package and the signal line. All N.C. (no connect) pins must be connected to ground.
PAGE 16
DS1337 I2C Serial Real-Time Clock REVISION HISTORY REVISION DATE 080508 071609 DESCRIPTION Added device access details to General Description section. Removed leaded ordering numbers from the Ordering Information table. Added Note 5 to Timekeeping VCC EC table range. Added “Full Operation” and “Timekeeping” to headers to clarify table usage. Added OSF parameter to EC table. Updated Pin Description to indicate max input voltage and that unused outputs may be left open.