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General Description

The DS1339B 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 I

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 device has a built-in

power-sense circuit that detects power failures and auto-

matically switches to the backup supply, maintaining time,

date, and alarm operation.

Applications

● Handhelds(GPS,POSTerminals)

● ConsumerElectronics(Set-TopBox,Digital

Recording, Network Appliance)

● OfceEquipment(Fax/Printers,Copier)

● Medical(Glucometer,MedicineDispenser)

● Telecommunications(Routers,Switches,Servers)

● Other(UtilityMeter,VendingMachine,

Thermostat, Modem)

Features

● Drop-InReplacementforDS1339

● SupportsHigh-ESRCrystalsUpTo100kΩ

● Real-TimeClock(RTC)CountsSeconds,Minutes,

Hours,Day,Date,Month,andYearwithLeap-Year

Compensationupto2200

● I

C 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Laboratories(UL)Recognized

Ordering Information appears at end of data sheet.

For related parts and recommended products to use with this part, refer

to www.maximintegrated.com/DS1339B.related.

DS1339B

/4 /4096

CONTROL LOGIC

OSCILLATOR

AND

DIVIDER

ALARMS,

TRICKLE CHARGER, AND

CONTROL REGISTERS

CLOCK AND

CALENDAR REGISTERS

USER BUFFER

(7 BYTES)

1Hz

SQW/INTB

4.096kHz

8.192kHz

32.768kHz

MUX/

BUFFER

SERIAL BUS

INTERFACE AND

ADDRESS

POWER

CONTROL

SCL

SDA

BACKUP

DS1339B Low-Current, I

C, Serial Real-Time Clock

For High-ESR Crystals

19-6682; Rev 0; 5/13

Functional Diagram

EVALUATION KIT AVAILABLE

Summary of content (18 pages)

PAGE 1
EVALUATION KIT AVAILABLE DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals General Description The DS1339B serial real-time clock (RTC) is a lowpower clock/date device with two programmable timeof-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.
PAGE 2
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals 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 Lead Temperature (soldering, 10 seconds)...................... +300°C Soldering Temperature (reflow)........................................
PAGE 3
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals DC Electrical Characteristics (continued) (VCC = MIN to MAX, VBACKUP = MIN to MAX, TA = -40°C to +85°C, unless otherwise noted.
PAGE 4
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals AC Electrical Characteristics (continued) (VCC = MIN to MAX, TA = -40°C to +85°C, unless otherwise noted.
PAGE 5
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals SDA tBUF tF tLOW tSP tHD:STA SCL tHD:STA tHIGH tR tHD:DAT STOP START tSU:STA tSU:STO tSU:DAT REPEATED START NOTE: TIMING IS REFERENCED TO VIL(MAX) AND VIH(MIN). Figure 1. I2C Timing VCC VPF tREC tVCCF tVCCR SCL RECOGNIZED DON’T CARE RECOGNIZED SDA VALID HIGH IMPEDANCE VALID Figure 2. Power-Up/Down Timing www.maximintegrated.
PAGE 6
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals Typical Operating Characteristics (VCC = 3.3V, TA = +25°C, unless otherwise noted.) TA = +85°C TA = +25°C 80 60 40 TA = -40°C 2.7 1.7 3.7 4.7 5.7 250 fSCL = 100kHz 200 fSCL = 1kHz 150 400 TA = +25°C 350 0.4 2.3 3.3 DS1339B toc03 VCC = 1.71V, TA = +25°C 0.7 0.5 0.4 0.3 0.2 0 2 4 6 8 BACKUP VOLTAGE (V) OUTPUT CURRENT (mA) INT/SQW OUTPUT CURRENT vs. OUTPUT VOLTAGE TRICKLE CHARGER RESISTORS vs.
PAGE 7
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals Pin Configuration TOP VIEW X1 1 X2 2 VBACKUP 3 GND 4 + DS1339B 8 VCC 7 SQW/INT 6 SCL 5 SDA µSOP Pin Description PIN NAME 1 X1 2 X2 FUNCTION Connections for Standard 32.768kHz Quartz Crystal. The internal oscillator circuitry is designed for operation with a crystal having a specified load capacitance (CL) of 6pF.
PAGE 8
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals Detailed Description Operation The DS1339B serial real-time clock (RTC) is a lowpower clock/date device with two programmable timeof-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.
PAGE 9
DS1339B 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.
PAGE 10
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals Table 3.
PAGE 11
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals Alarms The DY/DT bits (bit 6 of the alarm day/date registers) control whether the alarm value stored in bits 0 to 5 of that register reflects the day of the week or the date of the month. If DY/DT is written to a logic 0, the alarm is the result of a match with date of the month. If DY/DT is written to a logic 1, the alarm is the result of a match with day of the week. The device contains two time of day/date alarms.
PAGE 12
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals Control Register (0Eh) The control register controls the operation of the SQW/INT pin and provides oscillator status. Bit # Name POR BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 EOSC 0 0 BBSQI RS2 RS1 INTCN A2IE A1IE 0 0 1 1 0 0 0 Bit 7: Enable Oscillator (EOSC). When the EOSC bit is 0, the oscillator is enabled. When this bit is a 1, the oscillator is disabled.
PAGE 13
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals Status Register (0Fh) The control register controls the operation of the SQW/INT pin and provides oscillator status. Bit # BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 Name OSF 0 0 0 0 0 A2F A1F POR 1 0 0 0 0 0 0 0 Bit 7: Oscillator Stop Flag (OSF).
PAGE 14
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals Trickle Charger (10h) The simplified schematic in Figure 3 shows the basic components of the trickle charger. The trickle-charge select bits (TCS[3:0]) control the selection of the trickle charger. To prevent accidental enabling, only a pattern on 1010 enables the trickle charger. All other patterns disable the trickle charger. The trickle charger is disabled when power is first applied.
PAGE 15
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals I2C Serial Port Operation normal START condition. See Figure 1 for applicable timing. I2C Slave Address The device’s slave address byte is D0h. The first byte sent to the device includes the device identifier and the R/W bit (Figure 4). The device address sent by the I2C master must match the address assigned to the device. LSB MSB 1 1 0 1 DEVICE IDENTIFIER 0 0 0 R/W READ/ WRITE BIT Figure 4.
PAGE 16
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals Slave Address Byte: Each slave on the I2C bus responds to a slave address byte sent immediately following a START condition. The slave address byte contains the slave address in the most significant 7 bits and the R/W bit in the least significant bit. The whatever’s slave address is D0h and cannot be modified by the user. When the R/W bit is 0 (such as in D0h), the master is indicating it writes data to the slave.
PAGE 17
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals Manipulating the Address Counter for Reads: A dummy write cycle can be used to force the address counter to a particular value. To do this the master generates a START condition, writes the slave address byte (R/W = 0), writes the memory address where it desires to read, generates a repeated START condition, writes the slave address byte (R/W = 1), reads data with ACK or NACK as applicable, and generates a STOP condition.
PAGE 18
DS1339B Low-Current, I2C, Serial Real-Time Clock For High-ESR Crystals Package Information Ordering Information PART TEMP RANGE PIN-PACKAGE -40°C to +85°C 8 µSOP DS1339BU+ +Denotes a lead(Pb)-free/RoHS-compliant package. Chip Information PROCESS: CMOS SUBSTRATE CONNECTED TO GROUND www.maximintegrated.com For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only.