Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsIntegrated Circuits (ICs)Timer IC t- real time clock Clock/calendar TDFN 14 EP

Low-Current SPI/3-Wire RTCs

DS1343/DS1344

19-5801; Rev 2; 10/14

General Description

The DS1343/DS1344 low-current real-time clocks (RTCs)

are timekeeping devices that provide an extremely low

standby current, permitting longer life from a backup

supply source. The devices also support high-ESR

crystals, broadening the pool of usable crystals for the

devices. 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 24-hour or

12-hour format with an AM/PM indicator.

Address and data are transferred serially through an

SPI or 3-wire interface. Two programmable time-of-day

alarms are provided. Each alarm can generate an inter-

rupt on a combination of seconds, minutes, hours, and

day. Don’t-care states can be inserted into one or more

fields if it is desired for them to be ignored for the alarm

condition. The time-of-day alarms can be programmed

to assert two different interrupt outputs, or they can be

combined to assert one common interrupt output. Both

interrupt outputs operate when the device is powered by

either V

or V

BAT

The devices are available in a lead-free/RoHS-compliant,

20-pin TSSOP or 14-pin TDFN package, and support a

-40°C to +85°C extended industrial temperature range.

Applications

Medical

Handheld Devices

Telematics

Embedded Timestamping

Features

S Low Timekeeping Current of 250nA (typ)

S Compatible with Crystal ESR Up to 100kI

S Versions Available to Support Either 6pF or

12.5pF Crystals

S RTC Counts Seconds, Minutes, Hours, Day, Date,

Month, and Year with Leap Year Compensation

Valid Through 2099

S Power-Fail and Switch Circuitry

S Three Operating Voltages

1.8V ±5%

3.0V±10%

3.3V ±10%

S Trickle-Charge Capability

S Maintain Time Down to 1.15V (typ)

S Support Motorola SPI Modes 1 and 3, or Standard

3-Wire Interface

S Burst Mode for Reading/Writing Successive

Addresses in Clock/RAM

S 96-Byte Battery-Backed NV RAM for Data Storage

S Two Time-of-Day Alarms with Two Interrupt

Outputs

S Industrial Temperature Range

S 20-Pin TSSOP or 14-Pin TDFN Package

S Underwriters Laboratories (UL) Recognized

Ordering Information appears at end of data sheet.

Typical Operating Circuit

DS1343

DS1344

INT0

INT1

SCLK

SDI

SDO

BAT

GNDSERMODE

INT

RST

3-WIRE

PORT

μP

NOTE: SHOWN IN 3-WIRE I/O CONFIGURATION.

For pricing, delivery, and ordering information, please contact Maxim Direct at

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

Summary of content (20 pages)

PAGE 1
DS1343/DS1344 Low-Current SPI/3-Wire RTCs General Description The DS1343/DS1344 low-current real-time clocks (RTCs) are timekeeping devices that provide an extremely low standby current, permitting longer life from a backup supply source. The devices also support high-ESR crystals, broadening the pool of usable crystals for the devices. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information.
PAGE 2
DS1343/DS1344 Low-Current SPI/3-Wire RTCs ABSOLUTE MAXIMUM RATINGS Voltage Range on VCC or VBAT Relative to Ground.............................................-0.3V to +6.0V Voltage Range on Any Nonpower Pin Relative to Ground................................. -0.3V to (VCC + 0.3V) Operating Temperature Range........................... -40NC to +85NC Junction Temperature Maximum......................................+150NC Storage Temperature Range.............................
PAGE 3
DS1343/DS1344 Low-Current SPI/3-Wire RTCs DC ELECTRICAL CHARACTERISTICS (continued) (VCC = VCC(MIN) to +5.5V, VBAT = +1.3V to +5.5V, TA = -40°C to +85°C, unless otherwise noted.) (Notes 2, 3) PARAMETER Backup Current (Note 7) SYMBOL CONDITIONS MIN VBAT = 3V DS1343 IBAT2 DS1344 TYP MAX UNITS 300 VBAT = VBAT(MAX) 600 VBAT = 3V 400 VBAT = VBAT(MAX) nA 700 Input Leakage (CE, SERMODE, SCLK, SDI) II VIN = 0V to VCC -0.1 +0.
PAGE 4
DS1343/DS1344 Low-Current SPI/3-Wire RTCs AC ELECTRICAL CHARACTERISTICS (continued) (VCC = VCC(MIN) to VCC(MAX), TA = -40°C to +85°C, unless otherwise noted.
PAGE 5
DS1343/DS1344 Low-Current SPI/3-Wire RTCs SPI Write Timing tCWH CE tCCH tF tCC tCL tCH tR SCLK* tDC SDI tCDH tCDH A6 R/W = 1 A0 D7 WRITE ADDRESS BYTE D0 WRITE DATA BYTE *SCLK CAN BE EITHER POLARITY. TIMING SHOWN FOR CPOL = 1. SERMODE = VCC. SPI Read Timing tCWH CE tCC tCL tCH SCLK* tCDH tCDD tDC SDI R/W = 0 A6 SDO tCDZ A0 D7 WRITE ADDRESS BYTE D0 READ DATA BYTE *SCLK CAN BE EITHER POLARITY. TIMING SHOWN FOR CPOL = 1. SERMODE = VCC.
PAGE 6
DS1343/DS1344 Low-Current SPI/3-Wire RTCs 3-Wire Write Timing tCWH CE tCCH tCC tR tCL tF SCLK tCH tCDH tDC A0 I/O* A1 R/W = 1 D0 WRITE ADDRESS BYTE D7 WRITE DATA BYTE *I/O IS SDI AND SDO CONNECTED TOGETHER. SERMODE = GND. 3-Wire Read Timing tCWH CE tCC tCL tCDZ tCDD SCLK I/O* tCH tCDH tDC A0 A1 WRITE ADDRESS BYTE R/W = 0 D0 D7 READ DATA BYTE *I/O IS SDI AND SDO CONNECTED TOGETHER. SERMODE = GND.
PAGE 7
DS1343/DS1344 Low-Current SPI/3-Wire RTCs Typical Operating Characteristics (VCC = +3.3V, TA = +25°C, unless otherwise noted.) fSCLK = 4MHz 300 200 fSCLK = 1MHz 100 4.0 4.5 5.0 320 TA = +85°C TA = +25°C TA = -40°C 300 EGFIL = 1 DOSF = 0 IOUT = 0mA TA = +85°C 280 260 5.5 TA = +25°C 240 TA = -40°C 220 200 180 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 BATTERY VOLTAGE (V) BATTERY VOLTAGE (V) DS1344 BATTERY CURRENT1 vs. BATTERY VOLTAGE DS1344 BATTERY CURRENT2 vs.
PAGE 8
DS1343/DS1344 Low-Current SPI/3-Wire RTCs Pin Configurations VCC SERMODE PF SDO SDI SCLK CE TOP VIEW 14 13 12 11 10 9 8 TOP VIEW N.C. 17 N.C. 16 SDO 6 15 SDI INT0 7 14 SCLK N.C. 8 13 N.C. INT1 9 12 CE GND 10 11 SERMODE TSSOP DS1343 DS1344 EP + 1 2 3 4 5 6 7 GND 5 PF INT1 4 X2 18 N.C. N.C. DS1343 DS1344 N.C. INT0 3 VCC 19 X2 X1 20 X1 2 VBAT 1 N.C.
PAGE 9
DS1343/DS1344 Low-Current SPI/3-Wire RTCs Pin Descriptions (continued) PIN NAME FUNCTION TSSOP TDFN-EP 10 7 GND 11 13 SERMODE 12 8 CE 14 9 SCLK 15 10 SDI Serial-Data Input. When SPI communication is selected, SDI is the serial-data input for the SPI bus. When 3-wire communication is selected, this pin must be connected to SDO (SDI and SDO function as a single I/O pin when connected together). Ground Serial-Interface Mode Input.
PAGE 10
DS1343/DS1344 Low-Current SPI/3-Wire RTCs Detailed Description The DS1343/DS1344 low-current real-time clocks (RTCs) are timekeeping devices that consume an extremely low timekeeping current and also support high-ESR crystals, broadening the pool of usable crystals for the device. The devices provide a full binary-coded decimal (BCD) clock calendar that is accessed by a simple serial interface. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information.
PAGE 11
DS1343/DS1344 Low-Current SPI/3-Wire RTCs LOCAL GROUND PLANE (LAYER 2) X1 CRYSTAL X2 NOTE: AVOID ROUTING SIGNAL LINES IN THE CROSSHATCHED AREA (UPPER LEFT QUADRANT) OF THE PACKAGE UNLESS THERE IS A GROUND PLANE BETWEEN THE SIGNAL LINE AND THE DEVICE PACKAGE. GND Figure 1. Layout Example Register Map Table 1 shows the devices’ register map. During a multibyte RTC access, if the address pointer reaches the end of the register space (1Fh), it wraps around to location 00h.
PAGE 12
DS1343/DS1344 Low-Current SPI/3-Wire RTCs Table 1.
PAGE 13
DS1343/DS1344 Low-Current SPI/3-Wire RTCs Control Register (0Fh) BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 EOSC 1 X DOSF EGFIL SQW INTCN A1IE A0IE 0 0 0 0 0 0 0 BIT 7 EOSC: Enable oscillator. During battery backup, when EOSC is set to 0, the oscillator is enabled during backup operation. When set to 1, the oscillator is stopped when the device is powered by the backup supply. This bit is set to logic 1 on the initial application of power. BIT 6 Not used.
PAGE 14
DS1343/DS1344 Low-Current SPI/3-Wire RTCs Status Register (10h) BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 OSF 0 0 0 0 0 IRQF1 IRQF0 1 0 0 0 0 0 0 0 OSF: Oscillator stop flag. If the OSF bit is 1, the oscillator either has stopped or was stopped for some period and could be used to judge the validity of the clock and calendar data.
PAGE 15
DS1343/DS1344 Low-Current SPI/3-Wire RTCs R1 1kΩ R2 2kΩ VCC VBAT R3 4kΩ 1 0F 18 SELECT NOTE: ONLY 1010 CODE ENABLES CHARGER TRICKLE CHARGER REGISTER 1 OF 2 SELECT 1 OF 3 SELECT TCS = TRICKLE-CHARGER SELECT DS = DIODE SELECT RS = RESISTOR SELECT TCS TCS TCS TCS DS DS RS RS BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 Figure 2. Trickle Charger Block Diagram Table 3.
PAGE 16
DS1343/DS1344 Low-Current SPI/3-Wire RTCs Serial Peripheral Interface (SPI) The serial peripheral interface (SPI) is a synchronous bus for address and data transfer, and is used when interfacing with the SPI bus on specific Motorola microcontrollers, such as the 68HC05C4 and the 68HC11A8. The SPI mode of serial communication is selected by connecting SERMODE to VCC. Four pins are used for the SPI. The four pins are SDO (serial-data out), SDI (serialdata in), CE (chip enable), and SCLK (serial clock).
PAGE 17
DS1343/DS1344 Low-Current SPI/3-Wire RTCs CE SCLK* 1 SDI A6 A5 A4 R/W A3 A2 A1 A0 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D7 D6 D5 D4 D3 D2 D1 D0 HIGH-Z SDO *SCLK CAN BE EITHER POLARITY. SERMODE = VCC. Figure 4. SPI Single-Byte Write CE SCLK* 0 SDI A6 R/W SDO A5 A4 HIGH-Z D0 *SCLK CAN BE EITHER POLARITY. SERMODE = VCC. Figure 5.
PAGE 18
DS1343/DS1344 Low-Current SPI/3-Wire RTCs Reading and Writing in Burst Mode Applications Information 3-Wire Interface To achieve the best results when using the devices, decouple the VCC power supply with a 0.01µF and/or 0.1µF capacitor. Use a high-quality, ceramic, surfacemount capacitor if possible. Surface-mount components minimize lead inductance, which improves performance, and ceramic capacitors tend to have adequate highfrequency response for decoupling applications.
PAGE 19
DS1343/DS1344 Low-Current SPI/3-Wire RTCs Ordering Information PART TEMP RANGE TYP OPERATING VOLTAGE (V) OSC CL (pF) DS1343E-18+ -40NC to +85NC 1.8 6 20 TSSOP DS1343E-3+ -40NC to +85NC 3.0 6 20 TSSOP DS1343E-33+ -40NC to +85NC 3.3 6 20 TSSOP DS1343D-18+ -40NC to +85NC 1.8 6 14 TDFN-EP* DS1343D-3+ -40NC to +85NC 3.0 6 14 TDFN-EP* DS1343D-33+ -40NC to +85NC 3.3 6 14 TDFN-EP* DS1344E-18+ -40NC to +85NC 1.8 12.5 20 TSSOP DS1344E-3+ -40NC to +85NC 3.0 12.
PAGE 20
DS1343/DS1344 Low-Current SPI/3-Wire RTCs Revision History REVISION NUMBER REVISION DATE 0 3/11 Initial release 1 12/11 Removed future status from several DS1344 parts in the Ordering Information table; added UL recognized to the Features and Battery Charge Protection sections; added IBATLKG and DS1344 IBAT1, IBAT2 specs to the DC Electrical Characteristics section; added DS1344 Typical Operating Characteristics graphs 1, 2, 7, 18, 19 2 10/14 Added standby current and IOH and IOL for 3V and 1.