Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsIntegrated Circuits (ICs)Timer IC t- real time clock ETC TSSOP 24

General Description

The DS1318 parallel-interface elapsed time counter

(ETC) is a 44-bit counter that maintains the amount of

time that the device operates from main and/or backup

power or during an external event. The internal

frequency of the counter clock is 4.096kHz, which pro-

vides a 244µs resolution and a maximum count of over

136 years. A built-in power-sense circuit detects power

failures, automatically switches to the backup supply,

and controls the timer. If an external event timer is

desired, the control input EXT can control the counter

operation. An open-drain output provides an interrupt,

and a square-wave output provides a programmable

square wave. The DS1318 is accessed through a byte-

wide parallel interface, and operates over the industrial

temperature range.

Applications

Power Meters

Industrial Controls

Servers

Features

♦ Byte-Wide Parallel Interface

♦ 44-Bit Binary Counter Provides Timer with 244µs

Resolution

♦ Automatic Power-Fail Detect and Switch Circuitry

Selects Power Source from the Primary Power

and the Battery, and Write Protects the Internal

Registers

♦ Internal Power-Fail Circuit Allows Timer to

Provide Primary or Battery Operation Times

♦ Timer can Alternately Provide an Event Timer of

Either an Active-High or Active-Low Pulse

♦ Interrupt Output Generated Periodically or When

the Upper 32 Bits of the Counter Match an Alarm

♦ Square-Wave Output with 16 Selectable

Frequencies from 32.768kHz to 0.5Hz

♦ +3.3V Operation

♦ Industrial Temperature Range: -40°C to +85°C

♦ Underwriters Laboratories (UL) Recognized

DS1318

Parallel-Interface Elapsed Time Counter

______________________________________________

Maxim Integrated Products

DS1318

GND

TOP VIEW

BAT

DQ7

DQ6

DQ5

DQ4

DQ3

TSSOP

(4.4mm)

DQ2

DQ1

DQ0

SQW

IRQ

EXT

GND

Pin Configuration

Ordering Information

DS1318

CPU

DQ–DQ7

A3–A0

GND

RPU

SQW

IRQ

EXT

EXTERNAL

COUNTER

ENABLE

(EVENT TIMER)

0.1μF

BAT

Typical Operating Circuit

19-5664; Rev 1; 12/10

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

PART TEMP RANGE PIN-PACKAGE

DS1318E+ -40°C to +85°C 24 TSSOP

DS1318E+T&R -40°C to +85°C 24 TSSOP

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

T&R = Tape and reel.

Summary of content (15 pages)

PAGE 1
9-5664; Rev 1; 12/10 Parallel-Interface Elapsed Time Counter The DS1318 parallel-interface elapsed time counter (ETC) is a 44-bit counter that maintains the amount of time that the device operates from main and/or backup power or during an external event. The internal frequency of the counter clock is 4.096kHz, which provides a 244µs resolution and a maximum count of over 136 years. A built-in power-sense circuit detects power failures, automatically switches to the backup supply, and controls the timer.
PAGE 2
DS1318 Parallel-Interface Elapsed Time Counter ABSOLUTE MAXIMUM RATINGS Voltage Range on any Pin Relative to Ground ......-0.3V to +6.0V Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-55°C to +125°C Lead Temperature (soldering, 10s) .................................+260°C Soldering Temperature (reflow) .......................................
PAGE 3
Parallel-Interface Elapsed Time Counter DS1318 DC ELECTRICAL CHARACTERISTICS (VCC = 0V, VBAT = 3.7V, TA = -40°C to +85°C, unless otherwise noted.) (Note 2) PARAMETER SYMBOL CONDITIONS Battery Input Current (ENOSC = 1) IBAT (Note 8) Battery Input Current (ENOSC = 0) IBATDR (Note 8) MIN TYP MAX UNITS 750 1100 nA 100 nA MAX UNITS AC ELECTRICAL CHARACTERISTICS (VCC = VCC(MIN) to VCC(MAX), TA = -40°C to +85°C, unless otherwise noted.
PAGE 4
Parallel-Interface Elapsed Time Counter DS1318 Read Cycle Timing tRC A0–A4 tAA CE tOH tCEZ tCEA tCEL OE tOEZ tOEA tOEL VALID DQ0–DQ7 Write Cycle Timing, Write-Enable Controlled tWC A0–A4 VALID VALID tAS tAH CE tWEW tAS tWR WE tWEZ DQ0–DQ7 tDS DATA OUTPUT tDH DATA INPUT DATA INPUT Write Cycle Timing, Chip-Enable Controlled tWC A0–A4 VALID tAS VALID tCEW tAH CE tWR tAS WE tDS DQ0–DQ7 4 tDH DATA INPUT _____________________________________________________________________ DATA
PAGE 5
Parallel-Interface Elapsed Time Counter VCC VPF(MAX) VPF(MIN) tVCCF tVCCR tREC RECOGNIZED INPUTS RECOGNIZED DON'T CARE HIGH-Z OUTPUTS VALID VALID POWER-UP/POWER-DOWN CHARACTERISTICS (TA = -40°C to +85°C) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP (Note 10) MAX UNITS 150 ms Recovery at Power-Up tREC VCC Fall Time; VPF(MAX) to VPF(MIN) t VCCF 300 μs VCC Rise Time; V PF(MIN) to VPF(MAX) t VCCR 0 μs CAPACITANCE (TA = +25°C) MAX UNITS Capacitance on All Input Pins PARAMETER S
PAGE 6
AC TEST CONDITIONS PARAMETER TEST CONDITION Input Pulse Levels 0 to 2.7V Output Load Including Scope and Jig 25pF + 1TTL Gate Input and Output Timing Measurement Reference Levels VCC / 2 Input-Pulse Rise and Fall Times 4ns WARNING: Under no circumstances are negative undershoots, of any amplitude, allowed when device is in write protection. Limits at -40°C are guaranteed by design and not production tested. All voltages are referenced to ground. OE, CE, WE, EXT, and A3–A0.
PAGE 7
Parallel-Interface Elapsed Time Counter X1 32,768Hz 32,768Hz CRYSTAL OSCILLATOR AND PRESCALER COUNTER 4,096Hz X2 CLOCK CONTROL CIRCUITRY 4,096Hz EXT SQUARE-WAVE RATE SELECTOR AND PRESCALER SQW BUFFERED COUNTER REGISTERS, CONTROL AND STATUS REGISTERS VCC VBAT VCC LEVEL DETECT, POWER SWITCH, AND WRITE PROTECT SUBSECONDS0 SUBSECONDS1 SUBSECONDS1 SECONDS0 SECONDS0 SECONDS1 SECONDS1 SECONDS2 SECONDS2 SECONDS3 INTERNAL DIVIDERS AND COUNTERS CE OE WE A3–A0 BYTE-WIDE RAM INTERFACE TRANSFER ENA
PAGE 8
Parallel-Interface Elapsed Time Counter DS1318 Pin Description PIN NAME FUNCTION 1 X1 2 X2 3, 12 GND Ground. This pin must be connected to ground for proper operation. 4 EXT External Counter-Enable Input Connections for Standard 32.768kHz Quartz Crystal. The internal oscillator circuitry is designed for operation with a crystal having a 12.5pF specified load capacitance (CL). X1 is the input to the oscillator and can optionally be connected to an external 32.768kHz oscillator.
PAGE 9
Parallel-Interface Elapsed Time Counter DS1318 Table 2. Crystal Specifications* PARAMETER SYMBOL Nominal Frequency fO Series Resistance ESR Load Capacitance CL MIN TYP MAX UNITS 32.768 kHz 50 kΩ 12.5 pF *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.
PAGE 10
DS1318 Parallel-Interface Elapsed Time Counter Table 3.
PAGE 11
Parallel-Interface Elapsed Time Counter BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 TE ENOSC CCFG1 CCFG0 EPOL SQWE PIE AIE Special-Purpose Registers The DS1318 has three additional registers (control A, control B, and status) that control the clock, alarms, square wave, and interrupt output. The subseconds0 register has a square-wave synchronization (SQWS) bit in the bit 0 location. Writing the SQWS bit to 1 clears the square-wave prescaler and holds it in reset.
PAGE 12
DS1318 Parallel-Interface Elapsed Time Counter Control Register B (0Bh) BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 PRS3 PRS2 PRS1 PRS0 SRS3 SRS2 SRS1 SRS0 Bits 7 to 4: Periodic Rate Select (PRS3–PRS0).
PAGE 13
Parallel-Interface Elapsed Time Counter BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 OSF UIP 0 0 0 0 PF ALMF Bit 7: Oscillator Stop Flag (OSF). A logic 1 in this bit indicates that the oscillator either is or was stopped for some period of time and may be used to judge the validity of the timekeeping data. This bit is set to logic 1 any time the oscillator stops. The following are examples of conditions that can cause the OSF bit to be set: 1) The first time power is applied.
PAGE 14
DS1318 Parallel-Interface Elapsed Time Counter Chip Information PROCESS: CMOS SUBSTRATE CONNECTED TO GROUND 14 Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.
PAGE 15
Parallel-Interface Elapsed Time Counter REVISION NUMBER REVISION DATE 0 2/04 1 12/10 DESCRIPTION Initial release PAGES CHANGED — Added the UL recognized bullet to the Features section; added lead(Pb)-free parts to the Ordering Information table; updated the Absolute Maximum Ratings section to include lead temperature and soldering temperature information; added the Package Thermal Characteristics section; changed the battery voltage parameter symbol from VCC to VBAT in the Recommended DC Operating