Dallas Semiconductor DS1340Z-33, DS1340Z-3, DS1340Z-18, DS1340U-33, DS1340U-3 Datasheet

General Description

The DS1340 is a real-time clock (RTC)/calendar that is
pin compatible and functionally equivalent to the ST
M41T00, including the software clock calibration. The
device additionally provides trickle-charge capability
on the V

BACKUP

pin, a lower timekeeping voltage, and
an oscillator STOP flag. Block access of the register
map is identical to the ST device. Two additional regis­ters, which are accessed individually, are required for
the trickle charger and flag. The clock/calendar pro­vides seconds, minutes, hours, day, date, month, and
year information. A built-in power-sense circuit detects
power failures and automatically switches to the back­up supply. The device is programmed serially through
a 2-wire bidirectional bus.

Applications

Portable Instruments

Point-of-Sale Equipment

Medical Equipment

Telecommunications

Features

♦ Enhanced Second Source for the ST M41T00

♦ Fast (400kHz) 2-Wire Interface

♦ Software Clock Calibration

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

Month, and Year

♦ Automatic Power-Fail Detect and Switch Circuitry

♦ Trickle-Charge Capability

♦ Low Timekeeping Voltage Down to 1.3V

♦ Three Operating Voltage Ranges (1.8V, 3V, and

3.3V)

♦ Oscillator Stop Flag

♦ Available in 8-Pin µSOP or SO Packages

DS1340

2-Wire RTC with Trickle Charger

______________________________________________ Maxim Integrated Products 1

1

2

3

4

8

7

6

5

V

CC

FT/OUT

SCL

SDA

V

BACKUP

GND

X2

X1

TOP VIEW

DS1340

SO,

µSOP

Pin Configuration

Ordering Information

4

CPU

V

CC

V

CC

V

CC

5

6

8

12

SDA

SCL

GND

X2X1

V

CC

RPU RPU

CRYSTAL

FT/OUT

V

BACKUP

3

7

RPU = t

R

/ CB

DS1340

Typical Operating Circuit

Rev 0; 6/03

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

PART

TEMP RANGE

PIN­PACKAGE

TOP
MARK

DS1340Z-18

D1340-18

DS1340Z-3

DS1340-3

DS1340Z-33

D1340-33

DS1340U-18

8 µSOP

1340
A1-18

DS1340U-3

8 µSOP

1340
A1-3

DS1340U-33

8 µSOP

1340
A1-33

-40°C to +85°C 8 SO (0.150in)

-40°C to +85°C 8 SO (0.150in)

-40°C to +85°C 8 SO (0.150in)

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

DS1340

2-Wire RTC with Trickle Charger

2 _____________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

Voltage Range on VCCPin Relative to Ground .....-0.3V to +6.0V

Voltage Range on SDA, SCL, and FT/OUT

Relative to Ground..................................-0.3V to (V

CC

+ 0.3V)

Operating Temperature Range ...........................-40°C to +85°C

Storage Temperature Range .............................-55°C to +125°C

Soldering Temperature Range ..................................See JEDEC

J-STD-020A Specification

AC ELECTRICAL CHARACTERISTICS

(VCC= V

CC MIN

to V

CC MAX

, TA= -40°C to +85°C, unless otherwise noted.) (Note 1, Figure 1)

PARAMETER

CONDITIONS

UNITS

Standard mode 0

SCL Clock Frequency f

SCL

Fast mode

kHz

Standard mode 4.7

Bus Free Time Between STOP
and START Conditions

t

BUF

Fast mode 1.3

µs

Standard mode 4.0

Hold Time (Repeated) START
Condition (Note 2)

Fast mode 0.6

µs

Standard mode 4.7

Low Period of SCL Clock t

LOW

Fast mode 1.3

µs

Standard mode 4.0

High Period of SCL Clock t

HIGH

Fast mode 0.6

µs

Standard mode 0

Data Hold Time (Notes 3, 4)

Fast mode 0

µs

Standard mode

Data Setup Time (Note 5)

Fast mode

ns

Standard mode 4.7

START Setup Time

Fast mode 0.6

µs

Standard mode

Rise Time of SDA and SCL
Signals (Note 6)

t

R

Fast mode

ns

Standard mode

Fall Time of SDA and SCL Signals
(Note 6)

t

F

Fast mode

ns

Standard mode 4.7

Setup Time for STOP Condition

Fast mode 0.6

µs

Capacitive Load for Each Bus
Line

C

B

(Note 6)

pF

Pulse Width of Spikes that Must

be Suppressed by the Input Filter

t

SP

Fast mode 30 ns

Oscillator Stop Flag (OSF) Delay

t

OSF

(Note 7) 100 ms

SYMBOL

t

HD:STA

MIN TYP MAX

100

100 400

t

HD:DAT

t

SU:DAT

t

SU:STA

t

SU:STO

250

100

20 + 0.1C

20 + 0.1C

20 + 0.1C

20 + 0.1C

B

B

B

B

0.9

0.9

1000

300

300

300

400

DS1340

2-Wire RTC with Trickle Charger

_____________________________________________________________________ 3

RECOMMENDED DC OPERATING CONDITIONS

(VCC= V

CC MIN

to V

CC MAX

, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VCC= 3.3V, TA= +25°C, unless

otherwise noted.) (Note 1)

PARAMETER

CONDITIONS

UNITS

DS1340-18

1.8

DS1340-3 2.7 3.0 3.3

Supply Voltage (Note 8) V

CC

DS1340-33

3.3 5.5

V

Input Logic 1 (SDA, SCL) V

IH

(Note 8)

V

Input Logic 0 (SDA, SCL) V

IL

(Note 8)

V

Supply Voltage, Pullup (FT/OUT)

V

IH

(Note 8) 5.5 V

DS1340-18 1.3 3.7

DS1340-3 1.3 3.7

Backup Supply Voltage (Note 8)

DS1340-33 1.3 5.5

V

R1 (Notes 9, 10)

R2 (Note 11)

Trickle-Charge Current-Limiting
Resistors

R3 (Note 12)

Ω

DS1340-18

1.6

DS1340-3

2.6 2.7Power-Fail Voltage (Note 8) V

PF

DS1340-33

V

Input Leakage (SCL, CLK) I

LI

-1 +1 µA

I/O Leakage (SDA, FT/OUT) I

LO

-1 +1 µA

VCC > 2V; V

OL

= 0.4V 3.0

SDA Logic 0 Output I

OLSDA

1.7V < VCC < 2V; VOL = 0.2 x V

CC

3.0

mA

VCC > 2V; VOL = 0.4V 3.0

1.7V < VCC < 2V; VOL = 0.2 x V

CC

3.0

mA

FT/OUT Logic 0 Output I

OLSQW

1.3V < VCC < 1.7V; VOL = 0.2x V

CC

250 µA

DS1340-18 72 150

DS1340-3

200

Active Supply Current (Note 13) I

CCA

DS1340-33

300

µA

DS1340-18 60 100

DS1340-3 81 125Standby Current (Note 14) I

CCS

DS1340-33

150

µA

V

BACKUP

Leakage Current

V

BACKUP

= 3.7V 100 nA

DC ELECTRICAL CHARACTERISTICS

(VCC= 0V, V

BACKUP

= 3.7V, TA= -40°C to +85°C, unless otherwise noted.) (Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

OSC ON, FT = 0 (Note 15)

OSC ON, FT = 1 (Note 15)

Oscillator Current

OSC ON, FT = 0, V

BACKUP

= 3.0V,

T

A

= +25°C (Notes 15, 16)

nA

V

BACKUP

Data-Retention Current

OSC OFF

100 nA

SYMBOL

V

BACKUP

I

BACKUPLKG

I

BACKUP1

I

BACKUP2

I

BACKUP3

I

BACKUPDR

MIN TYP MAX

1.71

2.97

0.7 x V

-0.3 +0.3 x V

1.51

2.45

2.70 2.88 2.97

CC

V

250

2000

4000

108

192

100

800 1150

850 1250

800 1000

25.0

CC

1.89

+ 0.3

CC

1.71

DS1340

2-Wire RTC with Trickle Charger

4 _____________________________________________________________________

POWER-UP/POWER-DOWN CHARACTERISTICS

(TA= -40°C to +85°C) (Figure 2)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Recovery at Power-Up t

REC

(Note 17) 2 ms

VCC Fall Time; V

PF(MAX)

to

V

PF(MIN)

t

VCCF

µs

VCC Rise Time; V

PF(MIN)

to

V

PF(MAX)

t

VCCR

0µs

WARNING: Under no circumstances are negative undershoots, of any amplitude, allowed when device is in battery-backup mode.

Note 1: Limits at -40°C are guaranteed by design and not production tested.
Note 2: After this period, the first clock pulse is generated.
Note 3: A device must internally provide a hold time of at least 300ns for the SDA signal (referred to as the V

IH(MIN)

of the SCL

signal) to bridge the undefined region of the falling edge of SCL.

Note 4: The maximum t

HD:DAT

only has to be met if the device does not stretch the low period (t

LOW

) of the SCL signal.

Note 5: A fast-mode device can be used in a standard-mode system, but the requirement t

SU:DAT

≥ to 250ns must be met. This
is automatically the case if the device does not stretch the low period of the SCL signal. If such a device does stretch the
low period of the SCL signal, it must output the next data bit to the SDA line t

R MAX

+ t

SU:DAT

= 1000 + 250 = 1250ns

before the SCL line is released.

Note 6: C

B

—total capacitance of one bus line in pF.

Note 7: The parameter t

OSF

is the period of time the oscillator must be stopped for the OSF flag to be set over the 0V ≤ VCC≤

V

CCMAX

and 1.3V ≤ V

BAT

≤ 3.7V range.

Note 8: All voltages are referenced to ground.
Note 9: Measured at V

CC

= typ, V

BACKUP

= 0V, register 08h = A5h.

Note 10: The use of the 250Ω trickle-charge resistor is not allowed at V

CC

> 3.63V and should not be enabled.

Note 11: Measured at V

CC

= typ, V

BACKUP

= 0V, register 08h = A6h.

Note 12: Measured at V

CC

= typ, V

BACKUP

= 0V, register 08h = A7h.

Note 13: I

CCA

—SCL clocking at max frequency = 400kHz.

Note 14: Specified with 2-wire bus inactive.
Note 15: Measured with a 32.768kHz crystal attached to the X1 and X2 pins.
Note 16: Limits at +25°C are guaranteed by design and not production tested.
Note 17: This delay applies only if the oscillator is enabled and running. If the oscillator is disabled or stopped, no power-up delay

occurs.

SDA

SCL

t

HD:STA

t

LOW

t

HIGH

t

R

t

F

t

BUF

t

HD:DAT

t

SU:DAT

REPEATED

START

t

SU:STA

t

HD:STA

t

SU:STO

t

SP

STOP START

Figure 1. Data Transfer on 2-Wire Serial Bus

300