Rev 3; 1/06

I

2

C, 32-Bit Binary Counter Watchdog RTC with

Trickle Charger and Reset Input/Output

General Description

The DS1374 is a 32-bit binary counter designed to contin-

uously count time in seconds. An additional counter gen-

erates a periodic alarm or serves as a watchdog timer. If

disabled, this counter can be used as 3 bytes of non-

volatile (NV) RAM. Separate output pins are provided for

an interrupt and a square wave at one of four selectable

frequencies. A precision temperature-compensated refer-

ence and comparator circuit monitor the status of V

CC

to

detect power failures, provide a reset output, and auto-

matically switch to the backup supply when necessary.

Additionally, the reset pin is monitored as a pushbutton

input for externally generating a reset. The device is pro-

grammed serially through an I

2

C* serial interface.

Features

♦

32-Bit Binary Counter

♦

Second Binary Counter Provides Time-of-Day

Alarm, Watchdog Timer, or NV RAM

♦

Separate Square-Wave and Interrupt Output Pins

♦

I

2

C Serial Interface

♦

Automatic Power-Fail Detect and Switch Circuitry

♦

Single-Pin Pushbutton Reset Input/Open-Drain

Reset Output

♦

Low-Voltage Operation

♦

Trickle-Charge Capability

♦

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

♦

10-Pin µSOP, 16-Pin SO

♦

Available in a Surface-Mount Package with an

Integrated Crystal (DS1374C)

♦

Underwriters Laboratory (UL) Recognized

DS1374

Applications

Portable Instruments

Point-of-Sale Equipment

Medical Equipment

Telecommunications

Typical Operating Circuit

RPU = t

r

/C

B

V

CC

CRYSTAL

V

CC

RPU RPU

V

CC

X1

SCL

CPU

INT

RST

SDA

INT

RST

N.O.

PUSHBUTTON

RESET

V

BACKUP

GND

X2

V

CC

SQW

*Purchase

of I

2

C components of Maxim Integrated Products,

Inc., or one of its sublicensed Associated Companies, conveys

a license under the Philips I

2

C Patent Rights to use these com-

ponents in an I

2

C system, provided that the system conforms

to the I

2

C Standard Specification as defined by Philips.

DS1374

PRIMARY

BATTERY,

RECHARGEABLE

BATTERY, OR

SUPER CAPACITOR

Pin Configurations appear at the end of the data sheet.

Ordering Information

PART

DS1374C-18

DS1374C-18#

DS1374C-3

DS1374C-3#

DS1374C-33

DS1374C-33#

DS1374C-33/T&R

TEMP RANGE

-40°C to +85°C

VOLTAGE (V)

1.8

3.0

3.3

PIN-PACKAGE

16 SO (300 mils)

16 SO (300 mils)/Tape and Reel

TOP MARK**

DS1374C-18

DS1374C-3

DS1374C-33

Ordering Information continued at end of data sheet.

#Denotes

a RoHS-compliant device that may include lead that is exempt under 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 RoHS-compliant package.

______________________________________________

Maxim Integrated Products

1

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.

I

2

C, 32-Bit Binary Counter Watchdog RTC with

Trickle Charger and Reset Input/Output

DS1374

ABSOLUTE MAXIMUM RATINGS

Voltage Range on V

CC

Pin Relative to Ground .....-0.3V to +6.0V

Voltage Range on SDA, SCL, and WDS

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 the

Handling,

PC Board Layout, and Assembly

section.

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.

RECOMMENDED DC OPERATING CONDITIONS

(V

CC

= V

CC(MIN)

to V

CC(MAX)

, T

A

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

PARAMETER

Supply Voltage

(Notes 2, 3)

Input Logic 1

Input Logic 0

Pullup Resistor Voltage (INT,

SQW, SDA, SCL), V

CC

= 0V

Power-Fail Voltage

(Note 2)

SYMBOL

DS1374-33

V

CC

V

IH

V

IL

V

PU

DS1374-3

DS1374-18

(Note 2)

DS1374-33

V

PF

DS1374-3

DS1374-18

Backup Supply Voltage

(Notes 2, 3, 4)

V

BACKUP

DS1374-33

DS1374-3, DS1374-18

2.70

2.45

1.51

1.3

2.88

2.6

1.6

3.0

CONDITIONS

MIN

2.97

2.7

1.71

0.7 x V

CC

-0.3

TYP

3.3

3.0

1.8

MAX

5.50

3.3

1.89

V

CC

+ 0.3

+0.3 x

V

CC

5.5

2.97

2.7

1.71

V

CC

(

MAX)

3.7

V

UNITS

2

_____________________________________________________________________

I

2

C, 32-Bit Binary Counter Watchdog RTC with

Trickle Charger and Reset Input/Output

DC ELECTRICAL CHARACTERISTICS

(V

CC

= V

CC(MIN)

to V

CC(MAX)

, T

A

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

PARAMETER

Trickle-Charge Current-Limiting

Resistors

Input Leakage

I/O Leakage

RST

Pin I/O Leakage

SDA Logic 0 Output (V

OL

= 0.4V)

RST,

SQW, and

INT

Logic 0

Outputs (Note 11)

SYMBOL

R1

R2

R3

I

LI

I

LO

I

LORST

I

OLSDA

V

CC

> 2V; V

OL

= 0.4V

I

OL1

1.71V < V

CC

< 2V; V

OL

= 0.2 V

CC

1.3V < V

CC

< 1.71V; V

OL

= 0.2 V

CC

DS1374-18

Active Supply Current

(Notes 11, 12)

I

CCA

DS1374-3

DS1374-33

DS1374-18

Standby Current (Notes 11, 13)

V

BACKUP

Leakage Current

(V

BACKUP

= 3.7V)

I

CCS

DS1374-3

DS1374-33

I

BACKUPLKG

75

110

180

60

80

115

(Note 5)

(Note 6)

(Note 7)

(Note 8)

(Note 9)

(Note 10)

-1

-200

CONDITIONS

MIN

TYP

250

2000

4000

+1

3.0

250

150

200

300

100

125

175

100

nA

µA

mA

µA

Ω

MAX

UNITS

DS1374

DC ELECTRICAL CHARACTERISTICS

(V

CC

= 0V, V

BACKUP

= 3.7V,

T

A

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

PARAMETER

V

BACKUP

Current (OSC ON);

SQW OFF

V

BACKUP

Current (OSC ON);

SQW ON (32kHz)

V

BACKUP

Data-Retention Current

(OSC OFF)

SYMBOL

I

BKOSC1

I

BKOSC2

I

BACKUPDR

(Note 14)

(Notes 14, 15)

CONDITIONS

MAX

TYP

400

600

25

MAX

700

1000

100

UNITS

nA

_____________________________________________________________________

3

I

2

C, 32-Bit Binary Counter Watchdog RTC with

Trickle Charger and Reset Input/Output

DS1374

AC ELECTRICAL CHARACTERISTICS

(V

CC

= V

CC(MIN)

to V

CC(MAX)

, T

A

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

PARAMETER

SCL Clock Frequency (Note 16)

Bus Free Time Between STOP

and START Conditions

Hold Time (Repeated) START

Condition (Note 17)

Low Period of SCL Clock

High Period of SCL Clock

Data Hold Time (Notes 18, 19)

Data Setup Time (Note 20)

Start Setup Time

Rise Time of Both SDA and SCL

Signals (Note 16)

Fall Time of Both SDA and SCL

Signals (Note 16)

Setup Time for STOP Condition

Capacitive Load for Each Bus Line

I/O Capacitance (SDA, SCL)

Pulse Width of Spikes That Must

be Suppressed by the Input Filter

Pushbutton Debounce

Reset Active Time

Oscillator Stop Flag (OSF) Delay

SYMBOL

f

SCL

t

BUF

t

HD:STA

t

LOW

t

HIGH

t

HD:DAT

t

SU:DAT

t

SU:STA

t

R

t

F

t

SU:STO

C

B

C

I/O

t

SP

PB

DB

t

RST

t

OSF

Fast mode

Standard mode

Fast mode

Standard mode

Fast mode

Standard mode

Fast mode

Standard mode

Fast mode

Standard mode

Fast mode

Standard mode

Fast mode

Standard mode

Fast mode

Standard mode

Fast mode

Standard mode

Fast mode

Standard mode

Fast mode

Standard mode

(Note 16)

(Note 21)

Fast mode

(Figure 2)

(Note 22)

30

250

100

CONDITIONS

MIN

100

0

1.3

4.7

0.6

4.0

1.3

4.7

0.6

4.0

0

100

250

0.6

4.7

20 +

0.1C

B

20 +

0.1C

B

0.6

4.7

400

10

300

1000

300

0.9

TYP

MAX

400

100

UNITS

kHz

µs

ns

µs

ns

µs

pF

ns

ms

4

_____________________________________________________________________

I

2

C, 32-Bit Binary Counter Watchdog RTC with

Trickle Charger and Reset Input/Output

POWER-UP/POWER-DOWN CHARACTERISTICS

(T

A

= -40°C to +85°C) (Figure 3)

PARAMETER

V

CC

Detect to Recognize Inputs

(V

CC

Rising)

V

CC

Fall Time; V

PF(MAX)

to

V

PF(MIN)

V

CC

Rise Time; V

PF(MIN)

to

V

PF(MAX)

SYMBOL

t

RPU

t

F

t

R

(Note 23)

300

0

CONDITIONS

MIN

TYP

250

MAX

UNITS

ms

µs

DS1374

WARNING:

Under no circumstances are negative undershoots, of any amplitude, allowed when the device is in write protection.

Note 1:

Note 2:

Note 3:

Note 4:

Note 5:

Note 6:

Note 7:

Note 8:

Note 9:

Note 10:

Note 11:

Note 12:

Note 13:

Note 14:

Note 15:

Note 16:

Note 17:

Note 18:

Note 19:

Note 20:

Limits at -40°C are guaranteed by design and not production tested.

All voltages are referenced to ground.

V

BACKUP

should not exceed V

CC

MAX or 3.7V, whichever is greater.

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

CC

> 3.63V and should not be enabled.

Measured at V

CC

= typ, V

BACKUP

= 0V, register 09h = A5h.

Measured at V

CC

= typ, V

BACKUP

= 0V, register 09h = A6h.

Measured at V

CC

= typ, V

BACKUP

= 0V, register 09h = A7h.

SCL only.

SDA and SQW and

INT.

The

RST

pin has an internal 50kΩ pullup resistor to V

CC

.

Trickle charger disabled.

I

CCA

—SCL clocking at max frequency = 400kHz.

Specified with I

2

C bus inactive.

Measured with a 32.768kHz crystal attached to the X1 and X2 pins.

WDSTR = 1. BBSQW = 1 is required for operation when V

CC

is below the power-fail trip point (or absent).

C

B

—total capacitance of one bus line in pF.

After this period, the first clock pulse is generated.

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.

A device must internally provide a hold time of at least 300ns for the SDA signal (referred to as the V

IHMIN

of the SCL sig-

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

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.

Guaranteed by design. Not production tested.

The parameter t

OSF

is the period of time the oscillator must be stopped for the OSF flag to be set over the voltage range of

0V

≤

V

CC

≤

V

CC MAX

and 1.3V

≤

V

BACKUP

≤

3.7V.

This delay applies only if the oscillator is enabled and running. If the

EOSC

bit is 1, the startup time of the oscillator is

added to this delay.

Note 21:

Note 22:

Note 23:

_____________________________________________________________________

5

参数名称	属性值
是否无铅	不含铅
是否Rohs认证	符合
厂商名称	Maxim(美信半导体)
零件包装代码	SOIC
包装说明	SOP,
针数	16
Reach Compliance Code	compliant
ECCN代码	EAR99
可调阈值	NO
模拟集成电路 - 其他类型	POWER SUPPLY MANAGEMENT CIRCUIT
JESD-30 代码	R-PDSO-G16
JESD-609代码	e3
长度	10.3 mm
湿度敏感等级	1
信道数量	1
功能数量	1
端子数量	16
最高工作温度	85 °C
最低工作温度	-40 °C
封装主体材料	PLASTIC/EPOXY
封装代码	SOP
封装形状	RECTANGULAR
封装形式	SMALL OUTLINE
峰值回流温度（摄氏度）	260
认证状态	Not Qualified
座面最大高度	2.65 mm
最大供电电压 (Vsup)	5.5 V
最小供电电压 (Vsup)	2.97 V
标称供电电压 (Vsup)	3.3 V
表面贴装	YES
技术	CMOS
温度等级	INDUSTRIAL
端子面层	TIN
端子形式	GULL WING
端子节距	1.27 mm
端子位置	DUAL
处于峰值回流温度下的最长时间	NOT SPECIFIED
宽度	7.5 mm
Base Number Matches	1

DS1374C-33+T&R

DS1374C-33+T&R概述

DS1374C-33+T&R规格参数

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