PT7C4307WEX

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PT7C4337

Real-time Clock Module (I

2

C Bus)

Features







Using external 32.768kHz quartz crystal for

PT7C4337

Supports I

2

C-Bus's high speed mode (400 kHz)

Includes time (Hour/Minute/Second) and calendar

(Year/Month/Date/Day) counter functions (BCD

code)











Programmable square wave output signal

Two Time-of-Day Alarms

Oscillator Stop Flag

Operating range: 1.8V to 5.5V

Timekeeping range: 1.2V to 1.8V

Description

The PT7C4337 serial real-time clock is a low-power

clock/calendar with two programmable time-of-day

alarms and a programmable square-wave output.

Address and data are transferred serially via a 2-wire,

bidirectional bus. 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 the

24-hour or 12-hour format with AM/PM indicator.

The device is fully accessible through the serial interface

while VCC is between 1.8V and 5.5V. I

2

C operation is

not guaranteed below 1.8V. Timekeeping operation is

maintained with VCC as low as 1.2V.

Table 1 shows the basic functions of PT7C4337. More

details are shown in section: overview of functions.

Table 1.

Basic functions of PT7C4337

Item

Function

Source

Crystal(32.768KHz)

PT7C4337

External crystal









-





2

1, 4.096k, 8.192k, 32.768k



1

Oscillator

Oscillator enable/disable

Oscillator fail detect

Time

display

12-hour

24-hour

2

Time

Century bit

Time count chain enable/disable

3

4

5

Interrupt

Alarm interrupt output

2-wire I

2

C bus

Programmable square wave output (Hz)

Communication

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PT7C4337

Real-time Clock Module (I

2

C Bus)

Pin Assignment

PT7C4337

1

X1

VCC

8

2

X2

INTA

SQW/INTB

7

SCL

6

3

4

GND

SDA

5

Pin Description

Pin No.

1

2

6

5

Pin

X1

X2

SCL

SDA

Type

I

O

I

I/O

DIP-8、SOIC-8

MSOP8

Description

Oscillator Circuit Input.

Together with X1, 32.768kHz crystal is connected between them.

Or external clock input.

Oscillator Circuit Output.

Together with X1, 32.768kHz crystal is connected between

them. When 32.768kHz external input, X2 must be float.

Serial Clock Input.

SCL is used to synchronize data movement on the I

2

C serial interface.

Serial Data Input/Output.

SDA is the input/output pin for the 2-wire serial interface. The

SDA pin is open-drain output and requires an external pull-up resistor.

Interrupt Output.

When enabled, INTA is asserted low when the time matches the values

set in the alarm registers. This pin is an open-drain output and requires an external pull up

resistor.

Square-Wave/Interrupt Output.

Programmable square-wave or interrupt output signal. It

is an open-drain output and requires an external pull up resistor.

Power.

Primary power for PT7C4337.

Ground.

No Connect.

These pins are not connected internally, but must be grounded for proper

operation.

3

INTA

SQW/I

NTB

VCC

GND

NC

O

7

8

4

/

O

P

P

Maximum Ratings

Storage Temperature ............................................................ -65℃ to +150℃

Ambient Temperature with Power Applied ........................... -40℃ to +85℃

Supply Voltage to Ground Potential (V

CC

to GND) ............... -0.3V to +6.5V

DC Input (All Other Inputs except Vcc & GND)

......................................

-0.3V to (Vcc +0.3V)

DC Output Voltage (SDA, /INTA, /INTB pins)........................................-0.3V to +6.5V

DC Output Current (FOUT) ............................................... -0.3V to (Vcc +0.3V)

Power Dissipation .............................................320mW(depend on package)

Note:

Stresses greater than those listed under

MAXIMUM RATINGS may cause permanent

damage to the device. This is a stress rating

only and functional operation of the device at

these or any other conditions above those

indicated in the operational sections of this

specification is not implied. Exposure to

absolute maximum rating conditions for

extended periods may affect reliability.

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PT7C4337

Real-time Clock Module (I

2

C Bus)

Operating Mode

The amount of current consumed by the PT7C4337 is determined, in part, by the I

2

C interface and oscillator operation. The

following table shows the relationship between the operating mode and the corresponding I

CC

parameter.

V

CC

Operating Mode

Power

2

I C Interface Active

1.8V ≤ V

CC

≤ 5.5V

I

CC

Active (I

CCA

)

2

I C Interface Inactive

1.8V ≤ V

CC

≤ 5.5V

I

CC

Standby (I

CCS

)

2

I C Interface Inactive

1.2V ≤ V

CC

≤ 1.8V

Timekeeping (I

CCTOSC

)

2

I C Interface Inactive, Oscillator Disabled

1.2V ≤ V

CC

≤ 1.8V

Data Retention (I

CCTDDR

)

Recommended Operating Conditions

Part No.

Sym.

V

CC

V

CCT

V

OSC

PT7C4337

V

IH

V

IL

T

A

V

CC

supply voltage

Oscillator start up voltage

SCL, SDA

Input high level

INTA, SQW/INTB

Input low level

Operating temperature

Description

Min

1.8

1.2

1.2

0.7V

CC

-

-0.3

-40

Type

3.3

-

-

-

-

-

-

Max

5.5

1.8

5.5

V

CC

+0.3

5.5

0.3V

CC

85

º

C

V

Unit

DC Electrical Characteristics

Unless otherwise specified, V

CC

= 1.8~5.5V, T

A

= -40 ° to +85 °

C

C

Sym.

V

CC

V

CCT

V

OSC

V

IL1

V

IH1

V

IL2

V

IH2

I

OL

I

IL

I

OZ

Item

Supply voltage

Oscillator voltage

Low-level input voltage

High-level input voltage

Low-level input voltage

High-level input voltage

Low-level output current

Input leakage current

Output current when OFF

V

CC

V

CC

SCL

SCL

X1

X1

SDA, /INTA, /INTB

SCL

SDA, /INTA, /INTB

Pin

Condition

Full operation

Timekeeping (Note 5)

Min

1.8

1.2

1.2

-0.3

0.7V

CC

-

-

3

-1

-1

Typ

Max

Unit

-

5.5

V

-

1.8

-

5.5

V

-

0.3V

CC

V

-

V

CC

+0.3

0.53

-

V

0.53

-

-

-

mA

-

-

1

1

A

A

V

OL

= 0.4V

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PT7C4337

Real-time Clock Module (I

2

C Bus)

Min

-

-

-

-

-

-

Typ

450

-

-

0.6

-

1.0

Max

800

160

100

1.0

150

1.8

Unit

DC Electrical Characteristics

Sym.

Item

Pin

Condition

Unless otherwise specified, V

CC

= 1.3~1.8V, T

A

= -40 ° to +85 °

C

C

V

CC

Note 2, 4, 5

I

CCTOSC

Timekeeping current

V

CC

Note 2,4,5,6

I

CCTDDR

Data retention current

Unless otherwise specified, V

CC

= 1.8~3.6V, T

A

= -40 ° to +85 °

C

C

I

CCA

Active supply current

V

CC

Note 1, 5

I

CCS

Standby current

V

CC

Note 2, 3, 5

Unless otherwise specified, V

CC

= 3.6~5.5V, T

A

= -40 ° to +85 °

C

C

I

CCA

Active supply current

V

CC

Note 1, 5

I

CCS

Standby current

V

CC

Note 2, 3, 5

Note:

1. SCL clocking at max frequency = 400kHz, V

IL

= 0.0V, V

IH

= VCC.

2. Specified with 2-wire bus inactive, V

IL

= 0.0V, V

IH

= VCC.

3. SQW enabled.

4. Specified with the SQW function disabled by setting INTCN = 1.

5. Using recommended crystal on X1 and X2.

6. Crystal oscillator is disabled.

nA

A

A

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PT7C4337

Real-time Clock Module (I

2

C Bus)

Recommended Layout for Crystal

Note:

The crystal, traces and crystal input pins

should be isolated from RF generating signals.

Built-in Capacitors Specifications and Recommended External Capacitors

Symbol

Typ

Unit

X1 to GND

C

G

12

pF

Build-in capacitors

X2 to GND

C

D

12

pF

X1 to GND

C

1

13

pF

Recommended External capacitors for

crystal C

L

=12.5pF

X2 to GND

C

2

13

pF

X1 to GND

C

1

0

pF

Recommended External capacitors for

crystal C

L

=6pF

X2 to GND

C

2

0

pF

Note:

The frequency of crystal can be optimized by external capacitor C

1

and C

2

, for frequency=32.768KHz, C

1

and C

2

should

meet the equation as below:

Cpar + [(C

1

+C

G

)*(C

2

+C

D

)]/ [(C

1

+C

G

)+(C

2

+C

D

)] =C

L

Cpar is all parasitical capacitor between X1 and X2.

C

L

is crystal’s load capacitance.

Parameter

Crystal Specifications

Parameter

Nominal Frequency

Series Resistance

Load Capacitance

Symbol

f

O

ESR

C

L

Min

-

-

-

Typ

32.768

-

6/12.5

Max

-

70

-

Unit

kHz

k

pF

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