NPC SM8578BV Datasheet

❏

SM8578BV

NIPPON PRECISION CIRCUITS INC.

OVERVIEW

The SM8578BV is a CMOS serial interface, real­time clock IC that uses a 32.768 kHz crystal oscilla­tor for its reference timing.

It comprises second-counter to year-counter clock
and calendar circuits that feature automatic leap-year
adjustment, alarm and timer interrupt functions, as
well as oscillator stop, timer reloading, and other
detection functions. Data is transferred to and from
an external controller using a 3-wire serial interface.
It is available in compact 8-pin VSOP packages,
making it ideal for use in all types of portable, hand­held equipment.

FEATURES

■

3-wire serial interface control

■

Day (day of the month), weekday (Sunday to Sat­urday), hour and minute alarm interrupt function

■

1/4096 seconds to 255 minutes presettable interval
timer interrupt function

■

Oscillator stop and timer reload detect functions

■

Automatic leap-year adjustment function (W estern
and Japanese calendars)

■

1.6 to 5.5 V supply voltage range

■

0.5 µA (typ. at 3 V) current consumption

■

C

oscillator capacitor built-in

D

■

Compact 8-pin VSOP package

Real-time Clock IC

PINOUT

8-pin VSOP

Top view

INTN

XTN
XT

VSS

= date code

PACKAGE DIMENSIONS

Unit: mm

0.585 TYP

1

8578B

4

4.4±0.2

3.12±0.3

6.4±0.3

0.15

8

VDD
DATA
CLK
CE

5

0 to 10°

0.5±0.2

+0.1

-0.05

0.65

0.22±0.1

1.15±0.05

0.05±0.05

NIPPON PRECISION CIRCUITS—1

1.30 MAX

BLOCK DIAGRAM

SM8578BV

XTN

XT

INTN

CLK

DATA

CE

C

D

DETECT

OSC

OSC

DIVIDER

INPUT

CONTROLLER

VDD

INTERRUPT and FOUT

VSS

Control Line

CLOCK and CALENDAR

REGISTER

DIVIDER and

TIMER COUNTER

CONTROL REGISTER

CONTROLLER

ALARM REGISTER

SHIFT REGISTER

Internal Bus

CONTROL CIRCUIT

PIN DESCRIPTION

Number Name I/O Function

1 INTN O

2 XTN O Oscillator output. Oscillator capacitor C
3 XT I Oscillator input
4 VSS – Negative supply pin
5 CE I Chip enable. Chip is selected when HIGH. Pull-down resistor built-in

6 CLK I

7 DATA I/O

8 VDD – Positive supply voltage. A 0.1 µF pass capacitor should be connected between VDD and VSS.

Timer/alarm interrupt output and the setting frequency output,corresponding to the active internal mode.
N-channel open-drain output pin

built-in

D

Serial data clock.
In write mode, data is input on DATA on the rising edge of CLK.
In read mode, data is output on DATA on the rising edge of CLK.

Serial data input/output. When CE goes HIGH, initial 4-bit input data determines the device mode.
Subsequent data is transferred in write or read mode, as selected by the de vice mode.

NIPPON PRECISION CIRCUITS—2

−

−

−

−

SPECIFICATIONS

Absolute Maximum Ratings

V

= 0 V

SS

Parameter Symbol Condition Rating Unit

Supply voltage range V
Input voltage range V

Output voltage range

Power dissipation P
Storage temperature range T
Soldering temperature T
Soldering time t

V
V

DD

OUT1

OUT2

STG

SLD

SLD

−

°

°

−

° C

−

SM8578BV

0.3 to 7.0 V

IN

All inputs V
INTN V
DATA V

D

SS

SS

0.3 to V

SS

0.3 to V

+ 0.3 V

DD

0.3 to 8.0 V
+ 0.3 V

DD

150 mW

55 to 125

255

10 s

C
C

Recommended Operating Conditions

V

= 0 V

SS

Parameter Symbol Condition Rating Unit

Supply voltage range V
Operating temperature range T

DD

opr

DC Electrical Characteristics

V

= 0 V, V

SS

Current consumption

HIGH-level input voltage V
LOW-level input voltage V
Input leakage current I

Input resistance

HIGH-level output voltage

LOW-level output voltage

Output leakage current I
Oscillator stop detection time t

= 1.6 to 5.5V , C

DD

= 10 pF, T

G

= − 40 to 85 ° C unless otherwise noted

a

Parameter Symbol Condition

I
I

LEAK

R

DWN1

R

DWN2

V
V

V
V
V
V

OSC

DD1

DD2

OH1

OH2

OL1

OL2

OL3

OL4

OZ

V

= 5.0 V CE = V

DD

V

= 3.0 V – 0.5 1.0 µA

DD

CE, CLK, DATA 0.8V

IH

CE, CLK, DATA 0 – 0.2V

IL

CE, CLK: V
V

= 5.0 V

DD

V

= 3.0 V 150 300 600 k Ω

DD

V

= 5.0 V

DD

V

= 3.0 V 2.0 – 3.0 V

DD

V

= 5.0 V

DD

V

= 3.0 V – – V

DD

V

= 5.0 V

DD

V

= 3.0 V – – V

DD

DATA, INTN: V

DATA, INTN =
V

DD

= V

IN

DD

CE: V

DATA: I
mA

DATA: I
mA

INTN: I
mA

OUT

= V

or V

IN

DD

OL

SS

SS

= V

OH

OL

= − 1

= 1

= 1

or V

DD

1.6 to 5.5 V
40 to 85

Rating

min typ m ax

– 1.0 2.0 µA

DD

–V

-0.5 – 0.5 µA
75 150 300 k Ω

4.5 – 5.0 V

––V

––V

SS

0.5 – 0.5 µA

10 – – ms

DD

DD

+ 0.5 V

SS

+ 0.8 V

SS

+ 0.25 V

SS

+ 0.4 V

SS

Unit

V
V

NIPPON PRECISION CIRCUITS—3

Oscillator Characteristics

T

= 25 ° C, C

a

= 10 pF, Seiko Epson C-002SH crystal (C

G

SM8578BV

= 30 k Ω , C

I

= 6 pF) unless otherwise noted

L

−

−

Parameter Symbol Condition

Oscillator start time t
Oscillator stop voltage V

STA

STO

Frequency voltage characteristic f/V V
Frequency accuracy
Output capacitance C

ε

IC

D

AC Characteristics

V

= 0 V, C

SS

CLK clock period t
CLK HIGH-level pulsewidth t
CLK LOW-level pulsewidth t
CE setup time t
CE hold time t
CE recovery time t
CLK hold time t
Write data setup time t
Write data hold time t
Read data output delay time
Output disable delay time
Input rise and fall time t

1. C

=50pF

L

2. C

=50pF, RL=10k Ω

L

= 50 pF, T

L

= − 40 to 85 ° C unless otherwise noted

a

Parameter Symbol

CLK

WH

WL

CS

CH

CR

CKH

DS

DH

1

2

t

RD

t

RZ

RF

Rating

min typ m ax

V

= 1.6 V – – 5.0 s

DD

Unit

– – 1.5 V

= 1.6 to 5.5 V

DD

V

= 5.0 V

DD

V

= 5.0 V – 15 – pF

DD

V

= 5 V ± 10% V

DD

2 – +2 ppm/V

10 – +10 ppm

= 3.0 V ± 1 0 %

DD

Unit

min typ ma x min typ ma x

600 – – 1200 – – ns
300 – – 600 – – ns
300 – – 600 – – ns
150 – – 300 – – ns
200 – – 400 – – ns
300 – – 600 – – ns

50 – – 100 – – ns
50 – – 100 – – ns
50 – – 100 – – ns

– – 200 – – 400 ns
– – 100 – – 200 ns
––20––40ns

CLK

C E

50%

t

CS

50%

t

WL

t

CLK

t

WH

t

CHtCKH

t

CR

NIPPON PRECISION CIRCUITS—4