NPC SM8580AM Datasheet

−

SM8580AM

Real-time Clock IC with 4-bit Interface

NIPPON PRECISION CIRCUITS INC.

OVERVIEW

The SM8580AM is a real-time clock IC based on a 32.768 kHz crystal oscillator, which features a 4-bit paral­lel interface for communication with an external microcontroller.

It comprises second-counter to year-counter clock and calendar circuits that feature automatic leap-year adjust­ment up to year 2099, alarm and timer interrupt functions, clock counter change detect functions, ±30-second
correction function, time error correction function, and built-in temperature sensor.

The 4-bit parallel interface is compatible with general-purpose SRAM over a high-speed bus.

and Built-in Temperature Sensor

FEATURES

■

High-speed bus 4-bit parallel interface

■

Date, day, hour, minute, and second-counter pre­settable alarm interrupt

■

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

■

2 software-maskable alarm and timer interrupt
outputs

■

Clock counter change detect functions

■

4-digit western calendar display

■

Automatic leap year correction up to year 2099

■

±30-second adjust function

■

195 to +192ppm time error correction range

■

Built-in temperature sensor (analog voltage out­put)

■

2.4 to 5.5V interface voltage range

■

1.6 to 5.5V clock voltage range

■

0.6µA/3V (typ) current consumption

ORDERING INFORMATION

De vice Pack ag e

SM8580AM 24-pin SSOP

PINOUT

(Top view)

CE0N
FCON
FOUT

VTEMP

AIRQN
TIRQN

A0
A1
A2
A3

RDN

VSS

1

SM8580AM

12

24

VDD
XT
XTN
N.C.
N.C.
N.C.
CE1
D0
D1
D2
D3

13

WRN

NIPPON PRECISION CIRCUITS—1

PACKAGE DIMENSIONS

(Unit: mm)

24-pin SSOP

10.05 0.20

10.20 0.30

SM8580AM

7.80 0.30

5.40 0.20

0.15

+

−

0.1

0.05

0.8

BLOCK DIAGRAM

XTN

AIRQN
TIRQN

FOUT
FCON

A0 to A3

D0 to D3

WRN

RDN

CE0N

XT

CE1

0.36 0.10

0.10

CG

CD

OSC

Interrupt

Control

FOUT

Control

BUS

Interface

M

0.12

Divider

Clock and Calendar

1.80

0.10

0.20

1.90

0.10 0.10

Digital Trimming

Controller

Counter

Alarm Register

Timer Register

FOUT Register

Control Register

Temperature

Sensor

0.50 0.20

Control line

0 to 10

VDD VSS

VTEMP

NIPPON PRECISION CIRCUITS—2

PIN DESCRIPTION

SM8580AM

Number Name I/O Function

1 CE0N I

2 FCON I

3 FOUT O Frequency set register, frequency output (CMOS output)
4 VTEMP O Temperature voltage output (analog output)
5 AIRQN O Alarm interrupt output (N-channel open-drain output)
6 TIRQN O Timer interrupt output (N-channel open-drain output)
7A0I
8A1I
9A2I

10 A3 I

11 RDN I

12 VS S – Ground

13 WRN I

14 D 3 I/O
15 D 2 I/O
16 D 1 I/O
17 D 0 I/O

18 CE1 I

19 NC – No connection
20 NC – No connection
21 NC – No connection
22 X T N O Oscillator output, with built-in oscillator capacitance C
23 XT I Oscillator output, with built-in oscillator capacitance C
24 V D D – Supply

1. Connect a 0.1µF capacitor between VDD and VS S.

Chip enable 0 input with built-in pull-up resistor.
The SM8580AM can be accessed when CE0N is LOW and CE1 is HIGH.

FOUT output frequency select control input (when CE1 is HIGH).

32.768kHz fixed frequency output when FCON is LOW.
Output frequency determined by bit FD when FCON is HIGH (when FE bit is 1).
Note that a HIGH-level voltage should be applied to FCON to avoid unwanted 32.768kHz output during
backup.

Address inputs.
Connect to the microcontroller address bus.
The selected register address is input on this bus when accessing the SM8580AM (positive logic).

Read strobe input. Data can be read from SM8580AM when RDN is LOW and WRN is HIGH.
An error will occur if both RDN and WRN are simultaneously LOW.

W rite strobe input. Data can be written to SM8580AM when RDN is HIGH and WRN is LOW.
An error will occur if both RDN and WRN are simultaneously LOW.

Data bus input/outputs.
Connect to the microcontroller data bus.

Chip enable 1 input with built-in pull-down resistor.
The SM8580AM can be accessed when CE0N is LOW and CE1 is HIGH.
FOUT is in output mode when CE1 is HIGH, regardless of the state of CE0N. FOUT is high impedance
when CE1 is LOW.

1

D

G

NIPPON PRECISION CIRCUITS—3

−

−

−

−

−

° C

−

°

SM8580AM

FOUT Output and SM8580AM Access Relationship

CE0N CE1 FCON FE bit FOUT output SM8580AM accessible

HIGH L OW
LOW LOW

HIGH HIGH

LOW HIGH

××
××

High impedance No

High impedance No
LO W 0 32.768kHz output No
LO W 1 32.768kHz output No
HIGH 0 High impedance No
HIGH 1 FD bit select frequency output No
LO W 0 32.768kHz output Yes
LO W 1 32.768kHz output Yes
HIGH 0 High impedance Yes
HIGH 1 FD bit select frequency output Yes

SPECIFICATIONS

Absolute Maximum Ratings

V

= 0 V

SS

Parameter Symbol Condition Rating Unit

Supply voltage range V
Input voltage range V

Output voltage range

Storage temperature range T

Recommended Operating Conditions

V

= 0 V

SS

Parameter Symbol Condition Rating Unit

Supply voltage range V
Clock supply voltage range V
Operating temperature range T

V

OUT1

V

OUT2

DD

IN

stg

DD

CLK

opr

All inputs, D0 to D3 V
TIRQN, AIRQN V
FOUT, D0 to D3, VTEMP V

0.3 to 7.0 V

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

55 to 125

2.4 to 5.5 V

1.6 to 5.5 V
40 to 85

C

NIPPON PRECISION CIRCUITS—4

DC Electrical Characteristics

−

−

−

V

= 0V, V

SS

= 1.6 to 5.5V, T

DD

= − 40 to 85 ° C unless otherwise noted

a

SM8580AM

°

−

−

Parameter Symbol Condition

Current consumption 1 I

DD1

V

= 5V CE0N = RDN = WRN = V

DD

A0 to A3 = D0 to D3 = V
CE1 = FCON = V

Current consumption 2 I

DD2

V

= 3V – 0.6 1.0 µA

DD

AIRQN = TIRQN = FOUT = V
VTEMP output OFF (TEMP bit = 0)

Current consumption 3 I

DD3

V

= 5V Ta = 25

DD

CE0N = RDN = WRN = V
A0 to A3 = D0 to D3 = V

Current consumption 4 I

DD4

V

DD

CE1 = FCON = V

= 3V – 40 6 0 µA

AIRQN = TIRQN = FOUT = V
VTEMP output ON (TEMP bit = 1)

Current consumption 5 I

DD5

V

= 5V CE0N = CE1 = RDN = WRN = V

DD

A0 to A3 = D0 to D3 = V
FCON = V

Current consumption 6 I

DD6

V

DD

AIRQN = TIRQN = FOUT = VTEMP = Hi-Z,

= 3V – 1.7 4.5 µA

VTEMP output OFF (TEMP bit = 0),
FOUT = 32kHz output, C

Current consumption 7 I

DD7

V

= 5V CE0N = CE1 = RDN = WRN = V

DD

A0 to A3 = D0 to D3 = V
FCON = V

Current consumption 8 I

DD8

V

DD

AIRQN = TIRQN = FOUT = VTEMP = Hi-Z,

= 3V – 5.0 12 µ A

VTEMP output OFF (TEMP bit = 0),

FOUT = 32kHz output, C
HIGH-level input voltage 1 V
L O W -level input voltage 1 V
HIGH-level input voltage 2 V
L O W -level input voltage 2 V
HIGH-level input voltage 3 V
L O W -level input voltage 3 V

Input leakage current I

Pull-up resistance 1 R
Pull-up resistance 2 R
Pull-down resistance 1 R
Pull-down resistance 2 R
Pull-down resistance 3 R
Pull-down resistance 4 R
HIGH-level output voltage 1 V
HIGH-level output voltage 2 V
HIGH-level output voltage 3 V
L O W-level output voltage 1 V
L O W-level output voltage 2 V
L O W-level output voltage 3 V
L O W-level output voltage 4 V
L O W-level output voltage 5 V
Output leakage current I

IH1

V

= 4.5 to 5.5V,

DD

CE0N, FCON, RDN, WRN, A0 to A3, D0 to D3

IL1

IH2

V

= 2.4 to 3.6V,

DD

CE0N, FCON, RDN, WRN, A0 to A3, D0 to D3

IL2

IH3

V

= 1.6 to 5.5V,

DD

CE1

IL3

CE0N = V

LEAK

FCON = RDN = WRN = A0 to A3 = V
V

UP1

DD

V

UP2

DD

V

DWN1

DD

V

DWN2

DD

V

DWN3

DD

V

DWN4

DD

V

OH1

DD

V

OH2

DD

V

OH3

DD

V

OL1

DD

V

OL2

DD

V

OL3

DD

V

OL4

DD

V

OL5

DD

D0 to D3, AIRQN, TIRQN, FOUT, V

OZ

, CE1 = V

DD

= 5V

CE0N = V

= 3V 150 300 600 k Ω
= 5V

CE1 = V

= 3V 42.5 85 17 0 M Ω
= 5V

CE1 = 0.5V

= 3V 55 110 220 k Ω
= 5V

I

OH

= 3V 2.0 – 3.0 V
= 3V I

OH

= 5V

I

OL

= 3V 0 – 0.8 V
= 3V I

OL

= 5V

I

OL

= 3V 0 – 0.4 V

Rating

Unit

+ 0.3 V

+ 0.3 V

DD

+ 0.3 V

DD

C,

SS

SS

SS

min typ max

SS

,

DD

or V

,

DD

DD

SS

,

,

– 1.0 2.0 µA

–5075µA

,

DD

or V

,

DD

,

SS

= 0pF

L

,

SS

= 30pF

L

or V

DD

DD

SS

SS

,

DD

DD

,

,

– 3.0 7.5 µA

– 8.0 20 µ A

2.2 – V

V

0.3 – 0.8 V

SS

0.8V

DD

V

0.3 – 0.2V

SS

0.8V

DD

V

0.3 – 0.2V

SS

DD

–V

DD

–V

DD

0.5 – 0.5 µA

,

SS

,

,

,

75 150 300 k Ω

SS

20 40 80 M Ω

DD

30 60 120 k Ω

4.5 – 5.0 V

= − 1mA, D0 to D3, FOUT

= − 100µA, D0 to D3, FOUT 2.9 – 3.0 V

0 – 0.5 V

= 1mA, D0 to D3, FOUT

= 100µA, D0 to D3, FOUT 0 – 0.1 V

0 – 0.25 V

= 1mA, AIRQN, TIRQN

= V

OUT

DD

or V

SS

0.5 – 0.5 µA

V

V

NIPPON PRECISION CIRCUITS—5

Terminal Capacitance Characteristics

Ta = 25°C, f = 1MHz

SM8580AM

Parameter Symbol Condition

Address input capacitance C
Data output capacitance C

ADD

DATA

min typ max

A0 to A3 – – 8 pF
D0 to D3 – – 15 pF

Rating

Oscillator Characteristics

Ta = 25°C, Seiko Epson C-002SH crystal (CI = 30kΩ, CL = 10pF) unless otherwise noted

Parameter Symbol Condition

Oscillator start time t
Oscillator stop voltage V
Frequency voltage characteristic f/V VDD = 1.6 to 5.5V
Frequency accuracy
Input capacitance C
Output capacitance C

STA

STO

ε

IC

G

D

VDD = 1.6 V – – 3. 0 s

VDD = 3.0V
VDD = 3.0V – 15 – pF
VDD = 3.0V – 10 – pF

min typ max

– – 1.5 V

−

2 – +2 ppm/V

−

20 – +20 ppm

Rating

AC Characteristics (1)

VSS = 0V, Ta = −40 to 85°C unless otherwise noted

Unit

Unit

Parameter Symbol Condition

FOUT duty Duty

Oscillator failure detection time t

OSC

Rating

Unit

min m ax min

VDD = 5V ± 10% 40 – 60 %
VDD = 3V ± 10% 40 – 60 %
VDD = 5V ± 10% 10 – – ms
VDD = 3V ± 10% 10 – – ms

NIPPON PRECISION CIRCUITS—6

AC Characteristics (2)

SM8580AM

VDD = 2.4 to 3.6V, VSS = 0V, Ta = −40 to 85°C, inputs VI = 0.5VDD, outputs VO = 0.5V
output load capacitance CL = 100pF (t

Parameter Symbol

Read cycle time t
Address access time t
CE access time t
RD access time t
CE output set time t
CE output floating t
RD output set time t
RD output floating t
Output hold time t
W r ite cycle time t
Chip select time t
Address valid to end-of-write t
Address setup time t
Address hold time t
W r ite pulsewidth t
Input data set time t
Input data hold time t

ACC

, t

, t

ARD

)

ACS

Rating

min max

RC
ACC
ACS
ARD

CLZ
CHZ
OLZ
OHZ

OH
WC
CW

AW

AS
WR
WP
DW

DH

150 – ns

– 150 ns
– 150 ns
– 100 ns
5–ns
–60ns
5–ns
–60ns

10 – ns
150 – ns
140 – ns
140 – ns

0–ns
0–ns

130 – ns

80 – ns

0–ns

DD

Unit

VDD = 4.5 to 5.5V, VSS = 0V, Ta = −40 to 85°C, inputs VI = 0.5VDD, outputs VO = 0.5V
output load capacitance CL = 100pF (t

Parameter Symbol

Read cycle time t
Address access time t
CE access time t
RD access time t
CE output set time t
CE output floating t
RD output set time t
RD output floating t
Output hold time t
W r ite cycle time t
Chip select time t
Address valid to end-of-write t
Address setup time t
Address hold time t
W r ite pulsewidth t
Input data set time t
Input data hold time t

ACC

, t

, t

ARD

)

ACS

Rating

min max

RC
ACC
ACS
ARD

CLZ
CHZ
OLZ
OHZ

OH
WC
CW

AW

AS
WR
WP
DW

DH

85 – ns

–85ns
–85ns
–45ns
3–ns
–30ns
3–ns
–30ns

5–ns
85 – ns
70 – ns
70 – ns

0–ns

0–ns
65 – ns
35 – ns

0–ns

DD

Unit

NIPPON PRECISION CIRCUITS—7