NIPPON PRECISION CIRCUITS INC.
SM8580AM
Real-time Clock IC with 4-bit Interface
and Built-in Temperature Sensor
OVERVIEW
The SM8580AM is a real-time clock IC based on a 32.768 kHz crystal oscillator, which features a 4-bit paral-
lel interface for communication with an external microcontroller.
It comprises second-counter to year-counter clock and calendar circuits that feature automatic leap-year adjust-
ment 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.
FEATURES
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PINOUT
(Top view)
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High-speed bus 4-bit parallel interface
Date, day, hour, minute, and second-counter pre-
settable 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 out-
put)
2.4 to 5.5V interface voltage range
1.6 to 5.5V clock voltage range
0.6µA/3V (typ) current consumption
CE0N
FCON
FOUT
VTEMP
AIRQN
TIRQN
A0
A1
A2
A3
RDN
VSS
1
24
VDD
XT
XTN
N.C.
N.C.
N.C.
CE1
D0
D1
D2
D3
SM8580AM
12
13
ORDERING INFORMATION
D e vice
SM8580AM
P ackag e
24-pin SSOP
WRN
NIPPON PRECISION CIRCUITS—1
NPC [ NIPPON PRECISION CIRCUITS INC ]
