8576_nc9603ee

NR8576 series
Real-time Clock Modules
OVERVIEW
The NR8576 series devices are serial-interface type real-time clock modules with built-in crystal oscillator
elements. They feature timer counter circuits that keep track of time from the current second to the current
year, automatic leap-year adjustment, and a supply voltage detect function. Also, a 32.768kHz/1Hz select
output function is incorporated for independent hardware control.
FEATURES
■
■
■
■
■
■
■
■
PINOUT
Crystal oscillator element built-in for adjustmentfree use
Timer counters for second, minute, hour, day, day
of the week, month, and year
2.5 to 5.5V operating voltage range
1.7 ± 0.3V supply voltage detection threshold
1.0µA at 3.0V (typ) current consumption
Automatic leap-year calendar adjustment
32.768kHz and 1Hz output selectable
Package: 14-pin SOP
(Top view)
VSS
1
14
FOUT
NC
2
13
NC
CE
3
12
NC
FSEL
4
11
DATA
WR
5
10
CLK
FOE
6
9
VDD
NC
7
8
NC
SERIES CONFIGURATION
5 ± 23 ppm
(Unit: mm)
10.1 ± 0.2
0 to 10°
1.27
0.6 ± 0.2
14-pin SOP
NR8576AB
PACKAGE DIMENSIONS
7.4 ± 0.2
5 ± 12 ppm
0.10 ± 0.05
NR8576AA
Frequency deviation
5.0
Package
3.2 ± 0.1
Device
0.15
0.35 ± 0.1
SEIKO NPC CORPORATOIN—1
NR8576 series
BLOCK DIAGRAM
VDD
VSS
32.768kHz
OSC
Divider
Timer Counter
FOUT
Output
Controller
FSEL
FOE
Shift Register
Voltage
Detect
DATA
CLK
I/O
Controller
WR
Control
Circuit
CE
PIN DESCRIPTION
Number
Name
I/O
Description
1
VSS
–
Ground
Connect a ≥ 0.1µF capacitor between VDD and VSS.
2
NC
–
No connection. Leave open for normal use.
3
CE
I
Chip enable.
HIGH: Enable
LOW: DATA goes high impedance; input on WR, CLK, and DATA stops; and the TM bit is cleared.
4
FSEL
I
FOUT output frequency select.
HIGH: 1Hz
LOW: 32.768kHz
5
WR
I
DATA input/output control switch.
HIGH: Data input mode (RTC write)
LOW: Data output mode (RTC read)
6
FOE
I
FOUT output enable control.
HIGH: The frequency selected by FSEL is output on FOUT.
LOW: FOUT goes high impedance.
7
NC
–
No connection. Leave open for normal use.
8
NC
–
No connection. Leave open for normal use.
9
VDD
–
Supply voltage.
Connect a ≥ 0.1µF capacitor between VDD and VSS.
10
CLK
I
System clock input.
Data is input (RTC write mode) and output (RTC read mode) on the rising edge of CLK.
11
DATA
I/O
12
NC
–
No connection. Leave open for normal use.
13
NC
–
No connection. Leave open for normal use.
14
FOUT
O
Frequency output (output controlled by FOE and frequency selected by FSEL).
In 1Hz output mode, the 1Hz signal is synchronized to the internal 1 second signal.
FOUT output is not affected by the CE signal.
Data read and write input/output
SEIKO NPC CORPORATOIN—2
NR8576 series
SPECIFICATIONS
Absolute Maximum Ratings
VSS = 0V unless otherwise noted.
Parameter
Symbol
Condition
Rating
Unit
Supply voltage range
VDD
Ta = 25°C
−0.3 to 7.0
V
Input voltage range
VIN
Ta = 25°C
VSS − 0.3 to VDD + 0.3
V
Output voltage range
VOUT
Ta = 25°C
VSS − 0.3 to VDD + 0.3
V
Storage temperature range
TSTG
−55 to 125
°C
Rating
Unit
Recommended Operating Conditions
VSS = 0V unless otherwise noted.
Parameter
Symbol
Condition
Supply voltage range
VDD
2.5 to 5.5
V
Clock supply voltage range
VCLK
1.4 to 5.5
V
Operating temperature range
TOPR
−40 to 85
°C
Rating
Unit
NR8576AA
5 ± 12
ppm
NR8576AB
5 ± 23
ppm
+10/−120
ppm
Oscillator Characteristics
VSS = 0V unless otherwise noted.
Parameter
Symbol
Condition
∆f/fO
Ta = 25°C,
VDD = 5.0V
Frequency temperature characteristic
TOP
Ta = −10 to 70°C,
VDD = 5.0V, 25°C std
Frequency voltage characteristic
f/V
Ta = 25°C,
VDD = 2.0 to 5.5V
±2 max
ppm/V
Oscillator start time
tSTA
Ta = 25°C, VDD = 2.5V
3 max
sec
fA
Ta = 25°C, VDD = 5.0V,
first year
±5 max
ppm/year
Frequency deviation
Aging
SEIKO NPC CORPORATOIN—3
NR8576 series
DC Electrical Characteristics
VSS = 0V, VDD = 5.0V ± 10%, Ta = −40 to 85°C unless otherwise noted.
Rating
Parameter
Symbol
Condition
Unit
min
typ
max
–
1.5
3.0
µA
–
1.0
2.0
µA
–
0.5
1.0
µA
–
4.0
10.0
µA
–
2.5
6.5
µA
–
1.5
4.0
µA
IDD1
VDD = 5.0V
IDD2
VDD = 3.0V
IDD3
VDD = 2.0V
IDD4
VDD = 5.0V
IDD5
VDD = 3.0V
IDD6
VDD = 2.0V
HIGH-level input voltage
VIH
CE, FSEL, WR, FOE, CLK, DATA
0.8VDD
–
–
V
LOW-level input voltage
VIL
CE, FSEL, WR, FOE, CLK, DATA
–
–
0.2VDD
V
Input OFF leakage current
IOFF
CE, FSEL, WR, FOE, CLK;
VIN = VDD or VSS
–
–
0.5
µA
VOH1
VDD = 5.0V
4.5
–
–
V
VOH2
VDD = 3.0V
2.0
–
–
V
VOL1
VDD = 5.0V
–
–
0.5
V
VOL2
VDD = 3.0V
–
–
0.8
V
N/CL
FOUT
IOZH
VOUT = 5.5V; DATA, FOUT
−1.0
–
1.0
µA
IOZL
VOUT = 0V; DATA, FOUT
−1.0
–
1.0
µA
1.4
1.7
2.0
V
Current consumption
HIGH-level output voltage
LOW-level output voltage
Output load fanout
Output leakage current
Supply voltage detect
threshold voltage
VDT
CE = VSS, FOE = VSS,
FSEL = VDD,
FOUT: floating
CE = VSS, FOE = VDD,
FSEL = VSS,
FOUT: 32kHz output
IOH = −1.0mA;
DATA, FOUT
IOL = 1.0mA;
DATA, FOUT
2 LSTTL/30pF max
SEIKO NPC CORPORATOIN—4
NR8576 series
AC Characteristics
Ta = −40 to 85°C, CL = 50pF unless otherwise noted.
Rating
Parameter
Symbol
VDD = 5V ± 10%
VDD = 3V ± 10%
min
max
min
max
Unit
CLK clock period
tCLK
0.75
7800
1.5
7800
µs
CLK LOW-level pulsewidth
tCLKL
0.375
3900
0.75
3900
µs
CLK HIGH-level pulsewidth
tCLKH
0.375
3900
0.75
3900
µs
CE setup time
tCES
0.375
3900
0.75
3900
µs
CE hold time
tCEH
0.375
–
0.75
–
µs
CE enable time
tCE
–
0.9
–
0.9
sec
Write data setup time
tSD
0.1
–
0.2
–
µs
Write data hold time
tHD
0.1
–
0.1
–
µs
WR setup time
tWRS
100
–
100
–
ns
WR hold time
tWRH
100
–
100
–
ns
DATA output delay time
tDATD
–
0.2
–
0.4
µs
DATA output floating time
tDZ
–
0.1
–
0.2
µs
Clock rise time
tr1
–
50
–
100
ns
Clock fall time
tf1
–
50
–
100
ns
FOUT rise time (CL = 30pF)
tr2
–
100
–
200
ns
FOUT fall time (CL = 30pF)
tf2
–
100
–
200
ns
tHZ
–
100
–
200
ns
tLZ
–
100
–
200
ns
tZH
–
100
–
200
ns
tZL
–
100
–
200
ns
FOUT duty cycle (CL = 30pF)
Duty
40
60
40
60
%
Wait time
tRCV
0.95
–
1.9
–
µs
Disable time (CL = 30pF)
Enable time (CL = 30pF)
SEIKO NPC CORPORATOIN—5
NR8576 series
Timing Diagrams
Data read
tCE
WR
tWRH
tWRS
CE
tCES
tCEH
tCLK
tRCV
CLK
tCLKH tCLKL
tf1
tr1
tDZ
DATA
tDATD
Data write
tCE
WR
tWRS
tWRH
CE
tCES
tCEH
tCLK
tRCV
CLK
tCLKH tCLKL
tSD tHD
tf1
tr1
DATA
SEIKO NPC CORPORATOIN—6
NR8576 series
FOUT
tH
tf2
90%
FOUT
50%
10%
tr2
t
Duty =
tH
t 100 (%)
Disable/Enable
tZH
FOE
tHZ
50%
50%
90%
FOUT
10%
tZL
FOE
tLZ
50%
50%
90%
FOUT
10%
Note that FOE and FSEL do not have chatter elimination circuits. Consequently, switching either FOE or
FSEL during 32kHz mode operation may generate chatter noise on the FOUT output. Also, note that the 1Hz
and 32kHz oscillators are not synchronized to each other, so switching intervals shortens the duty cycle.
Accordingly, a wait time (≥ chattering time + output frequency period) should be incorporated when switching
intervals.
SEIKO NPC CORPORATOIN—7
NR8576 series
FUNCTIONAL DESCRIPTION
Timer data configuration
■
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Counter data in BCD code format
Automatic long/short month and leap-year adjustment
24-hour time display
LSB first write and read data
MSB
LSB
Second ( 0 to 59 )
FDT
S40
S20
S10
S8
S4
S2
S1
Minute ( 0 to 59 )
∗
mi40
mi20
mi10
mi8
mi4
mi2
mi1
Hour ( 0 to 23 )
∗
∗
h20
h10
h8
h4
h2
h1
∗
w4
w2
w1
Week ( 1 to 7 )
∗
∗
d20
d10
d8
d4
d2
d1
Month ( 1 to 12 )
TM
∗
∗
mo10
mo8
mo4
mo2
mo1
Year ( 0 to 99 )
y80
y40
y20
y10
y8
y4
y2
y1
Day ( 1 to 31 )
1. * bit: Optional write bits.
2. FDT bit: Supply voltage detect bit
• The FDT bit is set to 1 when the voltage between VDD and VSS falls below 1.7 ± 0.3V.
• The FDT bit is reset to 0 for data reads longer than 48 bits. Note that the FDT bit is not reset to 0 for data
reads of 47 bits or less.
• The read/write data bits should be should be set to 0. After the supply voltage is applied, the FDT bit
should be set to 0.
VDD
VDET
0.5 second
0.5 second
Detected Pulse
CE
(READ MODE)
FDT
3. TM bit: Factory test bit. Should be set to 0 for normal use.
SEIKO NPC CORPORATOIN—8
NR8576 series
Data Read
1
2
3
52
53
54
54+n
CLK
CE
WR
DATA
S1
S2
S4
S8
S10
S20 S40 FDT
y8
y10
y20
y40
y80
OUTPUT MODE
second
year
NON CHANGE
OUTPUT DATA
Data is output when WR is LOW and CE is HIGH.
Time and calendar data is loaded into shift registers on the first rising edge of the clock CLK, and the seconds’
digit LSB is output on DATA.
The data is then loaded and shifted in the sequence second, minute, hour, week, day, and month on the rising
edge of CLK, and output on DATA. The output data is valid after 52 rising edges of the clock; data input after
52 cycles does not alter the first 52 bits of valid data.
Within the 52 cycles of valid data, data already input can be output if there is a falling edge of CE after the corresponding number of cycles. For example, the data comprising the second-to-week is output is CE goes LOW
after 28 clock cycles.
For continuous data reads, a wait time (tRCV) is required before the next data cycle if CE has gone LOW.
Note that if an update operation (a 1s carry) occurs during a data read, an error of −1s in the read data is generated.
The data read time should be completed after tCE ≤ 0.9s.
SEIKO NPC CORPORATOIN—9
NR8576 series
Data Write
1
2
3
S1
S2
S4
52
53
54
54+n
CLK
CE
WR
DATA
INPUT MODE
S8
S10 S20 S40 FDT
second
y8
y10
y20
y40
y80
year
Data is input when WR is HIGH and CE is HIGH.
The seconds’ digit signal to the timer counter stops on the first falling edge of CLK and the counter remains
stopped until the next rising edge of CE. The 1Hz to 128Hz frequency divider step counters are reset during the
interval between the first and second rising edges of CLK.
The data is then input on DATA into the shift register, starting with seconds’ digit LSB synchronized with the
rising edge of CLK.
After the final data is input into the shift register following 52 cycles, the shift register contents are transferred
to the timer counters. Note that a data write must contain 52 bits of input data. If CE goes LOW before 52 bits
are input, the input data is invalid. If the input data exceeds 52 bits, data from the 53rd bit is ignored (the first
52 bits remain valid).
The data write time should be completed after tCE ≤ 0.9s.
If a data read occurs immediately after a data write, a wait time (tRCV) is required if CE has gone LOW.
Note that writing null data will cause incorrect operation. All bits must be valid data bits.
SEIKO NPC CORPORATOIN—10
NR8576 series
Please pay your attention to the following points at time of using the products shown in this document.
The products shown in this document (hereinafter “Products”) are not intended to be used for the apparatus that exerts harmful influence on
human lives due to the defects, failure or malfunction of the Products. Customers are requested to obtain prior written agreement for such
use from SEIKO NPC CORPORATION (hereinafter “NPC”). Customers shall be solely responsible for, and indemnify and hold NPC free and
harmless from, any and all claims, damages, losses, expenses or lawsuits, due to such use without such agreement. NPC reserves the right
to change the specifications of the Products in order to improve the characteristic or reliability thereof. NPC makes no claim or warranty that
the contents described in this document dose not infringe any intellectual property right or other similar right owned by third parties.
Therefore, NPC shall not be responsible for such problems, even if the use is in accordance with the descriptions provided in this document.
Any descriptions including applications, circuits, and the parameters of the Products in this document are for reference to use the Products,
and shall not be guaranteed free from defect, inapplicability to the design for the mass-production products without further testing or
modification. Customers are requested not to export or re-export, directly or indirectly, the Products to any country or any entity not in
compliance with or in violation of the national export administration laws, treaties, orders and regulations. Customers are requested
appropriately take steps to obtain required permissions or approvals from appropriate government agencies.
SEIKO NPC CORPORATION
1-9-9, Hatchobori, Chuo-ku,
Tokyo 104-0032, Japan
Telephone: +81-3-5541-6501
Facsimile: +81-3-5541-6510
http://www.npc.co.jp/
Email: sales@npc.co.jp
NC9603EE
2008.05
SEIKO NPC CORPORATOIN—11