Applications
n Utility meters
Battery operated and portable equipment
Consumer electronics
White/brown goods
Pay phones
Cash registers
Personal computers
Programmable controller systems
Data loggers
Automotive systems
n
n
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n
1
Features
n Supply current typically 390 nA at 3 V
50 ns access time with 50 pF load capacitance
Fully operational from 1.2 V to 5.5 V
No busy states or danger of a clock update while
accessing
Serial communication on one line of a standard parallel
data bus or over a conventional 3 wire serial interface
Interface compatible with both Intel and Motorola
Seconds, minutes, hours, day of month, month, year, week
day and week number in BCD format
Leap year and week number correction
Time set lock mode to prevent unauthorized setting of the
current time or date
Oscillator stability 0.3 ppm / volt
No external capacitor needed
Frequency measurement and test modes
o
Temperature range -40 to +85 C
TSSO8 and SO8 packages
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n
n
n
n
n
n
n
n
n
n
n
o
n On request extended temperature range, -40 to +125 C
n Pin compatible with the V3021
n
Description
The V3020 is a low power CMOS real time clock. Data is
transmitted serially as 4 address bits and 8 data bits, over one
line of a standard parallel data bus. The device is accessed by
chip select (CS) with read and write control timing provided by
either RD and WR pulse (Intel CPU) or DS with advanced R/W
(Motorola CPU). Data can also be transmitted over a
conventional 3 wire serial interface having CLK, data I/O and
strobe. The V3020 has no busy states and there is no danger of
a clock update while accessing. Supply current is typically 390
nA at V = 3.0 V. Battery operati on is supported by complete
DD
functionality down to 1.2 V. The oscillator s tability is typically 0.3
ppm/V.
Ultra Low Power 1-Bit 32 kHz RTC
Typical Operating Configuration
W
R
o
r
R
/
W
R
D
o
r
D
S
I/O
A
d
d
r
e
s
s
B
u
s
D
a
t
a
B
u
s
XI
XO
WR
WR
RD
RD
CS
CS
CPU
Address
Decoder
V3020
RAM
Fig. 1
Pin Assignment
S08
Fig. 2
TSSO8
XI
XO
CS
V
SS
V
DD
WR
RD
I/O
V3020
V3020
RD
I/O
V
SS
CS
WR
V
DD
XI
XO
EM MICROELECTRONIC-MARIN SA
V3020
R
Handling Procedures
Electrical Characteristics
Stresses above these listed maximum ratings may cause
permanent damage to the device. Exposure beyond specified
operating conditions may affect device reliability or cause
malfunction.
This device has built-in protection against high static voltages
or electric fields; however, it is advised that normal precautions
Table 2
1)
The maximum operating temperature is confirmed by
sampling at initial device qualification. In production, all
o
devices are tested at +85 C. On request devices tested at
o
+125 C can be supplied.
2)
See Fig. 5
2
Absolute Maximum Ratings
Table 1
Parameter
Maximum voltage at V
DD
Minimum voltage at V
DD
Maximum voltage at any signal pin
Minimum voltage at any signal pin
Maximum storage temperature
Minimum storage temperature
Electrostatic discharge maximum
to MIL-STD-883C method 3015
Maximum soldering conditions
V
DDmax
V
DDmin
V
max
V
min
T
STOmax
T
STOmin
V
Smax
T
Smax
V
+ 7.0V
SS
V
- 0.3V
SS
V
- 0.3V
SS
V
+ 0.3V
DD
O
+150 C
O
-65 C
1000V
O
250 C x 10s
Symbol Conditions
be taken as for any other CMOS component. Unless otherwise
specified, proper operation can only occur when all terminal
voltages are kept within the supply voltage range. Unused
inputs must always be tied to a defined logic voltage level.
Operating Conditions
T
A
-40
1.2
5.0
+125
O
C
V
V/
m
s
nF
kHz
pF
k
W
5.5
6
30
50
100
32.768
8.2
35
7
V
DD
C
L
R
S
f
Parameter
Symbol Min. Typ. Max. Units
1)
Operating temperature
Logic supply voltage
Supply voltage dv/dt
(power-up & power-down)
Decoupling capacitor
Crystal Characteristics
2)
Frequency
Load capacitance
Series resistance
O
V = 5.0V 10%, V = 0 V and T = -40 to +85 C, unless otherwise specified
DD
SS
A
Total static supply
Total static supply
Dynamic current
Input / Output
Input logic low
Input logic high
Output logic low
Output logic high
Input leakage
Output tri-state leakage
on I/O pin
Oscillator
Starting voltage
Input capacitance on XI
Output capacitance on XO
Start-up time
Frequency stability
Frequency Measurement Mode
Current source on I/O pin
pulsed on/off @ 256 Hz
I
SS
I
SS
I
SS
V
IL
V
IH
V
OL
V
OH
I
IN
I
TS
V
STA
C
IN
C
OUT
T
STA
D
f/f
I
ONF
all outputs open, all inputs at V
DD
V = 3.0 V, address 0 = 0
DD
o
T = 0 to +70 C
A
3.5
390
600
nA
nA
m
A
V
V
V
V
m
A
m
A
V
pF
pF
s
ppm/V
m
A
800
300
1.0
0.4
1
1
0.5
60
460
0.1
0.1
13
9
1
0.3
25
2.4
1.2
10
all outputs open, all inputs at V
DD,
V = 5 V, address 0 = 0
DD
o
T = 0 to +70 C
A
O
T = +25 C
A
O
T = +25 C
A
O
1.5
V
5.5 V, T = +25 C
DD A
Table 3
Parameter
Symbol Test Conditions
Min.
Typ.
Max.
Unit
CS high, addr.0, bit 0, high
V = 1 V
I/O
I = 4 mA
OL
I = 4 mA
OH
0.0 < V < 5.0 V
IN
CS high, and address 0,
bit 0, low
I/O to V through 1M
W
SS
RD = V , WR = V
,
SS
DD
CS = 4 MHz
address 0 = 0, read all 0
490 nA
600 nA
V3020
R
The V3020 will run slightly too fast, in order to allow the user to
adjust the frequency, depending on the mean operating
temperature. This is made since the crystal adjustment can only
work by lowering the frequency with an added capacitor
between XO and V . The printed circuit capacitance has also
SS
3
to be taken in consideration. The V3020 in DIL 8 package,
running with an 8.2 pF crystal at room temperature, will be
adjusted to better than 1 s/day with a 6.8 pF capacitor.
Typical Standby Current at V = 3 V
DD
510
490
470
450
430
410
390
370
350
-50
-30
-10
+10
0
T [ C]
A
Fig. 3a
I
[
n
A
]
S
S
+30
+50
+70
+90
Typical Standby Current at V = 3 V and Extended Temperature
DD
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
-50
-30
-10
+10
+30
+50
+70
+90
+110
+130
0
T [ C]
A
Fig. 3b
I
[
m
A
]
S
S
V3020
R
4
Typical Standby Current at V
= 5.5 V
DD
750
700
650
600
550
500
450
400
-50
-30
-10
+10
O
T [ C]
A
Fig. 4a
I
[
n
A
]
S
S
+30
+50
+70
+90
Typical Standby Current at V
= 5.5 V and Extended Temperature
DD
6.00
5.00
4.00
3.00
2.00
1.00
0.00
-50
-30
-10
+10
+30
+50
+70
+90
+110
+130
O
T [ C]
A
Fig. 4b
I
[
m
A
]
S
S
V3020
R
5
Typical Frequency on I/O Pin
+80
+30
-20
-70
-120
-170
+3
+2
+1
0
-1
-2
s/day
Address 10 hex = 00 hex
Quartz with 8.2 pF load capacitance
External trimming capacitor between X and V [pF]
O
SS
O
T
[ C]
A
Typical drift for ideal 32'768 Hz quartz
Note : The trimming capacitor value must not exceed 15 pF.
Greater values may disturb the oscillator function.
Fig. 5
-50
-30
-10
+10 30
50
70
90
0
3
6
9
12
15
[ppm]
D
F
F
o
Quartz Characteristics
= the ratio of the change in frequency to the nominal value
expressed in ppm (It can be thought of as the frequency
deviation at any temperature.)
o
= the temperature of interest in C
o
= the turnover temperature (25 5 C)
To determine the clock error (accuracy) at a given temperature, add
O
the frequency tolerance at 25 C to the value obtained from the
formula above.
Fig. 6
[ppm]
-100
-200
-300
-400
T - 100
O
T - 50
O
O
Temperature [ C]
O
T [ C]
T
O
T +50
O
T +100
O
D
F
F
o
D
F
F
o
ppm
2
O
C
=-0.038
2
(T - T ) 10%
O
D
F/F
o
T
T
O
F
r
e
q
u
e
n
c
y
r
a
t
i
o
[
p
p
m
]
m
in
.
m
ax
.
V3020
R
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