DS1646-120 Maxim Integrated Products, DS1646-120 Datasheet - Page 4
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DS1646-120
Manufacturer Part Number
DS1646-120
Description
Real Time Clock
Manufacturer
Maxim Integrated Products
Datasheet
1.DS1646-120.pdf
(12 pages)
Specifications of DS1646-120
Function
Clock, Calendar, NV Timekeeping RAM
Rtc Memory Size
131072 B
Supply Voltage (max)
5.5 V
Supply Voltage (min)
4.5 V
Maximum Operating Temperature
+ 70 C
Minimum Operating Temperature
0 C
Mounting Style
Through Hole
Rtc Bus Interface
Parallel
Package / Case
eDIP
Time Format
HH:MM:SS
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
DS1646-120
Manufacturer:
DALLAS
Quantity:
22
Part Number:
DS1646-120
Manufacturer:
DALLAS
Quantity:
20 000
Company:
Part Number:
DS1646-120+
Manufacturer:
Maxim
Quantity:
601
BLOCK DIAGRAM DS1646 Figure 1
TRUTH TABLE DS1646 Table 1
SETTING THE CLOCK
The MSB Bit, B7, of the control register is the write bit. Setting the write bit to a 1, like the read bit halts
updates to the DS1646 registers. The user can then load them with the correct day, date and time data in
24-hour BCD format. Resetting the write bit to a 0 then transfers those values to the actual clock counters
and allows normal operation to resume.
STOPPING AND STARTING THE CLOCK OSCILLATOR
The clock oscillator may be stopped at any time. To increase the shelf life, the oscillator can be turned off
to minimize current drain from the battery. The
to a 1 stops the oscillator.
FREQUENCY TEST BIT
Bit 6 of the day byte is the frequency test bit. When the frequency test bit is set to logic 1 and
the oscillator is running, the LSB of the second’s register will toggle at 512 Hz. When the seconds
register is being read, the DQ0 line will toggle at the 512 Hz frequency as long as conditions for access
remain valid (i.e.,
<4.5V >V
5V ± 10%
<V
V
CC
BAT
BAT
CE
low,
V
V
V
V
CE
X
X
X
OE
IH
IL
IL
IL
low, and address for seconds register remain valid and stable).
V
V
OE
X
X
X
X
X
IL
IH
WE
V
V
V
X
X
X
X
IH
IH
IL
OSC
4 of 12
DESELECT
DESELECT
DESELECT
DESELECT
WRITE
MODE
bit is the MSB for the second’s registers. Setting it
READ
READ
DATA OUT
DATA IN
HIGH-Z
HIGH-Z
HIGH-Z
HIGH-Z
HIGH-Z
DQ
DATA RETENTION
CMOS STANDBY
STANDBY
STANDBY
POWER
ACTIVE
ACTIVE
ACTIVE
MODE
DS1646/DS1646P