Rainbow Electronics DS1672 User Manual
www.maxim-ic.com
µ
www.maxim-ic.com
DS1672
Low-Voltage Serial Timekeeping Chip
GENERAL DESCRIPTION
The DS1672 low-voltage serial timekeeping chip
incorporates a 32-bit counter and powermonitoring functions. The 32-bit counter is
designed to count seconds and can be used to
derive time-of-day, week, month, month, and
year by using a software algorithm. A precision,
temperature-compensated reference and
comparator circuit monitors the status of VCC.
When an out-of-tolerance condition occurs, an
internal power-fail signal is generated that forces
the reset to the active state. When VCC returns to
an in-tolerance condition, the reset signal is kept
in the active state for 250ms to allow the power
supply and processor to stabilize.
TYPICAL OPERATING CIRCUIT
FEATURES
§ 32-bit counter
§ 2-wire serial interface
§ Automatic power-fail detect and switch
circuitry
§ Power-fail reset output
§ Low-voltage oscillator operation (1.3V min)
§ Trickle charge capability
§ Underwriters Laboratory (UL) recognized
ORDERING INFORMATION
PART
DS1672-2
DS1672-3
DS1672-33
DS1672S-2
DS1672S-3
DS1672S-33
DS1672U-2
DS1672U-3
DS1672U-
33
TEMP
RANGE
-40°C to +85°C 8 0.300" DIP DS1672-2
-40°C to +85°C 8 0.300" DIP DS1672-3
-40°C to +85°C 8 0.300" DIP DS1672-33
-40°C to +85°C 8 0.150" SO DS1672-2
-40°C to +85°C 8 0.150" SO DS1672-3
-40°C to +85°C 8 0.150" SO DS1672-33
-40°C to +85°C 8 µSOP 1672rr-2
-40°C to +85°C 8 µSOP 1672rr-22
-40°C to +85°C 8 µSOP 1672rr-33
PINPACKAGE
TOP
MARK
PIN CONFIGURATION
TOP VIEW
V
BACKUP
X1
X2
GND
Package Dimension Information
www.maxim-ic.com/TechSupport/DallasPackInfo.htm
Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata.
1 of 12 100302
1
2
3
4
DIP
SO
SOP
8
V
CC
RST
7
6
SCL
SDA
5
DS1672
ABSOLUTE MAXIMUM RATINGS
Voltage Range on Any Pin Relative to Ground -0.5V to +6.0V
Operating Temperature Range -40°C to +85°C
Storage Temperature Range -55°C to +125°C
Soldering Temperature See IPC/JEDEC J-STD-020A
This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operation
sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time can affect reliability.
RECOMMENDED DC OPERATING CONDITIONS
(TA = -40°C to +85°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Supply Voltage (DS1672-33)
(DS1672-3)
(DS1672-2)
Logic 1 V
Logic 0 V
Backup Supply Voltage V
Note 1: All voltages referenced to ground.
V
CC
V
CC
V
CC
IH
IL
BACKUP
2.97 3.3 3.63 V 1
2.7 3.0 3.3 V 1
1.8 2.0 2.2 V 1
0.7V
CC
-0.5 0.3V
V
+ 0.5 V 1
CC
CC
V1
1.3 3.0 3.63 V 1
DC ELECTRICAL CHARACTERISTICS
(V
Active Supply Current I
Standby Current I
Power-Fail Voltage V
Power-Fail Voltage V
Power-Fail Voltage V
V
Logic 0 Output (VOL = 0.4V) I
Logic 0 Output (DS1672-2)
(V
(V
Note 1: All voltages referenced to ground.
Note 2: I
Note 3: I
Note 4: SDA and RST .
< VCC < V
CCMIN
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Leakage Current I
BACKUP
> 2 V; VOL = 0.4V)
CC
< 2 V; VOL = .2VCC)
CC
specified with SCL clocking at max frequency (400kHz), trickle charger disabled.
CCA
specified with VCC = V
CCS
CCMAX, TA
CCTYP
= -40°C to +85°C)
CCA
CCS
PF
PF
PF
BACKUPLKG
OL
I
OL
and SDA, SCL = V
, trickle charger disabled.
CCTYP
600
500
mA
mA
2.80 2.88 2.97 V
2.5 2.6 2.7 V
1.6 1.7 1.8 V
25 50 nA
3 mA 1, 4
3
3
mA 1, 4
2
3
2 of 12
DC ELECTRICAL CHARACTERISTICS
(VCC = 0V, TA = -40°C to +85°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
V
V
Note 5: Using the recommended crystal on X1 and X2.
Current (Osc on) I
BACKUP
Current (Osc off) I
BACKUP
BACKUPOSC
BACKUP
0.425 1
200 nA
mA
DS1672
5
CRYSTAL SPECIFICATIONS
*
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Nominal Frequency F
O
32.768 kHz
Series Resistance ESR 45 kΩ
Load Capacitance C
*The crystal, traces, and crystal input pins should be isolated from RF generating signals. Refer to Application Note 58: Crystal Considerations
for Dallas Real-Time Clocks for additional specifications
L
6pF
3 of 12
AC ELECTRICAL CHARACTERISTICS
(VCC > V
PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS NOTES
, TA = -40°C to +85°C)
CCMIN
DS1672
SCL Clock
Frequency
Bus Free Time
Between a STOP and
START Condition
Hold Time
(Repeated) START
Condition
LOW Period of SCL
Clock
HIGH Period of SCL
Clock
Setup Time for a
Repeated START
Condition
Data Hold Time t
Data Setup Time t
Rise Time of Both
SDA and SCL
Signals
Fall Time of Both
SDA and SCL
Signals
Setup Time for STOP
Condition
f
SCL
t
BUF
t
HD:STA
t
LOW
t
HIGH
t
SU:STA
HD:DAT
SU:DAT
t
R
t
F
t
SU:STO
Fast Mode 100 400
Standard Mode 100
Fast Mode 1.3
Standard Mode 4.7
Fast Mode 0.6
Standard Mode 4.0
Fast Mode 1.3
Standard Mode 4.7
Fast Mode 0.6
Standard Mode 4.0
Fast Mode 0.6
Standard Mode 4.7
Fast Mode 0 0.9
Standard Mode 0
Fast Mode 100
Standard Mode 250
Fast Mode 20 + 0.1C
B
300
Standard Mode 1000
Fast Mode 20 + 0.1C
B
300
Standard Mode 300
Fast Mode 0.6
Standard Mode 4.0
kHz
ms
ms
ms
ms
ms
ms
ns 9
ns 10
ns 10
ms
6
7, 8
Capacitive Load for
Each Bus Line
I/O Capacitance C
Note 6: After this period, the first clock pulse is generated.
Note 7: A device must internally provide a hold time of at least 300ns for the SDA signal (referenced to the V
bridge the undefined region of the falling edge of SCL.
Note 8:The maximum t
Note 9: A fast mode device can be used in a standard mode system, but the requirement t
automatically be the case if the device does not stretch the LOW period of the SCL signal. If such a device does stretch the LOW
period of the SCL signal, it must output the next data bit to the SDA line t
released.
Note 10: C
– Total capacitance of one bus line in pF.
B
has only to be met if the device does not stretch the LOW period (t
HD:DAT
C
B
I/O
max + t
R
10 pF
LOW
SU:DAT
= 1000 + 250 = 1250ns before the SCL line is
SU:DAT
400 pF 10
) of the SCL signal.
>= to 250ns must then be met. This will
4 of 12
of the SCL signal) in order to
IHMIN
Loading...