DS1629
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The open-drain alarm output of the DS1629 will become active when either the measured temperature
exceeds the programmed overtemperature limit (T
H
) or current time reaches the programmed alarm
setting. The user can configure which event (time only, temperature only, either, or neither) will generate
an alarm condition. For storage of general system data or time/temperature data logging, the DS1629
features 32 bytes of SRAM. Applications for the DS1629 include personal computers/PDAs, cellular
telephones, office equipment, thermal data loggers, or any microprocessor-based, thermally-sensitive
system.
ORDERING INFORMATION
PART
TOP MARK
PIN-PACKAGE
DS1629S+
DS1629
8 SO 150 mils
D  1  2   +T  R
D  1  2
1    mil    2
i
+Denotes a lead(Pb)-free/RoHS-compliant package.
T&R = Tape and reel.
DETAILED PIN DESCRIPTION Table 1
PIN
NAME
FUNCTION
1
SDA
Data In  ut/Out  ut Pin for 2-Wire Serial Communication Port
2
SCL
Clock In  ut/Out  ut Pin for 2-Wire Serial Communication Port
3
ALRM
Alarm Output. Open drain time/temperature alarm output with configurable active
4
GND
Ground
5
X2
32.768kHz Feedback Out  ut
6
X1
32.768kHz Cr  stal In  ut
ill    r
n- r in
f r mi r    n r ll r  l   k in
8
V   
Su   l   Volta  e. 2.2V to 5.5V in  ut   ower   in.
OVERVIEW
A block diagram of the DS1629 is shown in Figure 1. The DS1629 consists of six major components:
1.
Direct-to-digital temperature sensor
2.
Real-time clock
3.
2-wire interface
4.
Data registers
5.
Thermal and clock alarm comparators
6.
Oscillator divider and buffer
The factory-calibrated temperature sensor requires no external components. The very first time the
DS1629 is powered up it begins temperature conversions, and performs conversions continuously. The
host can periodically read the value in the temperature register, which contains the last completed
conversion. As conversions are performed in the background, reading the temperature register does not
affect the conversion in progress.
The host can modify DS1629 configuration such that it does not power up in the auto-convert or
continuous convert modes. This could be beneficial in power-sensitive applications.