Datasheet

DS1620
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User–defined temperature settings are stored in nonvolatile memory, so parts can be programmed prior to
insertion in a system, as well as used in standalone applications without a CPU. Temperature settings and
temperature readings are all communicated to/from the DS1620 over a simple 3–wire interface.
ORDERING INFORMATION
PART PACKAGE MARKING DESCRIPTION
DS1620
DS1620 8-Pin DIP (300 mil)
DS1620+ DS1620 (See Note) Lead-Free 8-Pin DIP (300 mil)
DS1620S DS1620 8-Pin SOIC (208 mil)
DS1620S+ DS1620 (See Note) Lead-Free 8-Pin SOIC (208 mil)
DS1620S/T&R DS1620 8-Pin SOIC (208 mil), 2000-Piece Tape-and-Reel
DS1620S+T&R DS1620 (See Note) Lead-Free 8-Pin SOIC (208 mil), 2000-Piece
Tape-and-Reel
Note: A “+” symbol will also be marked on the package near the Pin 1 indicator
DETAILED PIN DESCRIPTION Table 1
PIN SYMBOL DESCRIPTION
1 DQ Data Input/Output pin for 3-wire communication port.
2
CLK/ CONV
Clock input pin for 3-wire communication port. When the DS1620 is used in a
stand-alone application with no 3–wire port, this pin can be used as a convert
pin. Temperature conversion will begin on the falling edge of CONV .
3
RST
Reset input pin for 3-wire communication port.
4 GND
Ground pin.
5 T
COM
High/Low Combination Trigger. Goes high when temperature exceeds TH;
will reset to low when temperature falls below TL.
6 T
LOW
Low Temperature Trigger. Goes high when temperature falls below TL.
7 T
HIGH
High Temperature Trigger. Goes high when temperature exceeds TH.
8 V
DD
Supply Voltage. 2.7V – 5.5V input power pin.
Table 2. DS1620 REGISTER SUMMARY
REGISTER NAME
(USER ACCESS)
SIZE
MEMORY
TYPE
REGISTER CONTENTS
AND POWER-UP/POR STATE
Temperature
(Read Only)
9 Bits SRAM
Measured Temperature (Two’s Complement)
Power-Up/POR State: -60ºC (1 1000 1000)
T
H
(Read/Write)
9 Bits EEPROM
Upper Alarm Trip Point (Two’s Complement)
Power-Up/POR State: User-Defined.
Initial State from Factory: +15°C (0 0001 1110)
T
L
(Read/Write)
9 Bits EEPROM
Lower Alarm Trip Point (Two’s Complement)
Power-Up/POR State: User-Defined.
Initial State from Factory: +10°C (0 0001 0100)
OPERATION-MEASURING TEMPERATURE
A block diagram of the DS1620 is shown in Figure 1.
. .