DS620U+T&R Maxim Integrated Products, DS620U+T&R Datasheet - Page 12

• Manufacturer Part Number: DS620U+T&R
• Description: IC THERMOMETER/STAT DIG 8MSOP
• Manufacturer: Maxim Integrated Products

Specifications of DS620U+T&R

• Function: Thermometer, Thermostat
• Topology: ADC (Sigma Delta), Register Bank
• Sensor Type: Internal
• Sensing Temperature: -55°C ~ 125°C
• Output Type: I²C™/SMBus™
• Output Alarm: No
• Output Fan: No
• Voltage - Supply: 1.7 V ~ 3.5 V
• Operating Temperature: -55°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP Exposed Pad, 8-HMSOP, 8-eMSOP
• Full Temp Accuracy: +/- 2 C
• Digital Output - Bus Interface: Serial (2-Wire)
• Digital Output - Number Of Bits: 13 bit
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

the DS620 commands. See Writing to the DS620 or Reading from the DS620 for more information on reading from
and writing to the DS620.
WRITING TO THE DS620
The master can write data to the DS620 by issuing an address byte following the control byte. The R/W bit in the
control byte must be a 0 (write). After receiving an ACK from the DS620 in response to the control byte, the master
sends the address of the first register byte to be written, loading the address counter with the desired location. The
DS620 responds with another ACK, after which the master sends the data to be written. After receiving each byte
of data, the DS620 responds with an ACK. The master continues to write data to successive address locations until
it indicates there is no more data to be written by sending a STOP or repeated START condition. The DS620
ignores any data written once the address increments past ADh, the last defined register in the DS620 memory,
and indicates this by sending a NACK after each byte. It also ignores data written to undefined addresses A8h and
A9h. All writes to the DS620 are made to the shadow RAM. Once data is written to the shadow RAM, it is only
stored to EEPROM by issuance of a Copy Data command from the master. At that time all registers are copied to
EEPROM, except the Temperature registers, which are SRAM only, and the undefined registers. The DS620 must
be set to the continuous conversion mode and be actively converting temperature to enable the Copy Data
command to function properly. See Copying to EEPROM Command Sequence for more information.
READING FROM THE DS620
The master can read data from the DS620 by issuing an address byte following the control byte. The R/W bit in the
control byte must be a 0 (write). After receiving an ACK from the DS620 in response to the control byte, the master
writes the address of the first register byte to be read, loading the address counter with the desired location. The
DS620 will respond with another ACK. The master then must issue a repeated START (or a STOP and a START)
followed by a control byte with the same slave address as the first control byte. However, this time the R/W bit must
be a 1 which tells the DS620 that a “read” is being performed. After the DS620 sends an ACK in response to this
control byte, it begins transmitting the requested data on the next clock cycle. The master responds with an ACK
between each byte of data read from the DS620 until no further bytes of data are to be read, at which time the
master responds with a NACK followed by a STOP. The DS620 sends all 1’s (FFh) once the address increments
past ADh, the last defined register in the DS620 memory. There is no guaranteed state of data read from the
undefined registers, A8h and A9h. The Recall Data command should be issued before a read to assure that the
contents of the EEPROM will be in the Shadow RAM when read.
COMMAND SET
The DS620 command set is detailed below:
Start Convert [ 51h ]
Initiates temperature conversions. If the part is in one-shot mode (1SHOT = 1), only one conversion is performed.
In continuous mode (1SHOT = 0), continuous temperature conversions are performed until a Stop Convert
command is issued (even if 1SHOT is changed to a 1).
Stop Convert [ 22h ]
Stops temperature conversions when the device is in continuous conversion mode (1SHOT = 0). This command
has no function if the device is in one-shot mode (1SHOT = 1)
Recall Data [ B8h ]
Refreshes SRAM shadow register with EEPROM data.
Copy Data [ 48h ]
Copies data from all SRAM shadow registers to EEPROM.
NOTE: The DS620 must be set to the continuous conversion mode and be actively converting temperature to
enable the Copy Data command to function properly. See example command sequence in the Copying to
EEPROM Command Sequence section for more information.
Software POR [ 54h ]
Initiates a software power-on-reset (POR), which stops temperature conversions and resets all registers and logic
to their power-up states. The software POR allows the user to simulate cycling the power without actually powering
down the device. This command should not be issued while a Copy Data command is in progress.
1011 1000
0100 1000
0101 0001
0010 0010
0101 0100
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