DS620U+T&R Maxim Integrated Products, DS620U+T&R Datasheet - Page 7

• 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

a) PO-high
Logic 0
Logic 1
THERMOSTAT OPERATION
The PO pin on the DS620 operates as the thermostat output when it is configured as PO
P01 and P02 bits of the configuration register. In both of these configurations, PO is updated after every
temperature conversion or write to the temperature register, and remains at the updated value until the next
conversion or write completes. PO
user-defined upper and lower trip-points. PO
the value stored in the upper trip-point register (T
value stored in the lower trip-point register (T
hysteresis into the output response. Similarly, PO
below the value stored in the low trip-point register (T
the value stored in the upper trip-point register (T
A0h (MSB) and A1h (LSB) and the T
DS620 memory.
The T
stored in EEPROM; therefore, they are nonvolatile (NV) and can be programmed prior to installation of the DS620
for use in standalone applications. All bits in the T
value in the temperature register for the thermostat operation, regardless of the number of bits used for the
temperature conversions as decided by the R0 and R1 bits in the configuration register. Therefore, to ensure
proper thermostat operation, any bits not used for the temperature measurement should be set to 0 in the T
T
0 prior to comparison to the measured temperature. (Bits 0 to 2 are automatically set to 0).
Another thermostat feature is the temperature high and low flags (THF and TLF) in the configuration register.
These bits provide a record of whether the temperature has ever been equal to or greater than T
less than T
exceeds the T
meets or falls below the T
set, it remains set until the power is cycled or it is overwritten with a 0 by the user.
Figure 4. Thermostat Operation
STANDALONE THERMOSTAT OPERATION
The DS620 can function as a standalone thermostat, i.e., it can provide thermostat functionality without requiring
communication with a microcontroller. For standalone thermostat operation, the T
must be programmed to the desired values prior to installation. For standalone operation, the AUTOC bit in the
configuration register must be set to 1 so that measurements begins automatically at power up. This also
configures the A1 pin as an input pin that can trigger a conversion. In addition, PO must be configured as PO
or PO
conversions at power up (1SHOT = 0) or a single conversion (one-shot) at power up or upon request (1SHOT = 1).
In one-shot mode, one conversion is performed at power-up and then the device enters a low-power standby state
until A1 is toggled high. The A1 pin must be toggled low and back high again to start another conversion.
L
registers. For example, for 11-bit temperature conversions, bits 3 and 4 in the T
H
-LOW
and T
. The 1SHOT bit in the configuration register is used to enable the DS620 to perform continuous
L
L
at anytime since power up or since the bits were last cleared. If the temperature ever meets or
H
registers (see Table 1) contain centigrade temperature values in two’s complement format and are
T
register value, the THF bit in the configuration register is set to 1, and if the temperature ever
L
L
value, the TLF bit in the configuration register is set to 1. Once THF or TLF has been
T
H
-HIGH
L
and PO
register is located in address spaces A2h (MSB) and A3h (LSB) of the
Temp
Tem
p
-HIGH
L
) (see Figure 4a). This allows the user to program any amount of
-LOW
H
-LOW
H
H
is activated when the measured temperature meets or exceeds
), and stays active until the temperature meets or falls below the
) (see Figure 4b). The T
and T
are active-low and are activated and deactivated based on
7 of 15
is activated when the measured temperature meets or goes
L
), and stays active until the temperature meets or exceeds
b) PO-low
Logic 1
Logic 0
L
registers are used in the comparison to the temperature
DS620 Digital Thermometer and Thermostat
T
H
L
register is located in address spaces
H
H
, T
and T
L
, and configuration registers
-HIGH
L
register should be set to
or PO
T
H
-LOW
H
or equal to or
through the
Temp
Tem
p
H
-HIGH
and