LM63CIMA National Semiconductor, LM63CIMA Datasheet - Page 10

• Manufacturer Part Number: LM63CIMA
• Manufacturer: National Semiconductor

Specifications of LM63CIMA

• Temperature Sensor Function: Temp Sensor
• Interface Type: Serial (2-Wire)
• Output Type: Digital
• Package Type: SOIC N
• Operating Temperature (min): 0C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (max): 3.6V
• Lead Free Status / Rohs Status: Not Compliant

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4.
5.
6.
7.
8.
The ARA, 000 1100, is a general call address. No device
should ever be assigned to this address.
The ALERT Configuration bit in the Remote Diode Tempera-
ture Filter and Comparator Mode Register must be set low in
order for the LM63 to respond to the ARA command.
The ALERT output can be disabled by setting the ALERT
Mask bit in the Configuration Register. The power-on default
is to have the ALERT Mask bit and the ALERT Configuration
bit low.
1.3 SMBus INTERFACE
Since the LM63 operates as a slave on the SMBus the
SMBCLK line is an input and the SMBDAT line is bi-direc-
tional. The LM63 never drives the SMBCLK line and it does
not support clock stretching. According to SMBus specifica-
tions, the LM63 has a 7-bit slave address. All bits, A6 through
A0, are internally programmed and cannot be changed by
software or hardware.
The complete slave address is:
1.4 POWER-ON RESET (POR) DEFAULT STATES
For information on the POR default states see Section 2.2
LM63 Register Map in Functional Order.
1.5 TEMPERATURE DATA FORMAT
Temperature data can only be read from the Local and Re-
mote Temperature registers. The High, Low and T_CRIT
setpoint registers are Read/Write.
Remote temperature data is represented by an 11-bit, two's
complement word with a Least Significant Bit (LSB) equal to
A6
1
Alerting Device(s) send their address. While transmitting
their address, alerting devices sense whether their
address has been transmitted correctly. (The LM63 will
reset its ALERT output and set the ALERT Mask bit once
its complete address has been transmitted successfully.)
Master/slave NoACK
Master sends STOP
Master attends to conditions that caused the ALERT to
be triggered. The ALERT Status Register is read and fan
started, setpoints adjusted, etc.
Master resets the ALERT Mask bit in the Configuration
Register.
FIGURE 5. ALERT Output as an SMBus ALERT
A5
Temperature Response Diagram
0
A4
0
A3
1
A2
1
20057009
A1
0
A0
0
10
0.125°C. The data format is a left justified 16-bit word avail-
able in two 8-bit registers:
Local Temperature data is represented by an 8-bit, two's
complement byte with an LSB equal to 1°C:
1.6 OPEN-DRAIN OUTPUTS
The SMBDAT, ALERT, and PWM outputs are open-drain out-
puts and do not have internal pull-ups. A “High” level will not
be observed on these pins until pull-up current is provided by
an internal source, typically through a pull-up resistor. Choice
of resistor value depends on several factors but, in general,
the value should be as high as possible consistent with reli-
able operation. This will lower the power dissipation of the
LM63 and avoid temperature errors caused by self-heating of
the device. The maximum value of the pull-up resistor to pro-
vide the 2.1 V high level is 88.7 kΩ.
1.7 DIODE FAULT DETECTION
The LM63 can detect fault conditions caused by the remote
diode. If the D+ pin is detected to be shorted to V
(1) the Remote Temperature High Byte (RTHB) register is
loaded with 127°C, (2) the Remote Temperature Low Byte
(RTLB) register is loaded with 0, and (3) the OPEN bit (D2) in
the status register is set. Therefore, if the Remote T_CRIT
setpoint register (RCS): (1) is set to a value less than +127°
C and (2) the ALERT Mask is disabled, then the ALERT output
pin will be pulled low. If the Remote High Setpoint High Byte
(RHSHB) is set to a value less than +127°C and (2) the
ALERT Mask is disabled, then the ALERT will be pulled low.
The OPEN bit by itself will not trigger an ALERT.
If the D+ pin is shorted to either ground or D−, then the Re-
mote Temperature High Byte (RTHB) register is loaded with
−128°C (1000 0000) and the OPEN bit in the ALERT Status
Register will not be set. A temperature reading of −128°C in-
dicates that D+ is shorted to either ground or D-. If the value
in the Remote Low Setpoint High Byte (RLSHB) Register is
more than −128°C and the ALERT Mask is Disabled,
ALERT will be pulled low.
Temperature
Temperature
+0.125°C
−0.125°C
+125°C
+125°C
+25°C
−25°C
−55°C
+25°C
−25°C
−55°C
+1°C
−1°C
+1°C
−1°C
0°C
0°C
0111 1101 0000 0000
0001 1001 0000 0000
0000 0001 0000 0000
0000 0000 0010 0000
0000 0000 0000 0000
1111 1111 1110 0000
1111 1111 0000 0000
1110 0111 0000 0000
1100 1001 0000 0000
0111 1101
0001 1001
0000 0001
0000 0000
1111 1111
1110 0111
1100 1001
Binary
Binary
Digital Output
Digital Output
DD
Hex
7D
C9
FF
E7
19
01
00
, or open:
7D00
FFE0
C900
1900
0100
0020
0000
FF00
E700
Hex