TCN75AVOA Microchip Technology, TCN75AVOA Datasheet - Page 27

• Manufacturer Part Number: TCN75AVOA
• Description: IC TEMP SENSOR SRL 2.7V 8SOIC
• Manufacturer: Microchip Technology

Specifications of TCN75AVOA

• Package / Case: 8-SOIC (3.9mm Width)
• Output Type: I²C™
• Function: Temp Monitoring System (Sensor)
• Topology: ADC (Sigma Delta), Register Bank
• Sensor Type: Internal
• Sensing Temperature: -55°C ~ 125°C
• Output Alarm: No
• Output Fan: Yes
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -55°C ~ 125°C
• Mounting Type: Surface Mount
• Temperature Threshold: Programmable
• Full Temp Accuracy: 3 C
• Digital Output - Bus Interface: 2-Wire, I2C
• Digital Output - Number Of Bits: 9 bit to 12 bit
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.7 V
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• Supply Current: 500 uA
• Ic Output Type: Digital
• Sensing Accuracy Range: ± 2°C
• Temperature Sensing Range: -40°C To +125°C
• Supply Voltage Range: 2.7V To 5.5V
• Resolution (bits): 12bit
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

6.0
6.1
The SDA and SCL serial interface are open-drain pins
that require pull-up resistors. This configuration is
shown in
FIGURE 6-1:
Interface.
The TCN75A is designed to meet 0.4V (maximum)
voltage drop at 3 mA of current. This allows the
TCN75A to drive lower values of pull-up resistors and
higher bus capacitance. In this application, all devices
on the bus must meet the same pull-down current
requirements.
6.2
Microchip provides several microcontroller product
lines with Master Synchronous Serial Port Modules
(MSSP) that include the I
module implements all master and slave functions and
simplifies
Figure 6-2
PIC16F737 as a master to control other Microchip
slave products, such as EEPROM, fan speed
controllers and the TCN75A temperature sensor
connected to the bus.
FIGURE 6-2:
Bus.
 2010 Microchip Technology Inc.
Microcontroller
APPLICATIONS INFORMATION
Connecting to the Serial Bus
Typical Application
PIC
MCU
Figure
PIC16F737
Fan Speed
Controller
the
shows a typical application using the
TC654
®
6-1.
firmware
Pull-up Resistors On Serial
Multiple Devices on I
SDA SCL
V
R
DD
2
development
C interface mode. This
R
Temperature
EEPROM
SDA
SCL
TCN75A
24LC01
Sensor
TCN75A
overhead.
2
C™
The ALERT output can be wire-ORed with a number of
other open-drain devices. In such applications, the
output needs to be programmed as an active-low
output. Most systems will require pull-up resistors for
this configuration.
6.3
The TCN75A does not require any additional
components besides the master controller in order to
measure temperature. However, it is recommended
that a decoupling capacitor of 0.1 µF to 1 µF be used
between the V
ceramic capacitor is recommended. It is necessary for
the capacitor to be located as close as possible to the
power pins in order to provide effective noise
protection.
For applications where a switching regulator is used to
power the sensor, it is recommended to add a 200Ω
resistor in series to V
from the sensor. It is also recommended to add the
series resistor in applications where a linear regulator
is used to step-down a switching regulator voltage to
power the sensor. For example, if a linearly regulated
3.3V from a 5V switching regulator is used to power the
sensor, add a 200Ω series resistor (refer to
FIGURE 6-3:
Single Resistor.
6.4
The TCN75A measures temperature by monitoring the
voltage of a diode located in the die. A low-impedance
thermal path between the die and the Printed Circuit
Board (PCB) is provided by the pins. Therefore, the
TCN75A effectively monitors the temperature of the
PCB. However, the thermal path for the ambient air is
not as efficient because the plastic device package
functions as a thermal insulator.
A potential for self-heating errors can exist if the
TCN75A SDA and SCL communication lines are
heavily loaded with pull-ups. Typically, the self-heating
error is negligible because of the relatively small
current consumption of the TCN75A. However, in order
to maximize the temperature accuracy, the SDA and
SCL pins need to be lightly loaded.
Switching
Regulator
Switching
Regulator
Layout Considerations
Thermal Considerations
DD
Regulator
Linear
and GND pins. A high-frequency
DD
200
Power-supply Filter using a
to filter out the switcher noise
bypass
0.1µF
bypass
200
0.1µF
TCN75A
TCN75A
DS21935D-page 27
TCN75A
V
DD
V
DD
Figure
6-3).