2002 Microchip Technology Inc.

DS21490B-page 1

TCN75

Features

· Solid-State Temperature Sensing;

0.5°C Accuracy (Typ.)

· Operates from -55°C to +125°C

· Operating Supply Range: 2.7V to 5.5V

· Programmable Trip Point and Hysteresis with

Power-up Defaults

· Standard 2-Wire Serial Interface

· Thermal Event Alarm Output Functions as

Interrupt or Comparator / Thermostat Output

· Up to 8 TCN75s may Share the Same Bus

· Shutdown Mode for Low Standby Power

Consumption

· 5V Tolerant I/O at V

= 3V

· Low Power:

- 250

A (Typ.) Operating

- 1

A (Typ.) Shutdown Mode

· 8-Pin SOIC and MSOP Packaging

Applications

· Thermal Protection for High Performance CPUs

· Solid-State Thermometer

· Fire/Heat Alarms

· Thermal Management in Electronic Systems:

- Computers

- Telecom Racks

- Power Supplies / UPS/ Amplifiers

· Copiers / Office Electronics

· Consumer Electronics

· Process Control

Package Type

General Description

The TCN75 is a serially programmable temperature
sensor that notifies the host controller when ambient
temperature exceeds a user programmed set point.
Hysteresis is also programmable. The INT/CMPTR
output is programmable as either a simple comparator
for thermostat operation or as a temperature event
interrupt.

Communication

with

the

TCN75

accomplished via a two-wire bus that is compatible with
industry standard protocols. This permits reading the
current temperature, programming the set point and
hysteresis, and configuring the device.

The TCN75 powers up in Comparator mode with a
default set point of 80°C with 5°C hysteresis. Defaults
allow

independent

operation

stand-alone

thermostat. A shutdown command may be sent via the
2-wire bus to activate the low power Standby mode.
Address selection inputs allow up to eight TCN75s to
share the same 2-wire bus for multizone monitoring.

All registers can be read by the host and the INT/
CMPTR output's polarity is user programmable. Both
polled

and

interrupt

driven

systems

are

easily

accommodated. Small physical size, low installed cost,
and ease of use make the TCN75 an ideal choice for
implementing

sophisticated

system

management

schemes.

TCN75MOA

TCN75MUA

SOIC

MSOP

SCL

INT/CMPTR

GND

SDA

SCL

INT/CMPTR

GND

SDA

2-Wire Serial Temperature Sensor and Thermal Monitor

TCN75

DS21490B-page 2

2002 Microchip Technology Inc.

Device Selection Table

Functional Block Diagram

Part Number

Supply Voltage

Package

Junction Temperature Range

TCN75-3.3MOA

3.3

8-Pin SOIC

-55°C to +125°C

TCN75-5.0MOA

5.0

8-Pin SOIC

-55°C to +125°C

TCN75-3.3MUA

3.3

8-Pin MSOP

-55°C to +125°C

TCN75-5.0MUA

5.0

8-PIn MSOP

-55°C to +125°C

Control

Logic

TCN75

INT/CMPTR

TSET

THYST

Configuration

Temp

Sensor

SCL

SDA

Temperature

9-Bit

A/D

Converter

Two Wire

Serial Port

Interface

2002 Microchip Technology Inc.

DS21490B-page 3

TCN75

1.0

ELECTRICAL
CHARACTERISTICS

Absolute Maximum Ratings*

Supply Voltage (V

) ............................................ 6.0V

ESD Susceptibility (Note 3) ............................... 1000V

Voltage on Pins:

A0, A1, A2 .......... (GND 0.3V) to (V

+ 0.3V)

Voltage on Pins:

SDA, SCL, INT/CMPTR .. (GND 0.3V) to 5.5V

Thermal Resistance (Junction to Ambient)

8-Pin SOIC.......................................... 170°C/W
8-Pin MSOP ....................................... 250°C//W

Operating Temperature Range (T

): -55°C to +125°C

Storage Temperature Range (T

STG

): -65°C to +150°C

*Stresses above those listed under "Absolute Maximum Rat-
ings" may cause permanent damage to the device. These are
stress ratings only and functional operation of the device at
these or any other conditions above those indicated in the
operation sections of the specifications is not implied. Expo-
sure to Absolute Maximum Rating conditions for extended
periods may affect device reliability.

TCN75 ELECTRICAL SPECIFICATIONS

Electrical Characteristics: V

= 2.7V 5.5V, -55°C

= T

)

125°C, unless otherwise noted.

Symbol

Parameter

Min

Typ

Max

Units

Test Conditions

Power Supply

Power Supply Voltage

2.7

5.5

Operating Current

--
--

0.250

1.0

Serial Port Inactive (T

= T

= 25°C)

Serial Port Active

DD1

Standby Supply Current

Shutdown Mode, Serial Port
Inactive (T

= T

= 25°C)

INT/CMPTR Output

Sink Current: INT/CMPTR,
SDA Outputs

Note 1

TRIP

INT/CMPTR Response Time

CONV

User Programmable

Output Low Voltage

0.8

= 4.0mA

Temp-to-Bits Converter

Temperature Accuracy (Note 2)

±3

-55°C

+125°C

= 3.3V: TCN75-3.3MOA,

TCN75-3.3MUA
V

= 5.0V: TCN75-5.0MOA,

TCN75-5.0MUA

±0.5

±3

25°C

100°C

CONV

Conversion Time

msec

SET(PU)

TEMP Default Value

Power-up

HYST(PU)

HYST

Default Value

Power-up

2-Wire Serial Bus Interface

Logic Input High

x 0.7

Logic Input Low

x 0.3

Logic Output Low

0.4

= 3mA

Input Capacitance SDA, SCL

LEAK

I/O Leakage

±100

= T

= 25°C)

OL(SDA)

SDA Output Low Current

TCN75

DS21490B-page 4

2002 Microchip Technology Inc.

TIMING DIAGRAM

TCN75 ELECTRICAL SPECIFICATIONS (CONTINUED)

Electrical Characteristics: 2.7V

5.5V; -55°C

= T

)

125°C, C

= 80pF, unless otherwise noted.

Symbol

Parameter

Min

Typ

Max

Unit

Test Conditions

Serial Port Timing

Serial Port Frequency

100

400

kHz

LOW

Low Clock Period

1250

nsec

HIGH

High Clock Period

1250

nsec

SCL and SDA Rise Time

250

nsec

SCL and SDA Fall Time

250

nsec

SU(START)

START Condition Setup Time (for
repeated START Condition)

1250

nsec

SCL Clock Period

2.5

sec

H(START)

START Condition Hold Time

100

nsec

DSU

Data in Setup Time to SCL High

100

nsec

Data in Hold Time after SCL Low

nsec

SU(STOP)

STOP Condition Setup Time

100

nsec

IDLE

Bus Free Time Prior to New Transi-
tion

1250

nsec

Note

Output current should be minimized for best temperature accuracy. Power dissipation within the TCN75 will cause self-heating and

temperature drift. At maximum rated output current and saturation voltage, 4mA and 0.8V, respectively, the error amounts to 0.544°C for
the SOIC.

All part types of the TCN75 will operate properly over the wider power supply range of 2.7V to 5.5V. Each part type is tested and specified
for rated accuracy at its nominal supply voltage. As V

varies from the nominal value, accuracy will degrade 1°C/V of V

change.

Human body model, 100pF discharged through a 1.5k resistor.

SCL

tSC

tDSU

(STOP)

(START)

SDA

Data In

SDA

Data Out

2002 Microchip Technology Inc.

DS21490B-page 5

TCN75

2.0

PIN DESCRIPTIONS

The descriptions of the pins are listed in Table 2-1.

TABLE 2-1:

PIN FUNCTION TABLE

Pin Number

(8-Pin SOIC)

8-Pin MSOP)

Symbol

Description

SDA

Bi-directional Serial Data.

SCL

Serial Data Clock Input.

INT/CMPTR

Interrupt or Comparator Output.

GND

System Ground.

Address Select Pin (MSB).

Address Select Pin.

Address Select Pin (LSB).

Power Supply Input

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