21450b.book

2002 Microchip Technology Inc.

DS21450B-page 1

TC650/TC651

Features

• Integrated Temperature Sensing and Multi-speed

Fan Control

• Built-in Over Temperature Alert (T

OVER

)

• Temperature Proportional Fan Speed Control for

Acoustic Noise Reduction and Longer Fan Life

• Pulse Width Modulation Output Drive for Cost and

Power Savings

• Solid-State Temperature Sensing

• ±1

C (Typical) Accuracy from 25

C to +70

• 2.8V – 5.5V Operating Range

• TC651 includes Auto Fan Shutdown

• Low Operating Current: 50

A (Typical)

Applications

• Thermal Protection For Personal Computers

• Digital Set-Top Boxes

• Notebook Computers

• Data Communications

• Power Supplies

• Projectors

Related Literature

• Application Note: AN771

Device Selection Table

The "X" denotes a suffix for temperature threshold settings.

Contact factory for other temperature ranges.

Package Type

General Description

The TC650/TC651 are integrated temperature sensors

and brushless DC fan speed controllers. The TC650/

TC651 measure their junction temperature and control

the speed of the fan based on that temperature, making

them especially suited for applications in modern

electronic equipment.

Temperature data is converted from the on-chip

thermal sensing element

and

translated

into

fractional fan speed from 40% to 100%. A temperature

selection guide in the data sheet is used to choose the

low and high temperature limits to control the fan. The

TC650/TC651 also include a single trip point over

temperature alert (T

OVER

) that eliminates the need for

additional temperature sensors. In addition, the TC651

features an auto fan shutdown function for additional

power savings.

The TC650/TC651 are easy to use, require no software

overhead and are therefore the ideal choice for

implementing thermal management in a variety of

systems.

Part Number

Package

Temperature

Range

TC650XXVUA

8-Pin SOIC

-40

C to +125

TC651XXVUA

8-Pin MSOP

-40

C to +125

Temperature

PWM

GND

OVER

GND

8-Pin MSOP

TC650

TC651

SHDN

8-Pin SOIC

Tiny Integrated Temperature Sensor & Brushless DC Fan

Controller with Over-Temperature Alert

2002 Microchip Technology Inc.

DS21450B-page 3

TC650/TC651

1.0

ELECTRICAL

CHARACTERISTICS

Absolute Maximum Ratings*

Input Voltage (V

to GND) ................................... +6V

Output Voltage (OUT to GND) ................................. 6V

Voltage On Any Pin ....... (GND – 0.3V) to (V

+ 0.3V)

Package Thermal Resistance (

)

.............. 250

C/W

Operating Temperature Range .......... -40

C to +125

Storage Temperature ......................... -65

C to +150

*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.

TC650/TC651 ELECTRICAL SPECIFICATIONS

Note 1: Transition from 90% to 100% Duty Cycle.

Electrical Characteristics: V

= 2.8V to 5.5V, SHDN = V

, T

= -40

C to 125

C unless otherwise specified.

Symbol

Parameter

Min

Typ.

Max

Units

Test Conditions

Supply Voltage

2.8

—

5.5

Supply Current

—

PWM, T

OVER

are open

SHDN Input

SHDN Input High Threshold

—

SHDN Input Low Threshold

—

PWM Output

PWM Output Low Voltage

—

0.3

SINK

= 1mA

PWM Output High Voltage

- 0.5

—

SOURCE

= 5mA

PWM Rise Time

—

sec

= 5mA, 1nF from

PWM to GND

PWM Fall Time

—

sec

= 1mA, 1nF from

PWM to GND

OUT

PWM Frequency

—

STARTUP

Start-up Time

—

32/f

OUT

—

sec

Rises from GND,

or SHDN Released

Temperature Accuracy

H ACC

High Temperature Accuracy

– 3

+ 3

Note 1

H –

)

ACC

Temp. Range Accuracy

-1.0

—

+1.0

- T

)

≤

-2.5

—

+2.5

- T

)

≥

HYST

Auto-shutdown Hysteresis

—

-T

)/5

—

TC651 Only

OVER

Output

HIGH

OVER

Output High Voltage

- 0.5

—

SOURCE

= 1.2mA

LOW

OVER

Output Low Voltage

—

0.4

SINK

= 2.5mA

OVER ACC

Absolute Accuracy

—

+ 10

—

At Trip Point

OVER HYST

Trip Point Hysteresis

—

2002 Microchip Technology Inc.

DS21450B-page 5

TC650/TC651

3.0

DETAILED DESCRIPTION

The TC650/TC651 acquire and convert their junction

temperature (T

) information from an on-chip solid-state

sensor with a typical accuracy of ±1°C. The temperature

data is digitally stored in an internal register. The

The six threshold values are equally distributed over a

pre-defined range of temperatures (see Table 3-1 and

Table 3-2). The TC650/TC651 control the speed of a

DC brushless fan using a fractional speed control

scheme. The output stage requires only a 2N2222-type

small-signal BJT for fans up to 300mA. For larger

current fans (up to 1 Amp) a logic-level N-channel

MOSFET may be used. In addition to controlling the

speed of the fan, the TC650/TC651 include an on-chip

over-temperature alarm (T

OVER

) that gives a low signal

when the temperature of the chip exceeds T

by 10°C,

(typical). This feature eliminates the need for a separate

temperature sensor for over-temperature monitoring.

TABLE 3-1:

TEMPERATURE RANGE

DEFINITION FOR TC650

(MINIMUM-SPEED MODE)

TABLE 3-2:

TEMPERATURE RANGE

DEFINITION FOR TC651

(AUTO-SHUTDOWN MODE)

FIGURE 3-1:

FUNCTIONAL BLOCK

DIAGRAM

3.1

PWM Output

The PWM pin is designed to drive a low cost transistor

or MOSFET as the low side power switching element in

the

system.

This

output

has

asymmetric

complementary drive and is optimized for driving NPN

transistors or N-channel MOSFETs. Since the system

relies on PWM rather than linear power control, the

dissipation in the power switch is kept to a minimum.

Generally,

very

small

devices

(TO-92

SOT

packages) will suffice. The frequency of the PWM is

about 15Hz. The PWM is also the time base for the

Start-up Timer (see paragraphs below). The PWM duty

cycle has a range of 40% to 100% for the TC650 and

50% to 100% for the TC651.

3.2

Start-Up Timer

To ensure reliable fan start-up, the Start-up Timer turns

PWM high for about 2 seconds whenever the fan is

started from the off state. This occurs at power-up and

when coming out of Shutdown mode.

3.3

Over-Temperature Alert (T

OVER

)

This pin goes low when the T

set point is exceeded by

C (typical). This indicates that the fan is at

maximum drive and the potential exists for system

overheating; either heat dissipation in the system has

gone beyond the cooling system's design limits, or

some FAULT exists such as fan bearing failure or an

airflow obstruction. This output may be treated as a

“System Overheat” warning and used to trigger system

shutdown, or bring other fans to full speed in the

system. The fan will continue to run at 100% speed

while T

OVER

is asserted. Built-in hysteresis prevents

OVER

from “chattering” when measured temperature

is at or near the T

+ 10°C trip point. As temperature

falls through the T

+ 10°C trip point, hysteresis

maintains the T

OVER

output low until measured

temperature is 5°C above the trip point setting.

Temperature (T = T

)

PWM Duty Cycle

T < T

40%

< = T < T

50%

< = T < T

60%

< = T <T

70%

< = T < T

80%

< = T < T

90%

< = T < T

100%

< = T

100% with Over Temp Alert

OVER

= L)

Temperature (T = T

)

PWM Duty Cycle

T < T

“OFF”

< = T < T

50%

< = T < T

60%

< =T < T

70%

< =T < T

80%

< = T < T

90%

< = T < T

100%

< = T

100% with Over-Temp Alert

OVER

= L)

Note:The temperature regions defined by the six temperature thresh-

olds are pre-defined in the TC650/TC651 by means of trimming. Once

a T

and T

are programmed, the T

– T

thresholds are automatically

equally spaced between T

and T

Temperature Sensor

Duty Cycle

Logic

Control

A/D Converter

Oscillator

Temperature

Set Point and

Trim Range

SHDN

OVER

PWM

V+

TC650/TC651

DS21450B-page 6

2002 Microchip Technology Inc.

3.4

Shutdown (SHDN)

The fan can be unconditionally shutdown by pulling low

the SHDN pin. During shutdown, the PWM output is

low. This is ideal for notebook computers and other

portable applications when you need to change

batteries and must not have the fan running at that

time. Thermal monitoring and T

OVER

are still in

operation during shutdown. I

shutdown current is

around 50

3.5

Auto-Shutdown Mode

The

TC651

features

auto-shutdown;

when

the

temperature is below the factory set point at minimum

speed (T

), PWM is low and the fan is automatically

shut off (Auto-shutdown mode). This feature is ideal for

notebook computers and other portable equipment that

need to conserve as much battery power as possible

and thus run a fan when it is only absolutely needed.

The TC651 will continue to be active so as to monitor

temperature for Tover. The TC651 exits Auto-shutdown

mode when the temperature rises above the factory set

point (T

3.6

Temperature Selection Guide

(Minimum Fan Speed/Full Speed)

The five temperature regions defined by the six

thresholds are defined in the TC650/TC651 by means

of factory trimming. Once a T

and T

are set, the T

–

thresholds

are

automatically

equally

spaced

between T

and T

Note: The Bold Type temperature settings are available for

ordering. Contact factory for other temperature selec-

tions.

and T

can be selected in 5°C increments. T

must

be chosen at least 10

C higher than T

. T

can range

anywhere from 25°C to 35°C.

As an example, suppose you wanted the fan to run at

40% speed at 25°C or less and go to full speed at

45°C. You would order the part number TC650AEVUA.

As another example, suppose you wanted the fan to

turn on at 30°C and go to full speed at 45°C. You

would order the part number TC651BEVUA.

Temp.

Range

Part #

10°C

15°C

20°C

30°C

TC650/TC651

DS21450B-page 8

2002 Microchip Technology Inc.

5.0

TYPICAL CHARACTERISTICS

The graphs and tables provided following this note are a statistical summary based on a limited number of samples

and are provided for informational purposes only. The performance characteristics listed herein are not tested or

guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., out-

side specified power supply range) and therefore outside the warranted range

-50

10 12 14 16 18 20

-25

100 125 150

TEMPERATURE (˚C)

vs. Temperature

(µA)

3.0

2.5

2.0

1.5

1.0

0.5

0.0

THRESHOLD

Temperature Accuracy vs. V

Temp Accuracy (˚

- V

(V)

SOURCE

(mA)

PWM, I

SOURCE

vs. (V

- V

), T

= 25˚C

= 2.8V

= 5.5V

= 2.7

5.6

= 5.6

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

(mV)

SINK

(mA)

PWM, I

SINK

vs. V

, T

= 25˚C

= 2.8V

= 5.5V

0.0

100

150

200

250

300

350

400

450

500

- V

(V)

SOURCE

(mA)

TOVER, ISOURCE vs. (VDD - VOH), TA = 25˚C

= 2.8V

= 5.5V

2002 Microchip Technology Inc.

DS21450B-page 9

TC650/TC651

6.0

PACKAGING INFORMATION

6.1

Package Marking Information

Package marking data not available at this time.

6.2

Taping Form

Component Taping Orientation for 8-Pin MSOP Devices

Package

Carrier Width (W)

Pitch (P)

Part Per Full Reel

Reel Size

8-Pin MSOP

12 mm

8 mm

2500

13 in

Carrier Tape, Number of Components Per Reel and Reel Size

PIN 1

User Direction of Feed

Standard Reel Component Orientation

for TR Suffix Device

Component Taping Orientation for 8-Pin SOIC (Narrow) Devices

Package

Carrier Width (W)

Pitch (P)

Part Per Full Reel

Reel Size

8-Pin SOIC (N)

12 mm

8 mm

2500

13 in

Carrier Tape, Number of Components Per Reel and Reel Size

Standard Reel Component Orientation

for TR Suffix Device

PIN 1

User Direction of Feed