MC74A5-50T [ONSEMI]

Serial Digital Temperature Sensor; 串行数字温度传感器


型号：	MC74A5-50T
厂家：	ONSEMI
描述：	Serial Digital Temperature Sensor 串行数字温度传感器传感器换能器温度传感器输出元件
文件：	总12页 (文件大小：126K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

The MC74 is a serial digital temperature sensor suited for low cost

applications. Temperature data is converted from the integrated thermal

sensing element and made available as an 8–bit serial digital word.

Communication with the MC74 is accomplished via 2–wire

SMBus/I²C–compatible serial port. Temperature resolution is 1°C.

Conversion rate is a nominal 8 samples/sec. Power consumption is

only 200 µA (5 µA Standby).

http://onsemi.com

Features

• Tested Operating Temperature Range: –40°C to +125°C

• Simple Serial Port Interface

• Solid State Temperature Sensing:

±2°C Accuracy from +25°C to +85°C

±3°C Accuracy from 0°C to +125°C

SOT–23–5

SN SUFFIX

CASE TBD

PRELIMINARY INFORMATION

• 3.3V and 5.5V Versions

PIN CONFIGURATION

(Top View)

Typical Applications

• Thermal Protection for Hard Disk Drives and Other PC Peripherals

• Low–Cost Thermostat Controls

• Power Supplies

SDA

SCL

GND

FUNCTIONAL BLOCK DIAGRAM

Serial Port

Interface

Internal Sensor

(Diode)

SDA

SCL

SOT–23–5*

NOTE: *SOT–23–5 is equivalent to EIAJ–SC74A

Modulator

Control

Logic

Temperature

TO–220–5

T SUFFIX

CASE TBD

PRELIMINARY INFORMATION

ORDERING INFORMATION

Device

Package

Voltage

MC74A5–33SNTR

SOT–23–5

3.3V V

MC74A5–50T

TO–220–5

5.0V V

Semiconductor Components Industries, LLC, 1999

Publication Order Number:

February, 2000 – Rev. 0

MC74/D

MC74

PIN DESCRIPTION FOR TO–220–5

Pin No.

Symbol

Type

None

Description

Not Connected

SDA

GND

SCL

Bi–directional

Power

SMBus Serial Data

System Ground

Input

SMBus Serial Clock

Power Supply Input

Power

PIN DESCRIPTION FOR SOT–23–5

Pin No.

Symbol

Type

None

Description

Not Connected

GND

Power

System Ground

Power

Power Supply Input

SMBus Serial Clock

SMBus Serial Data

SCL

SDA

Input

Bi–directional

PIN DESCRIPTION

SCL

Input. SMBus serial clock. Clocks data into and out of the

MC74.SeeSystemManagementBusSpecification, rev. 1.0,

for timing diagrams.

Input. Power supply input. See electrical specifications.

GND

Input. Ground return for all MC74 functions.

SDA

Bi–directional. Serial data is transferred on the SMBus in

both directions using this pin. See System Management Bus

Specification rev. 1.0 for timing diagrams.

ABSOLUTE MAXIMUM RATINGS*

Symbol

Parameter

Value

6.0

Unit

Power Supply Voltage

Voltage on Any Pin

(GND – 0.3 V) to (V

+ 0.3 V)

Operating Temperature Range

Storage Temperature Range

Current on Any Pin

–40 to +125

–65 to +150

±50

°C

stg

°C

Maximum Power Dissipation

330

* Maximum Ratings are those values beyond which damage to the device may occur.

http://onsemi.com

MC74

(5)

= 3.3 V or 5.0V , –40°C ≤ T ≤ 125°C, unless otherwise noted.)

DC ELECTRICAL CHARACTERISTICS (V

Characteristic

Symbol

Min

Typ

Max

Unit

Power Supply

Power–On Reset Threshold

(V Falling Edge or Rising Edge)

POR

1.2

—

200

5.0

2.2

350

Operating Current

(V = 5.5V, Serial Port Inactive)

(1)

Standby Supply Current

(V = 3.3 V, Serial Port Inactive)

DD–STANDBY

(4)

—

Temperature–to–Bits Converter

Temperature Accuracy MC74A

+25°C ≤ T ≤ +85°C

ERR

°C

–2.0

–3.0

—

±2.0

+2.0

+3.0

—

0°C ≤ T ≤ +125°C

–40°C ≤ T ≤ 0°C

(2)

Conversion Rate

4.0

8.0

—

sa/sec

Serial Port Interface

Logic Input High

Logic Input Low

0.8 x V

—

0.2 x V

SDA Output Low

(3)

—

0.4

0.6

= 3 mA

= 6 mA

(3)

Input Capacitance SDA, SCL

I/O Leakage

—

5.0

0.1

—

–1.0

1.0

LEAK

1. Operating current is an average value integrated over multiple conversion cycles. Transient current may exceed this specification.

2. Maximum guaranteed conversion time after Power–On RESET (POR to DATA_RDY) is 250 msec.

3. Output current should be minimized for best temperature accuracy. Power dissipation within the MC74 will cause self–heating and

temperature drift error.

4. SDA and SCL must be connected to V

or GND.

=5.0VforMC74A5–50T. AllparttypesoftheMC74willoperateproperlyoverthewiderpowersupply

5. V

=3.3VforMC74A5–33SNTR. V

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.

SERIAL PORT AC TIMING (V

= 3.3 V or 5.0V, –40°C ≤ (T = T ) ≤ 125°C; C = 80 pF unless otherwise noted.)

A J L

Symbol

Characteristic

SMBus Clock Frequency

Min

Typ

—

Max

100

—

Unit

kHz

sec

SMB

Low Clock Period (10% to 10%)

High Clock Period (90% to 90%)

SMBus Rise Time (10% to 90%)

SMBus Fall Time (90% to 10%)

4.7

4.0

—

LOW

—

sec

HIGH

—

1,000

300

—

nsec

sec

—

Start Condition Setup Time (90% SCL to 10% SDA)

(for Repeated Start Condition)

4.0

—

SU(START)

Start Condition Hold Time

Data in Setup Time

4.0

1,000

1,250

4.0

—

sec

nsec

sec

H(START)

SU–DATA

H–DATA

SU(STOP)

IDLE

Data in Hold Time

—

Stop Condition Setup Time

Bus Free Time Prior to New Transition

—

4.7

—

sec

Power–On Reset Delay (V

≥ V

DD POR

(Rising Edge))

—

500

sec

POR

http://onsemi.com

MC74

DETAILED OPERATING DESCRIPTION

MC74 Serial Bus Conventions

Term Explanation

The MC74 acquires and converts temperature

information from its integrated solid state sensor with a

basic accuracy of ±1°C . It stores the data in an internal

interface is a slave SMBus. The temperature data can be

read at any time through the SMBus port. Eight SMBus

addressesareprogrammablefortheMC74, whichallowsfor

a multi–sensor configuration. Also, there is low–power

Standby mode where temperature acquisition is suspended.

Transmitter The device sending data to the bus.

Receiver The device receiving data from the bus.

Master

The device which controls the bus: initiating

transfers (START), generating the clock, and

terminating transfers (STOP).

Slave

Start

The device addressed by the master.

A unique condition signaling the beginning

of a transfer indicated by SDA falling (High

— Low) while SCL is high.

Standby Mode

The MC74 allows the host to put it into a low power (I_DD

= 5µA, typical) Standby mode. In this mode, the A/D

converter is halted and the temperature data registers are

frozen. The SMBus port operates normally. Standby mode

is enabled by setting the SHDN bit in the CONFIG register.

The table below summarizes this operation.

Stop

ACK

A unique condition signaling the end of a

transfer indicated by SDA rising (Low —

High) while SCL is high.

A receiver acknowledges the receipt of

each byte with this unique condition. The

receiver drives SDA low during SCL high

of the ACK clock–pulse. The Master pro-

vides the clock pulse for the ACK cycle.

Standby Mode Operation

SHDN Bit

Operating Mode

Normal

Busy

Communication is not possible because

the bus is in use.

Standby

NOT Busy When the bus is idle, both SDA and SCL

will remain high.

SMBus Slave Address

The MC74 is internally programmed to have a default

SMBus address value of 1001 101b. Seven other addresses

are available by custom order (contact factory).

Data Valid The state of SDA must remain stable dur-

ing the High period of SCL in order for a

data bit to be considered valid. SDA only

changes state while SCL is low during nor-

mal data transfers (see Start and Stop

conditions).

SERIAL PORT OPERATION

The Serial Clock input (SCL) and bi–directional data port

(SDA) form a 2–wire bi–directional serial port for

programming and interrogating the MC74. The following

conventions are used in this bus architecture:

All transfers take place under control of a host, usually

a CPU or microcontroller, acting as the Master which

provides the clock signal for all transfers. The MC74

always operates as a Slave. The serial protocol is illustrated

in Figure 1. All data transfers have two phases; all bytes are

transferred MSB first. Accesses are initiated by a start

condition (START), followed by a device address byte and

one or more data bytes. The device address byte includes a

Read/Writeselectionbit. Eachaccessmustbeterminatedby

a Stop Condition (STOP).

A convention called

Acknowledge (ACK) confirms receipt of each byte. Note

thatSDAcanchangeonlyduringperiodswhenSCLisLOW

(SDAchangeswhileSCL isHIGHarereservedforStartand

Stop Conditions).

http://onsemi.com

MC74

Write Byte Format

ADDRESS

ACK

COMMAND

8 Bits

DATA

7 Bits

8 Bits

Slave Address

Command Byte: selects

which register you are

writing to.

Data Byte: data goes

into the register set

by the command byte.

Read Byte Format

ADDRESS WR ACK

COMMAND ACK

ADDRESS RD ACK

DATA NACK

7 Bits

8 Bits

7 Bits

8 Bits

Slave Address

Command Byte: selects

which register you are

reading from.

Slave Address: repeated

due to change in data–

flow direction.

Data Byte: reads from

the register set by the

command byte.

Receive Byte Format

ADDRESS RD ACK

7 Bits

DATA NACK

8 Bits

Data Byte: reads data from

the register commanded by

the last Read Byte.

S = Start Condition

P = Stop Condition

Shaded = Slave Transmission

Figure 1. SMBus Protocols

Acknowledge (ACK)

Start Condition (START)

The MC74 continuously monitors the SDA and SCL lines

for a start condition (a HIGH to LOW transition of SDA

whileSCLisHIGH)andwillnotresponduntilthiscondition

is met.

Acknowledge (ACK) provides a positive handshake

betweenthehostandtheMC74. ThehostreleasesSDAafter

transmitting eight bits, then generates a ninth clock cycle to

allow the MC74 to pull the SDA line LOW to acknowledge

that it successfully received the previous eight bits of data or

address.

Address Byte

Immediately following the Start Condition, the host must

transmit the address byte to the MC74. The states of A1 and

A0 determine the 7–bit SMBus address for the MC74. The

7–bit address transmitted in the serial bit stream must match

for the MC74 to respond with an Acknowledge (indicating

the MC74 is on the bus and ready to accept data). The eighth

bit in the Address Byte is a Read–Write Bit. This bit is a 1

for a read operation or 0 for a write operation. During the

first phase of any transfer this bit will be set = 0 to indicate

that the command byte is being written.

Data Byte

After a successful ACK of the address byte, the host must

transmit the data byte to be written or clock out the data to

be read. (See the appropriate timing diagrams. ) ACK will

be generated after a successful write of a data byte into the

MC74.

Stop Condition (STOP)

Communications must be terminated by a stop condition

(a LOW to HIGH transition of SDA while SCL is HIGH).

The Stop Condition must be communicated by the

transmitter to the MC74. NOTE: Refer to Timing Diagrams

for serial bus timing.

http://onsemi.com

MC74

SMBUS Write Timing Diagram

E F

LOW HIGH

SCL

SDA

SU(STOP) IDLE

SU(START) H(START)

SU–DATA

H–DATA

A = Start Condition

F = Acknowledge Bit Clocked into Master J = Acknowledge Clocked into Master

B = MSB of Address Clocked into Slave G= MSB of Data Clocked into Slave

C = LSB of Address Clocked into Slave H = LSB of Data Clocked into Slave

D = R/W Bit Clocked into Slave

E = Slave Pulls SDA Line Low

K = Acknowledge Clock Pulse

L = Stop Condition, Data Executed by Slave

M= New Start Condition

I = Slave Pulls SDA Line Low

SMBUS Read Timing Diagram

E F

LOW HIGH

SCL

SDA

IDLE

SU(START) H(START)

SU–DATA

SU(STOP)

A = Start Condition

E = Slave Pulls SDA Line Low

I = Acknowledge Clock Pulse

J = Stop Condition

K = New Start Condition

B = MSB of Address Clocked into Slave

C = LSB of Address Clocked into Slave

D = R/W Bit Clocked into Slave

F = Acknowledge Bit Clocked into Master

G= MSB of Data Clocked into Master

H = LSB of Data Clocked into Master

Figure 2.

http://onsemi.com

MC74

Temperature Register (TEMP), 8–Bits,

READ–ONLY

MC74 Command Set

(SMBus READ_BYTE and WRITE_BYTE)

The binary value (2’s complement format) in this register

represents temperature of the integrated sensor following a

conversion cycle. The registers are automatically updated in

an alternating manner.

Command Byte Description

Command

RTR

Code Function

Temperature Register (TEMP)

00h

01h

Read Temperature (TEMP)

Read/Write Configuration (CONFIG)

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

LSB

RWCR

MSB

Configuration Register (CONFIG), 8–BITS,

READ/WRITE

In the temperature data registers, each unit value

represents one degree (Celsius). The value is in

2’s–complement binary format such that a reading of 0000

0000b corresponds to 0°C. Examples of this temperature to

binary value relationship are shown in the following table.

Configuration Register (Config)

D[7]

D[6]

D[5] D[4] D[3] D[2] D[1] D[0]

SHDN

Data Rdy Reserved

Temperature–to–Digital Value Conversion (TEMP)

Bit

POR Function

Type Operation

ACTUAL

REGISTERED

BINARY HEX

D[7]

STANDBY switch

Read/ 1 = standby,

Write 0 = normal

TEMPERATURE

+130.00°C

+127.00°C

+126.50°C

+25.25°C

+0.50°C

+0.25°C

0.00°C

+127°C

+25°C

+1°C

0°C

0111 1111

0001 1001

0000 0001

0000 0000

1111 1111

1110 0111

1110 0110

1100 1001

1011 1111

D[6]

Data Ready*

Read 1 = ready,

Only

0 = not ready

D[5]—D[0]

Reserved — Al-

ways returns zero

when read.

N/A

*DATA_RDY bit reset at power–up and SHDN enable (see below).

0°C

-0.25°C

0°C

-0.50°C

0°C

-0.75°C

-1°C

-1.00°C

-1°C

DATA_RDY

SHDN

-25.00°C

-25.25°C

-54.75°C

-55.00°C

-65.00°C

-25°C

-55°C

-65°C

conv

Figure 3. . DATA_RDY, SHDN Operation Logic

Diagram

The MC74’s register set is summarized below. All

registers are 8–bits wide.

Name

Description

POR State

Read Write

TEMP

Internal sensor

temperature (2’s

complement)

0000 0000b*

√

CONFIG CONFIG register

0000 0000b

√

*NOTE: The TEMP register immediately will be updated by the

A/D converter after the DATA_RDY bit goes high.

http://onsemi.com

MC74

TAPING FORM

Component Taping Orientation for 5L SOT–23 Devices

USER DIRECTION OF FEED

DEVICE

MARKING

PIN 1

Standard Reel Component Orientation

for TR Suffix Device

(Mark Right Side Up)

Tape & Reel Specifications Table

Package

5L SOT–23

Tape Width (W)

Pitch (P)

Part Per Full Reel

Diameter

8 mm

4 mm

3000

7 inches

MARKING

SOT–23–5

MC74

Marking

MC74A5–33SNTR

Date Code

http://onsemi.com

MC74

PACKAGE DIMENSIONS

SOT–23–5

SNTR SUFFIX

PLASTIC PACKAGE

CASE TBD

ISSUE TBD

0.75 (1.90)

REFERENCE

.122 (3.10)

.098 (2.50)

.071 (1.80)

.059 (1.50)

.020 (0.50)

.012 (0.30)

.037 (0.95)

REFERENCE

.122 (3.10)

.106 (2.70)

.057 (1.45)

.035 (0.90)

.010 (0.25)

.004 (0.09)

10° MAX.

.006 (0.15)

.000 (0.00)

.022 (0.55)

.008 (0.20)

NOTE: SOT–23–5 is equivalent to EIAJ–SC74A

Dimensions: inches (mm)

http://onsemi.com

MC74

PACKAGE DIMENSIONS

TO–220

T SUFFIX

PLASTIC PACKAGE

CASE TBD

ISSUE TBD

.185 (4.70)

.165 (4.19)

.410 (10.41)

.390 (9.91)

.113 (2.87)

.103 (2.62)

.055 (1.40)

.045 (1.14)

.156 (3.96)

.146 (3.71)

DIA.

.258 (6.55)

.230 (5.84)

– 7.5

.594 (15.09)

.569 (14.45)

5 PLCS.

.037 (0.94)

.027 (0.69)

.560 (14.22)

.518 (13.16)

.020 (0.51)

.012 (0.30)

.072 (1.83)

.062 (1.57)

.115 (2.92)

.095 (2.41)

.273 (6.93)

.263 (6.68)

Dimensions: inches (mm)

http://onsemi.com

MC74

Notes

http://onsemi.com

MC74

ON Semiconductor and

are trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes

withoutfurthernoticetoanyproductsherein. SCILLCmakesnowarranty,representationorguaranteeregardingthesuitabilityofitsproductsforanyparticular

purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability,

including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or

specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be

validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others.

SCILLCproductsarenotdesigned, intended, orauthorizedforuseascomponentsinsystemsintendedforsurgicalimplantintothebody, orotherapplications

intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or

death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold

SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable

attorneyfees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim

alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer.

PUBLICATION ORDERING INFORMATION

NORTH AMERICA Literature Fulfillment:

CENTRAL/SOUTH AMERICA:

Literature Distribution Center for ON Semiconductor

P.O. Box 5163, Denver, Colorado 80217 USA

Spanish Phone: 303–308–7143 (Mon–Fri 8:00am to 5:00pm MST)

Email: ONlit–spanish@hibbertco.com

Phone: 303–675–2175 or 800–344–3860 Toll Free USA/Canada

Fax: 303–675–2176 or 800–344–3867 Toll Free USA/Canada

Email: ONlit@hibbertco.com

ASIA/PACIFIC: LDC for ON Semiconductor – Asia Support

Phone: 303–675–2121 (Tue–Fri 9:00am to 1:00pm, Hong Kong Time)

Toll Free from Hong Kong & Singapore:

Fax Response Line: 303–675–2167 or 800–344–3810 Toll Free USA/Canada

001–800–4422–3781

N. American Technical Support: 800–282–9855 Toll Free USA/Canada

Email: ONlit–asia@hibbertco.com

EUROPE: LDC for ON Semiconductor – European Support

German Phone: (+1) 303–308–7140 (M–F 1:00pm to 5:00pm Munich Time)

Email: ONlit–german@hibbertco.com

JAPAN: ON Semiconductor, Japan Customer Focus Center

4–32–1 Nishi–Gotanda, Shinagawa–ku, Tokyo, Japan 141–8549

Phone: 81–3–5740–2745

French Phone: (+1) 303–308–7141 (M–F 1:00pm to 5:00pm Toulouse Time)

Email: ONlit–french@hibbertco.com

English Phone: (+1) 303–308–7142 (M–F 12:00pm to 5:00pm UK Time)

Email: ONlit@hibbertco.com

Email: r14525@onsemi.com

ON Semiconductor Website: http://onsemi.com

EUROPEAN TOLL–FREE ACCESS*: 00–800–4422–3781

For additional information, please contact your local

Sales Representative.

*Available from Germany, France, Italy, England, Ireland

MC74/D

http://onsemi.com

MC74A5-50T [ONSEMI]

相关型号：

MC74A6-3.3SNTR

MC74A6-3.3T

MC74A6-5.0SNTR

MC74A6-5.0T

MC74A7-3.3SNTR

MC74A7-3.3T

MC74A7-5.0T

MC74AC00

MC74AC00

MC74AC00D

MC74AC00D

MC74AC00DC