Datasheet

ManualsBrandsMICROCHIP TECHNOLOGY ManualsPMICsTC74A0-3.3VAT

 2001-2012 Microchip Technology Inc. DS21462D-page 1

TC74

Features

• Digital Temperature Sensing in SOT-23-5 or

TO-220 Packages

• Outputs Temperature as an 8-Bit Digital Word

• Simple SMBus/I

C™ Serial Port Interface

• Solid-State Temperature Sensing:

- ±2°C (max.) Accuracy from +25°C to +85°C

- ±3°C (max.) Accuracy from 0°C to +125°C

• Supply Voltage of 2.7V to 5.5V

•Low Power:

- 200 µA (typ.) Operating Current

- 5 µA (typ.) Standby Mode Current

Applications

• Thermal Protection for Hard Disk Drives

and other PC Peripherals

• PC Card Devices for Notebook Computers

• Low Cost Thermostat Controls

• Power Supplies

• Thermistor Replacement

Package Types

General Description

The TC74 is a serially accessible, digital temperature

sensor particularly suited for low cost and small form-

factor applications. Temperature data is converted from

the onboard thermal sensing element and made

available as an 8-bit digital word.

Communication with the TC74 is accomplished via a 2-

wire SMBus/I

C compatible serial port. This bus also

can be used to implement multi-drop/multi-zone

monitoring. The SHDN bit in the CONFIG register can

be used to activate the low power Standby mode.

Temperature resolution is 1°C. Conversion rate is a

nominal 8 samples/sec. During normal operation, the

quiescent current is 200 µA (typ). During standby

operation, the quiescent current is 5 µA (typ).

Small size, low installed cost and ease of use make the

TC74 an ideal choice for implementing thermal

management in a variety of systems.

Functional Block Diagram

GND

VDD

SDA

SCLK

TO-220 SOT-23

GND

5 4

SDA

SCLK

TC74

2345

TC74

Note: The TO-220 tab is connected

to pin 3 (GND)

Internal Sensor

(Diode)



Modulator

Temperature

Serial Port

Interface

Control

Logic

SDA

SCLK

Tiny Serial Digital Thermal Sensor

Summary of content (18 pages)

PAGE 1
TC74 Tiny Serial Digital Thermal Sensor Features General Description • Digital Temperature Sensing in SOT-23-5 or TO-220 Packages • Outputs Temperature as an 8-Bit Digital Word • Simple SMBus/I2C™ Serial Port Interface • Solid-State Temperature Sensing: - ±2°C (max.) Accuracy from +25°C to +85°C - ±3°C (max.) Accuracy from 0°C to +125°C • Supply Voltage of 2.7V to 5.5V • Low Power: - 200 µA (typ.) Operating Current - 5 µA (typ.
PAGE 2
TC74 1.0 ELECTRICAL CHARACTERISTICS 1.1 Absolute Maximum Ratings† Supply Voltage (VDD) ............................................ +6V Voltage On Any Pin ....... (GND – 0.3V) to (VDD + 0.3V) † Notice: Stresses above those listed under "Maximum Ratings" may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operation listings of this specification is not implied.
PAGE 3
TC74 DC CHARACTERISTICS (CONTINUED) Electrical Specifications: Unless otherwise noted, VDD = 3.3V for TC74AX-3.3VXX and VDD = 5.0V for TC74AX-5.0VXX, -40°C  TA  125°C. Note 5 Parameters Sym Min Typ Max Units START Condition Setup Time (for repeated START Condition) tSU(START) 4.0 — — µsec START Condition Hold Time tH(START) 4.0 — — µsec Data In Setup Time tSU-DATA 1000 — — nsec Data In Hold Time tH-DAT 1250 — — nsec STOP Condition Setup Time tSU(STOP) 4.
PAGE 4
TC74 SMBUS Read Timing Diagram A B tLOW tHIGH C D E F G H I K J SCLK SDA tSU(START) tH(START) tSU-DATA tSU(STOP) E = Slave Pulls SDA Line Low F = Acknowledge Bit Clocked into Master G = MSB of Data Clocked into Master H = LSB of Data Clocked into Master A = Start Condition B = MSB of Address Clocked into Slave C = LSB of Address Clocked into Slave D = R/W Bit Clocked into Slave tIDLE I = Acknowledge Clock Pulse J = Stop Condition K = New Start Condition SMBUS Write Timing Diagram A B tLOW
PAGE 5
TC74 2.0 PIN DESCRIPTIONS The descriptions of the pins are listed in Table 2-1. TABLE 2-1: 2.1 PIN FUNCTION TABLE Pin No. (5-Pin SOT-23) Pin No. (5-Pin TO-220) Symbol Type Description 1 1 NC None No Internal Connection 2 3 GND Power System Ground 3 5 VDD Power Power Supply Input 4 4 SCLK Input SMBus/I2C Serial Clock 5 2 SDA Bidirectional SMBus/I2C Serial Data Ground (GND) Input. Ground return for all TC74 functions. 2.2 Power Supply Input (VDD) Power supply input.
PAGE 6
TC74 3.0 DETAILED DESCRIPTION 3.1 Functional Description TABLE 3-2: Term SERIAL BUS CONVENTIONS Explanation Transmitter The device sending data to the bus. The TC74 acquires and converts temperature information from its onboard solid-state sensor with a resolution of ±1°C. It stores the data in an internal register which is then read through the serial port. The system interface is a slave SMBus/I2C port, through which temperature data can be read at any time.
PAGE 7
TC74 Write Byte Format S Address WR ACK Command 7 Bits ACK Data 8 Bits Slave Address ACK P 8 Bits Command Byte: selects which register you are writing to. Data Byte: data goes into the register set by the command byte. Read Byte Format S Address WR ACK Command 7 Bits ACK S Address 8 Bits Slave Address RD ACK 7 Bits Command Byte: selects which register you are reading from. Data NACK P 8 Bits Slave Address: repeated due to change in dataflow direction.
PAGE 8
TC74 4.0 REGISTER SET AND PROGRAMMER’S MODEL TABLE 4-1: COMMAND BYTE DESCRIPTION (SMBUS/I2C READ_BYTE AND WRITE_BYTE) TABLE 4-3: TEMPERATURE REGISTER (TEMP) D[7] D[6] D[5] D[4] D[3] D[2] D[1] D[0] MSB X X X X X X LSB Command Code RTR 00h Read Temperature (TEMP) In 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.
PAGE 9
TC74 5.0 PACKAGING INFORMATION 5.1 SOT23A Package Marking Information 5-Pin SOT-23A 5 4 1 & 2 = part number code + temp. range and voltage 3 = year and quarter code 1 2 3 4 1 4 = lot ID number 3 2 SOT-23 Package Marking Codes SOT-23 (V) Address Code SOT-23 (V) Address Code TC74A0-3.3VCT 1001 000 V0 TC74A0-5.0VCT 1001 000 U0 TC74A1-3.3VCT 1001 001 V1 TC74A1-5.0VCT 1001 001 U1 TC74A2-3.3VCT 1001 010 V2 TC74A2-5.0VCT 1001 010 U2 TC74A3-3.3VCT 1001 011 V3 TC74A3-5.
PAGE 10
TC74 5.2 Taping Forms Component Taping Orientation for 5-Pin SOT-23A (EIAJ SC-74A) Devices User Direction of Feed Device Marking W PIN 1 P Standard Reel Component Orientation for TR Suffix Device (Mark Right Side Up) Carrier Tape, Number of Components Per Reel and Reel Size: Package Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size 5-Pin SOT-23A 8 mm 4 mm 3000 7 in. DS21462D-page 10  2001-2012 Microchip Technology Inc.
PAGE 11
TC74 5.3 Package Dimensions Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging SOT-23A-5 .075 (1.90) REF. .122 (3.10) .098 (2.50) .071 (1.80) .059 (1.50) .020 (0.50) .012 (0.30) PIN 1 .037 (0.95) REF. .118 (3.00) .010 (2.80) .057 (1.45) .035 (0.90) .010 (0.25) .004 (0.09) 10° MAX. .006 (0.15) .000 (0.00) .024 (0.60) .004 (0.10) Dimensions: inches (mm)  2001-2012 Microchip Technology Inc.
PAGE 12
TC74 Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging 5-Pin TO-220 .185 (4.70) .165 (4.19) .117 (2.97) .103 (2.62) .415 (10.54) .390 (9.91) .156 (3.96) .140 (3.56) DIA. .055 (1.40) .045 (1.14) .293 (7.44) .204 (5.18) 3 - 7.5 5 PLCS. .613 (15.57) .569 (14.45) .037 (0.95) .025 (0.64) .590 (14.99) .482 (12.24) .025 (0.64) .012 (0.30) .072 (1.83) .062 (1.57) PIN 1 .273 (6.93) .263 (6.68) .115 (2.92) .087 (2.
PAGE 13
TC74 6.0 REVISION HISTORY Revision D (December 2012) Added a note to each package outline drawing.  2001-2012 Microchip Technology Inc.
PAGE 14
TC74 NOTES: DS21462D-page 14  2001-2012 Microchip Technology Inc.
PAGE 15
TC74 PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. PART NO. Device XX -XX X XX Address Supply Operating Package Options Voltage Temperature Device: TC74: Address Options: A0 A1 A2 A3 A4 A5 A6 A7 Serial Digital Thermal Sensor = = = = = = = = 1001 1001 1001 1001 1001 1001 1001 1001 000 001 010 011 100 101 * 110 111 * Default Address Supply Voltage: 3.3 5.0 = Accuracy optimized for 3.
PAGE 16
TC74 NOTES: DS21462D-page 16  2001-2012 Microchip Technology Inc.
PAGE 17
Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature.
PAGE 18
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