ANALOG DEVICES AD7314 Service Manual

Low Voltage, 10-Bit Digital Temperature

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a

FEATURES
10-Bit Temperature-to-Digital Converter
–35C to +85C Operating Temperature Range
2C Accuracy
SPI® and DSP Compatible Serial Interface
Shutdown Mode
Space-Saving MSOP Package

APPLICATIONS
Hard Disk Drives
Personal Computers
Electronic Test Equipment
Office Equipment
Domestic Appliances
Process Control
Mobile Phones

GENERAL DESCRIPTION

The AD7314 is a complete temperature monitoring system in
an 8-lead MSOP package. It contains a band gap temperature
sensor and 10-bit ADC to monitor and digitize the temperature
reading to a resolution of 0.25∞C.

The AD7314 has a flexible serial interface that allows easy
interfacing to most microcontrollers. The interface is compat­ible with SPI, QSPI™, and MICROWIRE™ protocols and is
also compatible with DSPs. The part features a standby mode
that is controlled via the serial interface.

The AD7314’s low supply current and SPI compatible interface
make it ideal for a variety of applications, including personal
computers, office equipment, and domestic appliances.

Sensor in 8-Lead MSOP

AD7314

FUNCTIONAL BLOCK DIAGRAM

BAND GAP

TEMPERATURE

SENSOR

GND

AD7314

PRODUCT HIGHLIGHTS

1. The AD7314 has an on-chip temperature sensor that allows
an accurate measurement of the ambient temperature. The
measurable temperature range is –35∞C to +85∞C, with a
± 2∞C temperature accuracy.

2. Supply voltage of 2.65 V to 5.5 V.

3. Space-saving 8-lead MSOP package.

4. 10-bit temperature reading to 0.25∞C resolution.

5. The AD7314 features a standby mode that reduces the
current consumption to 1 mA max.

10-BIT

ANALOG-TO-DIGITAL

CONVERTER

TEMPERATURE

VALUE

REGISTER

SERIAL

BUS

INTERFACE

ID

V

DD

CE
SCLK
SDI
SDO

REV. A

Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] © 2003 Analog Devices, Inc. All rights reserved.

AD7314–SPECIFICATIONS

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(TA = T

MIN

to T

, VDD = 2.65 V to 5.5 V, unless otherwise noted.)

MAX

*

Parameter Min Typ Max Unit Test Conditions/Comments

TEMPERATURE SENSOR AND ADC

Accuracy ± 2.0 ∞CT

± 1.0 ∞CT

= –35∞C to +85∞C. VDD = 2.65 V to 2.9 V

A

= –35∞C to +85∞C. VDD = 3 V to 5.5 V

A

Resolution 10 Bits
Update Rate, t

R

400 ms

Temperature Conversion Time 25 ms

SUPPLIES

Supply Voltage 2.65 5.5 V For Specified Performance
Supply Current

Normal Mode (Inactive) 250 300 mA Part Not Converting, V

275 mA Part Not Converting, V

Normal Mode (Active) 1 mA Part Converting, V

1.2 mA Part Converting, V

Shutdown Mode 1 mAV

1 mAV

Power Dissipation 860 mWV

= 2.65 V to 2.9 V

DD

= 3 V to 5.5 V

DD

= 2.65 V. Using Normal Mode

DD

= 2.65 V to 2.9 V

DD

= 3 V to 5.5 V

DD

= 2.65 V to 2.9 V

DD

= 3 V to 5.5 V

DD

(Auto Conversion)

Power Dissipation V

= 2.65 V. Using Shutdown Mode

DD

1 SPS 3 mW
10 SPS 3.3 mW
100 SPS 6 mW

DIGITAL INPUT

Input High Voltage, V
Input Low Voltage, V

IL

Input High Voltage, V
Input Low Voltage, V
Input Current, I
Input Capacitance, C

IL

IN

IN

IH

IH

1.85 V VDD = 2.65 V to 2.9 V

0.53 V VDD = 2.65 V to 2.9 V

2.4 V VDD = 3 V to 5.5 V

0.8 V VDD = 3 V to 5.5 V
± 1 mAV

= 0 V to V

IN

DD

10 pF All Digital Inputs

DIGITAL OUTPUT

Output High Voltage, V
Output Low Voltage, V
Output Capacitance, C

*All specifications apply for –35∞C to +85∞C, unless otherwise noted.

Specifications subject to change without notice.

OH

OL

OUT

2.4 V I

0.4 V IOL = 200 mA
50 pF

SOURCE

= I

SINK

= 200 mA

TIMING CHARACTERISTICS

1, 2

3

(T

= T

to T

A

MIN

, VDD = 2.65 V to 5.5 V, unless otherwise noted. See Figure 1.)

MAX

Parameter Limit Unit Comments

t

1

t

2

t

3

4

t

4

t

5

t

6

t

7

4

t

8

NOTES

1

Guaranteed by design and characterization, not production tested.

2

All input signals are specified with tr = tf = 5 ns (10% to 90% of VDD) and are timed from a voltage level of 1.6 V.

3

All specifications apply for –35∞C to +85∞C, unless otherwise noted.

4

Measured with the load circuit of Figure 2.

Specifications subject to change without notice.

0 ns min CE to SCLK Setup Time
50 ns min SCLK High Pulse Width
50 ns min SCLK Low Pulse Width
35 ns max Data Access Time after SCLK Rising Edge
20 ns min Data Setup Time prior to SCLK Falling Edge
0 ns min Data Hold Time after SCLK Falling Edge
0 ns min CE to SCLK Hold Time
40 ns max CE to SDO High Impedance

–2–

REV. A

CE

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SCLK

SDO

SDI

AD7314

t

1

t

5

t

2

t

t

4

3

t

6

Figure 1. Timing Diagram

t

7

t

8

ABSOLUTE MAXIMUM RATINGS

VDD to GND . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V

Digital Input Voltage to GND . . . . . . . –0.3 V to V

Digital Output Voltage to GND . . . . . –0.3 V to V

Operating Temperature Range . . . . . . . . . . . –35°C to +85°C

Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C

Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . 150°C

1

+ 0.3 V

DD

+ 0.3 V

DD

TO

OUTPUT

PIN

50pF

C

L

200␮AI

OL

1.6V

MSOP Package, Power Dissipation . . . . . . . . . . . . . . 450 mW

Thermal Impedance . . . . . . . . . . . . . . . . . . . . 206°C/W

θ

JA

Lead Temperature, Soldering

200␮AI

OH

Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . 215°C

Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C

Latch-Up for ID Pin

2

. . . . . . . . . . . . . . . . . . . . . . . . ≤ –70 mA

Figure 2. Load Circuit for Data Access Time and Bus
Relinquish Time

Latch-Up for All Other Pins . . . . . . . . . . . . . . . . . ≥ –110 mA

NOTES

1

Stresses above those listed under Absolute Maximum Ratings may cause perma-

nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.

2

Correct usage of the ID pin will prevent any latch-up from occurring. In an

application, the ID pin should be either tied to V
circuit. If the application complies with this recommendation, the ID pin will never
see –70 mA.

via a 100 kΩ resistor or left open

DD

ORDERING GUIDE

Temperature Temperature Package Package

Model Range Error Description Option Branding

AD7314ARM –35°C to +85°C ±2°C 8-Lead MSOP RM-8 CKA
AD7314ARM-REEL –35°C to +85°C ± 2°C 8-Lead MSOP RM-8 CKA
AD7314ARM-REEL7 –35°C to +85°C ±2°C 8-Lead MSOP RM-8 CKA
AD7314ARMZ* –35°C to +85°C ± 2°C 8-Lead MSOP RM-8 CKA
AD7314ARMZ-REEL* –35°C to +85°C ±2°C 8-Lead MSOP RM-8 CKA
AD7314ARMZ-REEL7* –35°C to +85°C ± 2°C 8-Lead MSOP RM-8 CKA

*Z = Lead Free.

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the AD7314 features proprietary ESD protection circuitry, permanent damage may occur on
devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are
recommended to avoid performance degradation or loss of functionality.

REV. A

–3–