ANALOG DEVICES AD7415 Service Manual

www.BDTIC.com/ADI

±0.5°C Accurate, 10-Bit Digital

FEATURES

10-bit temperature-to-digital converter
Temperature range: −40°C to +125°C
Typical accuracy of ±0.5°C at +40°C
SMBus/I
3 µA power-down current
Temperature conversion time: 29 µs typ
Space-saving 6-lead (AD7414) and 5-lead (AD7415)

Pin selectable addressing via AS
Overtemperature indicator (AD7414 Only)
SMBus alert function (AD7414 only)
4 versions allow 8 I
2 versions allow 6 I

APPLICATIONS

Hard disk drives
Personal computers
Electronic test equipment
Office equipment
Domestic appliances
Process control
Cellular phones

GENERAL DESCRIPTION

The AD7414/AD7415 are complete temperature monitoring
systems in 6-lead and 5-lead SOT-23 packages. They contain a
band gap temperature sensor and a 10-bit ADC to monitor and
digitize the temperature reading to a resolution of 0.25°C.

The AD7414/AD7415 provide a 2-wire serial interface that is
compatible with SMBus and I
versions: the AD7414/AD7415-0, AD7414/AD7415-1, AD7414-2,
and AD7414-3. The AD7414/AD7415-0 and AD7414/AD7415-1
versions provide a choice of three different SMBus addresses for
each version. All four AD7414 versions give the possibility of eight
different I
six I

The AD7414/AD7415’s 2.7 V supply voltage, low supply current,
serial interface, and small package size make them ideal for a
variety of applications, including personal computers, office
equipment, cellular phones, and domestic appliances.

In the AD7414, on-chip registers can be programmed with high
and low temperature limits, and an open-drain overtemperature
indicator output (ALERT) becomes active when a programmed

Rev. E

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.
Specifications subject to change without notice. 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.

2

C®-compatible serial interface

SOT-23 packages

2

C addresses (AD7414)

2

C addresses (AD7415)

2

C interfaces. The parts come in four

2

C addresses while the two AD7415 versions allow up to

2

C addresses to be used.

Temperature Sensors in SOT-23

AD7414/AD7415

FUNCTIONAL BLOCK DIAGRAM

GND

AS

GND

AS

SENSOR

CONFIGURATION

REGISTER

T

SETPOINT

HIGH

REGISTER

T

SETPOINT

LOW

REGISTER

AD7414

AD7415

BAND GAP

TEMPERATURE

SENSOR

CONFIGURATION

REGISTER

SMBus/I2C

INTERFACE

SMBus/I2C

INTERFACE

Figure 1.

BAND GAP

TEMPERATURE

limit is exceeded. A configuration register allows programming of
the state of the ALERT output (active high or active low). This
output can be used as an interrupt or as an SMBus alert.

PRODUCT HIGHLIGHTS

1. On-chip temperature sensor. The sensor allows an accurate
measurement of the ambient temperature to be made. It is
capable of ±0.5°C temperature accuracy.

2

2. SMBus/I
selectable choice of three addresses per version of the
AD7414/AD7415, eight address options in total for the AD7414,
and six in total for the AD7415.

3. Supply voltage of 2.7 V to 5.5 V.

4. Space-saving 5-lead and 6-lead SOT-23 packages.

5. 10-bit temperature reading to 0.25°C resolution.

6. Overtemperature indicator. This indicator can be software
disabled. It is used as an interrupt of SMBus alert.

7. One-shot and automatic temperature conversion rates.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] © 2005 Analog Devices, Inc. All rights reserved.

C-compatible serial interface. The interface offers pin

10-BIT

ANALOG-DIGITAL

CONVERTER

TEMPERATURE

VALUE

REGISTER

SETPOINT

COMPARATOR

10-BIT

ANALOG-DIGITAL

CONVERTER

TEMPERATURE

VALUE

REGISTER

V

ALERT

SCL
SDA

V

SCL
SDA

DD

DD

02463-001

AD7414/AD7415

www.BDTIC.com/ADI

TABLE OF CONTENTS

Specifications .....................................................................................3

Absolute Maximum Ratings ............................................................5

ESD Caution ..................................................................................5

Pin Configurations and Function Descriptions............................6

Theory of Operation .........................................................................7

Circuit Information ......................................................................7

Functional Description.................................................................7

Measurement Technique..............................................................7

Temperature Data Format............................................................8

Internal Register Structure...............................................................9

Address Pointer Register..............................................................9

Configuration Register (Address 0X01).....................................9

Temperature Value Register (Address 0X00)...........................10

AD7414 T

AD7414 T

Register (Address 0X02)...................................10

HIGH

Register (Address 0X03) ....................................10

LOW

Serial Interface.................................................................................12

Serial Bus Address.......................................................................12

Writ e M o de ..................................................................................12

Read Mode...................................................................................12

SMBUS ALERT ............................................................................13

Power-On Defaults .....................................................................13

Operating Modes ........................................................................13

Power vs. Throughput ................................................................14

Mounting the AD7414/AD7415...............................................14

Supply Decoupling......................................................................14

Temperature Accuracy vs. Supply.............................................15

Typical Temperature Error Graph............................................15

Outline Dimensions........................................................................16

Ordering Guide...........................................................................17

REVISION HISTORY

4/05—Rev. D to Rev. E

Updated Format.................................................................. Universal

Changes to Absolute Maximum Ratings........................................6

Changes to Figure 6...........................................................................7

Changes to Ordering Guide...........................................................17

9/04—REV. C to REV. D.

C

hanges to ABSOLUTE MAXIMUM RATINGS.........................3

Updated ORDERING GUIDE.........................................................4

8/03—REV. B to REV. C.

Change to Temperature Range ......................................... Universal

Updated FEATURES.........................................................................1

Updated SPECIFICATIONS............................................................2

Updated ABSOLUTE MAXIMUM RATINGS.............................3

Updated ORDERING GUIDE.........................................................4

Updated CIRCUIT INFORMATION ............................................5

Updated TEMPERATURE DATA FORMAT................................6

Updated TEMPERATURE VALUE REGISTER ...........................8

Updated Figure 14...........................................................................11

Updated OUTLINE DIMENSIONS .............................................12

11/02—REV

Changes to ABSOLUTE MAXIMUM RATINGS......................... 3

10/02—REV. 0 to REV. A.

Changes to SPECIFICATIONS .......................................................2

Changes to PIN FUNCTION DESCRIPTIONS........................... 3

Changes to ABSOLUTE MAXIMUM RATINGS......................... 3

ORDERING GUIDE updated......................................................... 4

Change to Figure 2............................................................................ 5

Added to TYPICAL TEMPERATURE

ERROR GRAPH section ................................................................11

Added Figure 15..............................................................................11

OUTLINE DIMENSIONS updated..............................................12

7/01—Revision 0: Initial Version

. A to REV. B.

Rev. E | Page 2 of 20

AD7414/AD7415

www.BDTIC.com/ADI

SPECIFICATIONS

TA = T

Table 1.

Parameter A Version Unit Test Conditions/Comments

TEMPERATURE SENSOR AND ADC

POWER SUPPLIES

DIGITAL INPUT

DIGITAL OUTPUT (OPEN-DRAIN)

AC ELECTRICAL CHARACTERISTICS

MIN

Accuracy

to T

, VDD = 2.7 V to 5.5 V, unless otherwise noted. Temperature range as follows: A version = −40°C to +125°C.

MAX

1

±0.5 °C typ VDD = 3 V @ +40°C

−0.87 to +0.822°C max VDD = 3 V @ +40°C

±1.5 °C max VDD = 3 V @ −40°C to +70°C

±2.0 °C max VDD = 3 V @ −40°C to +85°C

±3.0 °C max VDD = 3 V @ −40°C to +125°C

±2.0 °C typ VDD = 3 V @ −40°C to +125°C

±1.872 °C max VDD = 5.5 V @ +40°C

±2.0 °C typ VDD = 5.5 V @ −40°C to +85°C

±3.0 °C max VDD = 5.5 V @ −40°C to +85°C

±3.0 °C typ VDD = 5.5 V @ −40°C to +125°C

Resolution 10 Bits

Update Rate, t

R

800 ms typ

Temperature Conversion Time 25 µs typ

Supply Current

Peak Supply Current

3

4

1.2 mA typ Current during conversion
Supply Current – Nonconverting 900 µA max Peak current between conversions
Inactive Serial Bus

Normal Mode @ 3 V 169 µA typ
Normal Mode @ 5 V 188 µA typ

Active Serial Bus

Normal Mode @ 3 V 180 µA typ
Normal Mode @ 5 V 214 µA typ

Shutdown Mode 3 µA max

5

Supply current with serial bus inactive. Part not
converting and D7 of configuration register = 0.

6

Supply current with serial bus active. Part not
converting and D7 of configuration register = 0.
D7 of configuration register = 1. Typical values
are 0.04 µA at 3 V and 0.5 µA at 5 V.

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

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

IH

IL

7

IN

IN

OH

OL

OH

OUT

ALERT Output Saturation Voltage 0.8 V max I

8, 9

Serial Clock Period, t
Data In Setup Time to SCL High, t
Data Out Stable after SCL Low, t

1

2

3

2.4 V min

0.8 V max

±1 µA max VIN = 0 V to V

DD

10 pF max All digital inputs

2.4 V min

0.4 V max IOL = 1.6 mA

1 µA max VOH = 5 V
10 pF max Typ = 3 pF

= 4 mA

OUT

2.5 µs min See Figure 2

50 ns min See Figure 2
0 ns min See Figure 2

Rev. E | Page 3 of 20

AD7414/AD7415

www.BDTIC.com/ADI

Parameter A Version Unit Test Conditions/Comments

SDA Low Setup Time to SCL Low

(Start Condition), t

4

SDA High Hold Time after SCL High

(Stop Condition), t

SDA and SCL Fall Time, t

5

6

Power-Up Time 4 µs typ

1

Accuracy specifications apply only to voltages listed under Test Conditions. See Temperature Accuracy vs. Supply section for typical accuracy performance over the

full VDD supply range.

2

100% production tested at 40°C to these limits.

3

These current values can be used to determine average power consumption at different one-shot conversion rates. Average power consumption at the automatic

conversion rate of 1.25 kHz is 940 µW.

4

This peak supply current is required for 29 µs (the conversion time plus power-up time) out of every 800 µs (the conversion rate).

5

These current values are derived by not issuing a stop condition at the end of a write or read, thus preventing the part from going into a conversion.

6

The current is derived assuming a 400 kHz serial clock being active continuously.

7

On power-up, the initial input current, IIN, on the AS pin is typically 50 µA.

8

The SDA and SCL timing is measured with the input filters turned on so as to meet the fast mode I2C specification. Switching off the input filters improves the transfer

rate but has a negative effect on the EMC behavior of the part.

9

Guaranteed by design. Not tested in production.

50 ns min See Figure 2

50 ns min See Figure 2

90 ns max See Figure 2

t

SCL

SDA

DATA IN

SDA

DATA OUT

t

4

1

t

2

t

3

t

5

t

6

02463-002

Figure 2. Diagram for Serial Bus Timing

Rev. E | Page 4 of 20

AD7414/AD7415

www.BDTIC.com/ADI

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

VDD to GND −0.3 V to +7 V
SDA Input Voltage to GND −0.3 V to +7 V
SDA Output Voltage to GND −0.3 V to +7 V
SCL Input Voltage to GND −0.3 V to +7 V
ALERT Output Voltage to GND −0.3 V to +7 V
Operating Temperature Range −40°C to +125°C
Storage Temperature Range −65°C to +150°C
Junction Temperature 150°C
5-Lead SOT-23 (RJ-5)

Power Dissipation
Thermal Impedance

θJA, Junction-to-Ambient

1, 2

3

W

= (T

JMAX

− TA)/θ

JA

MAX

240°C/W

(still air)

6-Lead SOT-23 (RJ-6)

Power Dissipation

1, 2

W

= (T

JMAX

− TA)/θ

JA

MAX

Thermal Impedance3

θJA, Junction-to-Ambient

190.4°C/W

(still air)

8-Lead MSOP (RM-8)

Power Dissipation

1, 2

W

= (T

JMAX

− TA)/θ

JA

MAX

Thermal Impedance3

θJA, Junction-to-Ambient

205.9°C/W

(still air)
θJC, Junction-to-Case 43.74°C/W

IR Reflow Soldering

Peak Temperature 220°C (0°C/5°C)
Time at Peak Temperature 10 sec to 20 sec
Ramp-up Rate 3°C/s max
Ramp-down Rate

Ramp from 25°C to Peak

−6°C/s max
6 minutes max

Temperature

IR Reflow Soldering in Pb-Free
Package

Peak Temperature 260°C (0°C)
Time at Peak Temperature 20 sec to 40 sec
Ramp Rate 3°C/s max
Ramp-Down Rate

Ramp from 25°C to Peak

−6°C/s max
8 minutes max

Temperature

1

Values relate to package being used on a standard 2-layer PCB.

2

TA = ambient temperature.

3

Junction-to-case resistance is applicable to components featuring a

preferential flow direction, such as components mounted on a heat sink.
Junction-to-ambient resistance is more useful for air-cooled, PCB-mounted
components.

Stresses above those listed under Absolute Maximum Ratings
may cause permanent 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.

ESD 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 this product 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. E | Page 5 of 20

AD7414/AD7415

A

T

www.BDTIC.com/ADI

PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS

SDA

AS

GND 2

V

DD

1

3

AD7414

Top View

(Not to Scale)

6

5

4

ALERT

SCL

02463-003

Figure 3. AD7414 Pin Configuration (SOT-23)

Table 3. Pin Function Descriptions

Mnemonic Description

AS

Logic Input. Address select input that selects one
of three I2C addresses for the AD7414/AD7415 (see
Table 4). Recommend a pull-up or pull-down

resistor of 1 kΩ.
GND Analog and Digital Ground.
V

DD

SDA

Positive Supply Voltage, 2.7 V to 5.5 V.

Digital I/O. Serial bus bidirectional data. Open-

drain output.
ALERT

AD7414 Digital Output. Overtemperature

indicator becomes active when temperature

exceeds T

. Open-drain output.

HIGH

SCL Digital Input. Serial bus clock.

1

NC

AD7414

SDA 2

LER

SCL V

Top View

(Not to Scale)

3

4

NC = NO CONNECT

NC

8

AS

7

GND

6

5

DD

02463-004

Figure 4. AD7414 Pin Configuration (MSOP)

2

Table 4. I

C Address Selection

Part Number AS Pin I2C Address

AD7414-0 Float 1001 000
AD7414-0 GND 1001 001
AD7414-0 V
AD7414-1 Float 1001 100
AD7414-1 GND 1001 101
AD7414-1 V
AD7414-2 N/A 1001 011
AD7414-3 N/A 1001 111
AD7415-0 Float 1001 000
AD7415-0 GND 1001 001
AD7415-0 V
AD7415-1 Float 1001 100
AD7415-1 GND 1001 101
AD7415-1 V

SDA

AS

GND 2

V

DD

1

3

AD7415

Top View

(Not to Scale)

5

SCL

4

02463-005

Figure 5. AD7415 Pin Configuration (SOT-23)

DD

DD

DD

DD

1001 010

1001 110

1001 010

1001 110

Rev. E | Page 6 of 20