MAXIM MAX6625, MAX6626 User Manual

General Description

The MAX6625/MAX6626 combine a temperature sensor, a programmable overtemperature alarm, and an I2Ccompatible serial interface into single compact packages. They convert their die temperatures into digital values using internal analog-to-digital converters (ADCs). The result of the conversion is held in a temperature register, readable at any time through the serial interface. A dedicated alarm output, OT, activates if the conversion result exceeds the value programmed in the high-temperature register. A programmable fault queue sets the number of faults that must occur before the alarm activates, preventing spurious alarms in noisy environments. OT has programmable output polarity and operating modes.

The MAX6625/MAX6626 feature a shutdown mode that saves power by turning off everything but the power-on reset and the I2C-compatible interface. Four separate addresses can be configured with the ADD pin, allowing up to four MAX6625/MAX6626 devices to be placed on the same bus. The MAX6625P/MAX6626P OT outputs are open drain, and the MAX6625R/MAX6626R OT outputs include internal pullup resistors.

The MAX6625 has a 9-bit internal ADC and can function as a replacement for the LM75 in most applications. The MAX6626 has a 12-bit internal ADC. Both devices come in the space-saving 6-pin SOT23 package, or the 6-pin TDFN package.

Applications

Fan Control Temperature Alarms System Temperature Control Industrial Equipment

Features

♦ 9-Bit Temperature-to-Digital Converter (MAX6625)

♦ 12-Bit Temperature-to-Digital Converter (MAX6626)

♦ I

C-Compatible Serial Interface

♦ Up to Four Devices on a Single Bus

♦ Versatile Alarm Output with Programmable Trip

Temperature and Hysteresis

♦ Low-Power Shutdown Mode

♦ Space-Saving TDFN or SOT23 Packages

♦ Lead-Free Version Available (TDFN Package)

MAX6625/MAX6626

9-Bit/12-Bit Temperature Sensors with

I2C-Compatible Serial Interface in a SOT23

________________________________________________________________ Maxim Integrated Products 1

GND

**EP = EXPOSED PADDLE

SCL

16V

5 ADD

SDA

MAX6625 MAX6626

SOT236

TDFN-EP**

TOP VIEW

Pin Configuration

0.1µF

MAX6625 MAX6626

SCL

TO I

MASTER

10kΩ (OMIT FOR MAX6625R AND MAX6626R)

SDA

1kΩ

OT OUTPUT

Typical Operating Circuit

19-1841; Rev 4; 10/06

Note: All devices operate over the -55°C to +125°C temperature range.

*For device options, see Selector Guide at end of data sheet.

Requires special solder temperature profile described in the Absolute Maximum Ratings section.

**EP = Exposed paddle.

PART PIN-PACKAGE PKG CODE

MAX6625PMUT* 6 SOT23-6 U6F-6

MAX6625RMUT* 6 SOT23-6 U6F-6 MAX6625PMTT* 6 TDFN-EP** T633-1 MAX6625RMTT* 6 TDFN-EP** T633-1 MAX6626PMUT* 6 SOT23-6 U6F-6 MAX6626RMUT* 6 SOT23-6 U6F-6 MAX6626PMTT* 6 TDFN-EP** T633-1 MAX6626RMTT* 6 TDFN-EP** T633-1

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Ordering Information

MAX6625/MAX6626

9-Bit/12-Bit Temperature Sensors with I2C-Compatible Serial Interface in a SOT23

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(+3V ≤ VS≤ +5.5V, T

A =

-55°C to +125°C, unless otherwise noted.)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

VSto GND ................................................................-0.3V to +6V

OT, SCL, SDA to GND..............................................-0.3V to +6V

ADD to GND .................................................-0.3V to (V

+ 0.3V)

Current into Any Pin............................................................±5mA

OT Sink Current.................................................................. 20mA

Continuous Power Dissipation

6-Pin SOT23 (derate 9.1mW/°C above +70°C)............727mW

6-Pin TDFN (derate 23.8mW/°C above +70°C) .........1905mW

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

Storage Temperature Range .............................-60°C to +150°C

ESD Rating (Human Body Model)......................................2000V

Lead Temperature .............................................................Note 1

Note 1: This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device

can be exposed to during board-level solder attach and rework. This limit permits only the use of the solder profiles recommended in the industry-standard specification, IPC/JEDEC J-STD-020A, paragraph 7.6, Table 3 for IR/VPR and Convection Reflow. Preheating is required. Hand or wave soldering is not allowed.

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Power-Supply Voltage V

3.0 5.5 V

I2C-compatible active 1 mA

I2C-compatible inactive

µAQuiescent Current I

Shutdown mode 1 µA

MAX6625 9

ADC Resolution

MAX6626 12

MAX6625 0.5

Temperature Resolution

MAX6626 TA = +25°C, VS = +3V to +3.6V ±1

0°C = TA ≤ +50°C, VS = +3.0V to +3.6V

Accuracy (Notes 2, 3)

0°C = T

≤ +70°C, VS = +3.0V to +3.6V

°C

Power-Supply Sensitivity VS = +3V to +5.5V 1

Conversion Time t

OT Pullup Resistor R

MAX6625R, MAX6626R only 25 50 kΩ

OT Saturation Voltage (Note 4) V

OUT

= 4mA (Note 4) 0.8 V

OT Delay (Programmable through fault queue)

HIGH

Default Temperature

80 °C

LOW

Default Temperature T

LOW

75 °C

I2C-COMPATIBLE I/O: SCL, SDA, ADD

VS < +3.6V 2

Input High Voltage V

VS > +3.6V 3

Input Low Voltage V

0.8 V

Input Hysteresis 0.2 V

250

0.0625

HIGH

133

1 × t

±1.5

±2.0

6 × t

Bits

°C/LSB

°C/V

MAX6625/MAX6626

9-Bit/12-Bit Temperature Sensors with

I2C-Compatible Serial Interface in a SOT23

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(+3V ≤ VS≤ +5.5V, T

A =

-55°C to +125°C, unless otherwise noted.)

Note 2: Guaranteed by design and characterization to ±5 sigma. Note 3: Quantization error not included in specifications for temperature accuracy. Note 4: Output current should be minimized for best temperature accuracy. Power dissipation within the MAX6625/MAX6626 causes

self-heating and temperature drift; see the Thermal Considerations section.

Note 5: A master device must provide a hold time of at least 300ns for the SDA signal in order to bridge the undefined region of

SCL’s falling edge.

Note 6: C

= total capacitance of one bus line in pF. Tested with CB= 400pF.

Note 7: Input filters on SDA, SCL, and ADD suppress noise spikes less than 50ns.

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Input High Leakage Current I

= +5V ±1 µA

Input Low Leakage Current I

= 0 ±1 µA

Input Capacitance C

10 pF

Output Low Voltage V

= 3mA 0.4 V

Output High Current I

VOH = 5V 1 µA

I2C-COMPATIBLE TIMING

Serial Clock Frequency f

SCL

kHz

Bus Free Time Between STOP and START Conditions

BUF

1.3 µs

START Condition Hold Time

0.6 µs

STOP Condition Setup Time

0.6 µs

Clock Low Period t

LOW

1.3 µs

Clock High Period t

HIGH

0.6 µs

Data Setup Time

Data Hold Time

(Note 5) 0 0.9 µs

Maximum Receive SCL/SDA Rise Time

(Note 6)

Minimum Receive SCL/SDA Rise Time

(Note 6)

20 +

Maximum Receive SCL/SDA Fall Time

(Note 6)

Minimum Receive SCL/SDA Fall Time

(Note 6)

20 +

Transmit SDA Fall Time t

CB = 400pF, IO = 3mA (Note 6)

20 +

Pulse Width of Suppressed Spike

(Note 7) 50 ns

Figure 1. Serial Bus Timing

SCL

SDA

LOW

SU:DAT

HD:STA

HD:DAT

SU:STO

BUF

HIGH

HD:STA

SU:STO

SU:DAT

HD:DAT

100

300

0.1C

300

0.1C

400

250

MAX6625/MAX6626

9-Bit/12-Bit Temperature Sensors with I2C-Compatible Serial Interface in a SOT23

4 _______________________________________________________________________________________

Typical Operating Characteristics

(VS = +3.3V, TA = +25°C, unless otherwise noted.)

Pin Description

100

-5 50101520

RESPONSE TO THERMAL SHOCK

TEMPERATURE vs. TIME

MAX6625 toc01

TIME (s)

OUTPUT TEMPERATURE (°C)

DEVICE IMMERSED IN +85°C FLUORINERT BATH

120

100

160

140

180

200

-55 5 35-25 65 95 125

STATIC QUIESCENT SUPPLY CURRENT

vs. TEMPERATURE

MAX6625 toc02

TEMPERATURE (°C)

INPUT CURRENT (µA)

120

100

160

140

180

200

-55 5 35-25 65 95 125

DYNAMIC QUIESCENT SUPPLY CURRENT

vs. TEMPERATURE

MAX6625 toc03

TEMPERATURE (°C)

INPUT CURRENT (µA)

-5

-2

-3

-4

-1

-50 -25 0 25 50 75 100 125

TEMPERATURE ERROR

vs. TEMPERATURE

MAX6625 toc04

TEMPERATURE (°C)

TEMPERATURE ERROR (°C)

MAXIMUM LIMIT

±5 SIGMA RANGE

MINIMUM LIMIT

PIN NAME FUNCTION

1 SDA I2C-Compatible Serial Bidirectional Data Line

2 GND Power-Supply Ground

3 SCL I2C-Compatible Clock Input

4 OT Temperature Alarm Output

5 ADD I2C-Compatible Address Set Pin: Ground (0), VS (1), SDA (2), SCL (3); see Table 1.

6VSPower-Supply Input, +3V to +5.5V. Bypass VS to GND with a 0.1µF capacitor.

—EP

Exposed Paddle. Internally connected to GND. Connect to a large ground plane for maximum thermal dissipation.

MAX6625/MAX6626

9-Bit/12-Bit Temperature Sensors with

I2C-Compatible Serial Interface in a SOT23

_______________________________________________________________________________________ 5

Detailed Description

The MAX6625/MAX6626 continuously convert their die temperatures into digital values using their self-contained delta-sigma ADCs. The resulting data is readable at any time through the I2C-compatible serial interface. A dedicated alarm output asserts if the result exceeds the value in the programmable high-temperature register. A programmable fault queue sets the number of faults that must occur before the alarm asserts, preventing spurious alarms in noisy environments. The alarm output polarity is selectable and deasserts based on either of two operating modes, comparator or interrupt. In comparator mode, the OT output deasserts if the temperature conversion result falls below the programmable low-temperature register value (subject to the fault queue conditions) providing adjustable hysteresis. In interrupt mode, the OT output deasserts when any register is read through the serial interface. Each conversion cycle takes about 130ms. At power-up, the temperature register is set to 8000H until the first conversion is completed.

The MAX6625/MAX6626 feature a shutdown mode, accessible through the serial interface, that saves power by turning off everything but the power-on reset and the I2C-compatible interface. While in shutdown mode, the temperature register is set to 8000H. The device func-

tions as a slave on the I

C-compatible bus supporting Write Byte, Write Word, Read Byte, and Read Word commands. Four separate addresses can be configured with the ADD pin, allowing up to four MAX6625/MAX6626 devices to be placed on the same bus. Figure 2 shows the functional diagram of the MAX6625/MAX6626.

Serial interface

I2C-Compatible Operation

The MAX6625/MAX6626 are readable and programmable through their I2C-compatible serial interface. Figures 3 and 4 show the timing details of the clock (SCL) and data (SDA) signals. The device functions as a slave on the I2C-compatible bus and supports Write Byte, Write Word, Read Byte, and Read Word commands.

Addressing

Four separate addresses can be configured with the ADD pin, allowing up to four MAX6625/MAX6626s to be placed on the same bus. The address is selected by connecting the ADD pin to either of four places: GND (address 0), VS(address 1), SDA (address 2), or SCL (address 3). Table 1 shows the full I2C-compatible address for each state.

MAX6625 MAX6626

TEMPERATURE REGISTER

HIGH

+Vs

GND SDA SCL ADD

SERIAL BUS INTERFACE

LOW

SET-POINT

COMPARATOR

ADDRESS POINTER REGISTER

BANDGAP

ADC

REFERENCE

TEMP SIGNAL

FAULT QUEUE

COUNTER

CONFIGURATION REGISTER

MAX665_ R

ONLY

Figure 2. Functional Diagram

MAX6625/MAX6626

9-Bit/12-Bit Temperature Sensors with I2C-Compatible Serial Interface in a SOT23

6 _______________________________________________________________________________________

Figure 3. I2C-Compatible Timing Diagram

ADDRESS

BYTE

ADDRESS

BYTE

ADDRESS

BYTE

(a) TYPICAL POINTER SET FOLLOWED BY IMMEDIATE READ FROM CONFIGURATION REGISTER

(b) CONFIGURATION REGISTER WRITE

HIGH

AND T

LOW

WRITE

POINTER

BYTE

POINTER

BYTE

POINTER

BYTE

MOST-SIGNIFICANT

DATA BYTE

LEAST-SIGNIFICANT

DATA BYTE

CONFIGURATION

BYTE

ADDRESS

BYTE

DATA

BYTE

ACK BY

MAX6625

ACK BY

MAX6625

ACK BY

MAX6625

ACK BY

MAX6625

ACK BY

MAX6625

ACK BY

MAX6625

ACK BY

MAX6625

START

MASTER

START

MASTER

START

MASTER

REPEAT

START

MASTER

ACK BY

MASTER

STOP

COND BY

MASTER

ACK BY

MAX6625

ACK BY

MAX6625

STOP

COND BY

MASTER

STOP

COND BY

MASTER

ACK BY

MAX6625

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