Rainbow Electronics MAX1989 User Manual

________________General Description

The MAX1668/MAX1805/MAX1989 are precise multi­channel digital thermometers that report the tempera­ture of all remote sensors and their own packages. The
remote sensors are diode-connected transistors—typi­cally low-cost, easily mounted 2N3904 NPN types—that
replace conventional thermistors or thermocouples.
Remote accuracy is ±3°C for multiple transistor manu­facturers, with no calibration needed. The remote chan­nels can also measure the die temperature of other ICs,
such as microprocessors, that contain an on-chip,
diode-connected transistor.

The 2-wire serial interface accepts standard system
management bus (SMBus™) write byte, read byte, send
byte, and receive byte commands to program the alarm
thresholds and to read temperature data. The data for­mat is 7 bits plus sign, with each bit corresponding to
1°C, in two’s-complement format.

The MAX1668/MAX1805/MAX1989 are available in
small, 16-pin QSOP surface-mount packages.

________________________Applications

____________________________Features

♦ Multichannel

4 Remote, 1 Local (MAX1668/MAX1989)
2 Remote, 1 Local (MAX1805)

♦ No Calibration Required

♦ SMBus 2-Wire Serial Interface

♦ Programmable Under/Overtemperature Alarms

♦ Supports SMBus Alert Response

♦ Accuracy

±2°C (+60°C to +100°C, Local)
±3°C (-40°C to +125°C, Local)
±3°C (+60°C to +100°C, Remote)

♦ 3µA (typ) Standby Supply Current

♦ 700µA (max) Supply Current

♦ Small, 16-Pin QSOP Package

MAX1668/MAX1805/MAX1989

†

Multichannel Remote/Local

Temperature Sensors

________________________________________________________________ Maxim Integrated Products 1

Pin Configuration

16

15

14

13

12

11

10

9

1

2

3

4

5

6

7

8

DXP1 GND

STBY

SMBCLK

SMBDATA

ALERT

ADD0

ADD1

V

CC

TOP VIEW

MAX1668
MAX1805
MAX1989

QSOP

DXN1

DXP2

(N.C.) DXN3

DXN2

(N.C.) DXP3

(N.C.) DXP4

( ) ARE FOR MAX1805.

(N.C.) DXN4

Typical Operating Circuit

19-1766; Rev 1; 8/02

PART

MAX1668MEE

-55°C to +125°C

TEMP RANGE PIN-PACKAGE

16 QSOP

_______________Ordering Information

SMBus is a trademark of Intel Corp. †Patents Pending

MAX1805MEE

-55°C to +125°C 16 QSOP

Desktop and Notebook
Computers

LAN Servers

Industrial Controls

Central-Office Telecom
Equipment

Test and Measurement

Multichip Modules

MAX1989MEE

-55°C to +125°C 16 QSOP

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.

*

*

*

DIODE-CONNECTED TRANSISTOR

0.1µF

V

STBY

CC

MAX1668
MAX1805
MAX1989

2200pF

DXP1

DXN1

DXP4

2200pF

DXN4

ADD0 ADD1

SMBCLK

SMBDATA

ALERT

GND

3V TO 5.5V

200Ω

10kΩ EACH

CLOCK

DATA

INTERRUPT
TO µC

MAX1668/MAX1805/MAX1989

†

Multichannel Remote/Local
Temperature Sensors

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +3.3V, STBY = VCC, configuration byte = X0XXXX00, TA= 0°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.

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

DXP_, ADD_, STBY to GND........................-0.3V to (V

CC

+ 0.3V)

DXN_ to GND ........................................................-0.3V to +0.8V

SMBCLK, SMBDATA, ALERT to GND ......................-0.3V to +6V

SMBDATA, ALERT Current .................................-1mA to +50mA

DXN_ Current......................................................................±1mA

Continuous Power Dissipation (T

A

= +70°C)

QSOP (derate 8.30mW/°C above +70°C)....................667mW

Operating Temperature Range .........................-55°C to +125°C

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

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

Lead Temperature (soldering, 10s) .................................+300°C

DXP_ forced to 1.5VRemote-Diode Source Current

Low level (POR state)

Configuration byte =
X0XXXX10, high level

Configuration byte =
X0XXXX01, high level

High level (POR state)

71013

200

50

DXN_ Source Voltage 0.7 V

Hardware or software standby,
SMBCLK at 10kHz

SMBus static

TA = 0°C to +85°C

TA = +60°C to +100°C

Average measured over 4s; logic inputs forced
V

CC

or GND

Temperature Error, Local Diode
(Notes 1, 2)

-3.5 +3.5

°C

-2.5 +2.5

Including long-term drift

Temperature Error, Remote Diode
(Notes 2, 3)

-5 +5

°C

-3 +3

TR = -55°C to +125°C

TR = +60°C to +100°C

PARAMETER MIN TYP MAX UNITS

Undervoltage Lockout Hysteresis 50 mV

Undervoltage Lockout Threshold 2.60 2.8 2.95 V

Supply Voltage Range 3.0 5.5 V

Initial Temperature Error,
Local Diode (Note 2)

-3 +3

°C

Power-On Reset (POR) Threshold 1.3 1.8 2.3 V

POR Threshold Hysteresis 50 mV

310

Standby Supply Current

512

µA

Temperature Resolution (Note 1) 8 Bits

-2 +2

Average Operating Supply Current 400 700 µA

Conversion Time 260 320 380 ms

70 100 130

µA

Address Pin Bias Current 160 µA

CONDITIONS

VCCinput, disables A/D conversion, rising edge

TA = 0°C to +125°C

VCC, falling edge

From stop bit to conversion complete (all channels)

Logic inputs
forced to V

CC

or GND

ADD0, ADD1; momentary upon power-on reset

Monotonicity guaranteed

TA = +60°C to +100°C

ADC AND POWER SUPPLY

MAX1668/MAX1805/MAX1989

†

Multichannel Remote/Local

Temperature Sensors

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3.3V, STBY = VCC, configuration byte = X0XXXX00, TA= 0°C to +125°C, unless otherwise noted.)

STBY, SMBCLK, SMBDATA; V

CC

= 3V to 5.5V

t

HIGH

, 90% to 90% points

t

LOW

, 10% to 10% points

(Note 4)

SMBCLK, SMBDATA

Logic inputs forced to VCCor GND

ALERT forced to 5.5V

STBY, SMBCLK, SMBDATA; VCC= 3V to 5.5V

ALERT, SMBDATA forced to 0.4V

CONDITIONS

µs4SMBCLK Clock High Time

µs4.7SMBCLK Clock Low Time

kHzDC 100SMBus Clock Frequency

pF5SMBus Input Capacitance

µA-1 +1Logic Input Current

µA1

ALERT Output High Leakage
Current

V2.2Logic Input High Voltage

V0.8Logic Input Low Voltage

mA6Logic Output Low Sink Current

UNITSMIN TYP MAXPARAMETER

t

SU:DAT

, 10% or 90% of SMBDATA to 10% of SMBCLK

t

SU:STO

, 90% of SMBCLK to 10% of SMBDATA

t

HD:STA

, 10% of SMBDATA to 90% of SMBCLK

t

SU:STA

, 90% to 90% points

ns250

SMBus Data Valid to SMBCLK
Rising-Edge Time

µs4SMBus Stop-Condition Setup Time

µs4SMBus Start-Condition Hold Time

ns250

SMBus Repeated Start-Condition
Setup Time

µs4.7SMBus Start-Condition Setup Time

nsSMBus Data-Hold Time

Master clocking in data µs1

SMBCLK Falling Edge to SMBus
Data-Valid Time

SMBus INTERFACE

ELECTRICAL CHARACTERISTICS

(VCC= +5V, STBY = VCC, configuration byte = X0XXXX00, TA= -55°C to +125°C, unless otherwise noted.) (Note 6)

CONDITIONS

Monotonicity guaranteed

TA= +60°C to +100°C

Bits8Temperature Resolution

-2 +2

TR= +60°C to +100°C

TA= -55°C to +125°C

°C

-3 +3

Initial Temperature Error,
Local Diode (Note 2)

V4.5 5.5Supply-Voltage Range

From stop bit to conversion complete (both channels) ms260 380Conversion Time

-3 +3

TR= -55°C to +125°C

°C

UNITSMIN TYP MAX

-5 +5

PARAMETER

Temperature Error, Remote Diode
(Notes 2, 3)

ADC AND POWER SUPPLY

t

HD:DAT

, slave receive (Note 5) 0

0

8

4

16

12

20

24

MAX1668/1805 toc03

FREQUENCY (MHz)

TEMPERATURE ERROR (°C)

TEMPERATURE ERROR

vs. SUPPLY NOISE FREQUENCY

100mV

P-P

0.1 1 10 100

WITH VCC 0.1µF CAPACITOR REMOVED
2200pF BETWEEN DXN_ AND DXP_

250mV

P-P

20

-20
1 10 100

TEMPERATURE ERROR

vs. PC BOARD RESISTANCE

-10

MAX1668/1805 toc01

LEAKAGE RESISTANCE (MΩ)

TEMPERATURE ERROR (°C)

0

10

PATH = DXP_ TO GND

PATH = DXP_ TO V

CC

(5V)

-2

-1

0

1

2

3

4

-50 -10-30 10 30 50 70 90 110

TEMPERATURE ERROR

vs. TEMPERATURE

MAX1668/1805 toc02

TEMPERATURE (°C)

TEMPERATURE ERROR (°C)

NPN (CMPT3904)

PNP (CMPT3906)

INTERNAL

Typical Operating Characteristics

(Typical Operating Circuit, VCC= +5V, STBY = VCC, configuration byte = X0XXXX00, TA = +25°C, unless otherwise noted.)

MAX1668/MAX1805/MAX1989

†

Multichannel Remote/Local
Temperature Sensors

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +5V, STBY = VCC, configuration byte = X0XXXX00, TA= -55°C to +125°C, unless otherwise noted.) (Note 6)

Note 1: Guaranteed by design, but not production tested.
Note 2: Quantization error is not included in specifications for temperature accuracy. For example, if the MAX1668/MAX1805/

MAX1989 device temperature is exactly +66.7°C, the ADC may report +66°C, +67°C, or +68°C (due to the quantization
error plus the +0.5°C offset used for rounding up) and still be within the guaranteed ±1°C error limits for the +60°C to
+100°C temperature range. See Table 2.

Note 3: A remote diode is any diode-connected transistor from Table 1. T

R

is the junction temperature of the remote diode. See the

Remote-Diode Selection section for remote-diode forward-voltage requirements.

Note 4: The SMBus logic block is a static design that works with clock frequencies down to DC. While slow operation is possible, it

violates the 10kHz minimum clock frequency and SMBus specifications, and can monopolize the bus.

Note 5: Note that a transition must internally provide at least a hold time in order to bridge the undefined region (300ns max) of

SMBCLK’s falling edge t

HD:DAT.

Note 6: Specifications from -55°C to +125°C are guaranteed by design, not production tested.

CONDITIONS UNITSMIN TYP MAXPARAMETER

STBY, SMBCLK, SMBDATA; VCC= 4.5V to 5.5V

Logic Input High Voltage V2.4

ALERT forced to 5.5V

µA1

ALERT Output High Leakage
Current

Logic inputs forced to VCCor GND µA-2 +2Logic Input Current

ALERT, SMBDATA forced to 0.4V

mA6Logic Output Low Sink Current

STBY, SMBCLK, SMBDATA; VCC= 4.5V to 5.5V

V0.8Logic Input Low Voltage

SMBus INTERFACE

0

20

40

60

80

100

120

140

160

012345

STANDBY SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX1668/1805 toc07

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (µA)

STBY = GND

ADD0 = ADD1 = HIGH-Z

ADD0 = ADD1 = GND

0

25

75

50

100

125

-2 20468

RESPONSE TO THERMAL SHOCK

MAX1668/1805 toc08

TIME (s)

TEMPERATURE (°C)

16 QSOP IMMERSED IN
+115°C FLUORINERT BATH

MAX1668/MAX1805/MAX1989

†

Multichannel Remote/Local

Temperature Sensors

_______________________________________________________________________________________ 5

Typical Operating Characteristics (continued)

(Typical Operating Circuit, VCC= +5V, STBY = VCC, configuration byte = X0XXXX00, TA = +25°C, unless otherwise noted.)

TEMPERATURE ERROR

vs. DXP_ TO DXN_ CAPACITANCE

MAX16681805 toc05

DXP_ TO DXN_ CAPACITANCE (nF)

TEMPERATURE ERROR (°C)

-10

-6

-8

-2

-4

2

0

4

0203010 40 50 60

STANDBY SUPPLY CURRENT

vs. CLOCK FREQUENCY

MAX1668/1805 toc06

SMBCLK FREQUENCY (kHz)

SUPPLY CURRENT (µA)

60

0

10

20

30

40

50

1 10 100 1000

STBY = GND

VCC = 5V

VCC = 3.3V

TEMPERATURE ERROR

vs. COMMON-MODE NOISE FREQUENCY

2.0
SQUARE-WAVE AC-COUPLED INTO DXN

1.8
2200pF BETWEEN DXN_ AND DXP_

1.6

100mV

1.4

1.2

1.0

0.8

0.6

TEMPERATURE ERROR (°C)

0.4

0.2

0

P-P

0.1 1 1000

10 100

FREQUENCY (MHz)

50mV

P-P

MAX1668/1805 toc04