Rainbow Electronics MAX1619 User Manual

________________General Description

The MAX1619 is a precise digital thermometer that reports
the temperature of both a remote sensor and its own
package. The remote sensor is a diode-connected transis­tor—typically a low-cost, easily mounted 2N3904 NPN
type—that replaces conventional thermistors or thermo­couples. Remote accuracy is ±3°C for multiple transistor
manufacturers, with no calibration needed. The remote
channel 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. Measurements can be done
automatically and autonomously, with the conversion rate
programmed by the user or programmed to operate in a
single-shot mode. The adjustable rate allows the user to
control the supply-current drain.

The MAX1619 is nearly identical to the popular MAX1617A,
with the additional feature of an overtemperature alarm out­put (OVERT) that responds to the remote temperature; this
is optimal for fan control.

________________________Applications

Desktop and Notebook Central Office
Computers Telecom Equipment

Smart Battery Packs Test and Measurement
LAN Servers Multichip Modules
Industrial Controls

____________________________Features

♦ Two Channels Measure Both Remote and Local

Temperatures

♦ No Calibration Required
♦ SMBus 2-Wire Serial Interface
♦ Programmable Under/Overtemperature Alarms
♦ OVERT Output for Fan Control
♦ Supports SMBus Alert Response
♦ Supports Manufacturer and Device ID Codes
♦ 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
♦ 70µA (max) Supply Current in Auto-Convert Mode
♦ +3V to +5.5V Supply Range
♦ Write-Once Protection
♦ Small 16-Pin QSOP Package

MAX1619

Remote/Local Temperature Sensor with Dual-

Alarm Outputs and SMBus Serial Interface

________________________________________________________________

Maxim Integrated Products

1

MAX1619

SMBCLK

ADD0 ADD1

V

CC

STBY

GND

ALERT

SMBDATA

DXP

DXN

INTERRUPT
TO µC

FAN
CONTROL

+3V TO +5.5V

200Ω

0.1µF

CLOCK

10k EACH

DATA

2N3904

2200pF

OVERT

___________________Pin Configuration

16
15
14
13
12
11
10

9

1
2

3
4
5

6

7
8

V

CC

N.C.
STBY
SMBCLK
N.C.
SMBDATA
ALERT
ADD0
OVERT

TOP VIEW

MAX1619

QSOP

GND
DXP

ADD1

DXN
N.C.

GND
GND

Typical Operating Circuit

19-1483; Rev 0; 4/99

PART

MAX1619MEE -55°C to +125°C

TEMP. RANGE PIN-PACKAGE

16 QSOP

Ordering Information

SMBus is a registered trademark of Intel Corp.

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone].

MAX1619

Remote/Local Temperature Sensor with Dual­Alarm Outputs and SMBus Serial Interface

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +3.3V, TA= 0°C to +85°C, configuration byte = XCh, 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_ to GND....................................-0.3V to (V

CC

+ 0.3V)

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

SMBCLK, SMBDATA, ALERT, OVERT,

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

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

DXN Current .......................................................................±1mA

ESD Protection (all pins, Human Body Model) ..................2000V

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, 10sec).............................+300°C

T

A

= +60°C to +100°C

Monotonicity guaranteed

ADD0, ADD1; momentary upon power-on reset

DXP forced to 1.5V

Logic inputs
forced to V

CC

or GND

Auto-convert mode

From stop bit to conversion complete (both channels)

VCC, falling edge

TA = 0°C to +85°C

VCCinput, disables A/D conversion, rising edge

Autoconvert mode, average
measured over 4sec. Logic
inputs forced to V

CC

or GND.

CONDITIONS

µA160Address Pin Bias Current

V0.7DXN Source Voltage

µA

81012

80 100 120

Remote-Diode Source Current

%-25 25Conversion Rate Timing Error

ms94 125 156Conversion Time

µA

120 180

35 70

Average Operating Supply Current

-2 2

Bits8Temperature Resolution (Note 1)

µA

5

Standby Supply Current

310

mV50POR Threshold Hysteresis

V1.0 1.7 2.5Power-On Reset Threshold

°C

-3 3

Initial Temperature Error,
Local Diode (Note 2)

V3.0 5.5Supply Voltage Range
V2.60 2.80 2.95Undervoltage Lockout Threshold

mV50Undervoltage Lockout Hysteresis

UNITSMIN TYP MAXPARAMETER

TR = +60°C to +100°C
TR = -55°C to +125°C (Note 4)

-3 3
°C

-5 5

Temperature Error, Remote Diode
(Notes 2, 3)

Including long-term drift

-2.5 2.5
°C

-3.5 3.5

Temperature Error, Local Diode
(Notes 1, 2)

0.25 conv/sec

2.0 conv/sec

TA = +60°C to +100°C
TA = 0°C to +85°C

High level
Low level

ADC AND POWER SUPPLY

SMBus static
Hardware or software standby,

SMBCLK at 10kHz

MAX1619

Remote/Local Temperature Sensor with Dual-

Alarm Outputs and SMBus Serial Interface

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3.3V, TA= 0°C to +85°C, configuration byte = XCh, 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 5)

SMBCLK, SMBDATA

Logic inputs forced to VCCor GND

ALERT, OVERT, forced to 5.5V

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

ns500

SMBus Repeated Start-Condition
Setup Time

µs4.7SMBus Start-Condition Setup Time

t

HD:DAT

(Note 6) µs0SMBus Data-Hold Time

Master clocking in data µs1

SMBCLK Falling Edge to SMBus
Data-Valid Time

SMBus INTERFACE

ELECTRICAL CHARACTERISTICS

(VCC= +3.3V, TA= -55°C to +125°C, configuration byte = XCh, unless otherwise noted.) (Note 4)

CONDITIONS

Monotonicity guaranteed
TA= +60°C to +100°C

Bits8Temperature Resolution (Note 1)

-2 2

TR= +60°C to +100°C

TA= -55°C to +125°C

°C

-3 3

Initial Temperature Error,
Local Diode (Note 2)

V3.0 5.5Supply Voltage Range
From stop bit to conversion complete (both channels)
Autoconvert mode

ms94 125 156Conversion Time

%-25 25Conversion Rate Timing Error

-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

0

6

3

9

12

50 5k 500k50k 5M500 50M

TEMPERATURE ERROR vs.

POWER-SUPPLY NOISE FREQUENCY

MAX1619-03

FREQUENCY (Hz)

TEMPERATURE ERROR (°C)

VIN = SQUARE WAVE APPLIED TO
V

CC

WITH NO 0.1µF VCC CAPACITOR

VIN = 250mVp-p
REMOTE DIODE

VIN = 100mVp-p
LOCAL DIODE

VIN = 100mVp-p
REMOTE DIODE

-20

-10

-15

0

-5

10

5

20
15

TEMPERATURE ERROR

vs. PC BOARD RESISTANCE

MAX1619-01

LEAKAGE RESISTANCE (MΩ)

TEMPERATURE ERROR (°C)

1 10 100

PATH = DXP TO GND

PATH = DXP TO VCC (5V)

-2

-1

0

1

2

-50 50 1000 150

TEMPERATURE ERROR

vs. REMOTE-DIODE TEMPERATURE

MAX1619-02

TEMPERATURE (°C)

TEMPERATURE ERROR (°C)

MOTOROLA MMBT3904

ZETEX FMMT3904

RANDOM
SAMPLES

__________________________________________Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

MAX1619

Remote/Local Temperature Sensor with Dual­Alarm Outputs and SMBus Serial Interface

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3.3V, TA= -55°C to +125°C, configuration byte = XCh, unless otherwise noted.) (Note 4)

Note 1: Guaranteed but not 100% tested.
Note 2: Quantization error is not included in specifications for temperature accuracy. For example, if the MAX1619 device tempera-

ture is exactly +66.7°C, the ADC may report +66°C, +67°C, or +68°C (due to the quantization error plus the +1/2°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
(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

Remote Diode Selection

for remote diode forward voltage requirements.

Note 4: Specifications from -55°C to +125°C are guaranteed by design, not production tested.
Note 5: 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 may monopolize the bus.

Note 6: 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.

CONDITIONS UNITSMIN TYP MAXPARAMETER

STBY, SMBCLK, SMBDATA

2.2

Logic Input High Voltage V

2.4

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

V0.8Logic Input Low Voltage

ALERT, OVERT forced to 5.5V

µA1

ALERT, OVERT Output High
Leakage Current

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

VCC= 3V
VCC= 5.5V

ALERT, OVERT, SMBDATA forced to 0.4V

mA6Logic Output Low Sink Current

SMBus INTERFACE

MAX1619

Remote/Local Temperature Sensor with Dual-

Alarm Outputs and SMBus Serial Interface

_______________________________________________________________________________________

5

0

2

4

8

6

10

TEMPERATURE ERROR vs.

COMMON-MODE NOISE FREQUENCY

MAX1619-04

FREQUENCY (MHz)

TEMPERATURE ERROR (°C)

0.1 10 1001

VIN = 100mVp-p

VIN = SQUARE WAVE
AC-COUPLED TO DXN

VIN = 50mVp-p

VIN = 25mVp-p

0

10

20

04060

80

20 100

TEMPERATURE ERROR vs.

DXP–DXN CAPACITANCE

MAX1619-07

DXP–DXN CAPACITANCE (nF)

TEMPERATURE ERROR (°C)

VCC = 5V

0

100

400

200

300

500

010.0625 40.25 20.125 0.5 8

OPERATING SUPPLY CURRENT

vs. CONVERSION RATE

MAX1619-10

CONVERSION RATE (Hz)

SUPPLY CURRENT (µA)

VCC = 5V
AVERAGED MEASUREMENTS

0

10

20

30

40

50

1 10010 1000

STANDBY SUPPLY CURRENT

vs. CLOCK FREQUENCY

MAX1619-08

SMBCLK FREQUENCY (kHz)

SUPPLY CURRENT (µA)

VCC = 5V

VCC = 3.3V

0

3

60

6

20

100

031425

STANDBY SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX1619-09

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (µA)

ADD0, ADD1 = GND

ADD0, ADD1 = HIGH-Z

0

25

100

50

75

125

-2 8 042610

INTERNAL DIODE

RESPONSE TO THERMAL SHOCK

MAX1619-11

TIME (sec)

TEMPERATURE (°C)

16-QSOP IMMERSED
IN +115°C FLUORINERT BATH

Typical Operating Characteristics (continued)

(TA = +25°C, unless otherwise noted.)

MAX1619

Remote/Local Temperature Sensor with Dual­Alarm Outputs and SMBus Serial Interface

6 _______________________________________________________________________________________

Pin Description

Detailed Description

The MAX1619 is a temperature sensor designed to work
in conjunction with an external microcontroller (µC) or
other intelligence in thermostatic, process-control, or
monitoring applications. The µC is typically a power­management or keyboard controller, generating SMBus
serial commands either by “bit-banging” general-pur­pose input/output (GPIO) pins or through a dedicated
SMBus interface block.

Essentially an 8-bit serial analog-to-digital converter
(ADC) with a sophisticated front end, the MAX1619
contains a switched current source, a multiplexer, an
ADC, an SMBus interface, and associated control logic
(Figure 1). Temperature data from the ADC is loaded
into two data registers (local and remote). The remote
temperature data is automatically compared with data
previously stored in four temperature-alarm threshold
registers. One pair of alarm-threshold registers is used
to provide hysteretic fan control; the other pair is used
for alarm interrupt. The local temperature data is avail­able for monitoring.

ADC and Multiplexer

The ADC is an averaging type that integrates over a
60ms period (each channel, typical) with excellent
noise rejection.

The multiplexer automatically steers bias currents
through the remote and local diodes, measures their
forward voltages, and computes their temperatures.
Both channels are automatically converted once the
conversion process has started, either in free-running
or single-shot mode. If one of the two channels is not
used, the device still performs both measurements, and
the user can simply ignore the results of the unused
channel.

The DXN input is biased at 0.65V above ground by an
internal diode to set up the analog-to-digital (A/D)
inputs for a differential measurement. The worst-case
DXP–DXN differential input voltage range is 0.25V to

0.95V.
Excess resistance in series with the remote diode caus-

es about +1/2°C error per ohm. Likewise, 200µV of off­set voltage forced on DXP–DXN causes about 1°C error.

SMBus Serial-Data Input/Output, Open DrainSMBDATA12
SMBus Serial-Clock InputSMBCLK14
Hardware Standby Input. Temperature and comparison threshold data are retained in standby mode.

Low = standby mode, high = operate mode.

STBY

15

SMBus Address Select Pin (Table 8). ADD0 and ADD1 are sampled upon power-up. Excess capacitance
(>50pF) at the address pins when floating may cause address-recognition problems.

ADD16

GroundGND7, 8

SMBus Slave Address Select PinADD010
SMBus Alert (interrupt) Output, Open Drain

ALERT

11

Combined Current Sink and A/D Negative Input. DXN is normally internally biased to a diode voltage
above ground.

DXN4

Combined Current Source and A/D Positive Input for Remote-Diode Channel. Do not leave DXP floating;
connect DXP to DXN if no remote diode is used. Place a 2200pF capacitor between DXP and DXN for
noise filtering.

DXP3

PIN

Supply Voltage Input, 3V to 5.5V. Bypass to GND with a 0.1µF capacitor. A 200Ω series resistor is recom­mended but not required for additional noise filtering.

V

CC

1

FUNCTIONNAME

Overtemperature Alarm Output, Open Drain. This is an unlatched alarm output that responds only to the
remote diode temperature.

OVERT

9

Not internally connected. Connect to GND to act against leakage paths from VCCto DXP.GND2

No Connection. Not internally connected. May be used for PC board trace routing.N.C.

5, 13,

16