MAXIM MAX6603 Technical data

General Description

The MAX6603 dual-channel, platinum RTD-to-voltage
signal conditioner excites and amplifies the signal from
two external 200Ω platinum-resistive temperature
devices (Pt RTD) to achieve high-voltage, level-filtered
signals for temperature measurements. The MAX6603
provides a direct ratiometric output voltage to simplify
the interface to microcontrollers with integrated analog­to-digital converters (ADCs). External precision resis­tors and calibration processes are not needed. The
MAX6603 provides the necessary signal-conditioning
functions, including ratiometric excitation current,
amplification, buffered voltage outputs, diagnostic fault
detections, and input protection. The MAX6603 ampli­fies signals from two RTDs operating over the -40°C to
+1000°C temperature range and provides the tempera­ture information as two independent analog voltages.
The MAX6603 features a ±6°C (max) accuracy over the
+400°C to +600°C temperature range.

The MAX6603 has overvoltage protection up to +16V
on RTD inputs, and ±5kV electrostatic discharge (ESD)
protection at RTD input pins for reliable operation
where RTD temperature-sensing probes are used. The
MAX6603 monitors the RTD for faults and asserts the
respective DG output low for fault conditions. The ana­log voltage outputs can be readily connected to a vari­ety of microcontrollers.

The MAX6603 is available in a small, 10-pin TDFN-EP
package and operates over the -40°C to +125°C auto­motive temperature range from a single +3V to +5.5V
power supply.

Applications

Automotive Exhaust Temperature Monitoring

Engine Control Management to Meet EURO IV
Regulations

Braking Systems

Industrial Temperature Sensors

Food Transportation Monitoring Systems

Industrial Process Measurements

Features

♦ Amplifies Pt RTD Temperature Signals

♦ ±5kV ESD Protection on RTD Inputs

♦ +16V Overvoltage Fault Protection on RTD Inputs

♦ Low RTD Excitation Current Minimizes Self-

Heating Errors

♦ Small, 10-Pin TDFN Package

♦ Fully Ratiometric Operation

♦ No Calibration Required for Standard RTDs

♦ RTD Diagnostic Check

♦ High Accuracy: ±6°C (max) from +400°C to +600°C

MAX6603

Dual-Channel, Platinum

RTD-to-Voltage Signal Conditioner

________________________________________________________________ Maxim Integrated Products 1

1

3

4

10

+

8

7

OUT1

V

CC

RS2+

RS1+

MAX6603

29

OUT2RS2-

56

GNDRS1-

TDFN

3mm x 3mm x 0.8mm

TOP VIEW

DG2

DG1

Pin Configuration

Ordering Information

19-3975; Rev 0; 4/06

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.

PART PIN-PACKAGE

PKG

CODE

MAX6603ATB+ 10 TDFN-EP*

T1033-1

EVALUATION KIT

AVAILABLE

Note: Device is specified over the -40°C to +125°C tempera-

ture range.

*EP = Exposed pad.
+Denotes lead-free package.
**Other base resistance values can be accommodated.

Contact the factory for more information.

RTD

200Ω**

MAX6603

Dual-Channel, Platinum RTD-to-Voltage
Signal Conditioner

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= 3.0V to 5.5V, resistor connected between RS1+ and RS1- = 560Ω, resistor connected between RS2+ and RS2- = 560Ω,
T

A

= -40°C to +125°C, unless otherwise noted. Typical values are at VCC= 5.0V, RL= 47kΩ between OUT_ and GND, TA= +25°C.)

(Note 1)

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.

(All voltages referenced to GND, unless otherwise noted.)
V

CC

........................................................................-0.3V to +6.0V

RS1+, RS1-, RS2+, RS2- .....................................-0.3V to +18.0V

OUT1, OUT2, DG1, DG2 ............................-0.3V to (V

CC

+ 0.3V)

Continuous Power Dissipation (T

A

= +70°C)
10-Pin TDFN Single-Layer Board

(derate 18.5 mW/°C above +70°C).........................1481.5mW

10-Pin TDFN Multilayer Board

(derate 24.4 mW/°C above +70°C).........................1951.2mW

ESD Protection (OUT1, OUT2, DG1, DG2,

Human Body Model) .....................................................> ±2kV

ESD Protection (RS1+, RS2+, RS1-, RS2-,

V

CC

, GND, Human Body Model) ..................................> ±5kV

Operating Temperature Range .........................-40°C to +125°C

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

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

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

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Supply Voltage V

CC

3.0 5.5 V

Input Over Voltage V

RS

RS1+, RS1-, RS2+, RS2- 16 V

3.9 5.5

Supply Current I

CC

Sink current during overvoltage fault

mA

CURRENT SOURCES

Excitation Current I

EXC

(Note 2)

1.0

mA

Excitation-Current Temperature
Coefficient

TCI

EXC

(Note 2) -7

ppm/°C

Minimum RS_- Voltage V

RS_-

3.4 V

Maximum RS_+ Voltage V

RS_+

4.0 V

Supply Ratiometric I

RATIO

VCC = +3V to +5.5V 0.2

mA/V

MAXIMUM TEMPERATURE ERROR (Note 3)

+400°C to +600°C, VCC = 5.0V ±6

-40°C to +400°C, VCC = 5.0V ±8

+600°C to +1000°C, VCC = 5.0V ±12

+400°C to +600°C, VCC = 3.0V ±10

-40°C to +400°C, VCC = 3.0V

RTD

+600°C to +1000°C, VCC = 3.0V ±20

°C

V

= V

RS1+

RS1 -

= V

RS2+

= V

= +16V

RS2-

0.58

36.2 47.1

1.12

±13.3

MAX6603

Dual-Channel, Platinum RTD-to-Voltage

Signal Conditioner

_______________________________________________________________________________________ 3

Note 1: All parameters are tested at TA= +25°C. Specifications over temperature are guaranteed by design.
Note 2: RTD resistance range is 150Ω to 900Ω for constant excitation current.
Note 3: A typical 200Ω RTD: R(T) = R

O

[1 + AT + BT2] is referenced for probe temperature-probe resistance relation. The parame-

ters in this section are not tested and are for reference only.

Note 4: RTD resistance is tested only at R

RTD

= 200Ω, 560Ω, 845Ω. The range is guaranteed by design.

Note 5: Parameters are tested in special test mode.

ELECTRICAL CHARACTERISTICS (continued)

(VCC= 3.0V to 5.5V, resistor connected between RS1+ and RS1- = 560Ω, resistor connected between RS2+ and RS2- = 560Ω,
T

A

= -40°C to +125°C, unless otherwise noted. Typical values are at VCC= 5.0V, RL= 47kΩ between OUT_ and GND, TA= +25°C.)

(Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

MAXIMUM INPUT RESISTANCE-TO-OUTPUT VOLTAGE ERROR

494Ω to 627Ω, VCC = 5.0V 19

200Ω to 494Ω, VCC = 5.0V 27

627Ω to 866Ω, VCC = 5.0V 33

494Ω to 627Ω, VCC = 3.0V 19

200Ω to 494Ω, VCC = 3.0V 27

RTD (Note 4)

627Ω to 866Ω, VCC = 3.0V 33

mV

ANALOG OUTPUTS (OUT1, OUT2)

Output-Voltage Low (Max) V

OL

RL = 47kΩ between OUT_ and V

CC

(Note 5)

0.1 V

Output-Voltage High (Min) V

OH

RL = 47kΩ between OUT_ and GND
(Note 5)

VCC -

0.1

V

V

OUT

= V

CC

22 mA

Short-Circuit Current I

SC

V

OUT

= GND 12 mA

Maximum Capacitive Load C

L

500 pF

Minimum Resistive Load R

L

Between OUT_ and GND 20 kΩ

DIAGNOSTIC OUTPUTS (DG1, DG2)

Output-Voltage Low V

OL

I

SOURCE

= 1mA 0.2 V

Output-Voltage High V

OH

I

SINK

= 1mA

V

CC

-

0.2

V

Minimum Resistance for RS+,
RS - Open

Ω

Maximum Resistance for RS+,
RS - Short

60 Ω

R

RS - OPEN

R

RS - SHORT

8000

MAX6603

Dual-Channel, Platinum RTD-to-Voltage
Signal Conditioner

4 _______________________________________________________________________________________

Typical Operating Characteristics

(VCC= 5.0V, TA= +25°C, unless otherwise noted.)

2.0

2.6

2.3

3.2

2.9

3.5

3.8

3.0 5.5

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX6603 toc01

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (mA)

4.03.5 4.5 5.0

TA = -40°C

TA = 0°C

TA = +125°C

TA = +85°C

TA = +25°C

-20

10

0

-10

20

-40 -10 20 50 80 110

OUTPUT-VOLTAGE DRIFT

vs. TEMPERATURE

MAX6603 toc02

TEMPERATURE (°C)

OUTPUT-VOLTAGE DRIFT (mV)

POWER-SUPPLY REJECTION RATIO

vs. FREQUENCY

MAX6603 toc03

FREQUENCY (kHz)

PSRR (dB)

100.0010.001.000.10

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

-100

0.01 1000.00

0

1

3

2

4

5

OUTPUT VOLTAGE

vs. RTD RESISTANCE

MAX6603 toc04

RTD RESISTANCE (Ω)

OUTPUT VOLTAGE (V)

100 500300 700 900

TA = 25°C

MAX6603

Dual-Channel, Platinum RTD-to-Voltage

Signal Conditioner

_______________________________________________________________________________________ 5

Detailed Description

The MAX6603 converts a Deutsche Institute for Normung
(DIN) standard 200Ω Pt RTD to a high-level analog volt­age without the need for external trims or precise dis­crete components. The Pt RTD resistance conveys
temperature information approximated by the Callendar­Van Dusen equation and is represented in Figure 1:

R(T) = R

O

[1 + AT + BT2+ CT3]

where: R(T) = Resistance of Pt RTD at temperature (T)

R0= Base resistance in ohms at 0°C

T = Temperature in °C

A = 3.9083 E-3 °C-1(alpha coefficient 1)

B = -5.7750 E-7 °C

-2

(alpha coefficient 2)

C = 0 (approximation for temperatures > 0°C)

(Alpha coefficients can vary depending on
standards.)

The MAX6603 applies a constant excitation current of
1mA (typ) through the Pt RTD, generating a voltage
drop that is amplified and results in a high-level output
voltage. The excitation current (I

EXC

) typically varies
ratiometrically by 0.2mA/V (typ) with respect to VCC,
and therefore, the amplified signal is ratiometric to the
power supply. The voltage amplification from input to
output is 5 (typ). The output voltage is applied to a
ratiometric ADC to produce a digital value independent
of supply voltage. For ADCs that use VCCas their refer­ence voltage, sudden changes in the supply voltage do
not affect the microcontroller’s reading of the tempera­ture. Ratiometricity simplifies the connection to most

Pin Description

PIN NAME FUNCTION

1VCCPower-Supply Input. Bypass to GND with a 0.1µF capacitor as close to VCC as possible.

2 RS2- Sense Resistor 2 Negative Input

3 RS2+ Sense Resistor 2 Positive Input

4 RS1+ Sense Resistor 1 Positive Input

5 RS1- Sense Resistor 1 Negative Input

6 GND Ground
7 DG1 Diagnostic Output Signal 1. DG1 asserts low upon fault detection.
8 OUT1 Output Analog Voltage 1. OUT1 is high impedance upon DG1 assertion.
9 OUT2 Output Analog Voltage 2. OUT2 is high impedance upon DG2 assertion.

10 DG2 Diagnostic Output Signal 2. DG2 asserts low upon fault detection.

—EPExposed Pad. Connect to GND.

Functional Block Diagram

MAX6603

RS1+

RS1-

OUT1

AMP

FAULT

DETECT

DG1

HI-V

DETECT

I

EXC

ESD

CLAMP

ESD

CLAMP

V

CC

R

SRC

RS2+

RS2-

OUT2

AMP

FAULT

DETECT

DG2

HI-V

DETECT

I

EXC

ESD

CLAMP

ESD

CLAMP

V

CC

R

SRC

V

CC

GND

MAX6603

Dual-Channel, Platinum RTD-to-Voltage
Signal Conditioner

6 _______________________________________________________________________________________

microcontrollers that incorporate an ADC and enables a
low-cost, low-complexity solution. Ratiometricity is an
important consideration for battery-operated instru­ments, automotive, and some industrial applications.

Temperature Information

The MAX6603 measures the resistance between the
RTD and translates that into a high-level output voltage.
The resistance range of the MAX6603 is between 150Ω
and 900Ω, covering a -40°C to +1000°C temperature
range. When R(T) goes too low or too high, a fault con­dition is asserted and the respective DG_ goes low.

Output Voltage

The following equation describes the output voltage:

where:

VCC= supply voltage
R(T) = RTD resistance given by Callendar­Van Dusen equation.

Using Other Pt RTDs

The MAX6603 is designed for a 200Ω Pt RTD, but the
device can work with any RTD as long as the resistance
is in the 150Ω to 900Ω range. A 500Ω Pt RTD can be
used for temperatures up to +208°C because that tem-
perature results in R(T) = 900Ω.

Input Overvoltage Protection to +16V

The input pins RS1+, RS1-, RS2+, and RS2- protect the
MAX6603 from overvoltage conditions up to +16V with­out damaging the device.

Diagnostic Outputs (

DG1, DG2

)

The MAX6603 continuously monitors the excitation
current to the RTD, the resultant voltage drop, and
voltage levels of the inputs to detect fault conditions.
Any fault condition causes the respective DG output to
assert low. Fault conditions occur for RTD open circuits;
RTD short circuits; and RS1+, RS1-, RS2+, and RS2­short to ground or supply. If any fault is detected, the
respective DG output asserts low. OUT1 and OUT2 are
high impedance on assertion of DG1 and DG2, respec-
tively. An example circuit showing potential fault condi­tions is shown in Figure 2.

Applications Information

Ratiometric Output Coupled to a

Microcontroller

The circuit of Figure 3 shows the MAX6603 connected to
the microcontroller using V

CC

as the ADC reference volt­age. The output is ratiometric to VCC, and temperature
measurements are independent of the supply voltage.

Chip Information

PROCESS: BiCMOS

V

VR

1

OUT

CC

=

× ()T

000

0

300

200

100

400

500

600

700

800

900

1000

0 400200 600 800 1000

200Ω Pt RTD

TEMPERATURE (°C)

RESISTANCE (Ω)

Figure 1. Typical 200Ω Pt RTD Representation by the
Simplified Callender-Van Dusen Equation

MAX6603

Dual-Channel, Platinum RTD-to-Voltage

Signal Conditioner

_______________________________________________________________________________________ 7

MAX6603

RS1+

RS1-

OUT1

AMP

FAULT

DETECT

DG1

HI-V

DETECT

I

EXC

ESD

CLAMP

ESD

CLAMP

V

CC

R

SRC

RS2+

RS2-

OUT2

AMP

FAULT

DETECT

DG2

HI-V

DETECT

I

EXC

ESD

CLAMP

ESD

CLAMP

V

CC

R

SRC

V

CC

GND

0.1µF 0.1µF

OUT1

ADC2

INPUT2

ADC1

INPUT1

+5V

V

CC

ADC-REF

±5kV ESD

SHORT TOGETHEROPEN

OPEN

SHORT TO BAT

(16V)

SHORT TO BAT

(16V)

SHORT TO GND

SHORT TO GND

RTD SENSOR

CHASSIS GND

MICROCONTROLLER

Figure 2. The various fault conditions that cause the diagnostic output to assert low are shown for a single channel.

MAX6603

Dual-Channel, Platinum RTD-to-Voltage
Signal Conditioner

8 _______________________________________________________________________________________

MAX6603

RS1+

RS1-

RS2+

RS2-

OUT1

AMP

FAULT

DETECT

DG1

HI-V

DETECT

I

EXC

ESD

CLAMP

ESD

CLAMP

V

CC

R

SRC

OUT2

AMP

FAULT

DETECT

DG2

HI-V

DETECT

I

EXC

ESD

CLAMP

ESD

CLAMP

V

CC

R

SRC

V

CC

GND

0.1µF 0.1µF

OUT1

ADC2

INPUT2

ADC1

INPUT1

+5V

ADC-REF

MICROCONTROLLER

Pt RTD PROBE

Pt RTD PROBE

CONNECTOR

CONNECTOR

Figure 3. A Typical Application Circuit with Ratiometric Output Coupled to Ratiometric Microcontroller ADC

MAX6603

Dual-Channel, Platinum RTD-to-Voltage

Signal Conditioner

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 9

© 2006 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.

6, 8, &10L, DFN THIN.EPS

COMMON DIMENSIONS

SYMBOL MIN. MAX.

A 0.70 0.80

D 2.90 3.10

E 2.90 3.10

A1 0.00 0.05

L 0.20 0.40

PKG. CODE N D2 E2 e JEDEC SPEC b

[(N/2)-1] x e

PACKAGE VARIATIONS

0.25 MIN.k

A2 0.20 REF.

2.00 REF0.25±0.050.50 BSC2.30±0.1010T1033-1

2.40 REF0.20±0.05- - - - 0.40 BSC1.70±0.10 2.30±0.1014T1433-1

1.50±0.10 MO229 / WEED-3

0.40 BSC - - - - 0.20±0.05 2.40 REFT1433-2 14 2.30±0.101.70±0.10

T633-2 6 1.50±0.10 2.30±0.10 0.95 BSC MO229 / WEEA 0.40±0.05 1.90 REF

T833-2 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF

T833-3 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF

2.30±0.10 MO229 / WEED-3 2.00 REF0.25±0.050.50 BSC1.50±0.1010T1033-2

Package Information

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages

.)