TMP411CD datasheet(7/32 Pages) TI

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TMP411

SBOS383C − DECEMBER 2006 − REVISED MAY 2008

www.ti.com

SERIES RESISTANCE CANCELLATION

Series resistance in an application circuit that typically

results from printed circuit board (PCB) trace resistance

and remote line length (see Figure 11) is automatically

cancelled by the TMP411, preventing what would

otherwise result in a temperature offset.

A total of up to 3k

Ω of series line resistance is cancelled

by the TMP411, eliminating the need for additional

characterization and temperature offset correction.

See the two Remote Temperature Error vs Series

Resistance typical characteristics curves for details on the

effect of series resistance and power-supply voltage on

sensed remote temperature error.

DIFFERENTIAL INPUT CAPACITANCE

The TMP411 tolerates differential input capacitance of up

to 1000pF with minimal change in temperature error. The

effect of capacitance on sensed remote temperature error

is illustrated in typical characteristic Remote Temperature

Error vs Differential Capacitance. (Figure 6).

TEMPERATURE MEASUREMENT DATA

Temperature measurement data are taken over a default

range of 0

°C to +127°C for both local and remote locations.

Measurements from −55

°C to +150°C can be made both

locally and remotely by reconfiguring the TMP411 for the

extended temperature range. To change the TMP411

configuration

from

the

standard

the

extended

temperature range, switch bit 2 (RANGE) of the

Configuration Register from low to high.

Temperature data resulting from conversions within the

default measurement range are represented in binary

form, as shown in Table 1, Standard Binary column. Note

that any temperature below 0

°C results in a data value of

zero (00h). Likewise, temperatures above +127

°C result in

a value of 127 (7Fh). The device can be set to measure

over an extended temperature range by changing bit 2 of

the Configuration Register from low to high. The change in

measurement range and data format from standard binary

to extended binary occurs at the next temperature

conversion.

For

data

captured

the

extended

temperature range configuration, an offset of 64 (40h) is

added to the standard binary value, as shown in Table 1,

Extended Binary column. This configuration allows

measurement of temperatures below 0

°C. Note that binary

values corresponding to temperatures as low as −64

°C,

and as high as +191

°C are possible; however, most

temperature sensing diodes only measure with the range

of −55

°C to +150°C. Additionally, the TMP411 is rated only

for ambient local temperatures ranging from −40

°C to

+125

°C. Parameters in the Absolute Maximum Ratings

table must be observed.

Table 1. Temperature Data Format

(Local and Remote Temperature High Bytes)

LOCAL/REMOTE TEMPERATURE REGISTER

HIGH BYTE VALUE (+1

°C RESOLUTION)

TEMP

STANDARD BINARY

EXTENDED BINARY

TEMP

(

°C)

BINARY

HEX

BINARY

HEX

−64

0000 0000

−50

0000 0000

0000 1110

−25

0000 0000

0010 0111

0000 0000

0100 0000

0000 0001

0100 0001

0000 0101

0100 0101

0000 1010

0100 1010

0001 1001

0101 1001

0011 0010

0111 0010

0100 1011

1000 1011

100

0110 0100

1010 0100

125

0111 1101

1011 1101

127

0111 1111

1011 1111

150

0111 1111

1101 0110

175

0111 1111

1110 1111

191

0111 1111

1111 1111

NOTE: Whenever changing between standard and

extended temperature ranges, be aware that the

temperatures stored in the temperature limit registers are

NOT automatically reformatted to correspond to the new

temperature range format. These temperature limit values

must be reprogrammed in the appropriate binary or

extended binary format.

Both local and remote temperature data use two bytes for

data storage. The high byte stores the temperature with

°C resolution. The second or low byte stores the decimal

fraction value of the temperature and allows a higher

measurement resolution; see Table 2. The measurement

resolution for the remote channel is 0.0625

°C, and is not

adjustable. The measurement resolution for the local

channel is adjustable; it can be set for 0.5

°C, 0.25°C,

0.125

°C, or 0.0625°C by setting the RES1 and RES0 bits

of the Resolution Register; see the Resolution Register

section.

TMP411CD Datasheet(PDF) 7 Page - Texas Instruments

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