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ONE-SHOT CONVERSION

CONFIGURATION REGISTER 2

CONVERSION RATE REGISTER

TMP441

TMP442

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.............................................................................................................................................. SBOS425A – DECEMBER 2008 – REVISED MARCH 2009

The LEN bit enables the local temperature

measurement channel. If LEN = '1', the local channel

When the TMP441/42 are in shutdown mode (SD = 1

is enabled; if LEN = '0', the local channel is disabled.

in the Configuration Register 1), a single conversion

can start on all enabled channels by writing any value The REN bit enables external temperature

to the One-Shot Start Register, pointer address 0Fh. measurement channel 1 (connected to pins 1 and 2.)

This write operation starts one conversion; the If REN = '1', the external channel is enabled; if REN =

TMP441/42 return to shutdown mode when that '0', the external channel is disabled.

conversion completes. The value of the data sent in

For the TMP442 only, the REN2 bit enables the

the write command is irrelevant and is not stored by

second external measurement channel (connected to

the TMP441/42. When the TMP441/42 are in

pins 3 and 4.) If REN2 = '1', the second external

shutdown mode, the conversion sequence currently

channel is enabled; if REN2 = '0', the second external

in process must be completed before a one-shot

channel is disabled.

command can be issued. One-shot commands issued

during a conversion are ignored.

The temperature measurement sequence is local

channel, external channel 1, external channel 2,

shutdown, and delay (to set conversion rate, if

necessary). The sequence starts over with the local

Configuration Register 2 (pointer address 0Ah)

channel. If any of the channels are disabled, they are

controls which temperature measurement channels

skipped in the sequence. Table 6 summarizes the

are enabled and whether the external channels have

bits of Configuration Register 2.

the resistance correction feature enabled or not.

The RC bit enables the resistance correction feature

for the external temperature channels. If RC = '1',

The Conversion Rate Register (pointer address 0Bh)

series resistance correction is enabled; if RC = '0',

controls the rate at which temperature conversions

resistance correction is disabled. Resistance

are performed. This register adjusts the idle time

correction should be enabled for most applications.

between conversions but not the conversion timing

However, disabling the resistance correction may

itself, thereby allowing the TMP441/42 power

yield slightly improved temperature measurement

dissipation to be balanced with the temperature

noise performance, and reduce conversion time by

about 50%, which could lower power consumption

rate options and corresponding current consumption.

when conversion rates of two per second or less are

A one-shot command can be used during the idle

selected.

time between conversions to immediately start

temperature conversions on all enabled channels.

Table 6. Configuration Register 2 Bit Descriptions

CONFIGURATION REGISTER 2 (Read/Write = 0Ah, POR = 1Ch for TMP441; 3Ch for TMP442)

BIT NAME FUNCTION POWER-ON RESET VALUE

7, 6 Reserved — 0

0 = External channel 2 disabled 1 (TMP442)

5 REN2

1 = External channel 2 enabled 0 (TMP441)

0 = External channel 1 disabled

4 REN 1

1 = External channel 1 enabled

0 = Local channel disabled

3 LEN 1

1 = Local channel enabled

0 = Resistance correction disabled

2 RC 1

1 = Resistance correction enabled

1, 0 Reserved — 0

Product Folder Link(s): TMP441 TMP442