Datasheet

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SBOS383C − DECEMBER 2006 − REVISED MAY 2008
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13
RESOLUTION REGISTER
The RES1 and RES0 bits (resolution bits 1 and 0) of the
Resolution Register set the resolution of the local
temperature measurement channel. Remote temperature
measurement channel resolution is not affected.
Changing the local channel resolution also affects the
conversion time and rate of the TMP411. The Resolution
Register is set by writing to pointer address 1Ah and is
read by reading from pointer address 1Ah. Table 6 shows
the resolution bits for the Resolution Register.
Table 6. Resolution Register:
Local Channel Programmable Resolution
RESOLUTION REGISTER (Read = 1Ah, Write = 1Ah, POR = 1Ch)
RES1 RES0 RESOLUTION
CONVERSION TIME
(Typical)
0 0 9 Bits (0.5°C) 12.5ms
0 1 10 Bits (0.25°C) 25ms
1 0 11 Bits (0.125°C) 50ms
1 1 12 Bits (0.0625°C) 100ms
Bits 2 through 4 of the Resolution Register must always be
set to ‘1’. Bits 5 through 7 of the Resolution Register must
always be set to ‘0’. The power-on reset value of this
register is 1Ch.
CONVERSION RATE REGISTER
The Conversion Rate Register controls the rate at which
temperature conversions are performed. This register
adjusts the idle time between conversions but not the
conversion timing itself, thereby allowing the TMP411
power dissipation to be balanced with the temperature
register update rate. Table 7 shows the conversion rate
options and corresponding current consumption.
ONE-SHOT CONVERSION
When the TMP411 is in shutdown mode (SD = 1 in the
Configuration Register), a single conversion on both
channels is started by writing any value to the One-Shot
Start Register, pointer address 0Fh. This write operation
starts one conversion; the TMP411 returns to shutdown
mode when that conversion completes. The value of the
data sent in the write command is irrelevant and is not
stored by the TMP411. When the TMP411 is in shutdown
mode, an initial 200µs is required before a one-shot
command can be given. (Note: When a shutdown
command is issued, the TMP411 completes the current
conversion before shutting down.) This wait time only
applies to the 200µs immediately following shutdown.
One-shot commands can be issued without delay
thereafter.
Table 7. Conversion Rate Register
CONVERSION RATE REGISTER (Read = 04h, Write = 0Ah, POR = 08h)
AVERAGE I
Q
(TYP)
(µA)
R7 R6 R5 R4 R3 R2 R1 R0 CONVERSION/SEC
V
S
= 2.7V V
S
= 5.5V
0 0 0 0 0 0 0 0 0.0625 11 32
0 0 0 0 0 0 0 1 0.125 17 38
0 0 0 0 0 0 1 0 0.25 28 49
0 0 0 0 0 0 1 1 0.5 47 69
0 0 0 0 0 1 0 0 1 80 103
0 0 0 0 0 1 0 1 2 128 155
0 0 0 0 0 1 1 0 4 190 220
07h to 0Fh 8 373 413