TMP05 Analog Devices, TMP05 Datasheet - Page 14

• Manufacturer Part Number: TMP05
• Description: 0.5C Accurate PWM Temperature Sensor in 5-Lead SC-70
• Manufacturer: Analog Devices

TMP05/TMP06
One Shot Mode
In one shot mode, the TMP05/TMP06 output one square wave
representing temperature when requested by the microcon-
troller. The microcontroller pulls the OUT pin low and then
releases it to indicate to the TMP05/TMP06 that an output is
required. The temperature measurement is output when the
OUT line is released by the microcontroller (see Figure 23).
In the TMP05 one shot mode only, an internal resistor is
switched in series with the pull-up MOSFET. The TMP05 OUT
pin has a push-pull output configuration (see Figure 24), and,
therefore, needs a series resistor to limit the current drawn on
this pin when the user pulls it low to start a temperature
conversion. This series resistance prevents any short circuit
from V
short-circuit damage.
The advantages of the one shot mode include lower average
power consumption, and the microcontroller knows that the
first low-to-high transition occurs after the microcontroller
releases the OUT pin.
T 0
DD
Figure 24. TMP05 One Shot Mode OUT Pin Configuration
µ
OUT LINE HERE
CONTROLLER PULLS DOWN
to GND, and, therefore, protects the TMP05 from
Figure 23. TMP05/TMP06 One Shot OUT Pin Signal
TMP05
5kΩ
TEMP MEASUREMENT
T
V+
H
TIME
µ
OUT LINE HERE
CONTROLLER RELEASES
T
L
OUT
Rev. 0 | Page 14 of 28
Conversion Rate
In continuously converting and one shot modes, the state of the
CONV/IN pin on power-up determines the rate at which the
TMP05/TMP06 measure temperature. The available conversion
rates are shown in Table 7.
Table 7. Conversion Rates
CONV/IN Pin
Low
Floating
High
The TMP05 (push-pull output) advantage when using the high
state conversion rate (double high/quarter low) is lower power
consumption. However, the trade-off is loss of resolution on the
low time. Depending on the state of the CONV/IN pin, two
different temperature equations must be used.
The temperature equation for the low and floating states’
conversion rates is
Table 8. Conversion Times Using Equation 2
Temperature (°C)
–40
–30
–20
–10
0
10
20
25
30
40
50
60
70
80
90
100
110
120
130
140
150
Temperature (°C) = 421 − (751 × (T
Conversion Rate
Quarter period
Nominal
Double high (T
T
65.2
66.6
68.1
69.7
71.4
73.1
74.9
75.9
76.8
78.8
81
83.2
85.6
88.1
90.8
93.6
96.6
99.8
103.2
106.9
110.8
L
(T
Quarter low (T
(ms)
H
÷ 4, T
L
÷ 4)
H
x 2)
Nominal Cycle Time (ms)
105
107
108
110
111
113
115
116
117
119
121
123
126
128
131
134
137
140
143
147
151
L
÷ 4)
H
/T
L
))
T
10/19 (ms)
40/76 (ms)
80/19 (ms)
H
/T
L
(25°C)
(2)