Texas Instruments 1.6 V, LLP-6, Temperature Switch and Temperature Sensor Evaluation Board LM26LVEB/NOPB LM26LVEB/NOPB 데이터 시트
제품 코드
LM26LVEB/NOPB
[ ]
T
J
= T
A
+
T
JA
(V
DD
I
Q
) + (V
DD
- V
TEMP
) I
L
SNIS144F – JULY 2007 – REVISED FEBRUARY 2013
C
LOAD
Minimum R
S
1.1 nF to 99 nF
3 k
Ω
100 nF to 999 nF
1.5 k
Ω
1
μ
F
800
Ω
VOLTAGE SHIFT
The LM26LV/LM26LV-Q1 is very linear over temperature and supply voltage range. Due to the intrinsic behavior
of an NMOS/PMOS rail-to-rail buffer, a slight shift in the output can occur when the supply voltage is ramped
over the operating range of the device. The location of the shift is determined by the relative levels of V
of an NMOS/PMOS rail-to-rail buffer, a slight shift in the output can occur when the supply voltage is ramped
over the operating range of the device. The location of the shift is determined by the relative levels of V
DD
and
V
TEMP
. The shift typically occurs when V
DD
−
V
TEMP
= 1.0V.
This slight shift (a few millivolts) takes place over a wide change (approximately 200 mV) in V
DD
or V
TEMP
. Since
the shift takes place over a wide temperature change of 5°C to 20°C, V
TEMP
is always monotonic. The accuracy
specifications in the
table already includes this possible shift.
Mounting and Temperature Conductivity
The LM26LV/LM26LV-Q1 can be applied easily in the same way as other integrated-circuit temperature sensors.
It can be glued or cemented to a surface.
It can be glued or cemented to a surface.
The best thermal conductivity between the device and the PCB is achieved by soldering the DAP of the package
to the thermal pad on the PCB. The temperatures of the lands and traces to the other leads of the
LM26LV/LM26LV-Q1 will also affect the temperature reading.
to the thermal pad on the PCB. The temperatures of the lands and traces to the other leads of the
LM26LV/LM26LV-Q1 will also affect the temperature reading.
Alternatively, the LM26LV/LM26LV-Q1 can be mounted inside a sealed-end metal tube, and can then be dipped
into a bath or screwed into a threaded hole in a tank. As with any IC, the LM26LV/LM26LV-Q1 and
accompanying wiring and circuits must be kept insulated and dry, to avoid leakage and corrosion. This is
especially true if the circuit may operate at cold temperatures where condensation can occur. If moisture creates
a short circuit from the V
into a bath or screwed into a threaded hole in a tank. As with any IC, the LM26LV/LM26LV-Q1 and
accompanying wiring and circuits must be kept insulated and dry, to avoid leakage and corrosion. This is
especially true if the circuit may operate at cold temperatures where condensation can occur. If moisture creates
a short circuit from the V
TEMP
output to ground or V
DD
, the V
TEMP
output from the LM26LV/LM26LV-Q1 will not be
correct. Printed-circuit coatings are often used to ensure that moisture cannot corrode the leads or circuit traces.
The thermal resistance junction-to-ambient (
θ
JA
) is the parameter used to calculate the rise of a device junction
temperature due to its power dissipation. The equation used to calculate the rise in the LM26LV/LM26LV-Q1's
die temperature is
die temperature is
(9)
where T
A
is the ambient temperature, I
Q
is the quiescent current, I
L
is the load current on the output, and V
O
is
the output voltage. For example, in an application where T
A
= 30 °C, V
DD
= 5 V, I
DD
= 9
μ
A, Gain 4, V
TEMP
= 2231
mV, and I
L
= 2
μ
A, the junction temperature would be 30.021 °C, showing a self-heating error of only 0.021°C.
Since the LM26LV/LM26LV-Q1's junction temperature is the actual temperature being measured, care should be
taken to minimize the load current that the V
taken to minimize the load current that the V
TEMP
output is required to drive. If The OVERTEMP output is used
with a 100 k pull-up resistor, and this output is asserted (low), then for this example the additional contribution is
[(152° C/W)x(5V)
[(152° C/W)x(5V)
2
/100k] = 0.038°C for a total self-heating error of 0.059°C.
shows the thermal resistance
of the LM26LV/LM26LV-Q1.
Table 2. LM26LV/LM26LV-Q1 Thermal Resistance
Device Number
NS Package Number
Thermal Resistance (
θ
JA
)
LM26LVCSID/LM26LVQCISD
NGF0006A
152° C/W
20
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