LM26CIM5X-XPA/HALF National Semiconductor, LM26CIM5X-XPA/HALF Datasheet - Page 5

• Manufacturer Part Number: LM26CIM5X-XPA/HALF
• Manufacturer: National Semiconductor

Specifications of LM26CIM5X-XPA/HALF

• Lead Free Status / Rohs Status: Supplier Unconfirmed

Functional Description
LM26 OPTIONS
The LM26 can be factory programmed to have a trip point
anywhere in the range of −55°C to +110°C.
Applications Hints
AFTER-ASSEMBLY PCB TESTING
The LM26's V
by following a simple test procedure. Simply measuring the
V
sembled properly and that its temperature sensing circuitry is
functional. The V
that can be overdriven by 1.5mA. Therefore, one can simply
force the V
state, thereby verifying that the comparator and output cir-
cuitry function after assembly. Here is a sample test proce-
dure that can be used to test the LM26CIM5-TPA which has
an 85°C trip point.
1.
2.
TEMP
Turn on V
temperature reading of the LM26 using the equation:
or
Verify that the temperature measured in step one is
within (±3°C + error of reference temperature sensor) of
the ambient/board temperature. The ambient/board
temperature (reference temperature) should be
measured using an extremely accurate calibrated
temperature sensor.
V
output voltage will verify that the LM26 has been as-
O
= (−3.479×10
TEMP
TEMP
+
and measure V
voltage to cause the digital output to change
TEMP
output allows after-assembly PCB testing
−30)) + 1.8015V
output has very weak drive capability
−6
×(T−30)
LM26-_ _A
LM26-_ _C
TEMP
2
) + (−1.082×10
. Then calculate the
FIGURE 1. Output Pin Options Block Diagrams
−2
×(T
10132312
10132314
(1)
(2)
5
3.
4.
5.
V
The V
40 µA sink). So care should be taken when attaching circuitry
to this pin. Capacitive loading may cause the V
oscillate. Simply adding a resistor in series as shown in Figure
2 will prevent oscillations from occurring. To determine the
value of the resistor follow the guidelines given in Table 1. The
same value resistor will work for either placement of the re-
sistor. If an additional capacitive load is placed directly on the
LM26 output, rather than across C
a factor of 10 smaller than C
TEMP
A.
B.
C. Observe that OS is now low.
D. Release the V
E.
A.
B.
C. When OS goes low, note the V
D. V
E.
A.
B.
TEMP
LOADING
Observe that OS is high.
Drive V
Observe that OS is now high.
Observe that OS is high.
Drive V
Calculate Ttrig using Equation 2.
Gradually raise V
V
Calculate T
TEMP
TEMP
output has very weak drive capability (1 µA source,
Trig = V
.
TEMP
TEMP
HYST
to ground.
voltage down gradually.
LM26-_ _B
LM26-_ _D
TEMP
TEMP
using Equation 2.
TEMP
at OS trigger (HIGH->LOW)
pin.
LOAD
until OS goes HIGH. Note
.
LOAD
, it should be at least
TEMP
voltage.
TEMP
www.national.com
10132315
10132313
output to