LM334S8 Linear Technology, LM334S8 Datasheet - Page 7

• Manufacturer Part Number: LM334S8
• Description: IC CURRENT SOURCE 8SOIC
• Manufacturer: Linear Technology

Specifications of LM334S8

• Function: Current Source
• Voltage - Input: 0.8 ~ 40 V
• Current - Output: 10mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Accuracy: -
• Sensing Method: -

APPLICATIO S I FOR ATIO
The two trims shown in Figure 3 are still intended to be a
“one point” temperature calibration, where the zero and
the slope are trimmed at a single temperature. The LT1009
reference is adjusted to give 2.700V at node “a” at T
= 25 C. The 1k trimmer then adjusts the output for 0.25V,
completing the calibration. If the calibration is to be done
at a temperature other than 25 C , trim the LT1009 for
2.7025—(1 A)[T
adjust the 1k trimmer for proper output.
TYPICAL APPLICATIO S
10mV/ C
OUTPUT
I
Figure 3. Centigrade Temperature Sensor
SET
Basic 2-Terminal
Current Source
LM334
“a”
V
–15V
S
SENSOR
–V
V
IN
IN
4V
U
V
V
1k
SLOPE
ADJ
9.53k
1%
10k
100
+
–
R
( C)](100 ) at node “a”, then
U
LT1009
ZERO
134 TA02
ADJ
10k
R
SET
U
W
V
V
+
–
*OUTPUT IMPEDANCE OF THE LM134 AT THE “R” PIN IS
APPROXIMATELY
EXTERNAL RESISTANCE CONNECTED TO THE V
NEGATIVE RESISTANCE CAN BE REDUCED BY A FACTOR OF
5 OR MORE BY INSERTING AN EQUIVALENT RESISTOR IN
SERIES WITH THE OUTPUT.
R
LM134-3
R
226
134 F03
LM334
0.1 F
SET
Low Output Impedance
Thermometer (Kelvin Output)
U
C1
V
SENSOR
IN
–R
16
4.8V
O
V
V
+
–
, WHERE R
R
If higher accuracy is required, a two point calibration
technique can be used. In Figure 4, separate zero and slope
trims are provided. Residual nonlinearity is now the limi-
tation on accuracy. Nonlinearity of the LM134 in a 100 C
span is typically less than 0.5 C. This particular method of
trimming has the advantage that the slope trim does not
interact with the zero trim. Trim procedure is to adjust for
zero output with T
output at some convenient second temperature. No fur-
ther trimming is required.
600
R1
230
1%
R2
10k
1%
R3*
*LOW TC, STABLE RESISTOR
226 *
O
LM134-3
Figure 4. Centigrade Temperature Sensor with 2 Point Trim
IS THE EQUIVALENT
V
Z
OUT
OUT
R
–
= 10mV/ K
PIN. THIS
134 TA03
100
V
V
+
–
SENSOR
Zero Temperature
Coefficient Current Source
= 0 C, then trim slope for proper
SLOPE
*SELECT RATIO OF R1 TO R
LM334
1N457
TRIM
OBTAIN ZERO DRIFT. I
500k
D1
V
+
V
LM134 Series
–V
V
+
IN
5V
50k
IN
V
–
R
–15V
I
+
SET
R
332k
1%
LT1009
15k
134 TA04
+
R1*
10 R
2 I
SET
SET
11k*
1%
SET
TO
.
OUTPUT
10mV/ C
ZERO
TRIM
10k
7
134 F04