Datasheet
REV. C
REF02
–9–
NOTES
1.
2.
3.
REF02 SHOULD BE THERMALLY CONNECTED
TO SUBSTANCE BEING HEATED.
NUMBERS IN PARENTHESES ARE FOR A
SETPOINT TEMPERATURE OF 60 ⴗC.
R3 = R1 R2 R6
HEATING
ELEMENT
(SEE NOTE 1)
V
IN
GND
REF02
V
O
4
6
2
T
3
R1
(9.2k⍀)
CMP02
2
3
8
4
R6
1
7
R7
27k⍀
R2
1.5k⍀
R4
2.7k⍀
R5
2.2k⍀
V+ (12V TO 32V)
R3
1.3k⍀
V+
V–
–
+
Figure 8. Temperature Controller
REFERENCE STACK WITH EXCELLENT LINE
REGULATION
Two REF01s and one REF02 can be stacked to yield 5.000 V,
15.000 V, and 25.000 V outputs. An additional advantage is
near-perfect line regulation of the 5.0 V and 15.0 V output. A
27 V to 55 V input change produces an output change that is
less than the
noise voltage of the devices. A load bypass resistor
(RB) provides a path for the supply current (I
SY
) of the 15.000 V
regulator.
In general, any number of REF01s and REF02s can be stacked
this way. For example, 10 devices will yield 10 outputs in 5 V or
10 V steps.
The line voltage can change from 100 V to 130 V.
However, care must be taken to ensure that the total load currents
do not exceed the maximum usable current (typically 21 mA).
V
IN
GND
REF02
V
O
V
IN
GND
REF02
V
O
V
IN
GND
REF02
V
O
TRIM
TRIM
10k⍀
10k⍀
R
B
6.8k⍀
10k⍀
2
6
5
4
2
6
5
4
2
6
5
4
15.000V
10.000V
5.000V
27V TO 55V
TRIM
Figure 9. Reference Stack
PRECISION CURRENT SOURCE
A current source with 35 V output compliance and excellent
output impedance can be obtained using this circuit. REF02
keeps the line voltage and power dissipation constant in device;
the only important error consideration at room temperature is
the negative supply rejection of the op amp. The typical 3 mV/V
PSRR of the OP02E will create an 20 ppm change (3 mV/V
35 V/5 V) in output current over a 25 V range. For example, a
5 mA current source can be built (R = 1 kW) with 350 MW
output impedance.
V
IN
GND
REF02
V
O
2
6
4
V
IN
GND
REF02
V
O
2
6
4
C
R
(TRIM FOR
CALIBRATION)
C
R
OP02E
2
3
–5V
4
6
7
I
O
=
5V
R
V
O
= 0V TO 35V
50V
R
O
=
35V
20
ⴛ
10
–6
ⴛ
5mA
Figure 10. Precision Current Source
V
IN
GND
TRIM
V
O
REF02
15V
2
6
5
4
R
VOLTAGE COMPLIANCE: –25V TO +8V
I
OUT
I
OUT
= + + 1mA
5V
R
3
TEMP
Figure 11. Current Source
V
IN
GND
TRIM
V
O
REF02
I
OUT
2
6
5
4
R
VOLTAGE COMPLIANCE: –8V TO +25V
I
OUT
= + + 1mA
5V
R
–15V
3
TEMP
Figure 12. Current Sink