ltz1000a Linear Technology Corporation, ltz1000a Datasheet - Page 5

• Manufacturer Part Number: ltz1000a
• Description: Ultra Precision Reference
• Manufacturer: Linear Technology Corporation

Setting Control Temperature
The emitter-base voltage of the control transistor sets the
stabilization temperature for the LTZ1000. With the values
given in the applications, temperature is normally 60°C.
This provides 15°C of margin above a maximum ambient
of 45°C, for example. Production variations in emitter-base
voltage will typically cause about ±10°C variation. Since
the emitter-base voltage changes about 2mV/°C and is
very predictable, other temperatures are easily set.
Because higher temperatures accelerate aging and decrease
long-term stability, the lowest temperature consistent with
the operating environment should be used. The LTZ1000A
should be set about 10°C higher than the LTZ1000. This
is because normal operating power dissipation in the
TYPICAL APPLICATIONS
APPLICATIONS INFORMATION
*PROVIDE TEMPERATURE COMPENSATION, DELETE FOR LTZ1000A
APPROXIMATE CHANGE IN REFERENCE VOLTAGE FOR A 100ppm CHANGE IN RESISTOR VALUES:
BOTH A1 AND A2 CONTRIBUTE LESS THAN 2μV OF OUTPUT DRIFT OVER A 50°C RANGE
1
2
R4/R5 RATIO
2N3904
R1
R2
R3
1k
100ppm = R(Ω)
R = 0.01%
0.012Ω
7
7Ω
7Ω
LT1013
+
–
5
6
0.3ppm
0.2ppm
1ppm
1ppm
1M
V
Negative Voltage Reference
Z
0.1μF
0.1μF
400k*
10k
R5
1k
R4
13k
8
R3
70k
LTZ1000A causes a temperature rise of about 10°C. Of
course both types of devices should be insulated from
ambient. Several minutes of warm-up is usual.
For applications not requiring the extreme precision or
the low noise of the LTZ1000, Linear Technology makes a
broad line of voltage references. Devices like the LT1021
can provide drifts as low as 2ppm/°C and devices such as
the LM399A can provide drifts of 1ppm/°C. Only applica-
tions requiring the very low noise or low drift with time
of the LTZ1000 should use this device. See Application
Notes AN-82 and AN-86 for further information. Consult
the Linear Technology Applications department for ad-
ditional help.
3
4
R1
120
7
5
R2
70k
0.022μF
2
3
LTZ1000/LTZ1000A
–
+
LT1013
V
–
≥ 10V
8
4
1
1N4148
V
GND
ZENER + SENSE
ZENER – FORCE
ZENER – SENSE
+
15V
1000 TA02
1000afc
5