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| 型號(hào)： | LTZ1000ACH |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | Ultra Precision Reference |
| 中文描述： | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 7.15 V, MBCY8 |
| 封裝： | 0.200 INCH, METAL CAN, TO-5, 8 PIN |
| 文件頁數(shù)： | 4/8頁 |
| 文件大?。?/td> | 136K |
| 代理商： | LTZ1000ACH |
LTZ1000/LTZ1000A
4
1000afb
APPLICATIONS INFORMATION
LTZ1000 and LTZ1000A are capable of providing ultimate
voltage reference performance. Temperature drifts of better
than 0.03ppm/°C and long term stability on the order of
1μV per month can be achieved. Noise of about 0.15ppm
can also be obtained. This performance is at the expense
of circuit complexity, since external influences can easily
cause output voltage shifts of more than 1ppm.
Thermocouple effects are one of the worst problems and
can give apparent drifts of many ppm/°C as well as cause
low frequency noise. The kovar input leads of the TO-5
package form thermocouples when connected to copper
PC boards. These thermocouples generate outputs of
35μV/°C. It is mandatory to keep the zener and transistor
leads at the same temperature, otherwise 1ppm to 5ppm
shifts in the output voltage can easily be expected from
these thermocouples.
Air currents blowing across the leads can also cause small
temperature variations, especially since the package is
heated. This will look like 1ppm to 5ppm of low frequency
noise occurring over a several minute period. For best
results, the device should be located in an enclosed area
and well shielded from air currents.
Certainly, any temperature gradient externally generated,
say from a power supply, should not appear across the
critical circuitry. The leads to the transistor and zener
should be connected to equal size PC traces to equalize
the heat loss and maintain them at similar temperatures.
The bottom portion of the PC board should be shielded
against air currents as well.
Resistors, as well as having resistance temperature coef-
ficients, can generate thermocouple effects. Some types of
resistors can generate hundreds of microvolts of thermo-
couple voltage. These thermocouple effects in the resistor
can also interfere with the output voltage. Wire wound
resistors usually have the lowest thermocouple voltage,
while tin oxide type resistors have very high thermocouple
voltage. Film resistors, especially Vishay precision film
resistors, can have low thermocouple voltage.
Ordinary breadboarding techniques are not good enough
to give stable output voltage with the LTZ1000 family
devices. For breadboarding, it is suggested that a small
printed circuit board be made up using the reference, the
amplifier and wire wound resistors. Care must be taken to
ensure that heater current does not flow through the same
ground lead as the negative side of the reference (emitter
of Q1). Current changes in the heater could add to, or
subtract from, the reference voltage causing errors with
temperature. Single point grounding using low resistance
wiring is suggested.
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
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.
相關(guān)PDF資料 |
PDF描述 |
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| LTZ1000CH | Ultra Precision Reference |
| LUDZS4.3B | Low Current Operation at 250??A???Low Reverse Leakage,Low Noise Zener Diode(250??A?·￥?????μ?μ?????°????????????μ?μ?????????a?￡°???é???o3?o???????) |
| LUDZS4.7B | Low Current Operation at 250??A???Low Reverse Leakage,Low Noise Zener Diode(250??A?·￥?????μ?μ?????°????????????μ?μ?????????a?￡°???é???o3?o???????) |
| LUDZS5.1B | Low Current Operation at 250??A???Low Reverse Leakage,Low Noise Zener Diode(250??A?·￥?????μ?μ?????°????????????μ?μ?????????a?￡°???é???o3?o???????) |
| LUDZS5.6B | Low Current Operation at 250??A???Low Reverse Leakage,Low Noise Zener Diode(250??A?·￥?????μ?μ?????°????????????μ?μ?????????a?￡°???é???o3?o???????) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTZ1000ACH#PBF | 功能描述:IC VREF SHUNT BURIED ZNR TO-5 RoHS:是 類別:集成電路 (IC) >> PMIC - 電壓基準(zhǔn) 系列:- 標(biāo)準(zhǔn)包裝:2,000 系列:- 基準(zhǔn)類型:旁路，可調(diào)節(jié)，精度 輸出電壓:1.24 V ~ 16 V 容差:±0.5% 溫度系數(shù):- 輸入電壓:1.24 V ~ 16 V 通道數(shù):1 電流 - 陰極:100µA 電流 - 靜態(tài):- 電流 - 輸出:20mA 工作溫度:-40°C ~ 85°C 安裝類型:通孔 封裝/外殼:TO-226-3、TO-92-3（TO-226AA）成形引線 供應(yīng)商設(shè)備封裝:TO-92-3 包裝:帶卷 (TR) |
| LTZ1000ACH#SPTPBF | 制造商:Linear Technology 功能描述: |
| LTZ1000ACH-PBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Ultra Precision Reference |
| LTZ1000ACH-TR | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Ultra Precision Reference |
| LTZ1000ACH-TRPBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Ultra Precision Reference |
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