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參數(shù)資料
| 型號： | AD1580BRT |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 基準電壓源/電流源 |
| 英文描述： | 1.2 V Micropower, Precision Shunt Voltage Reference |
| 中文描述： | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 1.225 V, PDSO3 |
| 封裝： | SOT-23, 3 PIN |
| 文件頁數(shù)： | 4/8頁 |
| 文件大小： | 161K |
| 代理商： | AD1580BRT |
AD1580
REV. 0
–4–
T HE ORY OF OPE RAT ION
T he AD1580 uses the “bandgap” concept to produce a stable,
low temperature coefficient voltage reference suitable for high
accuracy data acquisition components and systems. T he device
makes use of the underlying physical nature of a silicon
transistor base-emitter voltage in the forward-biased operating
region. All such transistors have approximately a –2 mV/
°
C
temperature coefficient, unsuitable for use directly as a low T C
reference; however, extrapolation of the temperature characteristic
of any one of these devices to absolute zero (with collector
current proportional to absolute temperature) reveals that its
V
BE
will go to approximately the silicon bandgap voltage. T hus,
if a voltage could be developed with an opposing temperature
coefficient to sum with V
BE
, a zero T C reference would result.
T he AD1580 circuit in Figure 6, provides such a compensating
voltage, V1 by driving two transistors at different current
densities and amplifying the resultant V
BE
difference (
V
BE
—
which has a positive T C). T he sum of V
BE
and V1 provide a
stable voltage reference.
V+
V–
V1
V
BE
V
BE
Figure 6. Schematic Diagram
APPLY ING T HE AD1580
T he AD1580 is simple to use in virtually all applications. T o
operate the AD1580 as a conventional shunt regulator (Figure
7a), an external series resistor is connected between the supply
voltage and the AD1580. For a given supply voltage the series
resistor, R
S
, determines the reverse current flowing through the
AD1580. T he value of R
S
must be chosen to accommodate the
expected variations of the supply voltage, V
S
, load current, I
L
,
and the AD1580 reverse voltage, V
R
, while maintaining an
acceptable reverse current, I
R
, through the AD1580.
T he minimum value for R
S
should be chosen when V
S
is at
its minimum, and I
L
and V
R
are at their maximum while
maintaining the minimum acceptable reverse current.
T he value of R
S
should be large enough to limit I
R
to 10 mA
when V
S
is at its maximum, and I
L
and V
R
are at their minimum.
T he equation for selecting R
S
is as follows:
R
S
= (
V
S
–
V
R
)/
(I
R
+
I
L
)
Figure 7b shows a typical connection with the AD1580BRT
operating at a minimum of 100
μ
A that can provide
±
1 mA to
its load, while accommodating
±
10% power supply variations.
V
S
+5V(+3V)
±
10%
I
R
V
R
I
R +
I
L
I
L
R
S
V
R
R
S
V
OUT
(a)
(b)
V
OUT
2.94k
(1.30k
)
Figure 7. Typical Connection Diagram
T E MPE RAT URE PE RFORMANCE
T he AD1580 is designed for reference applications where
stable temperature performance is important. Extensive
temperature testing and characterization ensures that the device’s
performance is maintained over the specified temperature range.
Some confusion exists in the area of defining and specifying
reference voltage error over temperature. Historically, references
have been characterized using a maximum deviation per degree
centigrade, i.e., 50 ppm/
°
C. However, because of nonlinearities
in temperature characteristics which originated in standard
Zener references (such as “S” type characteristics), most
manufacturers now use a maximum limit error band approach
to specify devices. T his technique involves the measurement of
the output at three or more different temperatures to guarantee
that the voltage will fall within the given error band. T he
proprietary curvature correction design techniques used to
minimize the AD1580 nonlinearities allow the temperature
performance to be guaranteed using the maximum deviation
method. T his method is of more use to a designer than the one
which simply guarantees the maximum error band over the
entire temperature change.
Figure 8 shows a typical output voltage drift for the AD1580
and illustrates the methodology. T he maximum slope of the
two diagonals drawn from the initial output value at 25
°
C to the
output values at 85
°
C and –40
°
C determines the performance
grade of the device. For a given grade of the AD1580 the
designer can easily determine the maximum total error from the
initial tolerance plus temperature variation. For example, the
AD1580BRT initial tolerance is
±
1 mV, a
±
50 ppm/
°
C
temperature coefficient corresponds to an error band of
±
4 mV
O
TEMPERATURE –
°
C
1.2238
–55
1.2248
1.2250
1.2252
1.2254
1.2256
1.2258
–35
–15
5
25
65
85
125
105
1.2244
1.2246
1.2240
1.2242
45
V
MIN
V
O
V
MAX
SLOPE = TC = (85
°
C – 25
°
C) x 1.225 x 10
–6
(V
MAX
– V
O
)
SLOPE = TC = (–40
°
C – 25
°
C) x 1.225 x 10
–6
(V
MIN
– V
O
)
Figure 8. Output Voltage vs. Temperature
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AD1580BRT-REEL1 | 1.2 V Micropower, Precision Shunt Voltage Reference |
| AD1580BRT-REEL7 | 1.2 V Micropower, Precision Shunt Voltage Reference |
| AD1584 | 2.5 V to 5.0 V Micropower, Precision Series Mode Voltage References |
| AD1584ART-R2 | 2.5 V to 5.0 V Micropower, Precision Series Mode Voltage References |
| AD1584ART-REEL7 | 2.5 V to 5.0 V Micropower, Precision Series Mode Voltage References |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AD1580BRT-R2 | 制造商:Analog Devices 功能描述:V-Ref Precision 1.225V 10mA 3-Pin SOT-23 T/R 制造商:Rochester Electronics LLC 功能描述:IC, 1.2V MICROPOWER REF - Bulk 制造商:Analog Devices 功能描述:IC MICROPOWER VOLT REF 1.2V |
| AD1580BRT-REEL | 制造商:Rochester Electronics LLC 功能描述:IC, 1.2V MICROPOWER REF - Tape and Reel |
| AD1580BRT-REEL1 | 制造商:AD 制造商全稱:Analog Devices 功能描述:1.2 V Micropower, Precision Shunt Voltage Reference |
| AD1580BRTREEL7 | 制造商:Analog Devices 功能描述: |
| AD1580BRT-REEL7 | 功能描述:IC VREF SHUNT PREC 1.225V SOT23 RoHS:否 類別:集成電路 (IC) >> PMIC - 電壓基準 系列:- 產(chǎn)品培訓(xùn)模塊:Voltage Reference Basics 標準包裝:100 系列:- 基準類型:旁路，精度 輸出電壓:4.096V 容差:±0.075% 溫度系數(shù):50ppm/°C 輸入電壓:- 通道數(shù):1 電流 - 陰極:1µA 電流 - 靜態(tài):- 電流 - 輸出:10mA 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 供應(yīng)商設(shè)備封裝:8-SOIC 包裝:管件 |
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