- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄362092 > AD549* Ultralow Input Bias Current Operational Amplifier PDF資料下載
參數(shù)資料
| 型號： | AD549* |
| 英文描述： | Ultralow Input Bias Current Operational Amplifier |
| 中文描述： | 超低輸入偏置電流運(yùn)算放大器 |
| 文件頁數(shù)： | 12/12頁 |
| 文件大?。?/td> | 418K |
AD549
REV. A
–12–
The pH probe output is ideally zero volts at a pH of 7 indepen-
dent of temperature. The slope of the probe’s transfer function,
though predictable, is temperature dependent (–54.2 mV/pH at
0 and –74.04 mV/pH at 100
°
C). By using an AD590 tempera-
ture sensor and an AD535 analog divider, an accurate tempera-
ture compensation network can be added to the basic pH probe
amplifier. The table in Figure 47 shows voltages at various points
and illustrates the compensation. The AD549 is set for a nonin-
verting gain of 13.51. The output of the AD590 circuitry (point
C) will be equal to 10 V at 100
°
C and decrease by 26.8 mV/
°
C.
The output of the AD535 analog divider (point D) will be a
temperature compensated output voltage centered at zero volts
for a pH of 7, and having a transfer function of –1.00 V/pH
unit. The output range spans from –7.00 V (pH = 14) to +7.00 V
(pH = 0).
P
ROBE
TEMP
A
(PROBE OUTPUT)
B
(A
3
13.51)
C
(590 OUTPUT)
D
(10 B/C)
0
25
8
C
37
8
C
60
8
C
100
8
C
54.20 mV
59.16 mV
61.54 mV
66.10 mV
74.04 mV
0.732 V
0.799 V
0.831 V
0.893 V
1.000 V
7.32 V
7.99 V
8.31 V
8.93 V
10.00 V
1.00 V
1.00 V
1.00 V
1.00 V
1.00 V
Figure 47. Table Illustrating Temperature Compensation
TEMPERATURE COMPENSATED pH PROBE
AMPLIFIER
A pH probe can be modeled as a mV-level voltage source with a
series source resistance dependent upon the electrode’s compo-
sition and configuration. The glass bulb resistance of a typical
pH electrode pair falls between 10
6
and 10
9
. It is therefore
important to select an amplifier with low enough input currents
such that the voltage drop produced by the amplifier’s input
bias current and the electrode resistance does not become an
appreciable percentage of a pH unit.
The circuit in Figure 46 illustrates the use of the AD549 as a
pH probe amplifier. As with other electrometer applications, the
use of guarding, shielding, Teflon standoffs, etc., is a must in
order to capitalize on the AD549’s low input current. If an
AD549L (60 fA max input current) is used, the error contrib-
uted by input current will be held below 60
μ
V for pH electrode
source impedances up to 10
9
. Input offset voltage (which can
be trimmed) will be below 0.5 mV.
Figure 46. Temperature Compensated pH Probe Amplifier
C
P
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
TO-99 (H) Package
0.045 (1.1)
0.020 (0.51)
0.034 (0.86)
0.028 (0.41)
1
3
5
0.2
(5.1)
TYP
2
4
6
7
8
45° EQUALLY
SPACED
BOTTOM VIEW
SEATING
PLANE
0.019 (0.48)
0.016 (0.41)
0.335 (8.50)
0.305 (7.75)
0.370 (9.40)
0.335 (8.50)
0.500
(12.70)
MIN
0.040
(1.0)
MAX
0.185 (4.70)
0.165 (4.19)
8 LEADS
DIA
INSULATION
0.05 (1.27) MAX
REFFERENCE
PLANE
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AD549JCHIPS | THERMISTOR, PTC; Series:B598; Thermistor type:PTC; Resistance:10R; Tolerance, resistance:+/-25%; Temp, op. max:125(degree C); Voltage, operating:160V; Case style:Radial; Current, tripping:0.5A; Diameter, body:13.5mm; Length, RoHS Compliant: Yes |
| AD549JH | THERMISTOR, PTC; Series:B598; Thermistor type:PTC; Resistance:15R; Tolerance, resistance:+/-25%; Temp, op. max:125(degree C); Voltage, operating:265V; Case style:Radial; Current, tripping:0.28A; Diameter, body:11mm; Length, RoHS Compliant: Yes |
| AD549 | Ultralow Input Bias Current Operational Amplifier |
| AD549J | Ultralow Input Bias Current Operational Amplifier |
| AD549K | Ultralow Input Bias Current Operational Amplifier |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AD549_08 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Ultralow Input Bias Current Operational Amplifier |
| AD549J | 制造商:AD 制造商全稱:Analog Devices 功能描述:Ultralow Input Bias Current Operational Amplifier |
| AD549JCHIPS | 制造商:Analog Devices 功能描述: |
| AD549JH | 功能描述:IC OPAMP GP 1MHZ LP 20MA TO99-8 RoHS:否 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:Topgate™ 標(biāo)準(zhǔn)包裝:2,500 系列:Excalibur™ 放大器類型:J-FET 電路數(shù):1 輸出類型:- 轉(zhuǎn)換速率:45 V/µs 增益帶寬積:10MHz -3db帶寬:- 電流 - 輸入偏壓:20pA 電壓 - 輸入偏移:490µV 電流 - 電源:1.7mA 電流 - 輸出 / 通道:48mA 電壓 - 電源，單路/雙路(±):4.5 V ~ 38 V，±2.25 V ~ 19 V 工作溫度:-40°C ~ 85°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:帶卷 (TR) |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。