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參數(shù)資料
| 型號(hào)： | AD693AD |
| 廠商： | Analog Devices Inc |
| 文件頁(yè)數(shù)： | 9/12頁(yè) |
| 文件大?。?/td> | 0K |
| 描述： | IC SGNL COND 4-20MA TX 20-CDIP |
| 標(biāo)準(zhǔn)包裝： | 19 |
| 類(lèi)型： | 信號(hào)調(diào)節(jié)器 |
| 輸入類(lèi)型： | 電壓 |
| 輸出類(lèi)型： | 電壓 |
| 接口： | 3 線 |
| 電流 - 電源： | 20mA |
| 安裝類(lèi)型： | 通孔 |
| 封裝/外殼： | 20-CDIP（0.300"，7.62mm） |
| 供應(yīng)商設(shè)備封裝： | 20-CDIP |
| 包裝： | 管件 |
| 產(chǎn)品目錄頁(yè)面： | 798 (CN2011-ZH PDF) |
AD693
REV. A
–6–
if the 6.2 V of the reference is unsuitable. Configured as a simple
follower, it can be driven from a user supplied voltage divider
or the precalibrated outputs of the AD693 divider (Pins 3 and
4) to provide a stiff voltage output at less than the 6.2 level, or
by incorporating a voltage divider as feedback around the amplifier,
one can gain-up the reference to levels higher than 6.2 V. If
large positive outputs are desired, IX, the Auxiliary Amplifier
output current supply, should be strapped to either VIN or
Boost. Like the Signal Amplifier, the Auxiliary requires about
3.5 V of headroom with respect to VIN at its input and about 2 V
of difference between IX and the voltage to which VX is required
to swing.
The output stage of the Auxiliary Amplifier is actually a high
gain Darlington transistor where IX is the collector and VX is the
emitter. Thus, the Auxiliary Amplifier can be used as a V/I
converter when configured as a follower and resistively loaded.
IX functions as a high-impedance current source whose current
is equal to the voltage at VX divided by the load resistance. For
example, using the onboard 100
resistor and the 75 mV or
150 mV application voltages, either a 750
A or 1.5 mA current
source can be set up for transducer excitation.
The IX terminal has voltage compliance within 2 V of VX. If the
Auxiliary Amplifier is not to be used, then Pin 2, the noninverting
input, should be grounded.
REVERSE VOLTAGE PROTECTION FEATURE
In the event of a reverse voltage being applied to the AD693
through a current-limited loop (limited to 200 mA), an internal
shunt diode protects the device from damage. This protection
mode avoids the compliance voltage penalty which results from
a series diode that must be added if reversal protection is
required in high-current loops.
Applying the AD693
CONNECTIONS FOR BASIC OPERATION
Figure 10 shows the minimal connections for basic operation:
0–30 mV input span, 4–20 mA output span in the two-wire,
loop-powered mode. If not used for external excitation, the
6.2 V reference should be loaded by approximately 1 mA
(6.2 k
to common).
USING AN EXTERNAL PASS TRANSISTOR
The emitter of the NPN output section, IOUT, of the AD693 is
usually connected to common and the negative loop connection
(Pins 7 to 6). Provision has been made to reconnect IOUT to the
base of a user supplied NPN transistor as shown in Figure 11.
This permits the majority of the power dissipation to be moved
off chip to enhance performance, improve reliability, and extend
the operating temperature range. An internal hold-down resistor
of about 3k is connected across the base emitter of the external
transistor.
The external pass transistor selected should have a BVCEO greater
than the intended supply voltage with a sufficient power rating for
continuous operation with 25 mA current at the supply voltage.
Ft should be in the 10 MHz to 100 MHz range and
β should be
greater than 10 at a 20 mA emitter current. Some transistors
that meet this criteria are the 2N1711 and 2N2219A. Heat
sinking the external pass transistor is suggested.
The pass transistor option may also be employed for other
applications as well. For example, IOUT can be used to drive an
LED connected to Common, thus providing a local monitor of
loop fault conditions without reducing the minimum compliance
voltage.
ADJUSTING ZERO
In general, the desired zero offset value is obtained by
connecting an appropriate tap of the precision reference/voltage
divider network to the inverting terminal of the V/I converter.
As shown in Figure 9, precalibrated taps at Pins 14, 13 and 11
result in zero offsets of 0 mA, 4 mA and 12 mA, respectively,
when connected to Pin 12. The voltages which set the 4 mA and
12 mA zero operating points are 15 mV and 45 mV negative
with respect to 6.2 V, and they each have a nominal source
resistance of 450
. While these voltages are laser trimmed to
high accuracy, they may require some adjustment to
accommodate variability between sensors or to provide
additional ranges. You can adjust zero by pulling up or down on
the selected zero tap, or by making a separate voltage divider to
drive the zero pin.
The arrangement of Figure 12 will give an approximately linear
adjustment of the precalibrated options with fixed limits. To
find the proper resistor values, first select IA, the desired range
Figure 10. Minimal Connection for 0–30 mV Unipolar Input, 4–20 mA Output
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| AD693AE | 功能描述:IC SGNL COND 4-20MA TX 20-CLCC RoHS:否 類(lèi)別:集成電路 (IC) >> 接口 - 傳感器和探測(cè)器接口 系列:- 其它有關(guān)文件:Automotive Product Guide 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:74 系列:- 類(lèi)型:觸控式傳感器 輸入類(lèi)型:數(shù)字 輸出類(lèi)型:數(shù)字 接口:JTAG，串行 電流 - 電源:100µA 安裝類(lèi)型:表面貼裝 封裝/外殼:20-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:20-TSSOP 包裝:管件 |
| AD693AQ | 功能描述:IC TRANSMITTER 4-20MA 20-CDIP RoHS:否 類(lèi)別:集成電路 (IC) >> 接口 - 傳感器和探測(cè)器接口 系列:- 其它有關(guān)文件:Automotive Product Guide 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:74 系列:- 類(lèi)型:觸控式傳感器 輸入類(lèi)型:數(shù)字 輸出類(lèi)型:數(shù)字 接口:JTAG，串行 電流 - 電源:100µA 安裝類(lèi)型:表面貼裝 封裝/外殼:20-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:20-TSSOP 包裝:管件 |
| AD693BQ | 制造商:AD 制造商全稱(chēng):Analog Devices 功能描述:Loop-Powered 4a??20 mA Sensor Transmitter |
| AD694 | 制造商:AD 制造商全稱(chēng):Analog Devices 功能描述:4.20 mA Transmitter |
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