Iso122sensor de Tension

8/10/2019 Iso122sensor de Tension

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Precision Lowest CostISOLATION AMPLIFIER

FEATURES

100% TESTED FOR HIGH-VOLTAGEBREAKDOWN

RATED 1500Vrms

HIGH IMR: 140dB at 60Hz

BIPOLAR OPERATION: VO

= 10V 16-PIN PLASTIC DIP AND 28-LEAD SOIC

EASE OF USE: Fixed Unity GainConfiguration

0.020% max NONLINEARITY

4.5V to 18V SUPPLY RANGE

APPLICATIONS

INDUSTRIAL PROCESS CONTROL:Transducer Isolator, Isolator for Thermo-

couples, RTDs, Pressure Bridges, andFlow Meters, 4mA to 20mA Loop Isolation

GROUND LOOP ELIMINATION

MOTOR AND SCR CONTROL

POWER MONITORING

PC-BASED DATA ACQUISITION

TEST EQUIPMENT

VOUT

VIN

+VS1

ISO122

DESCRIPTIONThe ISO122 is a precision isolation amplifier incor-

porating a novel duty cycle modulation-demodulation

technique. The signal is transmitted digitally across

a 2pF differential capacitive barrier. With digital modu-

lation the barrier characteristics do not affect signal

integrity, resulting in excellent reliability and good high

frequency transient immunity across the barrier. Both

barrier capacitors are imbedded in the plastic body of

the package.

The ISO122 is easy to use. No external components

are required for operation. The key specifications are

0.020% max nonlinearity, 50kHz signal bandwidth,

and 200V/C VOS

drift. A power supply range of

4.5V to 18V and quiescent currents of 5.0mA onV

S1and 5.5mA on V

S2make these amplifiers ideal

for a wide range of applications.

The ISO122 is available in 16-pin plastic DIP and 28-

lead plastic surface mount packages.

VS1

Gnd

+VS2

VS2

Gnd

1989 Burr-Brown Corporation PDS-857F Printed in U.S.A. November, 1993

International Airport Industrial Park Mailing Address: PO Box 11400 Tucson, AZ 85734 Street Address: 6730 S. Tucson Blvd. Tucson, AZ 85706

Tel: (520) 746-1111 Twx: 910-952-1111 Cable: BBRCORP Telex: 066-6491 FAX: (520) 889-1510 Immediate Product Info: (800) 548-6132

SBOS160


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2

ISO122

The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes

no responsibility for the use of this information, and all use of such information shall be entirely at the users own risk. Prices and specifications are subject to change

without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant

any BURR-BROWN product for use in life support devices and/or systems.

SPECIFICATIONSAt T

A= +25C , V

S1= V

S2= 15V, and R

L= 2kunless otherwise noted.

ISO122P/U ISO122JP/JU

PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

ISOLATION

Voltage Rated Continuous AC 60Hz 1500 * VAC

100% Test (1) 1s, 5pc PD 2400 * VAC

Isolation Mode Rejection 60Hz 140 * dB

Barrier Impedance 1014 || 2 * || pFLeakage Current at 60Hz V

ISO= 240Vrms 0.18 0.5 * * Arms

GAIN VO= 10V

Nominal Gain 1 * V/V

Gain Error 0.05 0.50 * * %FSR Gain vs Temperature 10 * ppm/ C Nonlinearity(2) 0.016 0.020 0.025 0.050 %FSR

INPUT OFFSET VOLTAGE

Initial Offset 20 50 * * mV vs Temperature 200 * V/C vs Supply 2 * mV/VNoise 4 * V/Hz

INPUT

Voltage Range 10 12.5 * * VResistance 200 * k

OUTPUT

Voltage Range 10 12.5 * * VCurrent Drive 5 15 * * mACapacitive Load Drive 0.1 * FRipple Voltage(3) 20 * mVp-p

FREQUENCY RESPONSE

Small Signal Bandwidth 50 * kHz

Slew Rate 2 * V/ sSettling Time V

O= 10V

0.1% 50 * s 0.01% 350 * sOverload Recover Time 150 * s

POWER SUPPLIES

Rated Voltage 15 * VVoltage Range 4.5 18 * * VQuiescent Current: V

S1 5.0 7.0 * * mA

VS2 5.5 7.0 * * mATEMPERATURE RANGE

Specification 25 +85 * * COperating 25 +85 * * CStorage 40 +85 * * C

JA100 * C/W

JC

65 * C/W

* Specification same as ISO122P/U.

NOTES: (1) Tested at 1.6 X rated, fail on 5pC partial discharge. (2) Nonlinearity is the peak deviation of the output voltage from the best-fit straight line. It is expressed

as the ratio of deviation to FSR. (3) Ripple frequency is at carrier frequency (500kHz).


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3

ISO122

Top View P Package

1

2

7

8

16

15

9

Gnd

VIN

VOUT

VS1

+VS1

10

+VS2

Gnd

VS2

Top ViewU Package

1

2

28

27

Gnd

VIN

VOUT

VS1

+VS1

+VS2

Gnd

VS2

16

15

13

14

CONNECTION DIAGRAM

ABSOLUTE MAXIMUM RATINGS

Supply Voltage ...................................................................................18VV

IN......................................................................................................100V

Continuous Isolation Voltage ..................................................... 1500Vrms

Junction Temperature .................................................................... +150CStorage Temperature ....................................................................... +85CLead Temperature (soldering, 10s) ................................................ +300C

Output Short to Common ......................................................... Continuous

PACKAGE INFORMATION(1)

PACKAGE DRAWING

MODEL PACKAGE NUMBER

ISO122P 16-Pin Plastic DIP 238

ISO122JP 16-Pin Plastic DIP 238

ISO122U 28-Pin Plastic SOIC 217-1

ISO122JU 28-Pin Plastic SOIC 217-1

NOTE: (1) For detailed drawing and dimension table, please see end of data

sheet, or Appendix D of Burr-Brown IC Data Book.

NONLINEARITY

MODEL PACKAGE MAX %FSR

ISO122P Plastic DIP 0.020ISO122JP Plastic DIP 0.050ISO122U Plastic SOIC 0.020ISO122JU Plastic SOIC 0.050

ORDERING INFORMATION


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4

ISO122

+10

0

10

0

OutputVoltage(V)

500

Time (s)

SINE RESPONSE

(f = 2kHz)

1000

Time (s)

+10

0

10

0

OutputVoltage(V)

10050

SINE RESPONSE

(f = 20kHz)

Time (s)

+10

0

10

0

OutputVoltage(V)

STEP RESPONSE

10050

Time (s)

+10

0

10

0

OutputVoltage(V)

STEP RESPONSE

500 1000

TYPICAL PERFORMANCE CURVEST

A= +25C, V

S= 15V unless otherwise noted.

100

0

100M10M

ISOLATION VOLTAGE

vs FREQUENCY

Typical

Performance

Frequency (Hz)

100k10k

Max DC Rating

1k

PeakIso

lationVoltage

Degraded

Performance

100 1k 1M

2.1k

IMR vs FREQUENCY

1M1

Frequency (Hz)

160

140

120

100

80

60

40

10 100 100k10k1k

IMR

(dB)


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5

ISO122

TYPICAL PERFORMANCE CURVEST

A= +25C, V

S= 15V unless otherwise noted.

PSRR vs FREQUENCY

60

40

20

0

Frequency (Hz)

1 10 100 1k 10k 100k 1M

54

PSRR

(dB)

VS1

, VS2

+VS1

, +VS2

Frequency (Hz)

100mA

10mA

1mA

100A

10A

1A

0.1A

1 10 100 1k 10k 100k 1M

ISOLATION LEAKAGE CURRENT

vs FREQUENCY

LeakageCurrent(rms)

1500Vrms

240Vrms

Input Frequency

0 500kHz 1MHz 1.5MHz

0

10

20

30

40

250

200

150

100

50

VOUT

/V

INdBm

SIGNAL RESPONSE TO

INPUTS GREATER THAN 250kHz

FrequencyOut

100kHzVOUT

/VIN Freq

Out

(NOTE: Shaded area shows aliasing frequencies that cannot

be removed by a low-pass filter at the output.)


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6

ISO122

THEORY OF OPERATIONThe ISO122 isolation amplifier uses an input and an output

section galvanically isolated by matched 1pF isolating ca-

pacitors built into the plastic package. The input is duty-

cycle modulated and transmitted digitally across the barrier.

The output section receives the modulated signal, converts it

back to an analog voltage and removes the ripple component

inherent in the demodulation. Input and output sections arefabricated, then laser trimmed for exceptional circuitry match-

ing common to both input and output sections. The sections

are then mounted on opposite ends of the package with the

isolating capacitors mounted between the two sections. The

transistor count of the ISO122 is 250 transistors.

MODULATOR

An input amplifier (A1, Figure 1) integrates the difference

between the input current (VIN/200k) and a switched

100A current source. This current source is implementedby a switchable 200A source and a fixed 100A currentsink. To understand the basic operation of the modulator,

assume that VIN = 0.0V. The integrator will ramp in onedirection until the comparator threshold is exceeded. The

comparator and sense amp will force the current source to

switch; the resultant signal is a triangular waveform with a

50% duty cycle. The internal oscillator forces the current

source to switch at 500kHz. The resultant capacitor drive is

a complementary duty-cycle modulation square wave.

DEMODULATOR

The sense amplifier detects the signal transitions across the

capacitive barrier and drives a switched current source into

integrator A2. The output stage balances the duty-cycle

modulated current against the feedback current through the

200kfeedback resistor, resulting in an average value at the

VOUT

pin equal to VIN

. The sample and hold amplifiers in the

output feedback loop serve to remove undesired ripple

voltages inherent in the demodulation process.

BASIC OPERATION

SIGNAL AND SUPPLY CONNECTIONSEach power supply pin should be bypassed with 1F tanta-lum capacitors located as close to the amplifier as possible.

The internal frequency of the modulator/demodulator is set

at 500kHz by an internal oscillator. Therefore, if it is desired

to minimize any feedthrough noise (beat frequencies) from

a DC/DC converter, use a filter on the supplies (see Figure4). ISO122 output has a 500kHz ripple of 20mV, which can

be removed with a simple two pole low-pass filter with a

100kHz cutoff using a low cost op amp. See Figure 4.

The input to the modulator is a current (set by the 200kintegrator input resistor) that makes it possible to have an

input voltage greater than the input supplies, as long as the

output supply is at least 15V. It is therefore possible whenusing an unregulated DC/DC converter to minimize PSR

related output errors with 5V voltage regulators on theisolated side and still get the full 10V input and outputswing. An example of this application is shown in Figure

10.

CARRIER FREQUENCY CONSIDERATIONS

The ISO122 amplifier transmits the signal across the isola-

tion barrier by a 500kHz duty cycle modulation technique.

For input signals having frequencies below 250kHz, this

system works like any linear amplifier. But for frequencies

above 250kHz, the behavior is similar to that of a sampling

amplifier. The signal response to inputs greater than 250kHz

1pF

200A

100A

200k

Isolation Barrier

1pF

1pF

200A

100A200kV

IN

+

Osc

Gnd 1 VS1+VS1

VOUT

S/H

G = 6

S/H

G = 1

Gnd 2+VS2 VS2

+A2

SenseSense

FIGURE 1. Block Diagram.

A1

150pF 150pF

1pF

| |


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7

ISO122

performance curve shows this behavior graphically; at input

frequencies above 250kHz the device generates an output

signal component of reduced magnitude at a frequency

below 250kHz. This is the aliasing effect of sampling at

frequencies less than 2 times the signal frequency (the

Nyquist frequency). Note that at the carrier frequency and its

harmonics, both the frequency and amplitude of the aliasing

go to zero.

ISOLATION MODE VOLTAGE INDUCED ERRORS

IMV can induce errors at the output as indicated by the plots

of IMV vs Frequency. It should be noted that if the IMV

frequency exceeds 250kHz, the output also will display

spurious outputs (aliasing), in a manner similar to that for

VIN

> 250kHz and the amplifier response will be identical to

that shown in the Signal Response to Inputs Greater Than

250kHz performance curve. This occurs because IMV-

induced errors behave like input-referred error signals. To

predict the total error, divide the isolation voltage by the

IMR shown in the IMR vs Frequency curve and compute the

amplifier response to this input-referred error signal from

the data given in the Signal Response to Inputs Greater than250kHz performance curve. For example, if a 800kHz

1000Vrms IMR is present, then a total of [(60dB) +

(30dB)] x (1000V) = 32mV error signal at 200kHz plus a

1V, 800kHz error signal will be present at the output.

HIGH IMV dV/dt ERRORS

As the IMV frequency increases and the dV/dt exceeds

1000V/s, the sense amp may start to false trigger, and theoutput will display spurious errors. The common mode

current being sent across the barrier by the high slew rate is

the cause of the false triggering of the sense amplifier.

Lowering the power supply voltages below 15V maydecrease the dV/dt to 500V/s for typical performance.

Isolation Barrier

VIN

1F

+VS2

VS1+V

S1

1F1F

Gnd

VS2

1F

VOUT

Gnd

VS1

VS2

FIGURE 2. Basic Signal and Power Connections.

HIGH VOLTAGE TESTING

Burr-Brown Corporation has adopted a partial discharge test

criterion that conforms to the German VDE0884 Optocou-

pler Standards. This method requires the measurement of

minute current pulses (


8/15

8

ISO122

FIGURE 4. OptionalFilter to Minimize Power Supply Feedthrough Noise; Output Filter to Remove 500kHz Carrier Ripple.

For more information concerning output filter refer to AB-023.

Isolation Barrier

VS1

10H

10H 10H

10H

1F

1F 1F 1F

1F

1F 1F 1F

VS1

VIN ISO122

+VS1

+VS2

VS2

Gnd

13k

13k

100pF

+

6

VOUT

= VIN

Gnd

4700pF

385

Charge/Discharge

Control

10k

10k

25k

25k

7

V+V

25k

25k+

INA105

1

3 V = e50 2

5

6

V = e1

2

Control

SectionMultiplex

er

+V

ISO122P

10k

10k

15

9

7

8

V

+V

ISO122P

9

7

8

V

4e

49=12V

e50

=12V

e1= 12V

e2= 12V

FIGURE 5. Battery Monitor for a 600V Battery Power System. (Derives Input Power from the Battery.)

10

VS2

This Section Repeated 49 Times.

10

1

2

16

15

16

2

1

OPA602

2

3

2


9/15

9

ISO122

10.0V

Thermocouple

REF

102

27kR

1

R4

+In

In

15V

2

14

13

1R

G

12

10

3

5

4

11

R5

R3

R2

IsothermalBlock with1N4148 (1)

Ground Loop Through Conduit

100

Zero Adj

R6

50100

+15V

+15V 15V +15V 15V

1

2

9

8

16

15 10 7V

OUT

ISO122P

FIGURE 6. Thermocouple Amplifier with Ground Loop Elimination, Cold Junction Compensation, and Up-scale Burn-out.

SEEBACK

ISA COEFFICIENT R2

R4

TYPE MATERIAL (V/C) (R3= 100) (R

5+ R

6= 100)

Chromel

E Constantan 58.5 3.48k 56.2kIron

J Constantan 50.2 4.12k 64.9kChromel

K Alumel 39.4 5.23k 80.6kCopper

T Constantan 38.0 5.49k 84.5k

NOTE: (1) 2.1mV/C at 2.00A.

1M

INA101

2

6 4

+15V

0.0

1

F

6

5

RTD

(PT100)

1mA1mA

2mA

R2= 2.5k

V

0V-5V

+V

Gnd

VS= 15V

on PWS740

4-20mA

ISO122P3

214

9

8

2

11

8

74

3

VOUT

10

7

12

4

10

XTR101

+VS=15V

on PWS740

R1= 100

10

11

5, 13

15

16

15

16

1

FIGURE 7. Isolated 4-20mA Instrument Loop. (RTD shown.)

RS

RCV420


10/15

10

ISO122

FIGURE 8. Isolated Power Line Monitor.

MPY100

X

Y

(V2)

PL= V

2(R

D1+ R

D2)

RS

RD2

XY

10

(V1)

10k

2

36

0.01FISO122P

V

(V3)

VL= V

3(R

D1+ R

D2)

RD2

+VISO122P

2kIL= V

1

10RS

0.1F

2k

+V

9715

16

8

Load IL

RD2

RD1

VL

RS

0.3F

0.3F

PWS740-3

63

1 4

2 13

46 5

PWS740-2

To PWS740-1

0.3F

0.3F

97

8

15

16

41

PWS740-3

3 6

PWS740-2

To PWS740-1

13 2

456

21

12

10

10

V

OPA602

+


11/15

11

ISO122

FIGURE 9. Three-Port, Low-Cost, Four-Channel Isolated, Data Acquisition System.

+V

Channel 2

(Same as Channel 1.)

PWS740-1

4 65

33

4 4

0.3F

ISO122P

0.3F

0.3F

64

1 1

66

16

15 7

0.3F

Channel 1

1

Channel 4


Channel 3


98

2

VIN

VOUT

123123

20H

PWS740-2 PWS740-2

50.3F

10F

6

3

4

8

5

10

PWS740-3 PWS740-3


12/15

12

ISO122

+15V

9

7

8

10

VIN

, up to

10V Swing

216

1 15

0.1F0.1F

0.33F 0.33F4

PWS7403

VOUT

To PWS7402,1

NOTE: The input supplies can be subregulated to 5V to reducePSR related errors without reducing the 10V input range.

12

3

1

2

3MC78L05

+5V

Regulator5V

Regulator

MC79L05

VS

INPUT RANGE

(V) (V)(1)

20+ 2 to +10

15 2 to +5

12 2 to +2

FIGURE 10. Improved PSR Using External Regulator.

FIGURE 11. Single Supply Operation of the ISO122P Isolation Amplifier. For additional information see AB-009.

NOTE: Since the amplifier is unity gain, the input

range is also the output range. The output can go to

2V since the output section of the ISO amp operates

from dual supplies.

ISO

122P

R1 R2

R4

INA105

Difference Amp

R3

RS

2

3

4

IN4689

5.1V

Reference

5

7

6

1VIN

Signal Source

+

NOTE: (1) Select to match R .S

10k

151

9

V (+15V)S1

+V (+15V)S2

V (15V)S2

162

VS1

Com 2

V = VOUT IN7

8

10

In

Gnd

ISO

122RC

(1)

ISO

122P

ISO

122P


13/15

13

ISO122

1516

1 2

10 9

ISO122PINPUT

SECTION

OUTPUT

SECTION

7 8

Gnd V IN V V+

V+ V V O Gnd

HPR117

65421

Output

Gnd

VO

VIN

+15V

15V

Auxiliary

Isolated

Power

Output

15V, 20mA

+15V, 20mAInput

Gnd

15V, 20mA

+15V, 20mA

1516

1 2

10 9

ISO122PINPUT

SECTION

OUTPUT

SECTION

7 8

Gnd VIN

V V+

V+ V VO

Gnd

HPR117

456 12

VIN

Input

Gnd

+15V, 20mA

15V, 20mA

Auxiliary

Isolated

Power

Output

HPR117

6541

VO

Output

Gnd

Auxiliary

Isolated

Power

Output

Gnd+15V

2

FIGURE 13. Powered ISO Amp with Three-Port Isolation. For additional information refer to AB-024.

FIGURE 12. Input-Side Powered ISO Amp. For additional information refer to AB-024.


14/15

IMPORTANT NOTICE

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any product or service without notice, and advise customers to obtain the latest version of relevant information

to verify, before placing orders, that information being relied on is current and complete. All products are sold

subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those

pertaining to warranty, patent infringement, and limitation of liability.

TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in

accordance with TIs standard warranty. Testing and other quality control techniques are utilized to the extent

TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily

performed, except those mandated by government requirements.

Customers are responsible for their applications using TI components.

In order to minimize risks associated with the customers applications, adequate design and operating

safeguards must be provided by the customer to minimize inherent or procedural hazards.

TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent

that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other

intellectual property right of TI covering or relating to any combination, machine, or process in which such

semiconductor products or services might be or are used. TIs publication of information regarding any thirdpartys products or services does not constitute TIs approval, warranty or endorsement thereof.

Copyright 2000, Texas Instruments Incorporated


15/15

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Iso122sensor de Tension