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1996 Burr-Brown Corporation
PDS-1312B
Printed in U.S.A. April, 1996
Precision, Powered, Three-Port Isolated
INSTRUMENTATION AMPLIFIER
DESCRIPTION
ISO255 is a precision three-port isolated instrumenta-
tion amplifier incorporating a novel duty cycle modu-
lation-demodulation technique and has excellent accu-
racy. Internal input protection can withstand up to
40V input differential without damage. The signal is
transmitted digitally across a differential capacitive
barrier. With digital modulation the barrier character-
istics do not affect signal integrity. This results in
excellent reliability and good high frequency transient
immunity across the barrier. The DC/DC converter,
amplifier and barrier capacitors are housed in a plastic
DIP.
A power supply range of 11V to 18V makes this
amplifier ideal for a wide range of applications.
ISO255
FEATURES
q
RATED
1500Vrms Continuous
2500Vrms for One Minute
100% Tested for Partial Discharge
q
GAINS OF 1 TO 10,000
q
LOW NONLINEARITY:
0.05% typ
q
LOW INPUT BIAS CURRENT:
10nA max
q
LOW INPUT OFFSET VOLTAGE
q
INPUTS PROTECTED TO
40V
q
BIPOLAR OPERATION V
O
=
10V
q
SYNCHRONIZATION CAPABILITY
q
28-PIN PLASTIC DIP: 0.6" Wide
ISO255
APPLICATIONS
q
INDUSTRIAL PROCESS CONTROL
Transducer Isolator, Thermocouple
Isolator, RTD Isolator, Pressure Bridge
Isolator, Flow Meter Isolator
q
POWER MONITORING
q
MEDICAL INSTRUMENTATION
q
ANALYTICAL MEASUREMENTS
q
BIOMEDICAL MEASUREMENTS
q
DATA ACQUISITION
q
TEST EQUIPMENT
q
GROUND LOOP ELIMINATION
+V
S1
Com1
V
IN
+V
IN
V
S1
GND1
28
26
3
4
27
25
+V
S2
Com2
V
S2
GND2
12
V
OUT
14
13
11
10
+R
G
1
R
G
2
ISO255
INA
17
GND3
16
SYNC
15
+V
S3
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
Internet: http://www.burr-brown.com/ FAXLine: (800) 548-6133 (US/Canada Only) Cable: BBRCORP Telex: 066-6491 FAX: (520) 889-1510 Immediate Product Info: (800) 548-6132
2
ISO255
ISO255P
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
ISOLATION
Voltage Rated Continuous:
AC
T
MIN
to T
MAX
1500
Vrms
100% Test (AC 50Hz)
1s; Partial Discharge
5pC
2500
Vrms
Rated One Min
2500
Vrms
Isolation-Mode Rejection
DC
120
dB
AC 50Hz
1500Vrms
95
dB
Barrier Impedance
10
14
|| 2
|| pF
Leakage Current
VISO = 240Vrms, 50Hz
1.4
2
Arms
GAIN
Gain Equation
1 + 50k
/R
G
V/V
Gain Error
G = 1
0.15
0.35
%
G = 10
0.15
G = 100
0.15
0.95
%
G = 1000
0.2
Gain vs Temperature
G = 1
50
ppm/
C
G = 10
50
ppm/
C
G = 100
50
ppm/
C
G = 1000
50
ppm/
C
Nonlinearity
G = 1
0.05
0.102
%
G = 10
0.05
G = 100
0.05
0.104
%
G = 1000
0.05
INPUT OFFSET VOLTAGE
Initial Offset
(0.125 + 101/G)
mV
vs Temperature
(1 + 520/G)
V/
C
CMRR
90
dB
vs Supply
1
mV/V
INPUT
Voltage Range
10
V
Bias Current
10
nA
vs Temperature
40
pA/
C
Offset Current
10
nA
vs Temperature
40
pA/
C
OUTPUT
Voltage Range
10
V
Current Drive
5
mA
Capacitive Load Drive
0.1
F
Ripple Voltage
25
mVp-p
FREQUENCY RESPONSE
Small Signal Bandwidth
G = 1
50
kHz
G = 10
50
kHz
G = 100
30
kHz
G = 1000
4
kHz
Slew Rate
G = 10
0.2
V/
s
Settling Time, 0.1%
G = 1
20
s
G = 10
20
s
G = 100
30
s
G = 1000
240
s
POWER SUPPLIES
Rated Voltage
15
V
Voltage Range
11
18
V
Quiescent Current
25
40
55
mA
Rated Output Voltage
No Load
13
14.5
V
50mA Load On Two Supplies
12
13.2
16
V
Load Regulation
28
mV/mA
Line Regulation
1
V/V
SYNC Frequency
1
1.4
MHz
Output Voltage Ripple
50
mV
TEMPERATURE RANGE
Operating
40
85
C
Storage
40
85
C
SPECIFICATIONS
At T
A
= +25
C, V
S3
= 15V, R
L
= 2k
, and 220nF capacitors on all generated supplies, unless otherwise noted.
3
ISO255
PIN CONFIGURATION
Any integrated circuit can be damaged by ESD. Burr-Brown
recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling
and installation procedures can cause damage.
ESD damage can range from subtle performance degrada-
tion to complete device failure. Precision integrated circuits
may be more susceptible to damage because very small
parametric changes could cause the device not to meet
published specifications.
PACKAGE INFORMATION
PACKAGE DRAWING
PRODUCT
PACKAGE
NUMBER
(1)
ISO255P
28-Pin Plastic DIP
335
NOTE: (1) For detailed drawing and dimension table, please see end of data
sheet, or Appendix C of Burr-Brown IC Data Book.
ELECTROSTATIC
DISCHARGE SENSITIVITY
ABSOLUTE MAXIMUM RATINGS
Supply Voltage ................................................................................... +18V
V
IN
, Analog Input Voltage Range .......................................................
40V
Com1 to GND1 ....................................................................................
1V
Com2 to GND2 ....................................................................................
1V
Continuous Isolation Voltage: .................................................... 1500Vrms
..................................................................................... 2500Vrms one min
IMV, dv/dt ...................................................................................... 20kV/
s
Junction Temperature ...................................................................... 150
C
Storage Temperature ........................................................ 40
C to +85
C
Lead Temperature (soldering, 10s) ................................................ +300
C
Output Short Duration .......................................... Continuous to Common
V
IN
+V
IN
+V
S2
V
S2
GND2
Com2
V
OUT
Com1
GND1
GND3
SYNC
+V
S3
R
G
V
S1
+R
G
1
2
3
4
10
11
12
13
14
28
27
26
25
17
16
15
+V
S1
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 user's 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.
ORDERING INFORMATION
PRODUCT
PACKAGE
ISO255P
28-Pin Plastic DIP
4
ISO255
TYPICAL PERFORMANCE CURVES
(CONT)
At T
A
= +25
C, +V
S3
= 15V, R
L
= 2k
, and 220nF capacitors on all generated supplies, unless otherwise noted.
0
Frequency (Hz)
10
0
10
20
30
40
50
60
70
80
90
Signal (dB)
800k
100k
200k
300k
400k
500k
600k
700k
SIGNAL RESPONSE vs CARRIER FREQUENCY
SINE RESPONSE
(f = 1kHz, G = 1)
10
5
0
5
5
0
5
10
Output (V)
Input (V)
Time (s)
0
500
1000
1500
2000
PULSE RESPONSE
(f = 1kHz, G = 1)
10
5
0
5
5
0
5
10
Output (V)
Input (V)
0
500
1000
Time (s)
SINE RESPONSE
(f = 10kHz, G = 1)
10
5
0
5
5
0
5
10
Output (V)
Input (V)
0
50
100
150
200
Time (s)
1
Frequency (Hz)
1k
100
10
1
Amps (rms)
ISOLATION LEAKAGE CURRENT vs FREQUENCY
(V = 240Vrms)
100
100k
10
1k
10k
1
Frequency (Hz)
120
100
80
60
40
Rejection (dB)
10k
10
100
1k
IMR vs FREQUENCY
5
ISO255
INPUT BIAS AND OFFSET CURRENT
vs TEMPERATURE
5
4
3
2
1
0
1
2
3
4
5
75
50
25
0
25
50
75
100
125
Temperature (C)
Input Bias and Offset Current (nA)
I
OS
I
b
TYPICAL PERFORMANCE CURVES
(CONT)
At T
A
= +25
C, +V
S3
= 15V, R
L
= 2k
, and 220nF capacitors on all generated supplies, unless otherwise noted.
100
Frequency (Hz)
10
1.0k
100
Peak Isolation Voltage
ISOLATION MODE VOLTAGE
vs FREQUENCY
10k
1M
100M
1k
100k
10M
2.1k
Max AC
Rating
Degraded
Performance
Max DC Rating
Typical
Performance
COMMON-MODE REJECTION vs FREQUENCY
Frequency (Hz)
Common-Mode Rejection (dB)
1
10
1k
100k
100
140
120
100
80
60
40
20
0
10k
G=1
G=10
G=100
G=1000
INPUT COMMON-MODE RANGE
vs OUTPUT VOLTAGE
Output Voltage (V)
Common-Mode Voltage (V)
15
10
0
5
15
5
15
10
5
0
5
10
15
10
G = 1
V
D/2
+
+
V
CM
V
O
V
D/2
G
10
All Gains
All Gains
G
10
G = 1
GAIN vs FREQUENCY
60
40
20
0
20
40
Gain (dB)
Frequency (Hz)
1
10
100
1k
10k
100k
1M
G = 1000
G = 100
G = 10
G = 1
PULSE RESPONSE
(f = 10kHz, G = 1)
1
1
1
1
Output (V)
Input (V)
0
80
20
40
60
100
Time (s)
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