1996 Burr-Brown Corporation
PDS-1311B
Printed in U.S.A. April, 1996
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
Precision, Powered, Three-Port Isolated
OPERATIONAL AMPLIFIER
DESCRIPTION
ISO256 is a precision three-port isolation operational
amplifier incorporating an uncommitted operational
amplifier for input conditioning and a novel duty cycle
modulation-demodulation technique which has excel-
lent accuracy. Internal input protection can withstand
up to
30V input differential without damage. The
signal is transmitted digitally across a differential
capacitive barrier. With digital modulation the barrier
characteristics do not affect signal integrity. This re-
sults 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.
ISO256
FEATURES
q
RATED
1500Vrms Continuous
2500Vrms for One Minute
q
100% TESTED FOR PARTIAL DISCHARGE
q
LOW NONLINEARITY:
0.05% typ
q
LOW INPUT BIAS CURRENT:
5nA max
q
INPUTS PROTECTED TO
30V
q
BIPOLAR OPERATION V
O
=
10V
q
SYNCHRONIZATION CAPABILITY
q
28-PIN PLASTIC DIP: 0.6" Wide
ISO256
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
4
3
27
25
+V
S2
Com2
V
S2
GND2
12
V
OUT
14
13
11
10
ISO256
OPA
17
GND3
16
SYNC
15
+V
S3
1
2
MOD
FB
2
ISO256
ISO256P
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 Minute
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 ISO AMP
Gain Error
G = 1
0.15
0.3
%
Gain vs Temperature
G = 1
50
ppm/
C
Nonlinearity
G = 1
0.046
0.1
%
INPUT OFFSET VOLTAGE OP AMP
Initial Offset
60
V
vs Temperature
1.2
V/
C
vs Supply
3
V/V
CMRR
115
dB
INPUT OP AMP
Voltage Range
10
V
Bias Current
5
nA
vs Temperature
60
pA/
C
Offset Current
5
nA
vs Temperature
85
pA/
C
INPUT ISO AMP
Initial Offset
50
100
mV
vs Supply
1
mV/V
Input Resistance
200
k
OUTPUT ISO AMP
Voltage Range
10
V
Current Drive
5
mA
Capacitive Load Drive
0.1
F
Ripple Voltage
10
mVp-p
FREQUENCY RESPONSE
Small Signal Bandwidth
G = 1
20
kHz
G = 10
20
kHz
G = 100
4
kHz
G = 1000
7
kHz
Slew Rate
0.2
V/
s
Settling Time, 0.1%
G = 1
100
s
G = 10
400
s
G = 100
600
s
G = 1000
950
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 to 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
ISO256
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)
ISO256P
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
FB
V
S1
MOD
1
2
3
4
10
11
12
13
14
28
27
26
25
17
16
15
+V
S1
ORDERING INFORMATION
PRODUCT
PACKAGE
ISO256P
28-Pin Plastic DIP
TYPICAL PERFORMANCE CURVES
At T
A
= +25
C, +V
S3
= 15V, R
L
= 2k
, and 220nF capacitors on all generated supplies, unless otherwise noted.
1
Frequency (Hz)
80
60
40
20
0
PSRR (dB)
PSRR vs FREQUENCY
(G = 10)
100
100k
10
1k
10k
1
Frequency (Hz)
80
60
40
20
0
PSRR (dB)
PSRR vs FREQUENCY
(G = 1)
100
100K
10
1K
10K
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.
4
ISO256
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)
1
0
1
1
0
1
Output (V)
Input (V)
0
50
100
150
200
Time (s)
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
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
ISO256
2
1
0
1
2
40
15
10
35
60
85
Temperature (C)
INPUT BIAS AND INPUT OFFSET CURRENT
vs TEMPERATURE
Input Bias and Input Offset Current (nA)
I
B
I
OS
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
G
10
G = 1
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
PULSE RESPONSE
(f = 10kHz, G = 1)
1
1
1
1
Output (V)
Input (V)
0
80
20
40
60
100
Time (s)
150
140
130
120
110
100
90
80
CMRR (dB)
1
10
100
1k
10k
100k
Frequency (Hz)
CMRR vs FREQUENCY
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
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