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Isolated Voltage or Current Input
7B40
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.326.8703
2004 Analog Devices, Inc. All rights reserved.
FEATURES
Interfaces, amplifies and filters unipolar and bipolar millivolt
and voltage inputs.
Module provides a precision output of either +1 V to +5 V or
0 V to +10 V.
All 7B40 series modules are mix-and-match and Hot
Swappable.
APPLICATIONS
Industrial signal conditioning
Industrial signal isolation
Industrial signal filtering
PRODUCT OVERVIEW
The 7B Series of signal conditioners feature small size, low cost
and a wide output voltage range for a variety of applications
including process control and factory-floor environments. The
single-channel 7B modules accept inputs from a range of
transducers and are fully rated over the extended -40
o
C to
+85
o
C industrial temperature range. All 7B Series modules are
rated for a nominal power supply input of +24 VDC; and, for
maximum flexibility, they will accept supply voltages in the +14
VDC to +35 VDC range. The input modules, with the exception
of the 7B21, provide a high-level output voltage that is factory
configured for either the +1 V to +5 V or 0 V to +10 V range.
The 7B21 is a unity gain, isolated input module with an
input/output range of +10V. Output modules are available that
provide either isolated process current or isolated bipolar
voltage output. Model 7B39 converts either a +1 V to +5 V input
to a 4 to 20 mA output or a 0 V to +10 V input to a 0-20 mA
output. The input/output ranges of the 7B39 are factory
configured. The 7B22 is a unity gain module that provides an
isolated +10V output signal. All modules have a universal pin-
out and may be readily hot-swapped under full power without
disrupting field wiring. Each module accepts analog transducer
signals and transfers them to a process control or factory data
collection system without the inherent noise, non-linearity, drift
and extraneous voltages which frequently accompany the
signals.
FUNCTIONAL BLOCK DIAGRAM
Figure 1. 7B40 Functional Block Diagram
The modules feature a maximum nonlinearity of +0.02% and
are factory calibrated to guarantee a maximum accuracy
specification of +0.1%.
The 7B Series offers up to 1500 V rms continuous common
mode voltage isolation and 120 V rms of field wiring input
protection. The power supplies necessary to drive each of the
individual module's input circuitry are internally isolated,
enabling the 7B Series modules to offer true channel-to-channel
isolation of the input signals.
The modules directly accept analog signals from
thermocouples, RTDs, current loop powered transmitters, and
other process control signals. The 7B Series modules amplify,
linearize, isolate, protect and convert the transducer output
signals to standardized analog inputs for high-level analog I/O
subsystems. The 7B Series Subsystem consists of 19-inch rack-
compatible hardware (model AC 1363), with universal
mounting backplane and a family of plug-in (up to 16 per
backplane) input and output signal conditioning modules. Four-
, eight-, and sixteen-channel backplanes are available. Each
backplane incorporates screw terminals for easy power
connections and field wiring, and includes a 25-pin D-type
connector for interfacing the high-level single-ended voltage
outputs to the user's equipment. Gold-plated sockets are
provided on each channel of the backplane to ensure the
reliability of each module's electrical connection.
7B40
Rev. 0 | Page 2 of 8
GENERAL DESCRIPTION
The 7B40 is a single-channel signal conditioning module that
interfaces, amplifies and filters unipolar and bipolar millivolt
and voltage inputs and provides a protected precision output of
either +1 V to +5 V or 0 V to +10 V. Model 7B40 features a
nonlinearity of +0.02% maximum and an accuracy of +0.1%
maximum (+0.01% typical). To accurately measure low level
signals in electrically noisy environments, 1500 V rms of
galvanic transformer-based isolation with a common mode
rejection (CMR) of 110 dB @50/60 Hz and a normal mode
rejection (NMR) of 100 dB @50/60 Hz are provided. Rated to
operate with a nominal +24 VDC supply, Model 7B40 is mix-
and-match and hot-swappable with other 7B Series input
modules, so it can be inserted or removed from any socket in
the same backplane without disturbing system power.
The floating differential input of Model 7B40 is fully protected
up to 240 V rms line voltage. A one-pole 10 KHz filter
preconditions the input signal prior to amplification by a low
drift input amplifier. Amplitude modulation is used to
implement transformer isolation (1500 V rms input-to-output
and power). Isolated front-end circuitry power is supplied by a
DC/DC converter. The output section contains a four-pole low
pass filter (-3 dB @ 10KHz), a buffer amplifier and a power
oscillator. The four-pole output filter and subsequent buffer
ensures that a low noise, low impedance (<1) signal is
available at the output to drive loads of 2 k minimum.
Figure 2
















7B40
Rev. 0 | Page 3 of 8
7B40 Models Available
Model
Input Range
Output Range
7B40-01-1 0-10mV
1-5V
7B40-01-2 0-10mV
0-10V
7B40-02-1 0-100mV
1-5V
7B40-02-2 0-100mV
0-10V
7B40-03-1 0-1V
1-5V
7B40-03-2 0-1V
0-10V
7B40-06-1 +/-10mV
1-5V
7B40-06-2 +/-10mV
0-10V
7B40-07-1 +/-100mV
1-5V
7B40-07-2 +/-100mV
0-10V
7B40-08-1 +/-1V
1-5V
7B40-08-2 +/-1V
0-10V
7B40 Specifications
Wideband mV/V Isolated Input module (typical @ +25C and +24 Vdc)
Description Model
7B40
Range
1
Standard Range
+/- 5mV to +/- 1V
Custom Ranges
YES
Output Range Options (RL > 2 k
)
1-5V or 0-10V (1)
Accuracy
2
Initial @25C
0.01% span (0.1% max)
Nonlinearity (BSL)
+/-0.02% max
Input Ofs vs. Temp
0.5uV/C
Zero Suppression vs. Temp
0.002%Vz/C
Span vs. Temp
+/-35ppm/C
Output Ofs vs. Temp
+/-0.001% span
Input Bias Current
+/- 100 pA
Input Resistance
Power On
>1G Ohm
Power Off
>1G Ohm
Overload
200K Ohm
Output Noise
5MHz Bandwidth
2mV peak
10Hz-100KHz Bandwidth
1mV rms
7B40
Rev. 0 | Page 4 of 8
0.1Hz-10Hz Bandwidth
0.5uV peak
Bandwidth, -3dB (7-pole Butterworth Filter)
10 KHz (2)
Output Rise Time, 10-90% span
40 us (2)
Common-Mode Voltage (CMV)
Input-to-Output and Power Continues
1500 Vrms min
Common Mode Rej. (CMR)
110 dB
Normal Mode Rej. (NMR) 50/60 Hz
100 dB/dec >10 Khz (2)
Input Protection
240 Vrms, +/-35Vdc continuous
Input Transient Protection
ANSI/IEEE C37.90.1-1989
Output Resistance
<1 Ohm
Output Voltage/ Current Limit
+/-12V, +/-14mA
Power Supply
Voltage, Rated Performance
14-35Vdc
Current
20mA max
Sensitivity
+/-0.0001%/%Vs
Mechanical Dimensions
1.663"x2.11"x0.563"
(42.24mm x 53.6mm x 14.3mm)
Weight
60 gms
Environmental
Temperature Range, Operating
-40C to +85C
Temperature Range, Storage
-40C to +85C
Relative Humidity
0 to 90% @ +60C non-condensing
ESD Sensitivity
IEC 801-2, Level 2
RFI Susceptibility
0.1% span max @ 158,440 MHz, 5W, 3 ft.

Warm-up time required to meet specifications is approximately 10 minutes.
(1) +/- 5V and +/- 10V output ranges are available as custom configurations.
(2) Custom Bandwidths available, Rise and Fall times, NMR frequency will vary accordingly
Specifications subject to change without notice.
7B40
Rev. 0 | Page 5 of 8
PIN CONFIGURATIONS AND FUNCTIONAL DESCRIPTIONS
Figure 3 7B40 Input Field Connections
Table 1. Pin Function Descriptions--
Pin
No.
Input Module Function
Output Module Function
0
SENSOR INPUT
NOT USED
1
INPUT HIGH
OUTPUT HIGH
2
INPUT LOW
OUTPUT LOW
3
POWER SUPPLY (DC)
POWER SUPPLY (DC)
4 OUTPUT
VOLTAGE INPUT
VOLTAGE
5
OUTPUT & POWER
COMMON
INPUT AND POWER
COMMON
Figure 4 . Model 7B Series Module, with pin-out assignments.
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human
body and test equipment and can discharge without detection. Although this product features proprietary ESD
protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges.
Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.